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Table of contents

PLENARY TALKS ...... 22 PL01_429 Nanopolarity: new manifestations of classical electrostatics ...... 23 PL02_427 Probing ultrafast electron and spin dynamics in momentum, space and time ...... 24 PL03_431 Graphene: the freedom of a surface without bulk ...... 25 PL04_430 Magnetic remanence in single atoms ...... 26 PL05_432 Chemical reactions at surfaces: Single Molecular view ...... 27 ADS - Adsorption and desorption ...... 28 O1-ADS _52 Deuterium/hydrogen isotope exchange on beryllium and beryllium nitride ...... 29 O2-ADS _97 Adhesion Properties of Hydrogen on Antimony(111) Probed by Helium Atom Scattering ...... 30 O3-ADS _231 Revisiting H2 adsorption on Pd(210): Nuclear spin species separation and conversion ...... 31 O4-ADS _139 Tuning the Adsorption of Water on Pt Films supported on Ru(0001) - A Low-temperature STM Investigation ...... 32 O5-ADS _215 Modification of the chemical and electronic properties of n-type GaN(0001) surfaces by potassium and water adsorption ...... 33 O6-ADS _263 Chemo-mechanical coupling from first principles: On the strain dependence of oxygen adsorption on Pd(111) ...... 34 O7-ADS _49 Adsorption under nano-confinement: Prediction of distinct entropic effects on equilibrium coverage ...... 35 O8-ADS _152 Free-Base 5,10,15-tris(pentafluorophenyl)corrole adsorption on Ag(111) ...... 36 O9-ADS _358 Using Subsurface Effects of Plasma Films for Altering Protein Adsorption ...... 37 O10-ADS _417 Electronic properties of Sulfur covered Ruthenium (0001) surfaces: an STM-DFT comparative study ...... 38 P1-ADS_12 Effect of hydrogenation of amorphous silicon surfaces on protein adsorption ...... 39 P2-ADS_264 Adsorption properties of ethanol on gold decorated h- BN nanomesh prepared on Rh(111) surface ...... 40 P3-ADS_291 Adsorption of Magnesium, Manganese and Strontium on calcite studied by XPS and AFM ...... 41 P4-ADS_312 The surface science of calcium carbonate ...... 42 P5-ADS_399 Kinetic study of the adsorption of dye "methylene blue" on adsorbents supported on usy zeolite or (γAl2O3-SiO2) ...... 43 P6-ADS_372 Competing forces in chiral surface chemistry: Enantiospecificity versus enantiomer disproportionation ...... 44

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BSS - Band structure of surfaces ...... 45 O1-BSS _63 Spin-Resolved Electronic Structure of the Octahedral MoTe2 Polytype ...... 46 O2-BSS _68 Spin polarization and time delay in photoemission from spin-degenerate states ...... 47 O3-BSS _217 Magnetic behavior of thin Fe films grown on Ni/W(110) through the fcc-bcc transition: a spin-polarized photoemission study ...... 48 O4-BSS _144 Electron Spin Dynamics Reveals Half-metallicity in Fe3O4 Thin films ...... 49 O5-BSS _140 Entanglement of the magnetic and spin-orbit order in multiferroic Rashba semiconductors...... 50 O6-BSS _235 Coexistence of Bi and InBi cystrals at the Bi/InAs(111)-A interface...... 51 O7-BSS _175 Quantum Well States in thin Ag films grown on Ga/Si(111)-√3×√3 surface ...... 52 O8-BSS _360 2D - 1D Surface State Evolution Using a Curved Bi(111) Sample ...... 53 CAT - Catalysis under ideal and real conditions ...... 54 I22_CAT_433 Single atom catalysis: an atomic-scale view ...... 55 O1-CAT _308 Ammonia Oxidation on Palladium: In operando study ...... 56 O2-CAT _311 High-Pressure Scanning Tunneling Microscopy During Hydrodesulfurization Catalysis ...... 57 O3-CAT _254 An attempt to finally determine the active phase for CO oxidation over Pd and Rh ...... 58 O4-CAT _157 In situ Study of the CO Oxidation on Pt-Zn Nanoparticles with Ambient-Pressure X-ray Photoelectron Spectroscopy ...... 59 O5-CAT _165 Decomposition of methanol on Au-Rh bimetallic nanoclusters on a thin film of Al2O3/NiAl(100) ...... 60 O6-CAT _90 Adsorption and transformations of ethanol over ceria based model catalysts ...... 61 O7-CAT _126 Model Cu/Au catalytic surfaces for coupled dehydrogenation/hydrogenation reactions ...... 62 P1-CAT_6 Preparation of nanometer CoFe2O4 by co-precipitation using different precipitants and its characterization ...... 63 P2-CAT_9 Photo-oxidation Activities Depending on Metal-Doped TiO2 Nanoparticles ...... 64 P3-CAT_65 Phenol peroxide oxidation over Fe-FSM-16 ...... 65 P4-CAT_81 Varying the degree of reduction of ceria layers by anion doping with fluorine ...... 66 P5-CAT_142 Synchrotron-radiation-induced formation of surface oxides on Ag(111) in a high-pressure flow reactor...... 67 P6-CAT_169 Dissociation of water molecules on cleaved GaN(1- 100) ...... 68 P7-CAT_262 Surface characterization of supported catalysts...... 69

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ELC - Electrochemistry at surfaces ...... 70 O1-ELC_426 The GITSAXS-based study of operando Al anodization ...... 71 O2-ELC_74 Active sites of nitrogen-doped carbon materials for oxygen reduction reaction ...... 72 I02_ELC_435 Electrocatalysts and "anti-electrocatalysts" for energy applications ...... 73 I25_ELC_436 Advancing oxygen electroreduction on the basis of model investigations of Pt-alloy surfaces ...... 74 O3-ELC_365 Coupling between electrochemistry and surface X-ray diffraction for a multiscale analysis of the Pd/M(111°)-H system (M=Pt,Au) ...... 75 O4-ELC_315 Operando SXRD of E-ALD deposited sulphides ultra- thin films: crystallite strain and size...... 76 O5-ELC_202 Electrochemical layer by layer deposition: an in-situ SXRD study ...... 77 O6-ELC_309 Electrochemical modification of indium phosphide induced by ionic bombardment ...... 78 O7-ELC_323 Understanding corrosion inhibition with DFT methods: the case of benzotriazole ...... 79 O8-ELC_128 A new probe of the electrochemical interface: surface magnetism ...... 80 O9-ELC_227 Structural dynamics of metal deposition on Au(111) electrode ...... 81 P1-ELC_127 In vitro Electrochemical and Antibacterial Performance of P(acrylic acid-co- 2-ethylhexyl acrylate)/silica nanohybrids ...... 82 P2-ELC_136 In-Situ Studies of the Lithium Incorporation into Silicon as an Lithium-Ion Battery Model System ...... 83 P3-ELC_205 Electroless Deposition of Nanostructures on Micropatterned Substrates: From Nanowires to Nanopores ...... 84 P4-ELC_288 Electrochemical study of a copper seed-layer dissolution for 3D interconnections ...... 85 P5-ELC_307 Electroleaching process, technique improved by addition of nanoparticles ...... 86 P6-ELC_376 EFFECT OF TEMPERATURE ON THE CORROSION BEHAVIOUR OF Zn AND Zn-0.2Al ALLOY IN 3% NaCl ...... 87 P7-ELC_403 Photo-electrochemical study of: Antimony doped SnO2 film/ Chromate solution ...... 88 P8-ELC_330 In-Situ x-Ray Diffraction Study of Pt(111) Oxidation during Oxygen Reduction Reaction ...... 89 P9-ELC_411 One-pot synthesized P(acrylic acid)/silica nanohybrids coatings for protective applications ...... 90 ELPS - Electronic properties of strong correlations systems ...... 91 I06_ELPS_437 1D and 2D materials characterization using combined STM & nc-AFM ...... 92 O1-ELPS_10 How atomic defects modify the electronic structure in 2-D Transition Metal Dichalcogenides and lead to novel properties ...... 93

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O2-ELPS_332 STM study of local band offsets in tungsten diselinide flakes transferred on graphene ...... 94 O3-ELPS_61 Tuning the electronic structure of Au(111) and graphene by molecular patterning ...... 95 O4-ELPS_91 Correlation between morphology and transport properties of quasi-free-standing monolayer graphene (QFMLG) ...... 96 O5-ELPS_214 Secondary electron emission from nanographene: a real-time first-principles simulation ...... 97 O6-ELPS_272 Atomic size effects studied by transport in single silicide nanowires ...... 98 O7-ELPS_135 Determining the critical Josephson current in STM Junctions ...... 99 O8-ELPS_42 Electronic properties of Cr atoms inserted in the first layers of GaAs(110) surface probed by STM/STS ...... 100 O9-ELPS_306 Controlling the Formation of Spin Chains at Stepped Silicon Surfaces ...... 101 O10-ELPS_196 Calculating the reactivity of metal surfaces ...... 102 O11-ELPS_138 Scanning tunneling microscopy on bulk FeSe ...... 103 O12-ELPS_111 Surface polarization on a Si(111) reconstructed surface measured by noncontact scanning nonlinear dielectric potentiometry ...... 104 O13-ELPS_193 Detecting electronegativity variation at the atomic scale with the atomic force microscope ...... 105 P1-ELPS_51 Single Tripyridyl−Triazine Molecular Junction with Multiple Binding Sites ...... 106 P2-ELPS_92 Electronic States of Termination-Controlled Surfaces of SrTiO3(001) ...... 107 P3-ELPS_185 Auger and X-ray photoemission spectroscopy of planar and nanostructured surfaces ...... 108 P4-ELPS_209 Asymmetry in the excitation of plasmons by swift particles traversing a surface at oblique incidence ...... 109 P5-ELPS_257 Effects of charge dynamics in electrostatic force microscopy ...... 110 P6-ELPS_274 The effect of adsorbates on the transport characteristics of Au chains on vicinal Si(hhk) surfaces ...... 111 P7-ELPS_297 Plasmon peaks in Fe-Si alloys in Auger and X-ray photoemission spectroscopy ...... 112 P8-ELPS_331 Formation of Single-Electron Transistor Arrays by Field-Emission-Induced Electromigration ...... 113 P9-ELPS_412 Unoccupied electronic states in Ru(0001)...... 114 GRA - Graphene and carbon-based nanomaterials ...... 115 I15_GRA_438 Self-assembled sealed graphene nanoblisters as cages for squeezed rare gas atoms ...... 116 O1-GRA_296 Moving towards chemically patterned graphene; controlled formation of new bonds at the graphene basal plane ...... 118 O2-GRA_178 Graphene band gap tailoring by substrate nanostructuration ...... 119

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O4-GRA_313 Tailoring electronic properties in long range ordered on surface synthetized polymers ...... 120 I05_GRA_439 Deformations in Graphene on a Metal ...... 121 O5-GRA_368 Femtomagnetism in graphene induced by core level excitation of organic adsorbates ...... 122 O6-GRA_248 Electronic structure of low-angle disordered rotated graphene layers ...... 123 O7-GRA_117 First principles study of CO adsorption on Pt clusters deposited on defective graphene ...... 124 O8-GRA_355 Tailoring Graphene Corrugation and Electronic Properties on Metallic Substrates via Atomic Oxygen Intercalation ...... 125 I24_GRA_440 Surface assisted synthesis of graphene nanostructures on silver...... 126 O9-GRA_208 Graphene formation in transmission electron microscope (TEM) ...... 127 O10-GRA_180 Molecular dynamics simulation of graphene on Cu(111) with different Lennard-Jones parameters...... 128 I12_GRA_441 Probing and modifying graphene at the atomic scale with STM and NCAFM ...... 129 O11-GRA_391 Molecular Hydrogen for Graphene Functionalization ...... 130 I18_GRA_442 Atomically precise graphene nanoribbons through on-surface synthesis ...... 131 O12-GRA_316 Electronic interaction between organic molecules and nitrogen-doped graphene ...... 132 O13-GRA_289 Fourier transform microscopy-based universal classification of twisted and sheared graphene moiré superlattices ...... 133 P1-GRA_58 Effect of advancing liquid contact line on deposits of arc-discharge multiwalled carbon nanotubes ...... 134 P2-GRA_93 Application of nanodiamonds for development of composites with reinforcing TiC nanoparticles...... 135 P3-GRA_120 Influence of the Graphene Buffer Layers on the Molecular Fe complexes Deposited on Ni(111) ...... 136 P4-GRA_199 Tip-induced interaction effects in STM studies of moirés on graphene on SiC(000-1) ...... 137 P5-GRA_210 Energy dissipation and transition radiation produced by the interaction of charged particles with a graphene sheet ...... 138 P6-GRA_212 Silicene and few-layer silicon films on metal surfaces ...... 139 P7-GRA_230 Novel graphene-titania interfaces as a potential catalytic material towards clean energy production ...... 140 P9-GRA_349 Periodic array of graphene quantum dots embedded in a carbon-boron-nitrogen alloy ...... 141 P10-GRA_357 Ab initio study of azomethine derivative cancer drug on Boron nitride and Graphene nanoflakes ...... 142 P11-GRA_374 Design of Graphene-Based New Generation Supercapacitors as an Energy Storage Device ...... 143 P13-GRA_425 Applying graphene: A corrosion preventing coating ...... 144

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P14-GRA_286 Polycylcic carbon molecules with zigzag edges as sources of defects in graphene on a metal ...... 145 LSI - Liquid/solid and liquid/liquid interfaces ...... 146 O1-LSI _4 Evaluation of Surface Hydrophobicity at Elevated Temperature and Pressure for Oil & Gas Applications ...... 147 O2-LSI _240 SU-8 and epoxy hierarchical structures for icephobicity ...... 148 O3-LSI _259 Metalation, Demetalation and Metal Center Exchange of Porphyrins at the Solid/Liquid Interface ...... 149 I03_LSI_443 The Water Surface: Complex, Dynamic and Wet ...... 150 O4-LSI _19 Discovery of Static Shear-Elasticity in Liquids & Melts ...... 151 O5-LSI _83 XPS enables visualization of charge screening in metal- ionic liquid interfaces with temporal- and lateral- resolution...... 152 O6-LSI _101 STABILITY OF IONIC LIQUID BASED ELECTROLYTES IN LITHIUM METAL BATTERIES INVESTIGATED BY X-RAY PHOTOEMISSION AND ELECTROCHEMICAL IMPEDANCE SPECTROSCOPIES ...... 153 O7-LSI _156 Swelling of hydroxylated hectorite and saponite clays monitored by NAP-XPS ...... 154 O8-LSI _174 Contribution of Liquid Properties to Quantitative Measurements using Quartz Crystal Microbalance with Dissipation ...... 155 O9-LSI _137 Electrochemistry of Iron Oxide Thin Films ...... 156 O10-LSI _3 Disclosing the early stages of electrochemical intercalation of anions in graphite by a combined AFM/STM investigation ...... 157 P1-LSI_94 Mechanism of GaSb (001) surface passivation with aqueous solution of sodium sulfide ...... 158 P2-LSI_164 Carbon dioxide stabilisation within 1-octyl-3- methylimidazolium containing ionic liquids ...... 159 P3-LSI_389 The liquid metal embrittlement effect in Armco-Iron during high and gigacycle fatigue loading ...... 160 M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc...... 161 O1-M4E _354 Design and electrochemical properties of nickelate- based cathodes for solid oxide fuel cells: role of the interfaces ...... 162 O2-M4E _36 Investigation of the Surface Reactivity of Electrode Materials: an experimental and theoretical combined approach ...... 163 O3-M4E _361 Understanding active interfaces in oxygen electrodes for solid oxide fuel cells by time dependent 3D FEM model ...... 164 I17_M4E_445 Model studies in energy-related catalysis and electrocatalysis ...... 165 I20_M4E_446 Epitaxial oxide engineering for solar water splitting ...... 166 O4-M4E _28 Reduction in Optical Reflection at Intermediate Adhesive Layer for Mechanically Stacked Multi-Junction Solar Cells ...... 167 O6-M4E _26 PV cells based on CIGS thin films: an original cross strategy approach of surface and volume characterizations ...... 168

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O7-M4E _292 Time-Resolved Surface Photovoltage Spectroscopy Study of Charge Dynamics at the Colloidal Quantum Dot/ZnO Heterojunction for Photovoltaics ...... 169 O8-M4E _284 Nickel silicide formation for silicon solar cell metallization: thermal and laser annealing...... 170 O9-M4E _326 XPS study of PEALD oxysulfide Inx(S,O)y thin films for photovoltaic applications: Understanding of plasma-surface interaction ...... 171 P1-M4E_13 Structural studies of the hydrogenated silicon ...... 172 P3-M4E_39 Degradation of organic photovoltaic thin layers by radiation exposure investigated by photoelectron spectroscopy ...... 173 P4-M4E_73 Lithium sulfide-based thin-film electrolytes for all solid- state microbatteries ...... 174 P5-M4E_88 Forest of Structured Silicon Nanowires For Thermoelectrics ...... 175 P6-M4E_134 ToF-SIMS and XPS Characterization of R.F. Magnetron Sputtered Li-Ni-Mn-Co-O Thin Films for Li-ion Batteries ...... 176 P7-M4E_333 Facile Recovery of Silicon Nanoparticles from Wafer Slicing Waste and Application to Energy Storage Materials ...... 177 P8-M4E_409 Nanoporous Cobalt and Silver Catalysts for Direct Ammonia-Borane Fuel Cells ...... 178 P9-M4E_219 Combined Experimental and DFT–TDDFT Study of Zinc-Porphyrin Sensitizers for Dye-Sensitized Solar Cells: Effect of Anchoring Group Number on the Cell Performance ...... 179 MAQ - Metal, alloy and quasicrystal surfaces ...... 180 O1-MAQ _343 First surface structure determination of a quasicrystalline approximant using combined surface x-ray diffraction and ab initio calculations...... 181 O2-MAQ _324 Order Disorder Phase Transition of a Two- Dimensional Alloy Made of Immiscible Elements ...... 182 O3-MAQ _141 How to Sort Regular-Alloyed, Core-Shell and Skin- Heart AuCu Bimetallic Nanoparticles From a DFT Approach? ...... 183 O4-MAQ _100 Carbon segregation and oxidation on Fe0.85Al0.15(110) : a STM, LEED and XPS study ...... 184 O5-MAQ _86 Tribological properties of plasma sprayed Ferrochromium-Nickel composite coatings ...... 185 O6-MAQ _260 Van der Waals density-functional study for low-index metallic surfaces ...... 186 O7-MAQ _405 Bi1Te1: A New Dual Topological Insulator ...... 187 O8-MAQ _373 Methods for high throughput study of alloy corrosion across alloy composition space ...... 188 P1-MAQ_85 Heat activated blur of surface of antiphase boundaries in the CuZn alloy...... 189 P2-MAQ_273 Spinodal decomposition of Cu-Ni alloy on Ni(111) ...... 190 P3-MAQ_420 Production and Scale-up of Size-Controlled Elemental and Selected Binary Nanoclusters ...... 191 P4-MAQ_423 Nanosize-induced structures and distortion in supported Pt-Ag nanoparticles ...... 192

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MOS - Molecules at surfaces ...... 193 O0-MOS_294 Fullerene: a nanoscale sensor to probe the surface potential of metals and alloys ...... 194 O1-MOS _119 Electric field driven chemical reaction of individual molecular subunits by scanning tunneling microscopy ...... 195 O2-MOS _415 Electronic structure of alkanethiols and BDMT monolayers on Au (1 1 1) ...... 196 O3-MOS _225 Formic Acid Decomposition on the Cu(111) Surface: van der Waals Density Functional Study ...... 197 O4-MOS _362 Dipyranylidenes (DIP) as hole collectors in PV heterostructures studied by scanning transmission X-ray microscopy ...... 198 O6-MOS _55 Molecules on Surfaces: Whispering galleries for electrons ? ...... 199 O7-MOS _184 Self-assembling and chemistry of ferrocene dicarboxylic acid on different metal and insulator substrates ...... 200 O8-MOS _385 The (root3xroot3)R30º surface structure of long alkanethiols on the Au(111) surface ...... 201 O9-MOS _268 An electrically actuated molecular toggle switch ...... 202 O10-MOS_462 Graphene-mediated anti-ferromagnetic coupling between metalphthalocyanine ...... 203 O11-MOS _356 Atomic-Scale Insight into the Complexation and Tautomerization of Guanine Molecules on Surface ...... 204 O12-MOS _334 Molecule-metal interaction controlled by hydrogen manipulation in an organic molecule ...... 205 O13-MOS _345 Kondo effect in 2D self-assembly of cerium-based molecules investigated by scanning tunnelling microscopy and spectroscopy ...... 206 O14-MOS_464 Surface-confined polymerization by Ullmann and Schiff-base coupling reactions ...... 207 O15-MOS _224 Naphthalene Adsorption on Graphene: van der Waals Density Functional Study ...... 208 O16-MOS _275 Optical properties of single-molecule junctions ...... 209 I11_MOS_102 Metalation of porphyrins interacting with surfaces ...... 210 O17-MOS _5 A thermodynamic model for wafer-bonding ...... 211 O18-MOS _108 Proton order at ice surfaces: can helium scattering provide quantitative answers? ...... 212 O19-MOS _290 Nanostructuration of Dy-based Single Molecule Magnets ...... 213 O20-MOS _189 Tuning of the oxidation state of metal ions by using alternative tetrapyrrole ligands: Synthesis of Co(III) and Ni(III)- corroles on Ag(111) ...... 214 I28_MOS_465 Revealing Atomic Site-dependent g-factor within a Single Magnetic Molecule via Extended Kondo Effect ...... 215 O23-MOS _75 Electronic structure and transport properties of switchable diarylethene molecule...... 216 O24-MOS _302 On-Surface Synthesis of Large Organic Molecules and Organometallic Nanostructures ...... 217

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O25-MOS _246 Reversible ring-open and ring-closure reactions of spiropyran molecules in direct contact with a Bi(111) surface ...... 218 O26-MOS _353 Enhancement mechanism for surface-enhanced Raman scattering at metal nanostructures ...... 219 O27-MOS _161 Electronic Structure of PTCDI on Ag/Si(111)-√3×√3 studied by STM and ARUPS ...... 220 O28-MOS _282 Adsorption of Organic Molecules at Insulating Surfaces: Role of Molecular Flexibility ...... 221 O29-MOS _33 Fabrication of a surface-confined covalent organic framework on a reactive surface...... 222 O30-MOS _21 On-surface manipulation of the ion metalation and exchange between phthallyconine and surface ...... 223 O31-MOS _47 Porphyrin Chemical Modification on TiO2(110): Hydrogenation, Self-Metalation, Conformational Change ...... 224 O32-MOS _192 Reactivity of Lutetium bis-phthalocyanine towards oxygen ...... 225 O33-MOS _237 Interactions of transition metal phthalocyanines at metal surfaces – influence of graphene buffer layers and intercalation ...... 226 O34-MOS _104 Dihydrotetraazapentacene growth on alumina: from the submonolayer to nm thick films ...... 227 O35-MOS _67 Bromine-functionalized pyrene derivatives on noble metal surfaces: self-assembly and on-surface polymerization ...... 228 O36-MOS _218 Impact of hydrophilic and hydrophobic functionalisation of ultra-flat titanium surfaces on proteins adsorption ...... 229 O37-MOS _182 Self-assembling of 5-fold symmetric molecules on quasicrystalline surfaces...... 230 O38-MOS _172 Beyond the hexagon: Non-alternant aromatic molecules on metal surfaces ...... 231 O39-MOS _155 Adsorption study of terephthalic and benzoic acids on HOPG, Au(111) and Al-oxide with Metastable Induced Electron Spectroscopy (MIES) ...... 232 P1-MOS_11 Post-deposition Hydrogen treatment effect on surface roughness and hydrophobicity of amorphous silicon films ...... 233 P2-MOS_37 Fabrication of a surface-confined covalent organic framework on a reactive surface...... 234 P3-MOS_43 Time-integrated copper phthalocyanine patterns on Tl(1×1)/Si(111)...... 235 P4-MOS_50 Dipyranylidenes (DIP) as hole collectors in PV heterostructures: impact of chalcogen substitutions studied by Resonant Photoelectron Spectroscopy (ResPES) ...... 236 P6-MOS_110 NO Adsorption and Its Magnetism on the FeO2 Terminated LaFeO3 (001) Surface with and without Oxygen Vacancies: First-Principles Study ...... 237 P7-MOS_159 High-resolution AFM/STM imaging and force spectroscopy of van der Walls nanostructures on metal surface ...... 238 P8-MOS_170 A new possible type of molecular switch – CuPc on Si(100)-Sn-√3×√3 studied by scanning tunneling microscopy ...... 239

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P9-MOS_181 Adsorption and Growth of Sexiphenyl on In2O3(111) ...... 240 P10-MOS_190 Adsorption of thiophene derivatives on gold and molecular dissociation processes...... 241 P11-MOS_195 Reactivity of Lutetium bis-phthalocyanine towards oxygen ...... 242 P12-MOS_198 Density Functional Theory Study of Benzene Adsorption on Fe Surfaces ...... 243 P13-MOS_204 Controlling Kondo Effect of Magnetic Molecules on Au(111) by Vertical Binding of Ammonia ...... 244 P14-MOS_232 Ethylene Adsorption on Cu(210), Revisited: Bonding Nature and Coverage Effects ...... 245 P15-MOS_253 Electrical conductance and structure of copper atomic junctions in the presence of water molecules ...... 246 P16-MOS_261 Thermopower and current-voltage characteristics of 1,4-benzenedithiol-single molecular junctions ...... 247 P17-MOS_281 Dimerization of benzoic acid on TiO2 surfaces - an ab-initio study ...... 248 P18-MOS_298 On-Surface Engineering of a Magnetic Organometallic Nanowire ...... 249 P19-MOS_339 Nickel octa ethyl porphyrin on Au(111): a surface X ray diffraction study ...... 250 P20-MOS_352 A full DFT-D study of drug encapsulation inside nanocapsules ...... 251 P21-MOS_393 Change of Electronic State Induced by Structural Transition of DNTT and Picene Monolayers ...... 252 P22-MOS_406 On the phase behavior of adsorption monolayers of binary gas mixtures: modeling ...... 253 P23-MOS_158 A structural study of the ionic liquid 1-ethyl-3- methylimidazolium bis[(trifluoromethy)sulfonyl] imide on Au(110) using NIXSW ...... 254 P24-MOS_242 Tunable Energy-Level Alignment in Donor-Acceptor Bilayers on Metals ...... 255 P26-MOS_458 The diffusion of COT on Cu(111) observed in the angstrom-picosecond window ...... 256 P27-MOS_459 IN VITRO ANTIOXIDANT ACTIVITY OF ROOT FRACTIONS OF Aristolochia baetica ...... 257 P28-MOS_310 Molecular orientation in thin films of spontaneously polarised molecular solids ...... 258

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NAM - Novel advancement of experimental and computational methods ...... 259 O1-NAM _7 Force-detected nuclear magnetic resonance for nanoscale imaging ...... 260 O2-NAM _25 Image deconvolution of k-space patterns measured in NanoESCA microscope ...... 261 O3-NAM _191 Cleaved probes for scanning probe microscopy ...... 262 O4-NAM_474 Non-destructive imaging of nanostructures by analysis of the photoelectron peak shape...... 263 O5-NAM _392 Molecular Interferometry – a New Experimental Approach for Studying Gas-Surface Interactions...... 264 O6-NAM _269 Deposition of discrete organic molecules via e-beam evaporation ...... 265 O7-NAM _329 Transmission Surface Diffraction: a new tool for in- situ and operando surface science ...... 266 O8-NAM _8 EnviroESCA - Fully Automated XPS Analysis under Environmental Conditions ...... 267 O9-NAM _31 Recent Advances in Low Energy Ion Scattering for Extreme Surface Sensitive Analysis ...... 268 O10-NAM _35 Transport of fast electrons in diamond ...... 269 O11-NAM _167 Thin Film Analysis using variable period X-ray standing waves ...... 270 O12-NAM _342 Inelastic Background Analysis in HAXPES: Application to deeply buried Ta/Al interfaces in advanced power devices ...... 271 O13-NAM_64 Wave function and phase retrieval of RHEED from growing surfaces ...... 272 P1-NAM_53 Development of a low-energy electron gun using the photoelectric effect ...... 273 P3-NAM_166 CALCULATION OF THE SCATTERING PROBABILITY AND ENERGY SPECTRA IN LEIS ...... 274 P4-NAM_251 EUSpec - Modern tools for spectroscopy on advanced materials: a European modeling platform ...... 275 P5-NAM_395 Development of a high intensity electrospray source for UHV deposition of large functional molecules for in-situ STM studies ...... 276 P6-NAM_220 Advanced materials designed by computational simulation ...... 277 P7-NAM_422 Monte Carlo simulation of electron transport in diamond and graphite ...... 278 P8-NAM_424 HAXPES-Lab: The first laboratory based hard X-ray photoelectron spectroscopy system using a 9.25 keV X-ray source ...... 279 P9-NAM_473 Investigation of surface structures and dynamics at the ID03 beamline of the ESRF ...... 280 OXI - Oxide surfaces, interfaces and thin oxide films ...... 281 O1-OXI_256 Persistent photoconductivity in m-plane ZnO as a function of oxygen vacancy concentration probed by laser-pump synchrotron radiation-probe x-ray photoelectron spectroscopy ...... 282 O2-OXI_186 Vicinal ZnO(10-14): surface structure and stability ...... 283

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I04_OXI_447 Modelling the surfaces of oxide materials ...... 284 O3-OXI_179 Fe-and Cr-doped MgO/Mo(001) films: morphology, electronic structure and dopant-induced diffusion processes ...... 285 O4-OXI_346 Investigations of cobalt oxide nanoislands on Au(111), Pt(111) and Ag(111) and their active sites for water dissociation ...... 286 O5-OXI_30 Activation Energies for Sodium and Potassium Ion Incorporation into Temperature Treated CVD-SiOx Layers ...... 287 O6-OXI_387 The chemistry of cobalt oxide thin films studied with high resolution and high-pressure core level spectroscopy ...... 288 I26_OXI_448 Reactions on transition metal oxide surfaces studied by high-resolution STM ...... 289 O7-OXI_153 Epitaxial growth of ultrathin magnetite films on Ag(100) ...... 290 O8-OXI_131 In Situ X-ray Studies of Crystalline Texture and Strain During the Initial Stages of ZnO Atomic Layer Deposition ...... 291 O9-OXI_79 Polaron-mediated surface reconstruction in the reduced rutile TiO2 (110) surface ...... 292 O10-OXI _223 Interaction of free-base tetraphenyl porphyrin with MgO(001) surface ...... 293 O11-OXI_56 Evidencing sharp Verwey transition in a ultrathin Magnetite layer by Resonant X ray Scattering ...... 294 O12-OXI_187 Charge transfer to organic molecules on ultrathin insulating films ...... 295 O13-OXI_76 Origin of resistivity changes in CBRAMs studied by X- ray photoelectron spectroscopy ...... 296 O14-OXI_211 Towards Molecular Electronics: Selective Deposition of Metal Oxides ...... 297 O15-OXI_228 Exploring Pd adsorption, diffusion, permeation, and nucleation on bilayer SiO2/Ru as a function of hydroxylation ...... 298 O16-OXI_300 Thermal reduction of Nb-doped TiO2 single crystals: surface properties and composition evolution ...... 299 I27_OXI_449 Perovskite oxide surfaces: New structures and surprising interface properties ...... 300 O17-OXI_255 Metal↔Insulator Transition Evidenced By Atomic Force Microscopy In V2O3 Thin Films ...... 301 O18-OXI_200 Two-dimensional hole gas at ferroelectric Bariumtitanate film surfaces ...... 302 O19-OXI_118 Adsorption of oxygen on ruthenate perovskite surfaces ...... 303 O20-OXI_124 Adsorption of Water on Calcium Ruthenate ...... 304 O21-OXI_183 Promotion and inhibition effects of molybdenum oxides on the reactivity of atomically thin Rh films ...... 305 O22-OXI_84 Methanol oxidation over terbium oxide thin films ...... 306 O23-OXI_114 Substrate dependent reactivity of FeO ultra-thin films ...... 307 I19_OXI_450 Reducible oxides as ultrathin epitaxial films ...... 308 O24-OXI_318 Combined Experimental and Computational Study of Water on Fe3O4 (001) ...... 309

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O25-OXI_305 MgO-doped TiO2(011) surface ...... 310 I23_OXI_451 Structural, electronic and magnetic reconstructions of the the 2DEG formed at titanate oxide interfaces ...... 311 O26-OXI_60 Piezoelectric and Ferroelectric Properties PZN-PT Perovskite Nanoparticles Thin Layer Deposited on Nanostructured p-Type Silicon Substrate...... 312 O27-OXI_279 Band bending in Pt/Pb(Zr,Ti)O3 investigated by X- ray photoelectron spectroscopy ...... 313 P1-OXI_1 Optical characterization of ultra-thin films, surfaces and interfaces using Spectroscopic Ellipsometry ...... 314 P2-OXI_17 Heat Treatment in Liquid Water Used to Passivate Silicon Surfaces ...... 315 P4-OXI_54 Physical and chemical properties of CeOx/SrTiO3(100) films ...... 316 P5-OXI_62 BIOFUNCTIONALIZATION OF TITANIUM SURFACE WITH DMP1 PEPTIDES FOR BIOMEDICAL APPLICATIONS ...... 317 P6-OXI_80 Formation of silicon nanoislands and silicon nanocrystal on c-Si substrates in SiOx films deposited by HFCVD ...... 318 P7-OXI_115 Chemical-state analysis of trace-level alkali metals and alkaline-earth metals sorbed in layered oxides by total- reflection X-ray photoelectron spectroscopy ...... 319 P8-OXI_130 Control of crystal order in RF-sputtered BiFeO3/SrTiO3 heterojunctions by means of X-ray photoelectron diffraction: demonstration of epitaxial growth for polarity-driven applications...... 320 P9-OXI_145 Raman spectroscopy and CL from ZnO induced by fs laser irradiation ...... 321 P10-OXI_151 Synthesis and characterization of TiO2 nanotubes enriched with Calcium and Phosphorous: a promising multifunctional surface for biomedical applications ...... 322 P11-OXI_177 High-Throughput Characterisation of the Energetics of All Metal Oxide Junctions ...... 323 P12-OXI_250 Formation of a thermally stable bilayer exploiting the surface corrugation of rutile TiO2(110) ...... 324 P13-OXI_280 Combined Neutron and X-ray reflectivity characterization of microelectronics sensible interfaces in the framework of the IRT Nanoelec ...... 325 P14-OXI_303 Effects of mechanical stress on electronic properties of single III-Nitride nanowires ...... 326 P15-OXI_314 Ultra thin Pt-doped CeO2 films by DLI-CVD ...... 327 P16-OXI_377 Quartzes: structure, water absorption and surface modification ...... 328 P17-OXI_381 Suppression of the Co spin-state and metal-insulator transitions in epitaxial thin films of Pr0.50Ca0.50CoO3 on LaAlO3 ...... 329 P18-OXI_400 Ultrathin interfacial oxyde layers in epitaxial CoO/Fe magnetic systems ...... 330 P19-OXI_407 Infrared spectroscopy and ellipsometry caracteriation of sol gel dioxide titanium thin films ...... 331

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P20-OXI_457 Resistive switching behaviour of graphene oxide metal-insulator-metal heterostructures for emerging non-volatile memory applications ...... 332 P21-OXI_460 Polarization dependent Pt/Ru/Pb(Zrx Ti1-x)O3 interface chemistry and electronic structure studied by operando Hard X-ray Photoemission Spectroscopy ...... 333 POL - Polymer surfaces and interfaces ...... 334 I08_POL_452 Solid capillarity: when surface properties dominate the mechanics of soft solids ...... 335 O1-POL _378 Correlation of foam film stability to the interfacial composition of polyelectrolyte/surfactant mixtures ...... 336 O2-POL _41 A sprayable protective coating for marble with water- blocking and anti-graffiti properties ...... 337 O3-POL _154 In situ FTIR study of CO2 adsorption on polyethylene-imine membranes ...... 338 O4-POL _369 Silver nanoparticles using chitosan as reducing and stabilizing agent: a combined XPS, AFM and UV-Vis study ...... 339 P1-POL_15 Operando photoelectron Spectroscopy at polymer- cathode interface of organic light-emitting diode ...... 340 P2-POL_16 The characteristics of Poly styrene /Montmorillonite Nanocomposites ...... 341 P3-POL_40 Microdroplet pullout test : interfacial shear strength measurements between reactive polyamide-6 and cellulosic or glass fibres...... 342 P4-POL_59 Ageing and degradation of phenol-urea-formaldehyde binder...... 343 P5-POL_107 An alternative strategy to activate polymer samples for electroless copper deposition ...... 344 P6-POL_113 Sequence controlled growth of cross-linked polymer layers on surfaces ...... 345 P7-POL_168 Characterization of Surface Modified Materials Used for Biological Applications ...... 346 P8-POL_188 Application of atmospheric pressure plasma treatment to imporve the adhesion of a waterborne paint on polymer surfaces ...... 347 P9-POL_283 Effects of thin amorphous hydrogenated carbon (a- C:H) coatings on Si (100) and high-density polyethylene ...... 348 RTP - Real-time processes at surfaces ...... 349 O2-RTP_203 Electron and Exciton Dynamics in Amorphous and Crystalline Sexithiophene Films on Au(111) ...... 350 O3-RTP_277 Structure and Growth Mechanisms of Silicene Layers on Ag(111) Surface ...... 351 O4-RTP_116 Formation of Au-Rh surface alloy and the effect of Au on the structure of h-BN film grown on Rh(111) surface ...... 352 O5-RTP_24 Self-propelled motion of Au-Si droplets and Si nanowires growth on different Si substrates ...... 353 O6-RTP_467 In situ synchrotron X-ray scattering of SiGe nanowires: growth, strain and bending ...... 354

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O7-RTP_388 Progress in characterizing submonolayer island growth: Capture-zone distributions, growth exponents, & transient mobility ...... 355 O8-RTP_122 Dynamics of atom detachment from 1D Sn chains grown on Si(100)2×1 – determination of activation energies from STM real time observations ...... 356 O9-RTP_265 Step bunching and macrostep formation in 1D atomistic scale model of unstable vicinal crystal evaporation ...... 357 I09_RTP_453 The initial stages of ZnO thin film growth by Atomic Layer Deposition ...... 358 O11-RTP_125 The strength of nonadiabatic effects in the surface diffusion of hydrogen on Pd(111): evidence from spin-echo experiments ...... 359 O12-RTP_98 Surface diffusion of dimers and clusters of larger size ...... 360 O13-RTP_78 Dynamics of pit filling in heteroepitaxy via phase-field simulations ...... 361 P1-RTP_171 Early stages of growth of group-14 elements on Ru(0001): A DFT study ...... 362 P2-RTP_243 Structure and Growth Mechanisms of Silicene Layers on Ag(111) Surface ...... 363 P3-RTP_351 Controlling the growth of Bi(110) and Bi(111) films on an insulating substrate ...... 364 P4-RTP_394 CO/Pd(111): From isolated diffusion to the onset of strong inter-adsorbate interaction ...... 365 P5-RTP_285 Dynamic Effects on Adsorption of Organic Molecules at Insulating Surfaces ...... 366 P6-RTP_252 Surface pattern formation in crystal growth kinetics ...... 367 SAS - Self-assembly at surfaces ...... 368 O1-SAS _367 Arginine and aspartic acid on Cu(110): unraveling the different adsorption mechanisms of peptides structural units ...... 369 O2-SAS _320 Thermodynamic balance of perylene self-assembly on Ag(110) ...... 370 O3-SAS _382 The adsorption of proteins on polymer brushes: the impact of neutron reflectometry ...... 371 I16_SAS_454 Dynamics of solid state dewetting by Low Energy Electron Microscopy ...... 372 O4-SAS _418 A novel X-ray diffractometer-deflector end-station at the ESRF ID10 beamline for studies on liquid surfaces and interfaces ...... 373 O5-SAS _46 Ordering and dynamic behavior of copper phthalocyanines on the thallium-passivated Si(111) surface ...... 374 O6-SAS_397 Direct Observation of Structural Changes in Articulating Cartilage on Confinement ...... 375 O7-SAS _398 From molecular self-assembly to metal-organic coordination: Trimesic acid on Ag(111): ...... 376 P1-SAS_258 Self-assembly of Chiral Conformational Switches Studied by UHV‐STM ...... 377

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P2-SAS_270 Rationalising the structural details of complex polymers using a combination of electrospray deposition and Scanning Tunnelling Microscopy ...... 378 P3-SAS_293 Understanding Nucleation And Self-Assembly Of Large Organic Molecules On An Insulating Surface ...... 379 P4-SAS_321 Hybrid Metal-organic Coordination Networks for CO2 and O2 Activation at Room Temperature ...... 380 P5-SAS_325 Self-assembly of cross-shaped functional organic molecules on heterogeneous surfaces with simple topographies ...... 381 P6-SAS_344 Raman Study of the Vibration Eigenmodes of the Ordered Adsorbate Surface Au-(5x2)/Si(111) ...... 382 P7-SAS_359 Lattice dynamics and crystal field splitting in CePt5 layers on Pt(111), determined by Raman spectroscopy ...... 383 P8-SAS_371 The adsorption structure of TCNQ on Ag(111) ...... 384 P9-SAS_401 Nanoclusters on graphene/Ir(111): insights from ab- initio calculations and experiments ...... 385 P10-SAS_413 Synthesis of hybrid (C60)-(Au35) nano-clusters on graphite ...... 386 P11-SAS_2 Structure and electronic properties of Zn-tetra-phenyl- porphyrins single- and multi-layers films grown on Fe (001) p(1x1)O ...... 387 SCR - Surface chemical reactions and kinetics ...... 388 I01_SCR_428 Intra-particular mobility in supported nanoalloys: from a metastable to an equilibrium structure ...... 389 O1-SCR _245 Investigating core/shell Pd/Au nanoparticle structure by probing CO adsorption with SFG ...... 390 O2-SCR _336 Palladium and Carbon monoxide oxidation Au30Pd70(110) upon oxygen and carbon monoxide elevated pressure ...... 391 O3-SCR _238 Experimental and Theoretical Studies on Oxidation of Cu-Au Alloy Surfaces —Effect of Bulk Au Concentration— ...... 392 O4-SCR _348 Identifying the Adsorption Configuration and Thermal Decomposition Mechanism of Guaiacol on Pt(111): An Integrated X-ray Photoelectron Spectroscopy and Density Functional Theory Study ...... 393 O5-SCR _149 Reaction dynamics of formate formation and decomposition on Cu single crystal surfaces ...... 394 O6-SCR _194 XPS and STM studies of the effect of oxygen concentration on HCl reaction at Cu(100) and (111) surfaces ...... 395 O7-SCR_466 Operando CO Oxidation Study of MgAl2O4(001)- supported Pt0.33Rh0.67 Nanoparticles using Surface X-Ray Diffraction ...... 396 O8-SCR _317 Anise on Pt(111): adsorption and reactivity ...... 397 O9-SCR_470 Atomic-scale study of the Ziegler-Natta catalyst ...... 398 O10-SCR _173 Simultaneous AFM/STM study of chirality and on- surface chemistry of Dibenzo[7]helicene deposited on Ag(111) ...... 399

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O11-SCR _226 Phthalic acid on MgO(100) as a model for the anchoring of carboxylic acid functionalized large organic molecules ...... 400 O12-SCR _221 Mechanistic Study of NO Reduction by Cr- phthalocyanine Monolayer Investigated by DFT Calculations ...... 401 O13-SCR _239 Energy release and surface chemistry of the molecular solar energy storage system Norbornadiene / Quadricyclane ...... 402 O14-SCR _206 Chemical Bath Deposition of Molybdenum Disulfide Ultra-Thin Films ...... 403 O15-SCR _99 Interaction of ionic liquids with lithium metal films studied with photoelectron spectroscopy ...... 404 O16-SCR _150 First-Principles Simulations of Platinum-Assisted Water Etching of SiC ...... 405 I21_SCR_455 Surface properties of elemental 2D materials in ambiant conditions ...... 406 P2-SCR_112 Adsorption and reactions of bifunctional 2- chloropropanoic acid on Cu(100) and O/Cu(100) ...... 407 P3-SCR_207 Ga on SiO2 as catalyst for nanowire growth: Investigation by X-ray Photoelectron Spectroscopy ...... 408 P4-SCR_299 The hydrated electron at the ice surface: insight into dissociative electron attachment to adsorbates ...... 409 P5-SCR_304 NaCe(WO4)2 microstructures with hierarchical morphologies: EDTA-assisted hydrothermal synthesis , growth mechanisms, electrical and photocatalytic properties...... 410 SMC - Semiconductor surfaces ...... 411 P1-SMC_14 Combination system: Adsorption/Photo-electrodialysis for lead removal using Bentonite-Memebrane-Sr2Fe2O5 ...... 412 P2-SMC_29 Surface morphology of thin films based on Ge-Si-Sn materials at different growth conditions ...... 413 P3-SMC_69 Ultrasonic treatment influence on the Si-SiO2 system defects structure ...... 414 P4-SMC_96 Critical Metal Thickness for the Schottky Barrier Formation: Synchrotron Radiation Photoemission Study of Ag on p- GaAs(001)-2x4 ...... 415 P5-SMC_70 Ultrasound influence on the Si-SiO2 system defects structure ...... 416 P6-SMC_71 Ultrasound influence on the Si-SiO2 system defects structure ...... 417 P7-SMC_160 Continuum Modeling of Cyclic Growth in SiGe/Si(001) Heteroepitaxial Systems ...... 418 P8-SMC_278 Photodegradation of methylene blue on the basis of solid copper based on solid Zinc oxide ...... 419

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SMG - Surface magnetism ...... 420 O1-SMG _129 Electric field effects on magnetic properties of ultrathin films: Why not using the electrochemical contact?...... 421 O2-SMG _133 High temperature ferromagnetism in a monolayer- thick GdAg2 surface alloy ...... 422 O3-SMG _222 Influence of atomic-scale disorder on ferromagnetism of monatomic-layer iron nitride ...... 423 O4-SMG _143 Magnetic behavior of nanopatterned cobalt ultrathin films grown on Si/Ag(110) ...... 424 O5-SMG _176 Ferromagnetic Nanostructures produced on metastable fcc Fe Film on H/Si(100) and Diamond by Focused Ion Beam ...... 425 O6-SMG _241 Kondo effect of a Co atom exchanged coupled to a ferromagnetic tip ...... 426 O7-SMG _57 Strong ferromagnetism at the silicon surface of antiferromagnets caused by buried magnetic moments ...... 427 O8-SMG _201 Magnetic anisotropy in Shiba bound states across a quantum phase transition ...... 428 O9-SMG _89 Spin-hybridization between molecule and metal at room temperature through interlayer exchange coupling ...... 429 O10-SMG _247 Portability of a molecular quantum spin ...... 430 P1-SMG_45 Magneto-optical study of cylindrically shaped magnets. Surface domain structure and magnetization reversal...... 431 P3-SMG_416 Antiferromagnetic long range spin ordering in Fe and NiFe2 doped BaTiO3 multiferroic layers ...... 432 SMI - Soft Matter at Interfaces ...... 433 O1-SMI_469 Solvent Extraction: Structure of the Liquid–Liquid Interface Containing a Diamide Ligand ...... 434 O2-SMI _366 A COMBINED NEUTRON REFLECTOMETRY AND ATR-FTIR STUDY ON THE EFFECTS OF SHEAR ON LIPID MEMBRANES ...... 435 O3-SMI _236 Loaded polyelectrolyte/surfactant membranes spread from neutral aggregates...... 436 O4-SMI _234 VUV treatment as a resource saving method for Fibre-reinforced plastic (FRP) surface preparation prior to bonding ...... 437 O5-SMI _461 Reduction in Tension and Stiffening of Lipid Membranes in an Electric Field Revealed by X-ray Scattering ...... 438 O6-SMI_383 Structural Characterization of Membranes of Increasing Complexity ...... 439 I13_SMI_434 Scattering Methods and Force Spectroscopy Reveal Molecular Level Structure and Interactions of Lipid Membranes ...... 440 P1-SMI_18 A straightforward approach for concurrent particle formation and surface modification of Boehmite nanoparticles via in-situ surface modification ...... 441

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SST - Surface structure ...... 442 O1-SST _82 Ab initio study of structure phase transition in atom- wide Co wires on a vicinal Cu(111) surface ...... 443 O2-SST _105 Surface structure of (110) terminated magnetite investigated by scanning tunneling microscopy and density functional theory ...... 444 O3-SST _77 Cobalt thin films intercalation under Graphene on Iridium(111): intermixing effects and the role of Graphene ...... 445 O4-SST _390 Wetting layer of copper on the tantalum (001) surface ...... 446 O5-SST _249 Surface tug of war: direct quantitative identification of the “surface trans-effect” ...... 447 I10_SST_456 Three decades of atomic force microscopy - what is in for surface science? ...... 448 O6-SST _340 The Surface Structure of V2O3(0001) ...... 449 O8-SST _72 The new generation of the hemispherical energy analyser in the novel surface science research ...... 450 O9-SST _363 Structure of a model dye/titania interface: Geometry of benzoate on rutile-TiO2 (110)(1×1) ...... 451 O10-SST _364 Gold-palladium nanoparticles on TiO2 (110): Correlation between morphology/structure and UV-Vis response ...... 452 O11-SST _233 Identification of surface structures of titania nanoparticles by photoemission spectroscopy ...... 453 O12-SST _38 Structural and morphological changes of Co and Rh nanoparticles on CeO2 and Al2O3 ...... 454 P1-SST_20 Giant flexoelectric induced surface layer in BiFeO3 thin film ...... 455 P2-SST_146 DFT and STM study of reconstructed Au(100) surface ...... 456 P3-SST_338 Ordering in self-organized Pd-Au arrays of nanoparticles studied by in situ grazing incidence X-ray scattering ...... 457 P4-SST_347 Strain engineering across the H-, O- and OH-Pt(111) systems ...... 458 P5-SST_379 Rich interfacial films formed from aggregates in alfa- cyclodextrin solutions ...... 459 P6-SST_408 Study of effect of alumina on aluminium characteristic properties in composite alloys ...... 460 P7-SST_341 Addressing the vibrational and structural properties of polymorph exfoliated MoS2 phases ...... 461 TPI - Topological insulators ...... 462 O1-TPI _121 Determination of the atom-surface interaction potential for a topological insulator: 3He-Bi2Te3(111) ...... 463 O2-TPI_471 Topological quantum phase transition from weak to strong topological insulator in PbSnBiSe ...... 464 O4-TPI _213 IV-VI monolayers with alkaline-earth chalcogenide supports ...... 465 P2-TPI_244 Assessing topological protection in real space ...... 466

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Special sessions ...... 467 O01-ASC_475 See atoms move in real time: ultrafast electron diffraction ...... 468 O02-ASC_476 From Molecular Self-Assembly to On-Surface Chemistry ...... 469 O03-ASC_477 Solution processed 2d crystals for energy and (opto)electronic applications ...... 470 O04-ASC_478 Building Electronic and Optical Devices from Colloidal Nanocrystals ...... 471 O05-ASC_479 Building with artificial atoms: The design of multifunctional nanomaterials and devices through nanocrystal self- assembly ...... 472 O06-ASC_480 Advances in Raman Spectroscopy of Graphene and Layered Materials ...... 473 NANOCAR_472 THE NANOCAR RACE USING SINGLE MOLECULE-VEHICLES ...... 474 Authors index ...... 475 A ...... 476 B ...... 476 C ...... 479 D ...... 480 E ...... 481 F ...... 482 G ...... 483 H ...... 484 I ...... 485 J ...... 486 K ...... 486 L ...... 488 M ...... 489 N ...... 491 O ...... 491 P ...... 492 Q ...... 493 R ...... 493 S ...... 494 T ...... 496 U ...... 497 V ...... 497 W ...... 498 X ...... 499 Y ...... 499 Z ...... 499

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PLENARY TALKS

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PL01_429 NANOPOLARITY: NEW MANIFESTATIONS OF CLASSICAL ELECTROSTATICS

Plenary talks C. Noguera *, J. Goniakowski Paris Nanoscience Institute - Paris (France) Among all compound surfaces, polar surfaces are those which researchers have first tried to avoid as much as they could due to their inherent electrostatic instability. Stability can only be recovered if a simple electrostatic condition is fulfilled, but this can be achieved in many different ways: large cell reconstructions, nanometric surface patterning, unusual electronic structure and/or adsorption of charged species, according to the experimental conditions. This richness of behaviours has stimulated important research effort, especially in the oxide community [1,2]. More recently, it has appeared that polarity has also a sound influence on the stability and properties of nano-objects, such as ultra-thin films, two-dimensional ribbons or nano-islands. For them, however, unexpected stabilization processes are at work, which depend strongly on the dimensionality, size and shape of the objects. Nano-oxides with structure and/or stoichiometry with no bulk equivalent have been produced. Strong lattice relaxations, support effects, inhomogeneous charge redistributions, formation of 2D or 1D electron/hole gases have been observed and/or predicted [3-5]. Relying on selected examples which were the subject of recent experimental and/or theoretical works, we will review how electrostatic laws manifest themselves in polar nano- oxides at various length scales and what consequences they have on their physico-chemical properties. References [1] C. Noguera, J. Phys Condensed Matter 2000 12, R367-R410 [2] J. Goniakowski, F. Finocchi, C. Noguera, Rep. Prog. Phys. 2008 71, 016501 [3] C. Noguera, J. Goniakowski, Chem Rev. 2013 113, 4073 [4] C. Noguera, J. Goniakowski, in “Oxide Materials at the Two-Dimensional Limit”, Eds. F. P. Netzer and A. Fortunelli, Springer Series in Materials Science 2016 234 Chapter 7, pp 201-231 [5] J. Goniakowski, C. Noguera, C. R. Physique 2016 17, 471-480

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PL02_427 PROBING ULTRAFAST ELECTRON AND SPIN DYNAMICS IN MOMENTUM, SPACE AND TIME

Plenary talks M. Aeschlimann * Department of Physics and Research Center OPTIMAS, University of Kaiserslautern (Germany) Optically excited (hot) electrons play a crucial role for many fundamental chemical and physical phenomena occurring at surfaces, interfaces, and in bulk materials. They, for instance, determine the properties of photo-induced catalysis at surfaces, and the efficiency of charge and spin transfer across interfaces between different materials. For the investigation of such processes, time-resolved photoelectron spectroscopy did turn out to be a very powerful tool through its direct access to transient band-structure dynamics. In particular, very recent progresses in the development of ultrashort pulsed light sources and electron spectrometers have paved the way for a completely new generation of real-time photoemission techniques. In the first part of my talk, I will show how femtosecond-ARPES can be used to understand the transient changes of the valence band during photo-induced phase transitions. In this context, capturing the dynamic of the electronic band structure of a correlated electron material presents a powerful capability for uncovering the complex couplings between the electronic and structural degrees of freedom [1]. When this technique is nowadays combined with a fs HHG light source and a novel spin detector, a “complete” photoemission experiment can be realized, with full access to the spin-resolved transient band-structure dynamics on the femtosecond time scale. Here, I will exemplify these capabilities via the investigation of the transient spin-resolved band-structure during the optically induced loss of magnetic order in the 3d ferromagnet Co [2] In the second part I will show how the high sensitivity and lateral resolution of the time- resolved photoemission electron microscopy technique (fs-PEEM) was used to verify simultaneous spatial and temporal control of nanooptical fields in the vicinity of metallic (plasmonic) nanostructures. This opens a route towards space- and time-resolved spectroscopy on nanometer length-scales and femtosecond time-scales [3,4]. The third focus is on the momentum dependent dynamics of excited electrons at metal- organic hybrid interfaces using time-resolved momentum microscopy [5]. This novel tool for angle resolved photoemission allows us to study the electron dynamics throughout the entire momentum space. The review concludes with an outlook to the feasibility of future real-time studies in surface and material science. References [1] T. Rohwer et al, , Nature 471, 490-493 (2011) [2] M. Plötzing et al, Rev. Sci. Instrum. 87, 043903 (2016) [3] M. Aeschlimann et al, Nature 446, 301 (2007) [4] M. Aeschlimannet al, Science 333, 1723-1726 (2011) [5] B. Yan et al, Nature Communications 6, 10167 10167 (2015)

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PL03_431 GRAPHENE: THE FREEDOM OF A SURFACE WITHOUT BULK

Plenary talks A. Fasolino * Institute for Molecules and Materials, Radboud University - Nijmegen (Netherlands) Graphene is made of just an atomic layer, peeled off bulk graphite. Getting read of the bulk endows it with many properties which are really unique in material science, including the possibility to choose another bulk, making a van der Waals heterostructure. In this talk I will focus on the structural and elastic properties that make graphene interesting both for fundamental physics and applications. References For a review see: Graphene as a Prototype Crystalline Membrane, M. I. Katsnelson and A. Fasolino, Accounts of Chemical Research 46, 97 (2013) Scaling Behavior and Strain Dependence of In-Plane Elastic Properties of Graphene, J. H. Los, A. Fasolino, and M. I. Katsnelson, Phys. Rev. Lett. 116, 015901 (2016) Melting temperature of graphene, J.H. Los, K. V. Zakharchenko, M. I. Katsnelson and A. Fasolino,Phys. Rev. B 91, 045415 (2015) Moire Patterns as a Probe of Interplanar Interactions for Graphene on h-BN, M. M. van Wijk, A. Schuring, M. I. Katsnelson and A. Fasolino, Phys. Rev. Lett. , 113, 135504 (2014) Effect of structural relaxation on the electronic structure of graphene on hexagonal boron nitride, G. J. Slotman, M. M. van Wijk, P.-L. Zhao, A. Fasolino, M. I. Katsnelson, and S. Yuan, Phys. Rev. Lett. 115, 186801 (2015)

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PL04_430 MAGNETIC REMANENCE IN SINGLE ATOMS

Plenary talks H. Brune * Institute of Physics, École Polytechnique Fédérale de Lausanne - Lausanne (Switzerland) The magnetic states of nanostructures are of high interest for information storage and quan- tum information processing. This has triggered the search for the smallest possible magnets. In devices, electrodes have to be attached to them for readout and manipulation of the mag- netic quantum states. This corresponds to their adsorption onto conducting surfaces. Possible candidates for the smallest surface adsorbed magnets are molecules and small metal clusters down to the ultimate size limit of single metal adatoms. The benchmarks for these quantum magnets are their magnetic relaxation and coherence times, T1 and T2. The first determines how long information can be stored in a magnetic quantum state, and the second defines the time one has to take out a quantum computation step. Many molecular magnets that exhibit promising properties in bulk samples loose them en- tirely when they are surface adsorbed, and all single metal adatoms reported since very recently are perfect paramagnets, despite their high magnetic anisotropies [1, 2]. The mechanisms giving rise to the finite lifetimes of magnetic quantum states are scattering with substrate electrons and phonons, as well as mixing of quantum states in the crystal field of the adsorption site of the magnetic atom [3]. We show that these problems can largely be overcome by using oxide and graphene spacer layers that significantly enhance the magnetic lifetimes of the surface adsorbed species as compared to direct adsorption onto a metal substrate. Pc2Tb double-decker molecules ad- sorbed on MgO(100) thin films grown on Ag(100) have much longer spin-relaxation time and wider hysteresis than in bulk samples [4]. Ho atoms on the same surface are the first single atom magnets [5]. They exhibit spin-relaxation times of an hour at 2 K and display hysteresis up to 30 K, thus outperforming best molecular magnets.

Fig. 1: STM image and XMCD magnetization curve (10 K) for Ho atoms on MgO on Ag(100) [5]. References [1] I. G. Rau et al., Science 344, 988 (2014). [2] S. Baumann et al., Phys. Rev. Lett. 115, 237202 (2015). [3] C. Hübner et al., Phys. Rev. B 90, 155134 (2014). [4] C. Wäckerlin et al., Adv. Mater. 28, 5195 (2016). [5] F. Donati et al., Science 352, 318 (2016).

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PL05_432 CHEMICAL REACTIONS AT SURFACES: SINGLE MOLECULAR VIEW

Plenary talks M. Kawai 1,*, M. Kawai 2, Y. Kim 3, K. Motobayashi 4, H. Ueba 5, N. Tsukahara 2, N. Takagi 2 1Institute for Molecular Science, National Institute of Natural Science - Okazaki (Japan), 2Department of Advanced Materials Science, University of Tokyo - Kashiwa (Japan), 3Surface and Interface Science Lab., RIKEN - Wako (Japan), 4Nagoya Institute of Technology - Nagoya (Japan), 5Toyama University - Toyama (Japan) STM is a useful tool for spectroscopy utilizing its ultimate spatial resolution. STS including inelastic electron tunneling spectroscopy (IETS) is not only applied to the static spectroscopy but also reflects dynamical phenomena as motion or reaction of molecules induced by the excitation of molecular states, and is utilized to identify the quantum states of the materials. Dynamical information includes as how molecular vibrations can couple with the relevant dynamical processes et al [1-3]. At the conference I will present some typical examples of how the fundamental excitation of vibration modes are coupled to chemical reactions at surfaces. Inelastic electron tunneling spectroscopy (IETS) is widely used to identify the electronic states and is especially useful when the molecule is in contact with solid surfaces. Utilizing the tunneling feature of electron as Multiple Andreev reflection caused between superconductor electrodes, we have recently succeeded to unveil the electron transfer channels though a molecule sandwiched within superconducting metals [4]. Spin state of the molecule is one of the examples, where it depends on the strength of the coupling between the molecule and substrate. With strong coupling with Cu(110) the spin of FePc is completely killed whereas if decoupled as on Cu(110) 2x1-O, spin survives with change in the direction of easy axis [5]. On Au, weak coupling leads to appearance of Kondo state, where a competition between the RKKY interaction affects the spin state [6]. Kondo state of FePc on Au depends on the adsorption site, where the difference was originating from the coupling with the substrate electrons [7]. References [1] Y. Kim, et al., Progress in Surface Science, 90 (2015) 85-143., and the references within. [2] Kenta Motobayashi, et al., Surf. Sci. 634 (2016) 18-22. [3] Oh, Phys. Rev. Lett. 116 (2016) 056101. [4] Ryoichi Hiraoka, et al., Phys. Rev. B 90 (2014) 241405(R). [5] N. Tsukahara, et al., Phys. Rev. Lett. 102 (2009) 167203. [6] N. Tsukahara, et al., Phys. Rev. Lett. 106 (2011) 187201. [7] E. Minamitani, et al., Phys. Rev. Lett. 109 (2012) 086602.

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ADS - Adsorption and desorption

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O1-ADS _52 DEUTERIUM/HYDROGEN ISOTOPE EXCHANGE ON BERYLLIUM AND BERYLLIUM NITRIDE

ADS - Adsorption and desorption P. Dollase *, M. Köppen, C. Linsmeier Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Plasmaphysik - 52425 Jülich (Germany) Nuclear fusion research aims to produce energy with the hydrogen isotopes deuterium and tritium as fuel. Deuterium and tritium ions are implanted into the first wall during plasma operation. In order to reclaim the tritium fuel and to minimize the radioactive inventory, an efficient method for the regeneration of the first wall is required. In this context, the isotope exchange of hydrogen isotopes is investigated. Here, the exchange of hydrogen and deuterium is studied to avoid working with radioactive tritium. The first wall in the main vessel of the fusion experiments JET and in the future ITER is made of beryllium. In combination with nitrogen gas, which is used as radiator to lower the energy deposited at the first wall, beryllium nitride Be3N2 can be formed. The properties concerning hydrogen isotope retention and release of Be3N2 are different than those of metallic Be. Therefore, a comparative study of the hydrogen isotope exchange in these two materials is performed. In this contribution, the hydrogen isotope exchange is studied in a laboratory experiment replacing the plasma by ions from an electron impact source. Hydrogen and deuterium ions are implanted with a maximum acceleration voltage of 5 kV into polycrystalline Be and Be3N2. The surface is then analysed in-situ with photoelectron spectroscopy (XPS and UPS). The release of the implanted hydrogen isotopes as a function of the sample temperature is observed with thermal desorption spectroscopy (TDS). Various implantation energies of the hydrogen isotopes, interchanged implantation order and different sample materials are compared. The implantation order plays an important role for which trap sites are occupied by which isotope. The TDS shows that the first implanted species occupies the energetically favoured trap sites. This leads to the conclusion that at an implantation energy of 1.5 keV there is no isotope exchange on the energetically favoured trap sites. Furthermore, simulations of the implantation profiles of the two different hydrogen isotopes were performed with the code SDTrimSP which is based on a binary collision model. These simulations indicate that atoms of the second implanted isotope are located deeper in the sample than the atoms of the first implanted isotope. In conclusion, these experiments deliver valuable insights in the fundamental properties of ion-driven isotope exchange.

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O2-ADS _97 ADHESION PROPERTIES OF HYDROGEN ON ANTIMONY(111) PROBED BY HELIUM ATOM SCATTERING

ADS - Adsorption and desorption A. Ruckhofer *, P. Kraus, C. Gösweiner, A. Tamtögl, F. Apolloner, E. Wolfgang Institute of Experimental Physics, Graz University of Technology, Austria - Graz (Austria) While antimony (Sb) is a topological semimetal, Sb nanofilms have been proposed to be topological insulators[1,2] and recent calculations showed that the adsorption of hydrogen on Sb thin films is capable of modulating the topological surface states[3]. The adsorption of hydrogen on metal surfaces has been the subject of many experimental and theoretical efforts in the last decades, but very little experimental data exists for the adsorption properties of semimetal surfaces apart from graphene[4,5]. We have carried out a series of helium atom scattering (HAS) measurements in order to characterise the adsorption properties of hydrogen on Sb(111). HAS is particularly useful for the investigation of adsorbed hydrogen atoms due to the much higher scattering cross section compared to electron scattering. Molecular hydrogen does not adsorb at temperatures above 110 K in contrast to pre- dissociated atomic hydrogen. Depending on the substrate temperature, two different adlayer phases of atomic hydrogen on Sb(111) occur. At low substrate temperatures (110 K), the deposited hydrogen layer does not show any ordering while we observe a perfectly ordered (1x1) H/Sb(111) structure for deposition at room temperature. Furthermore, the amorphous hydrogen layer deposited at low temperature forms an ordered overlayer upon heating the crystal to room temperature. The resulting diffraction peak intensities indicate a somewhat lower electronic corrugation of the hydrogen adlayer than of the clean Sb(111) substrate. Hydrogen starts to desorb at 430 K which corresponds to a desorption energy of (1.33 ± 0.06) eV. Using measurements of the helium reflectivity during hydrogen exposure at different surface temperatures, we conclude that the initial sticking coefficient of atomic hydrogen on Sb(111) decreases with increasing surface temperature. Furthermore, the scattering cross section for the diffuse scattering of helium from hydrogen on Sb(111) is determined as (12 ± 1) Å2. References [1] P.F. Zhang et al. Phys. Rev. B, 85, 201410 (2012). [2] Bian et al. Phys. Rev. Lett., 108, 176401 (2012). [3] D. Wang et al. Phys. Chem. Chem. Phys., 17, 3577 (2015). [4] J. Shan et al. Chem. Phys. Lett., 517, 46 (2011). [5] C. Lin et al. Nano Lett., 15, 903 (2015).

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O3-ADS _231 REVISITING H2 ADSORPTION ON PD(210): NUCLEAR SPIN SPECIES SEPARATION AND CONVERSION

ADS - Adsorption and desorption E. Arguelles *, W.A. Dino Department of Applied Physics, Osaka University - Suita, Osaka (Japan)

We revisit H2 adsorption on Pd(210) surface, with the emphasis on the molecule’s nuclear spin species separation and conversion using a combination of density functional theory (DFT)-based and model calculations. It is known that molecular adsorption of H2 is only possible after the accumulation of atomic hydrogen on Pd(210) and temperature programmed desorption (TPD) peaks point to three possible adsorption sites[1]. Our results show that H2 molecule favors adsorption on top of Pd atoms located at the step-edge regardless of orientation and atomic H coverage. Further, we found that H2 adsorbed in parallel orientation with respect to the surface has higher adsorption energy compared to the one adsorbed perpendicularly at low atomic H coverage (Θ < 3 ML). From these molecular orientation-dependent adsorption energies, we obtain the anisotropy potential that hinders rotation of H2 on the surface[2] and calculate its rotational state energies. Subsequently, the molecular spin conversion and desorption energies for H2 of different nuclear spins are calculated, the details of which will be presented at the conference. References [1] P.K. Schmidt, et al., Phys. Rev. Lett. 87(2001) 096103-1-096103-4 [2] E. Arguelles, et al., submitted.

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O4-ADS _139 TUNING THE ADSORPTION OF WATER ON PT FILMS SUPPORTED ON RU(0001) - A LOW-TEMPERATURE STM INVESTIGATION

ADS - Adsorption and desorption M. Schilling *, S. Brimaud, R.J. Behm Institute of Surface Chemistry and Catalysis, Ulm University - Ulm (Germany) The detailed understanding of the fundamental electrochemical/-catalytic processes on electrode surfaces requires the characterization of the solid | liquid interface, including the water-metal interaction. For single metal surfaces, this has already been intensely studied using model systems consisting of 2D-ice layers adsorbed on various single crystal metal surfaces [1]. Due to the interest in bimetallic Pt-based electrocatalysts, we started a systematic study on the interaction of water with epitaxially grown Pt-film surfaces on Ru(0001). As has been shown before for CO adsorption on pseudomorphic Pt/Ru(0001) surfaces [2], the adsorption properties of these surfaces are sensitively affected by strain and vertical ligand effects, which in turn depend on the thickness of the Pt film. We will present results of a low temperature scanning tunneling microscopy (STM) study on the structure of water adlayers on such pseudomorphic Pt/Ru(0001) model surfaces under UHV conditions. We will demonstrate that the structure of the water adlayer depends in a systematic way on the thickness of the Pt film, in the range from 1 to 4 Pt monolayers [3]. This reaches from relatively mobile monomer and dimer adsorbate species over stable hexamers to continuous hexagonal wetting layers, as the vertical influence (vertical ligand effect) of the Ru substrate decreases with increasing thickness of the Pt film, whereas due to the pseudomorphic growth the Ru(0001) induced lateral strain in the Pt film remains constant. We will correlate the trend observed for the adsorbate structure and the water uptake under constant dosing and imaging conditions with the change in the water-metal binding energy induced by the vertical ligand effect. Since such tuning of the adsorbate-metal interaction is expected to also affect the adsorbate-adsorbate interaction, the influence of co-adsorbed CO molecules is currently being investigated, and first results will be presented. References [1] A. Hodgson and S. Haq, Surface Science Reports 64 (2009) 381. [2] A. Schlapka, et al., Phys. Rev. Lett. 91, 016101 (2003). [3] M. Schilling, S. Brimaud and R.J. Behm, Water adsorption on pseudomorphic Pt films on Ru(0001) – A low temperature STM study, in preparation.

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O5-ADS _215 MODIFICATION OF THE CHEMICAL AND ELECTRONIC PROPERTIES OF N-TYPE GAN(0001) SURFACES BY POTASSIUM AND WATER ADSORPTION

ADS - Adsorption and desorption S. Krischok *, V. Irkha, A. Eisenhardt, S. Reiß, M. Himmerlich TU Ilmenau - Ilmenau (Germany) Group III-nitrides are, besides applications in high frequency and high power electronics as well as optoelectronics, aloso interesting for (bio)sensing applications. For example GaN- capped open gate AlGaN/GaN based HEMTs are used for sensing pH values and ion concentrations in liquid environments. One practical example is the monitoring of cell metabolism processes via exchange of potassium ions in a bioreactor. For these applications the interactions of atoms/ions in the presence of aqueous environment plays a crucial role. In order to get insight into the relevant processes, the potassium and water interaction with the GaN surface was studied. We present experiments for the potassium, water as well as potassium and water coadsorption onto n-type GaN(0001) surfaces grown in situ by PAMBE. These surfaces initially show strong surface states due to dangling bond states.

At 300K, K adsorption and K & H2O coadsorption at the clean surface initially lead to the saturation of these surface states and the formation of a strong surface dipole. In our experiments two stages, depending on K coverage are identified: At low coverage the ionization of potassium induces an increase of GaN surface electron density, whereas above a critical coverage, the residual 4s electron density induces the formation of intra-gap surface states and recovery of the GaN surface electron depletion for pure K adsorption. For the coadsorption. hydroxyl formation is observed in the second stage and nearly flat band conditions are found at the GaN surface. Within the set of our experiments, we are able to tune the surface band bending between between 0.5 eV upward band bending and -0.5 eV downward bending, which clearly demonstrates that the electron density at the GaN surface can be reversibly tuned by alkali- based adlayers and depend on their nature and thickness.

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O6-ADS _263 CHEMO-MECHANICAL COUPLING FROM FIRST PRINCIPLES: ON THE STRAIN DEPENDENCE OF OXYGEN ADSORPTION ON PD(111)

ADS - Adsorption and desorption G. Feldbauer *, A. Michl, S. Müller Hamburg University of Technology - Hamburg (Germany) Mechanical deformation can affect the adsorption and reaction processes of reactants on surfaces. Thus, by straining catalytically active surfaces their reactivity as well as selectivity can be influenced, which is of high importance in the field of heterogeneous catalysis. [1,2] Here, the adsorption of atomic oxygen on Pd(111) is used as a model system. At first, the dependence of the adsorption energetics on various oxygen adsorption sites and coverages is investigated within the framework of density functional theory (DFT). Furthermore, the incorporation of oxygen below the Pd surface, which is considered to be the first step in oxide formation [3], is studied. Using the DFT results as input data a cluster-expansion Hamiltonian is constructed to scan exhaustively the configuration space of the examined model system. This allows to identify the most favorable adsorption configurations. For various configurations biaxial strain is applied in the surface plane to obtain the response of the adsorption energetics. Particularly, the coupling parameter between strain and adsorption energies is of interest to allow for a comparison with experiments. The coupling parameter is affected by the oxygen coverage as well as the occurrence of oxygen incorporation. Thanks Supported by the DFG, grant MU1648/6-1. References [1] Gsell et al., Science 280 (1998) 717. [2] Mavrikakis et al., Physical Review Letters 81 (1998) 2819. [3] Todorova et al., Physical Review Letters 89 (2002) 096103.

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O7-ADS _49 ADSORPTION UNDER NANO-CONFINEMENT: PREDICTION OF DISTINCT ENTROPIC EFFECTS ON EQUILIBRIUM COVERAGE

ADS - Adsorption and desorption M. Polak *, L. Rubinovich Ben-Gurion University of the Negev - Beer Sheva (Israel) A nanoconfinement entropic effect shifting the macroscopic chemical equilibrium (NCECE) was previously introduced using original statistical-mechanical formulation [1]. A prerequisite is the participation of a small number of reactant molecules confined to a nanospace. The effect was verified by evaluation of experimental data concerning DNA hybridization inside nano-chambers [2]. While our previous studies [1-4] dealt with regular chemical reactions, the present study reveals the manifestation of the effect in the case of gas adsorption on a solid surface. The NCECE, associated with significant variations in mixing-entropy and pressure fluctuations, is evaluated in the combined framework of the ideal- and lattice-gas models for several nondissociative adsorption processes: (i) single molecule per surface site; (ii) multiple adsorbed molecules per surface site; (iii) selective molecular adsorption on distinct multiple surface sites; (iv) exchange between multiple adsorbate configurations; (v) competitive adsorption of two molecular species. The computations, based mainly on published DFT data, focus on H2 and CO2 adsorption on Li/Ti- doped and N-doped carbon nanopore surfaces, respectively, and on H2 adsorbed on Al2O3 fullerene-like structures. Also, competitive adsorption of CO and H2O, and of two CO adsorption configurations on N-doped carbon nanotubes are modeled. In most of the systems NCECE-induced extra adsorption is predicted (Figs.1-2, case (i)), whereas only in case (ii) the opposite effect is possible. These results seem to have practical implications, such as the enhancement of H2 storage capacity and CO2 capture in nano-porous materials. References 1. Micha Polak and Leonid Rubinovich, Nano Letters 8, 3543 (2008). 2. Leonid Rubinovich and Micha Polak, Nano Letters 13, 2247 (2013). 3. Micha Polak and Leonid Rubinovich, Phys. Chem. Chem. Phys. 13, 16728 (2011). 4. Micha Polak and Leonid Rubinovich, Surf. Sci. 641, 294 (2015).

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O8-ADS _152 FREE-BASE 5,10,15-TRIS(PENTAFLUOROPHENYL)CORROLE ADSORPTION ON AG(111)

ADS - Adsorption and desorption H. Aldahhak 1,*, S. Tebi 2, M. Paszkiewicz 3, E. Rauls 1, U. Gerstmann 1, F. Klappenberger 3, S. Müllegger 2, W. Schöfberger 4, W.G. Schmidt 1 1Lehrstuhl für Theoretische Materialphysik, Universität Paderborn - Paderborn (Germany), 2Festkörperphysik, Universität Linz - Linz (Austria), 3Physik Department E20, Technische Universität München - München (Germany), 4Institut für Organische Chemie, Universität Linz - Linz (Austria) Tetrapyrrole compounds such as porphyrins and corroles, are intriguing macrocycles omnipresent in diverse science fields. While corroles are structurally closely related to porphyrins, their compounds have lower symmetry and smaller cavities, which enables them to stabilize metal ions in exceptionally high oxidation states. This makes them highly interesting molecules for a variety of applications in medicine, catalysis, sensors as well as for solar cells [1, 2]. For the related higher-symmetry compounds (porphyrins and phthalocyanines), intensive studies have been carried out to disclose their interfacial properties. In contrast, only few studies on the surface-supported corroles have been performed so far. First principles calculations have been performed to investigate the adsorption of the free- base 5,10,15-tris(pentauorophenyl)corrole on Ag(111) surface. The theoretical approach was supported by complementary scanning tunneling microscopy (STM) as well as X-ray photoelectron spectroscopy (XPS) measurements. Both single adsorbed molecules as well as monolayer thin films have been studied. Single molecules adsorb with their macrocycles tilted with respect to the surface. The tilted adsorption geometries enable the molecules to aggregate in non-trivial interwoven monolayer structures. The simulated STM data [3] as well as the simulated X-ray photoelectron spectroscopy (XPS) data for the C1s, F1s and N1s edges in conjunction with the measurements nicely confirm the site-selective single deprotonation reaction of a specific N atom as well as a ring-closing reaction taking place between a fluorophenyl ring and the macrocycle upon annealing to 430 K [4]. References [1] Z. Gross and N. Galili, Angew. Chem. Int. Ed., 1999, 38, 2366. [2] R. Paolesse, L. Jaquinod, D. J. Nurco, S. Mini, F. Sagone, T. Boschia, and K. M. Smith, Chem. Commun., 1999, 307. [3] S. Tebi, H. Aldahhak, G. Serrano, W. Schöfberger, E. Rauls, W. G. Schmidt, R. Koch, and S. Müllegger, Nanotechnology 27, 2016, 025704. [4] M. Paszkiewicz, H. Aldahhak, S. Tebi, E. Rauls, U. Gerstmann, P. Deimel, P. Casado Aguilar, D. A. Duncan, A. C. Papageorgiou, Y.-Q. Zhang, F. Allegretti, W. Schöfberger, S. Müllegger, R. Koch, W. G. Schmidt, J. V. Barth, F. Klappenberger. JACS (submitted, 2016)

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O9-ADS _358 USING SUBSURFACE EFFECTS OF PLASMA FILMS FOR ALTERING PROTEIN ADSORPTION

ADS - Adsorption and desorption D. Hegemann *, N. Blanchard, M. Heuberger Empa, Swiss Federal Laboratories for Materials Science and Technology - St. Gallen (Switzerland) Protein adsorption is affected by different molecular interactions with the surface. As a novel finding, it was observed that also the subsurface of hydrated thin films can contribute to the interaction via long-range forces of a few nm. The wettability of a surface generally influences the way amphiphilic molecules adsorb onto it. Since amphiphilic molecules contain both hydrophilic and hydrophobic groups, a different interaction with hydrophilic or hydrophobic surfaces is anticipated. Using, for example, bovine serum albumin (BSA) as an amphiphilic probe molecule, a different amount of protein is thus observed to adsorb on hydrophilic quartz-like (ppSiOx) and hydrophobic silicone-like (ppHMDSO) surfaces. Hence, plasma-deposited siloxane films with low (hydrophilic) and high hydrocarbon content (hydrophobic) reveal expected BSA adsorption. Both plasma polymer films were combined to form an ultrathin hydrophobic/hydrophilic vertical chemical gradient at the surface [1]. Starting with the hydrophilic base layer, a nanometer thin adlayer of the hydrophobic film has been applied as a hydrophobic surface termination (vgrad-4nm). As an unexpected result, the BSA adsorption on such vertical gradient structures was measured to be significantly reduced. The subsurface region thus has an additional effect on protein adsorption, most likely due to water molecules that are able to penetrate the hydrophobic/hydrophilic structure. The effects were observed for gradient structures in the range of 2-8 nm thickness. Such subsurface water, as confined in a vertical chemical gradient, might thus be exploited in future bio-medical and technical applications to obtain additional control over protein adsorption and energetics on resilient plasma polymer surfaces.

References [1] D. Hegemann, N.E. Blanchard, M. Heuberger, Plasma Process. Polym. 2016, DOI: 10.1002/ppap.201500228.

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O10-ADS _417 ELECTRONIC PROPERTIES OF SULFUR COVERED RUTHENIUM (0001) SURFACES: AN STM-DFT COMPARATIVE STUDY

ADS - Adsorption and desorption M. Pisarra 1,*, R. Bernardo Gavito 2, A. Vazquez De Parga 3, C. Díaz 1, F. Martín 1 1Chemistry Department, Universidad Autónoma de Madrid - Madrid (Spain), 2Physics Department, Lancaster University - Lancaster (United Kingdom), 3Condensed Matter Physics Department, Universidad Autónoma de Madrid - Madrid (Spain) The structural properties of Sulfur atoms adsorbed on Ruthenium(0001) surfaces (S-Ru) received a lot of interest due to the very rich phase diagram that the S- Ru system offers[1]; in fact, different ordered and disordered structure, each one characterized by a well defined surface coverage η, has been reported for S adsorbed on Ru(0001). Such a versatile interface has lately received renewed interest because of the fact that sulfur can be successfully intercalated in the Graphene/Ru(0001) interface (G-Ru). The Graphene- S-Ru system could allow a tunable intercalation with controlled quantity of S atoms in the G-Ru system, which may lead to a tunable doping of a quasi-freestanding graphene layer, as observed in the case of Silicon oxide[2]. Surprisingly, despite the thorough knowledge of the structural properties of the S-Ru system, significantly less effort have been devoted to the determination of its electronic properties; in fact, to the best of our knowledge, there is no work concerning the electronic properties of S-Ru. In this contribution, we present a comparative experimental/theoretical study of the electronic properties of sulfur adsorbed Ru(0001) surface for different values of the surface coverage. We focus our attention on the empty part of the band structure just below the vacuum level. Using a scanning tunneling microscope(STM) we are able to identify four different ordered phases formed by the S atoms on the Ru(0001) surfaces; by means of scanning tunneling spectroscopy (STS) measurements we can study the conduction band of these surfaces. The experimental spectra exhibit a striking dependence on the surface coverage, with one of the peaks dispersing with η. To investigate the origin of the revealed spectral features, we carry out density functional theory (DFT) calculation for the experimentally observed geometries. Through calculation of the projected density of states and band structure we can assign to each measured spectral peak a distinct one electron state. We find that some of the observed peaks are due to interface states generated by the substrate d bands and the sulfur 3p orbitals. Furthermore, a comparative DFT study involving Sulfur monolayers reveals that the dispersing peak is generated by a potential well state (similar to the image potential states of graphene[3]) due to the S monolayer adsorbed on the Ru surface. References [1] R. Dennert et al., Surf. Sci. 271, 1 (1992). [2] R. Larciprete et al., Nanoscale 7, 12650 (2015). [3] V. M. Silkin et al., Phys. Rev. B 80, 121408 (2009).

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P1-ADS_12 EFFECT OF HYDROGENATION OF AMORPHOUS SILICON SURFACES ON PROTEIN ADSORPTION

ADS - Adsorption and desorption L. Filali *, Y. Brahmi, J.D. Sib, D. Benlekhal, Y. Bouizem, L. Chahed University of Oran1 Ahmed Ben Bella - Oran (Algeria) We studied in this work, the adsorption of proteins on thin layers of amorphous silicon, depending on the surface conditions. We have a set of samples of sputtered silicon thin films, with different hydrogen concentration at the surface. Infrared spectroscopic analysis with the ATR method, ellipsometry and scanning electron microscopy revealed that the adsorption on the surfaces is enhanced on samples with highest hydrogen surface concentration. This result leads to the conclusion that the adsorption is caused by hydrogen bonds at the film / protein interface, which seems to be the dominant effect compared to surface roughness and wettability, which were found to decrease as hydrogen surface concentration increases.

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P2-ADS_264 ADSORPTION PROPERTIES OF ETHANOL ON GOLD DECORATED H-BN NANOMESH PREPARED ON RH(111) SURFACE

ADS - Adsorption and desorption A.P. Farkas 1,*, D. Jurdi 1, R. Gubó 2, G. Vári 2, L. Óvári 3, A. Berkó 3, J. Kiss 1, Z. Kónya 4 1University of Szeged, Department of Physical Chemistry and Materials Science - Szeged (Hungary), 2University of Szeged, Department of Applied and Environmental Chemistry - Szeged (Hungary), 3MTA - SZTE Reaction Kinetics and Surface Chemistry Research Group of the Hungarian Academy of Sciences at the University of Szeged - Szeged (Hungary), 4University of Szeged, Department of Applied and Environmental Chemistry, MTA - SZTE Reaction Kinetics and Surface Chemistry Research Group of the Hungarian Academy of Sciences at the University of Szeged - Szeged (Hungary) Self-assembly of nanostructures is at present in the focus of surface science. In this context, the epitaxial growth of ultra-thin layers of hexagonal boron nitride on transition metal surfaces has attracted a lot of attention. The h-BN/Rh(111) system has been particularly interesting, since the discovery of a self-organized superstructure of boron nitride on a Rh(111) surface by Corso et al. [1]. It displays an h-BN nanomesh, a highly corrugated superstructure, into which molecules and nanoparticles can be readily adsorbed and thus arranged on the atomic length scale [2,3]. Controlled shape and size distribution of metal nanoparticles for surface catalytic reactions are important and feasible through deposition onto the periodic surface of h-BN. In the case of gold catalysts, the most dramatic and well- known factors influencing the catalytic activity are the size and shape of the nanoparticles. In this study adsorption measurements performed in an UHV chamber equipped with facilities for Auger electron spectroscopy (AES), high-resolution electron energy loss spectroscopy (HREELS), X-ray photoelectron spectroscopy (XPS) and temperature - programmed desorption (TPD). STM, XPS and low energy ion scattering spectroscopy (LEIS) measurements were carried out to characterize the gold nanoparticles on BN/Rh(111). Our main purpose was to follow the adsorption properties of ethanol on clean and gold decorated h-BN nanomesh prepared on Rh(111). In the examined temperature range (below 600 K) we don’t have to count with the intercalation of gold, only the size and shape of metal nanoclusters can change upon heating. After low temperature adsorption, ethanol desorbed from the clean BN/Rh(111) below 250 K; however, it showed enhanced stability on gold evaporated nanomesh as it was verified by TPD results. HREEL spectroscopic measurements also indicated the presence of surface species even at 5-600 K. Presumably a small part of ethanol dissociate to hydrogen and acetaldehyde; however, in contrast to the behavior found for the substrate metal, we didn’t observe any sign of CO. The stabilization effect was more pronounced at lower gold coverage. For comparison we characterized the ethanol adsorption on the clean Au(111) surface too. References [1] M. Corso, W. Auwärter, M. Muntwiler, A. Tamai, T. Greber, J. Osterwalder, Science 303 (2014) 217. [2] Matthew C. Patterson, Bradley F. Habenicht, Richard L. Kurtz, Li Liu, Ye Xu, Phillip T. Sprunger, Phys Rev B. 89 (2014) 205423. [3] M.L. Ng, A.B. Preobrajenski A.S. Vinogradov, N. Martensson, Surf. Sci. 602 (2008) 1250.

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P3-ADS_291 ADSORPTION OF MAGNESIUM, MANGANESE AND STRONTIUM ON CALCITE STUDIED BY XPS AND AFM

ADS - Adsorption and desorption M. Ceccato *, J. Generosi, M. P. Andersson, N. Bovet, T. Hassenkam, K. Dideriksen, J.D. Rodriguez-Blanco, K.N. Dalby, S.L. S. Stipp University of Copenhagen - Copenhagen (Denmark) Calcite is one of the most common minerals in carbonate sedimentary rocks, playing a key role in both natural phenomena (e.g., biomineralisation, ocean chemistry) and industrial applications (e.g., medicine, paper production). Adsorption of ions from solution can modify its surface properties, such as wettability and affinity for organic molecules. A better understanding of the adsorption process in terms of temperature and solution concentration is thus essential for various applications, such as preventing scale in pipes, promoting remediation in contaminated soils, or manipulating biomineralisation. We investigated the adsorption of three common ions (Mg2+, Mn2+, and Sr2+) on calcite with X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The XPS analysis revealed that, at high temperature (> 40 °C), adsorption of Mg2+ and Mn2+ increases with time, while Sr2+ does not adsorb at all. This can be explained through the dehydration of the ions prior to adsorption on the calcite surface. [1] The AFM force mapping analysis showed that the adsorption of Mg2+ or Mn2+ promotes changes in calcite wettability towards a more hydrophilic surface. These results provide an insight into the interaction between a few common ions and calcite surfaces, where the extent of ions adsorption changes as a function of temperature and solution concentration. References [1] Sakuma, H., Andersson, M.P., Bechgaard, K. & Stipp, S.L.S. J. Phys. Chem. C 118, 3078-3087, (2014).

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P4-ADS_312 THE SURFACE SCIENCE OF CALCIUM CARBONATE

ADS - Adsorption and desorption T. Belete *, M. Gleeson, M.C.M. Van De Sanden, Dutch Institute for Fundamental Energy Research - Eindhoven (Netherlands)

Calcium carbonate (CaCO3) forms part of the “calcium looping cycle” (CLC) [1, 2] that is one the more promising candidates for capture of CO2 from large-scale industrial emitters. CO2 is captured from the exhaust gas in an exothermic reaction react with calcium oxide (CaO) to produce CaCO3. The CaCO3 is subsequently decomposed (calcined) at higher temperature to regenerate the CaO and produce a pure stream of CO2. The main drawbacks of the CLC are the elevated temperatures that are required for its operation and a tendency to lose CO2 carrying capacity over repeated cycles due to material sintering. The carbonation of CaO is characterized by an initial rapid uptake that is superseded by slow layer growth once a surface layer of ~50 nm has been formed [3] Fig.1. For the most rapid cycling of the loop it is the formation and decomposition of this thin outer layer that is most interesting. This intrinsically make it a “surface problem”. However, while the CLC is the focus of very active and interesting research of an applied nature, fundamental aspects of the surface processes involved on carbonation and calcination have not been extensively studied. We have commenced a program or research that is focused on the study of calcium layer under UHV conditions. The objective is to provide more insight into how CO2 interacts with CaO layers and how it is evolved from CaCO3 layers. This work is also connected with more applied studies on the decomposition of CaCO3 in a flow-reactor type setup. Furthermore the project seeks to evaluate the potential for plasma-driven conversion of CO2. We will present details of the UHV setup, its capabilities (RAIRS, TPD, Ellipsometry, Mass Spectrometry), and some preliminary results. In addition, results from the decomposition of CaCO3 in the flow-reactor will be presented. References 1. J. Blamey et al. Progress in Energy and Combustion Science, 2010. 36(2): 260-279 2. A. Martinez et al. International Journal of Greenhouse Gas Control, 2012. 7: 74-81 3. B. Arias et al. Chemical Engineering Journal, 2011. 167(1): 255-261

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P5-ADS_399 KINETIC STUDY OF THE ADSORPTION OF DYE "METHYLENE BLUE" ON ADSORBENTS SUPPORTED ON USY ZEOLITE OR (ΓAL2O3-SIO2)

ADS - Adsorption and desorption F. Bali *, O. Samia, H. Djamila Faculté de chime - Universite USTHB Bab Ezzouar - Algiers (Algeria) Numerous of industries use coloring agent, the most part are toxic on our environment. The control and the legislation on their elimination of the effluents are more and more rigorous[ 1]. A wide variety physical and chemical and biological technics was developed and tested in the effluent treatment loaded in coloring agent. Among these, the adsorption is a method spread enough and easy to implement. The active carbon is the most widely used because of its big adsorption capacity of organic material [2,3]. However, this adsorbent has high cost and rest difficult to regenerate. Our interest has focused on the development of another adsorbents less expensive synthetised with Ni or Ni/Co on an amorphous support made up of mixture of silica and alumina or on a zeolite of type faujasite HUSY of report Si/Al=3,5. . Our work concerns the kinetic study of the adsorption of the methylene blue on these adsorbents. The isotherms of adsorption were established and the parameters of the Langmuir and Freundlich equations was determined as well as the parameters thermodynamics at a constant temperature (T=300 K).The made essays showed that it is of Langmuir type and the kinetics of adsorption are perfectly adjustable in the pseudo-second order [ 4,5], with very big coefficients of regression. Finally, the parameters thermodynamics predicts an adsorption essentially of physisorption type.

References D. K. Laing, R. J. Dudley, A. W. Hartshorne, J. M. Home, R. A. Rickard and D. C. Bennett, Forensic Science International, 1991, 50, 23-35. G. M. Walker and L. R. Weatherley, Water Research, 1997, 31, 2093-2101. R.S. Juang, F.C. Wu and R.L. Ts eng, Environ. Technol., 1997, 18, 525-531. Tsai. W.T., Y.M.Chang, C.W. Lai, C.C. Lo.Adsorption of basic dyes in aqueous solution by clay adsorbent from regenerated bleaching earth. Appl. Clay Sci., 2005, 29, 149-154. Tsai W.T., H.C. Hsu , T.Yi Su, K.Yu Lin, C. Ming Lin, T.H. Dai. J. Hazard. Mater., 2007, 147, 1056-1062

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P6-ADS_372 COMPETING FORCES IN CHIRAL SURFACE CHEMISTRY: ENANTIOSPECIFICITY VERSUS ENANTIOMER DISPROPORTIONATION

ADS - Adsorption and desorption A. Gellman *, Y. Yun Carnegie Mellon University - Pittsburgh (United States of America) The enantiospecific adsorption of chiral molecules on chiral surfaces is dictated by two competing forces: the enantiospecificity of adsorption energetics and the propensity of enantiomers to disproportionate into homochiral (conglomerate) or heterochiral (racemate) clusters. These phenomena have been studied by measuring the surface enantiomeric excess, ees, of mixtures of chiral amino acids adsorbed on Cu surfaces and in equilibrium with gas phase mixtures of varying enantiomeric excess, eeg. Alanine adsorption on Cu{3,1,17}R&S surfaces is non-enantiospecific, ees = 0, because alanine enantiomers do not interact enantiospecifically with either the surface or one another [1]. Aspartic acid adsorbs enantiospecifically on the Cu{3,1,17}R&S surfaces; ees not= eeg, even during exposure to a racemic mixture in the gas phase, eeg = 0 [2]. Exposure of the achiral Cu{111} surface to non-racemic aspartic acid, eeg not= 0, results in local amplification of enantiomeric excess, |ees| > |eeg|, as a result of homochiral disproportionation [3]. Finally, in spite of the fact that the Cu{653}R&S surface are chiral, adsorption of aspartic acid mixtures is dominated by homochiral disproportionation of adsorbed enantiomers rather than enantiospecific adsorbate-surface interactions, |ees| > |eeg|. All of these types of behavior are captured by a Langmuir-like adsorption isotherm that describes competition between enantiospecific adsorption and both homochiral (conglomerate) and heterochiral (racemate) clustering of adsorbed molecules (Figure 1).

Thanks This work has been supported by the US Dept.of Energy under grant DE SC0008703. References 1. Y. Yun, D. Wei, D.S. Sholl, and A.J. Gellman, “Equilibrium adsorption of D- and L-alanine mixtures on naturally chiral Cu{3,1,17}R&S surfaces” Journal of Physical Chemistry C 118, (2014), 14957-14966 (10.1021/jp503796u) 2. Y. Yun, A.J. Gellman, “Enantioselective separation of DL-aspartic acid on naturally chiral Cu(3,1,17)R&S surfaces” Angewandte Chemie International Edition 52, (2013), 3394-3397 (10.1002/anie.201209025) 3. Y. Yun, A.J. Gellman, “Auto-amplification of enantiomeric excess on an achiral surface” Nature Chemistry 7, (2015), 520 – 525 (10.1038/NCHEM.2250)

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BSS - Band structure of surfaces

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O1-BSS _63 SPIN-RESOLVED ELECTRONIC STRUCTURE OF THE OCTAHEDRAL MOTE2 POLYTYPE

BSS - Band structure of surfaces A. Weber 1,*, N. Xu 1, S. Muff 1, M. Fanciulli 2, Z. Wang 3, A. Magrez 2, J. Mesot 2, H. Ding 4, M. Shi 1, H. Dil 2 1Swiss Light Source, Paul Scherrer Institute - Villigen (Switzerland), 2Institute of Physics, École Polytechnique Fédérale de Lausanne - Lausanne (Switzerland), 3Department of Physics, Princeton University - Princeton (United States of America), 4National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences - Beijing (China) Type II Weyl semimetals [1] provide a realization of Weyl fermion quasiparticles with broken Lorentz symmetry, for which there are is no analogue elsewhere in physics, and offer a unique avenue for exploring chiral magnetic effects. Several claims have been made recently that low-temperature octahedral (Td) polytypes of 1T'-MoTe2 are type II Weyl semimetals based on computational [2] and spectroscopic evidence. However, interpretations differ in terms of the number and location of bulk Weyl points and surface Fermi arcs in energy-momentum space. To clarify matters, we present a comprehensive investigation of Td-MoTe2 electronic structure determined from spin- and angle-resolved photoemission spectra collected over a range of photon energies, light-polarizations, and measurement geometries. We find evidence that surface and bulk states near the Fermi energy are strongly (>50%) spin-polarized, identify spin-splittings in the bulk Fermi surface of up to 0.05 Å-1, and track the variation of the Fermi arc spin-polarization with momentum over more than 12% of the Brillouin zone. Implications of the spin-spilt bulk electron- structure for magnetotransport properties and the superconducting phase of the matieral [3] will be discussed. Thanks This work was supported by the Swiss National Science Foundation. We would like to thank P. Bugnon and H. Berger of École Polytechnique Fédérale de Lausanne for assistance with sample growth and B.Q. Lv, C.E. Matt, B.B. Fu, and N.C. Plumb of Paul Scherrer Institue for synchrotron beamline support. References [1] A.A. Soluyanov, D. Gresch, Z.J. Wang, Q.S. Wu, M. Troyer, Xi Dai, and B.A. Bernevig. Nature 527 495 (2015) [2] Yan Sun, Shu-Chun Wu, M.N. Ali, C. Felser, and B. Yan. Phys. Rev. B 92, 161107(R) (2015) [3] Yanpeng Qi et al., Nature Comm. 7 11038 (2016)

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O2-BSS _68 SPIN POLARIZATION AND TIME DELAY IN PHOTOEMISSION FROM SPIN- DEGENERATE STATES

BSS - Band structure of surfaces M. Fanciulli 1,*, H. Volfová 2, S. Muff 1, J. Braun 2, H. Ebert 2, U. Heinzmann 3, J. Minár 2, H. Dil 1 1Institut de Physique, École Polytechnique Fédérale de Lausanne - Lausanne (Switzerland), 2Department of Chemistry, Ludwig Maximilian University - Munich (Germany), 3Faculty of Physics, University of Bielefeld - Bielefeld (Germany) In the photoemission process the photoelectrons can show spin polarization even if the probed initial state is spin-degenerate [1]. A possible cause is the interference of energy- degenerate outgoing partial waves in the presence of spin-orbit coupling. In particular, for the case of linearly polarized radiation where a spin transfer from the photon is not possible one finds an angular dependent spin polarization that is a function of the radial parts and phase shift of the complex matrix elements describing the two transitions l→l-1 and l→l+1 allowed by selection rules. In addition, the case of condensed matter targets is more complicated than atomic gases since the group symmetry of the energy-momentum dispersion relationship plays a role in the definition of the spin polarization [2]. Remarkably, the phase information is also intrinsically related to the time delay between the two partial waves according to the Eisenbud-Wigner-Smith relationship. Therefore, in principle, by measuring the spin polarization by means of spin- and angle-resolved photoemission spectroscopy (SARPES) one can access the phase information [3] and also make a connection to the results of the recently developed attosecond-resolved photoemission spectroscopy [4], where relative time delays between different initial states can be directly probed. This is the first systematic experimental characterization of the 3D spin polarization vector with both momentum and energy resolution by means of SARPES of the quasi-free electron-like sp-bulk- derived conduction band of a model system Cu(111) (Fig. 1(a)). In Fig. 1(b) the spin-resolved momentum distribution curve at binding energy labelled as (2) is shown as example. Several measurements have been performed by varying the sample geometry and the light energy and polarization. Similar experiments have been done for Au(111) and quasi-free standing graphene. A semi-quantitative model [5] will be discussed, together with possible future developments in the direction of a phase-resolved photoemission spectroscopy. References [1] J. Kessler, Polarized electrons 2nd edition. Berlin, Heidelberg: Springer, 142 (1985) [2] S.-W. Yu et al., Surf. sci., 416, 396 (1998) [3] U. Heinzmann and H. Dil, J. Phys. Condens. Matter, 24, 173001 (2012) [4] A. L. Cavalieri et al., Nature, 449, 1029 (2007) [5] M. Fanciulli et al., arXiv:1601.07309

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O3-BSS _217 MAGNETIC BEHAVIOR OF THIN FE FILMS GROWN ON NI/W(110) THROUGH THE FCC-BCC TRANSITION: A SPIN-POLARIZED PHOTOEMISSION STUDY

BSS - Band structure of surfaces A. Calloni *, G. Berti, G. Bussetti, M. Finazzi, F. Ciccacci, L. Duò Politecnico di Milano - Milan (Italy) The electric-field-induced switching of the magnetic behavior of nanosized Fe islands [1], or the development of a magnetic anisotropy perpendicular to the plane of thin films [2] are recent examples of peculiar phenomena related to the stabilization of out-of-equilibrium Fe phases, with potential applications in the field of information storage and spintronics. In this context, the epitaxial growth of Fe films on a Ni/W(110) substrate enables a detailed study of their transition from a pseudo-morphic fcc phase to the equilibrium bcc phase by increasing the Fe film thickness within few atomic layers [3]. Although the morphological evolution of this and similar model systems has been addressed also recently with local probes, such as scanning tunneling microscopy [4], information on the electronic structure is provided only by scattered results and a comprehensive view of its evolution with the Fe thickness is still missing. In the present work, we provide such information by means of spin-resolved photoemission spectroscopy (PES). Samples were grown by molecular beam epitaxy in ultra-high vacuum conditions, magnetized and characterized in-situ at cryogenic temperatures (down to 30 K). The surface morphology was assessed by low energy electron diffraction (LEED). Our results provide a strong evidence that ferromagnetism in this system is related to the formation of bcc-like phases even before the onset of a large scale surface restructuring, as detected by LEED. In such conditions, our choice of a Ni/W(110) substrate (with a sufficiently thin Ni layer) allows to stabilize an intermediate phase featuring a specific orientation of bcc domains which is also reflected in the sample magnetization detected by PES [5]. A continuous evolution towards a bulk-like electronic structure is then observed and interpreted as due to a progressive relaxation of a distorted bcc lattice. References [1] Gerhard et al. Phys.Rev.B 91 (2015) 184107 [2] Lee et al. Phys.Rev.B 83 (2011) 144420 [3] Johnston et al. Phys.Rev.B 55 (1996) 13221 [4] An et al. Phys.Rev.B 79 (2009) 085406 [5] Berti, Calloni et al. Rev.Sci.Instrum. 85 (2014) 73901

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O4-BSS _144 ELECTRON SPIN DYNAMICS REVEALS HALF-METALLICITY IN FE3O4 THIN FILMS

BSS - Band structure of surfaces K. Hricovini 1,*, C. Cacho 2,*, M. Battiato 3, J.M. Mariot 4, M.C. Richter 1, O. Heckmann 1, F. Parmigiani 5, H. Ebert 6, J. Minár 6 1LPMS, Université de Cergy-Pontoise - Cergy-Pontoise (France), 2Central Laser Facility, STFC, Rutherford Appleton Laboratory - Harwell Oxford (United Kingdom), 3Institute of Solid State Physics, Vienna University of Technology - Vienna (Austria), 4Laboratoire de Chimie Physique–Matière et Rayonnement, Univ. Paris 6 - Paris (France), 5CNR, Laboratorio TASC INFM - Trieste (Italy), 6LMU München - München (Germany) It is still under debate that magnetite, Fe3O4 (FO), belongs to the family of half- metals, characterized by an insulating gap for one spin state resulting in a fully spin- polarised transport at the Fermi level, which attracts a high interest for spintronic devices. In spite of intensive theoretical and experimental studies, the magnetic and electronic properties of FO remain controversial. We studied the demagnetisation process in FO by spin- and time-resolved pump-probe photoemission experiments using the third harmonic (4.65 eV) of Ti-Sapphire laser with a repetition rate of 250 kHz. For the maximum of the photoexcitation we observe a clear reduction of the spin polarisation in a region of ~200 meV around the Fermi level. At higher binding energy no variation is observed up to a 1000 fs delay indicating that the spin polarisation reduction observed comes from the electron dynamics and not from the demagnetization. The Boltzmann equation for out-of-equilibrium dynamics combined with the calculated spin-resolved electronic density-of-states fully describes the decay of the excited electrons as well as the variation of the spin polarisation, confirming the half-metallic properties of FO.

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O5-BSS _140 ENTANGLEMENT OF THE MAGNETIC AND SPIN-ORBIT ORDER IN MULTIFERROIC RASHBA SEMICONDUCTORS.

BSS - Band structure of surfaces J. Krempasky 1,*, H. Dil 2, V. Strocov 1, J. Minár 3, G. Springholz 4 1Paul Scherrer Institut - Villigen (Switzerland), 2EPFL Lausanne - Lausanne (Switzerland), 3Department of Chemistry, Ludwig Maximillian University - Munich (Germany), 45Institut fur Halbleiter-und Festkorperphysik, Johannes Kepler Universitat - Linz (Austria) Recently a giant spin splitting in GeTe ferroelectric Rashba semiconductors (FERS) was theoretically predicted [1] and experimentally verified [2, 3]. Doping of GeTe with magnetic Mn impurities, (GeMn)Te maintains the ferroelectric properties for moderate concentrations [4]. We show that multiferroic (GeMn)Te inherits from its parent ferroelectric GeTe compound a giant Rashba splitting of three- dimensional bulk states that is in marked competition with the Zeeman spin splitting induced by the magnetic exchange interactions. We give experimental evidence that (GeMn)Te is a multiferroic Rashba semiconductor (MUFERS) that combines both ferroelectric and ferromagnetic properties. Our experimental data show that the three-dimensional Rashba-type spin texture can be manipulated by external magnetic field, confirming that MUFERS is a new class of material with entangled magnetic and spin-orbit order, opening new prospectives for spintronic devices. Thanks Dr. Amina Taleb Ibrahimi, Research Director/UR1-CNRS-Synchrotron SOLEIL/Deputy Scientific Director, for discussions related to the (GeMn)Te B-field control of spin-texture at the Soleil Cassiopee beamline. References [1] Di Sante, D., Barone, P., Bertacco, R. & Picozzi, S. Electric Control of the Giant Rashba Effect in Bulk GeTe. Advanced Materials 25, 509–513 (2013). [2] Krempasky, J. et al. Giant Rashba splitting of bulk states in the ferroelectric GeTe (111)semiconductor. arXiv:1503.05004 (2015). [3] Liebmann, M. et al. Giant Rashba-Type Spin Splitting in Ferroelectric GeTe(111). AdvancedMaterials 28, 560–565 (2016). [4] Przybyli´nska, H. et al .Magnetic-Field-Induced Ferroelectric Polarization Reversal in the Multiferroic Ge1-xMnxTe Semiconductor. Phys. Rev. Lett. 112, 047202 (2014).

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O6-BSS _235 COEXISTENCE OF BI AND INBI CYSTRALS AT THE BI/INAS(111)-A INTERFACE

BSS - Band structure of surfaces L. Nicolaï 1,*, K. Hricovini 2, J.M. Mariot 3, U. Djukic 4, M.C. Richter 5, O. Heckmann 5, T. Balasubramanian 6, M. Leandersson 6, J. Sadowski 6, J. Denlinger 7, I. Vobornik 8, J. Braun 9, H. Ebert 9, J. Minár 10 1Ludwig-Maximilians-Universität, Munich, Germany/Université de Cergy-Pontoise,France/DSM- IRAMIS, Spec, Cea-Saclay, France - Munich (Germany), 2Université de Cergy- Pontoise,France/DSM-IRAMIS, Spec, Cea-Saclay, France - Cergy (France), 3LCP-MR, UPMC Université de. Paris 06/CNRS - Paris (France), 4Université de Cergy-Pontoise - Cergy (France), 5Université de Cergy-Pontoise/DSM-IRAMIS, Spec, Cea-Saclay, France - Cergy (France), 6Max- Lab, Lund University - Lund (Sweden), 7Advanced Light Source - Berkeley (United States of America), 8Elettra Synchrotrone Trieste - Basovizza (Italy), 9Ludwig-Maximilians-Universität - Munich (Germany), 10Ludwig-Maximilians-Universität, Munich, Germany/University of West Bohemia, Plzen, Czech Republic - Munich (Germany) Bi is a heavy element characterised by a strong spin-orbit coupling (SOC) and is thus a good prototype to study Rashba-split states. Furthermore, due to its strong SOC, Bi is a parent compound of well known topological insulators, such as Bi2Se3 or Bi1-xSbx, and is also theoretically predicted to exhibit non-trivial states under certain conditions[1][2]. Bi films are mainly deposited on Si(111) surface. Here we propose an alternative substrate, InAs(111). The growth of Bi on InAs(111)-A is epitaxial and a crystal of excellent quality is obtained after evaporating of about 20ML. The system was characterised by angle- resolved photoemission spectroscopy. The measurements were compared to theoretical calculations performed with the SPR-KKR package [3][4] based on the Dirac equation, thus being fully relativistic, and on the one-step model of photoemission. The theoretical analysis confirms the high quality of the Bi crystal as testified by a good agreement between measured (Fig. a) and calculated (Fig. b) Fermi surfaces. Furthermore, the circular dichroism effect observed close to the Γ point is in details reproduced by calculations. This allows us to understand the influence of the different orbitals l. However, as it can be seen from figures, some measured features, such as rings-like structures (pointed in red) remain unexplained. STM images reveal as well the presence of tetragonal clusters that can be attributed to InBi crystals. Including these structures in the theoretical calculations we can reproduce the circular dichroism exhibited by the ring-like states. References [1] M. Wada et al., PRB 83, 121310 (2011) [2] Z-Q Huang et al., PRB 88, 165301 (2013) [3] H. Ebert, D. Ködderitzsch and J. Minár, RPP 74, 096501 (2011) [4] J. Braun, RPP 59, 1267 (1996)

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O7-BSS _175 QUANTUM WELL STATES IN THIN AG FILMS GROWN ON GA/SI(111)-√3×√3 SURFACE

BSS - Band structure of surfaces S. Starfelt *, H.M. Zhang, L.S.O. Johansson Department of Engineering and Physics, Karlstad University, S-651 88 - Karlstad (Sweden) Discrete electronic energy states, referred to as Quantum Well States (QWS), formed by spatial confinement in thin films, have been studied extensively for the past thirty years due to their importance both in low dimensional physics and device applications [1]. Metal films on semiconductor substrates, such as Ag on Si, where the Ag sp-band is quantized into QWS, are examples of such systems. Recently, it was shown that the Ga/Si(111)-√3×√3 surface is a good substrate for epitaxial layer-by-layer room-temperature (RT) growth of Ag above 2 monolayers (ML) [2] Inspired by these results, we have investigated the properties of QWS in Ag thin films on the Ga/Si(111)-√3×√3 substrate. Angle-resolved photoelectron spectroscopy (ARPES) measurements using synchrotron radiation have been performed on Ag thin films formed on a Ga/Si(111)- √3×√3 surface, with a Ag nominal coverage of less than 10 ML. Measurements reveal both fully confined QWS above the bulk Si sp-band as well as resonant states below. Well defined QWS can be observed already at three ML coverage. The curvature of the QWS parabola exhibits "kinks" which represent changes in the effective mass (m*), where the QWS couple with the substrate electronic structure (Fig. 1 (a) ). There are also umklapp-mediated quantized states at the begin mathsize 12px style M with bar on top end style points of the Si Surface Brillouin Zone (Fig. 1 (b) ). In-plane effective mass below the Si sp-band was calculated by parabolic approximation for the QWS, showing an increase of m* with quantum well binding energies. The effective mass also showed a reduction with increased film thicknesses. These results open an opportunity for studying many-body effects on ultra-thin Ag films with well- defined quantum well states. Thanks Support from the MAX-lab staff is gratefully acknowledged. The project presented here was funded by the Swedish Research Council. References [1] T.-C. Chiang, Surf. Sci. Rep. 39, 181-235 (2000) [2] He J.-H., Jiang L.-Q., Qiu J.-L., Chen L., Wu K.-H., Chin. Phys. Lett. 31, 128102 (2014)

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O8-BSS _360 2D - 1D SURFACE STATE EVOLUTION USING A CURVED BI(111) SAMPLE

BSS - Band structure of surfaces J. Lobo-Checa 1,*, F. Mazzola 2, L. Barreto 3, F.M. Schiller 4, J.W. Wells 2, M. Corso 5, L.A. Miccio 4, I. Piquero-Zulaica 4, N.C. Plumb 6, P. Hofmann 3, J.E. Ortega 7 1Instituto de Ciencia de Materiales de Aragón (ICMA) and Departamento de Física de la Materia Condensada, CSIC-Universidad de Zaragoza - Zaragoza (Spain), 2Department of Physics, Norwegian University of Science and Technology (NTNU) - Trondheim (Norway), 3Department of Physics and Astronomy, Interdisciplinary Nanoscience Center (iNANO) - Aarhus (Denmark), 4Centro de Física de Materiales CSIC/UPV-EHU-Materials Physics Center, Manuel Lardizabal 5 - San Sebastian (Spain), 5Universidad del País Vasco, Dpto. Física Aplicada I; 5IKERBASQUE, Basque Foundation for Science - San Sebastian (Spain), 6Swiss Light Source, Paul-Scherrer-Institut - Villigen (Switzerland), 7Universidad del País Vasco, Dpto. Física Aplicada I - San Sebastian (Spain) Bismuth is a semimetal whose surface shows better metal behaviour than its bulk counterpart due to the presence of metallic-like surface states. These are spin-split given its large atomic weight and spin orbit interaction [1]. Depending on the crystal termination these states behave as two dimensional (2D), delocalized states, or one dimensional (1D), localized states [2]. Such modification of the electron wavefunction is induced by the presence of step arrays, by repulsive scattering at steps and confinement within terraces [3] and has been widely explored for Shockley states in noble metals [3-5]. Semimetals have not received such a widespread attention but the investigation of this 2D to 1D transition is particularly interesting since Bi is very close to being a topological insulator and great interest has emerged in topologically guaranteed 1D surface states. We present a study that finely explores the 2D to 1D surface states transition in Bismuth using a curved crystal (cf. Fermi surfaces in Figure). Such special samples allows for a smooth variation of the surface orientation, which translates into a smooth variation of the step separation, i.e. the step potential barriers. The evolution of the electronic structure is investigated by state-of-the-art ARPES and correlated to the local structure obtained from STM and LEED. We find that unreconstructed single bilayer height terraces stabilize these one-dimensional states. Moreover, we observed the existence of coherent 1D edge states which are delocalized across the terrace length in spite of the absence of topological protection. They hold similar characteristics of quantum spin hall states and can help realizing electronic transport via edge channels, essential for future spintronic devices. Thanks We acknowledge Johan Adell, European Light Source Activities program (CALIPSO), the Spanish Ministry of Economy (MAT2013-46593- C6-4-P), the Basque Government (IT621- 13) and the Spanish Research Council (CSIC-201560I022). References 1. Ph. Hofmann, Prog. In Surf. Sci. 81,191 (2006). 2. J. W. Wells et al., Phys. Rev. Lett., 102, 096802 (2009). 3. L. Bürgi et al., Phys. Rev. Lett. 81, 5370 (1998). 4. J. E. Ortega et al., Phys. Rev. B 87, 115425 (2013). 5. J. Lobo-Checa et al., Phys. Rev. B, 84, 245419 (2011).

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CAT - Catalysis under ideal and real conditions

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I22_CAT_433 SINGLE ATOM CATALYSIS: AN ATOMIC-SCALE VIEW

CAT - Catalysis under ideal and real conditions G. Parkinson * Institute of Applied Physics, TU Wien - Vienna (Austria) Single atom catalysis is a rapidly emerging but controversial area of catalysis research that aims to maximize the efficient usage of precious metals through the use of single atom active sites [1]. Although catalytic activity has been demonstrated for several single atom catalyst systems, the inability to accurately characterize a catalyst based on single atom active sites ensures that that the field remains controversial, and little is really known about how a single atom adsorbed on a metal oxide support can catalyze a chemical reaction. In this lecture, I will describe how we are addressing the crucial issues of stability and reaction mechanism using a surface science approach. The work is based on the magnetite (001) surface, which exhibits an unusual reconstruction based on subsurface cation vacancies [2]. A remarkable property of this reconstruction is that it stabilizes ordered arrays of metal adatoms (of almost any variety) with a nearest neighbor distance of 0.84 nm to temperatures as high as 700 K [3]. Crucially, because the geometry of the adatoms is uniform and precisely known, reactivity experiments are performed on a well-defined model system, and theoretical calculations can be performed to shed light on the mechanisms underlying catalytic activity and deactivation. Several examples of our recent work will be used to illustrate the trends we have discovered to date, including how strong CO adsorption destabilizes Pd and Pt adatoms leading to mobility and rapid sintering [4], and how extraction of lattice oxygen from the metal-oxide is central to catalytic activity in the CO oxidation reaction [5]. References [1] X.-F. Yang, A. Wang, B. Qiao, J. Li, J. Liu, T. Zhang, Single-Atom Catalysts: A New Frontier in Heterogeneous Catalysis, Accounts of Chemical Research 46 (2013) 1740-1748. [2] R. Bliem, E. McDermott, P. Ferstl, M. Setvin, O. Gamba, J. Pavelec, M.A. Schneider, M. Schmid, U. Diebold, P. Blaha, L. Hammer, G.S. Parkinson, Subsurface Cation Vacancy Stabilization of the Magnetite (001) Surface, Science 346 (2014) 1215-1218. [3] G.S. Parkinson, Iron Oxide Surfaces, Surface Science Reports http://dx.doi.org/10.1016/j.surfrep.2016.02.001 (2016). [4] G.S. Parkinson, Z. Novotny, G. Argentero, M. Schmid, J. Pavelec, R. Kosak, P. Blaha, U. Diebold, Carbon Monoxide-Induced Adatom Sintering in a Pd–Fe3O4 Model Catalyst, Nature Materials 12 (2013) 724-728. [5] R. Bliem, J. van der Hoeven, A. Zavodny, O. Gamba, J. Pavelec, P.E. de Jongh, M. Schmid, U. Diebold, G.S. Parkinson, An Atomic-Scale View of CO and H2 Oxidation on a Pt/Fe3O4 Model Catalyst, Angewandte Chemie International Edition 54 (2015) 13999–14002.

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O1-CAT _308 AMMONIA OXIDATION ON PALLADIUM: IN OPERANDO STUDY

CAT - Catalysis under ideal and real conditions A. Resta *, A. Vlad, A. Coati, Y. Garreau Synchrotron SOLEIL - Gif-Sur-Yvette (France) Over the past decades, thanks to conventional surface science techniques, was collected an impressive body of information concerning structural and electronic properties, molecular dynamics and processes of surfaces. However, industrial applications use catalyst with broad characteristics and working at ambient or high pressures, whereas fundamental studies are often performed on model catalysts under UHV, resulting in the so-called “pressure gap” and “material gap”. X-ray scattering techniques under grazing incidence are powerful probes for the structural study of the nanoparticles and/or single crystal surface under realistic conditions. A new environmental setup to try to bridge over those gaps it is now available at SIXS beamline at Soleil. As case study I will report on the ammonia oxidation performed at 0.3Bar. Industrially ammonia is used for nitrates' production, which are used in many fields from paints to fertilizers. The system exhibits three competing reactions; the possibility to select the desired reaction path is of high interest for the industry [1]. Earlier studies select palladium as one of the most active catalysts for this reaction [2-3] and recent theoretical papers [4] address the metal state as the most active phase for ammonia dehydrogenation, nevertheless experimental evidences for the active phase in the ammonia oxidation need to be provided. The data presented concern Pd(100) single crystal and 15nm palladium particles with the aim to establish a correlation between surface structure and reactivity. The Figure panels contain the production rate (A) (molecules produced per unit of time) for three reactions products and intensities ratio between Pd(111) and PdO(110) (B) reflections collected during a temperature scan from 500 to 800 K and back. As a first result, the data indicate a change in the reaction products from nitrogen (N2) to nitrogen oxide (NO) in coincidence with decreasing of the metallic palladium signal. This suggests that on the metallic particles the ammonia is transformed to nitrogen while on oxidized particles is transformed into NO.

References 1) Applied catalyst B, 18 (1998) Issues 1–2, pp 1 2) Russian Chem. Rev., 45 (1976) pp 1119, 3) Catalysis Letters 78 (2002) pp 353 4) Applied Surface Science 292 (2014) pp 494

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O2-CAT _311 HIGH-PRESSURE SCANNING TUNNELING MICROSCOPY DURING HYDRODESULFURIZATION CATALYSIS

CAT - Catalysis under ideal and real conditions R. Mom 1,*, J.W.M. Frenken 2, I.M.N. Groot 3 1Huygens-Kamerlingh Onnes Laboratory - Leiden (Netherlands), 2Advanced Research Center for Nanolithography - Leiden (Netherlands), 3Gorlaeus Laboratories - Leiden (Netherlands) Many catalysts show reversible physical and chemical changes during operation. To capture these changes, in situ studies at elevated temperatures and pressures are essential. Using a home-built high-pressure scanning tunneling microscope1 we have studied reversible changes during the hydrodesulfurization reaction, in which sulfur is removed from hydrocarbons.

CxHyS + H2 --> CxHy + H2S

To mimic the industrial catalyst, MoS2 nanoparticles were deposited on Au(111). We have studied the surface dynamics of this model catalyst during the conversion of CH3SH to CH4 in 1 bar of various CH3SH/H2 mixtures at temperatures up to 250°C. From our observations, it is clear that the atomic arrangement of the active sites, located on the particle edges, depends on the gas environment. Using simulated STM images2, we identify these atomic arrangements. By comparison to ab initio thermodynamics calculations, we show that the sulfur coverage of the active sites during catalysis is higher than expected for equilibrium conditions. We show that this can be explained by the high energy barrier required for the removal of sulfur atoms from the edge sites.

References 1. C.T. Herbschleb et al., Rev.Sci.Instr. 85 (2014) 083703 2. J.V. Lauritsen et al., Journal of Catalysis 221 (2004) 510–522

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O3-CAT _254 AN ATTEMPT TO FINALLY DETERMINE THE ACTIVE PHASE FOR CO OXIDATION OVER PD AND RH

CAT - Catalysis under ideal and real conditions J. Gustafson 1,*, C. Zhang 1, M. Shipilin 1, L.R. Merte 1, O. Balmes 2, A. Schaefer 1, B. Hagman 1, M. Jankowski 1, S. Blomberg 1, J. Zetterberg 1, J. Zhou 1, E. Lundgren 1 1Lund University - Lund (Sweden), 2MAX IV Laboratory - Lund (Sweden) There is, since about 15 years, a debate going on concerning the active phase of Pt group metals for CO oxidation [see for instance refs 1-4]. Several studies have shown that the activity increases dramatically in conjunction with the formation of a (surface) oxide phase, while others have concluded that the active phase is metallic. The core of the disagreement is that most studies have concentrated on the activation rather than extinction but a higher activity is needed in order to activate the catalyst than to keep it active and phases may form during high activity, which are not the most active. Figure 1 shows in situ SXRD results from CO oxidation over Rh(111), which has been activated, and the temperature is lowered slowly in order to follow the extinction. Panel A show the mass spectrometry signal of CO2, and B shows the SXRD surface oxide signal. Three significant points are marked with vertical lines. The surface oxide signal drops throughout the measurements, but at point I, the drop becomes steeper, indicating that something has happened to the surface. After this point the activity shows some oscillations, but mainly stays high. At point II, the SXRD intensity seems gone, and the surface is metallic. The activity is still high, but the oscillations are stronger. Finally at point III, the activity drops suddenly. The fact that the oxide signal drops and disappears before the extinction of the catalyst shows that the metallic surface is more active than the oxide. We have repeated similar measurements on Pd(100), which is different to Rh since the PdO(101) surface exposes undercoordinated Pd atoms, where CO can adsorb. Any effects from this difference will be discussed in the presentation. References 1. H. Over, et al., Science 287, 1474 (2000). 2. F. Gao, et al., J. Phys. Chem. C 113, 174 (2009), J. Phys. Chem. C 114, 6874 (2010). 3. R. van Rijn et al., J. Phys. Chem. C 114, 6875 (2010), Phys. Chem. Chem. Phys. 13, 13167 (2011). 4. J. Gustafson, et al., Phys. Rev. B 78, 045423 (2008), Catalysis Today, 145, 227, (2009)

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O4-CAT _157 IN SITU STUDY OF THE CO OXIDATION ON PT-ZN NANOPARTICLES WITH AMBIENT-PRESSURE X-RAY PHOTOELECTRON SPECTROSCOPY

CAT - Catalysis under ideal and real conditions A. Boucly 1,*, A. Naitabdi 1,*, R. Fagiewicz 1, G. Olivieri 1, F. Bournel 1, J.J. Gallet 1, H. Tissot 1, R. Benbalagh 1, M. Silly 2, F. Sirotty 2, F. Rochet 1 1Université Pierre et Marie Curie, Sorbonne Universités, Laboratoire de Chimie Physique Matière et Rayonnement, UMR 7614, 11, rue Pierre et Marie Curie, 75005 Paris - Paris (France), 2Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, 91192 Gif sur Yvette - Paris (France) The investigation of nanocatalysts under their realistic conditions of pressures and temperatures represents a real strategy toward a deeper understanding of their chemical state and reactivity. Additionally, the reduction of Pt load in the catalysts while maintaining their optimum performances is essential for large scale practical applications. Here, we show that small PtZn bimetallic nanoparticles (NPs) supported on the surface of rutile TiO2(110)- (1×1) can be prepared by a two steps deposition process where Pt was deposited first and Zn afterwards. Moreover, in situ Synchrotron-based Ambient Pressure Photoemission Spectroscopy (AP- XPS) experiments were used to monitor the evolution of the oxidation states and real-time CO oxidation reaction of pure Pt, Zn and Pt-Zn NPs under high pressure (1 mbar) exposure 1 to O2 and CO. Simultaneous monitoring of the chemical composition at the surface and in the near-surface gas phase, revealed the onset temperature of the CO oxidation reaction and the chemical state of the active material in both pure Pt and PtZn NPs at 1:4 CO:O2 partial pressure ratio. The formation of Pt surface oxide was evidenced in both pure Pt and PtZn NPs. While a sizeable encapsulation of pure Pt NPs by TiOx was seen after annealing at 440 K under 1 mbar of O2, no such effect was noticed for PtZn NPs. The formation of a zinc oxide layer on PtZn NPs enhances the stability of PtZn NPs. In addition, we found that the deposition of Zn leads to a substantial modification of the electronic properties of the 3+ TiO2(110), particularly the formation of Ti states that should enhance the electronic conductivity of this surface. Spontaneous formation of a Pt-Zn alloy phase at room temperature was seen in PtZn NPs. References 1 A. Naitabdi, R. Fagiewicz, A. Boucly, et al. Topics in Catalysis , volume: 59, pages 550-563, (2016)

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O5-CAT _165 DECOMPOSITION OF METHANOL ON AU-RH BIMETALLIC NANOCLUSTERS ON A THIN FILM OF AL2O3/NIAL(100)

CAT - Catalysis under ideal and real conditions M. Luo *, H. Lee *, Z.H. Liao, P.W. Hsu, T.C. Hung National Central University - Taoyuan (Taiwan, republic of china) Decomposition of methanol on Au-Rh bimetallic nanoclusters, grown by sequential deposition of Au and Rh evaporated onto thin-film Al2O3/NiAl(100) at 300 K, was studied with various surface probe techniques including STM, RHEED, TPD, IRAS and synchrotron- based PES. The bimetallic nanoclusters, with mean diameter < 3.0 nm and height < 1.0 nm, were structurally ordered, had a fcc phase and grew with their facets (001) parallel to the θ- Al2O3(100) surface. Although Au preferentially decorated the surface of the bimetallic clusters, the surface comprised both Au and Rh, despite the order of metal deposition. The decomposition of methanol adsorbed on the bimetallic clusters proceeded through only dehydrogenation, and the reaction occurred primarily on the surface Rh. The CO and hydrogen produced from dehydrogenated methanol increased in general with the extent of Rh sites, whereas the production per surface Rh, the reactivity, depended on the surface structure and composition of the bimetallic clusters. For the clusters formed by Au deposited onto Rh clusters (first Rh and then Au), the production decreased dramatically at first with decreasing Rh sites, deposition of Au, but the rate declined at greater Au coverage; in contrast, for the clusters formed by metal deposition of reverse order (Rh onto Au clusters), the production increased evidently with the Rh sites in the beginning, but reached a saturation at greater Rh coverage. On reactive small Rh clusters (diameter < 1.3 nm), the production decreased linearly with decreasing Rh sites (deposition of Au). The results imply that the Rh sites on the bimetallic clusters are not equally reactive. We shall discuss the possibly reactive Rh sites and the origin of the reactivity in this report.

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O6-CAT _90 ADSORPTION AND TRANSFORMATIONS OF ETHANOL OVER CERIA BASED MODEL CATALYSTS

CAT - Catalysis under ideal and real conditions Z. Pászti *, O. Hakkel, G.P. Szíjjártó Research Centre for Natural Sciences, Hungarian Academy of Sciences - Budapest (Hungary) Demands of the transition towards a hydrogen-based energy economy require intense research for catalysts tailored for hydrogen energy applications including reforming catalysts. Current results indicate that highly efficient noble metal free reforming catalysts can be developed around Ni as the key ingredient, but since a delicate balance between different surface functionalities is needed for suppression of unwanted side reactions, use of carefully selected supports as well as doping with further metal or oxide components is unavoidable. In order to elucidate the interplay of the support and the active metal in ethanol steam reforming, model catalysts were developed by growing Ni particles onto epitaxial CeO2 films deposited on CaF2-buffered Si(111). In this contribution a detailed study of the adsorption behaviour of ethanol and other stable compounds thought to be important in ethanol steam reforming (acetaldehyde, acetic acid, water) carried out on the model catalysts by photoelectron spectroscopy will be presented.

Low temperature molecular ethanol adsorbates on CeO2(111) transform into ethoxy moieties around 200 K along with considerable desorption and surface reduction. Upon annealing above room temperature, the UPS spectra reveal a gradual change in the electronic structure of the remaining adsorbates towards that of acetaldehyde. On heavily reduced CeO2 stronger interaction resulting in pronounced dissociation and more stable adsorbates are seen. The presence of Ni complicates the adsorption behaviour as slowly proceeding decomposition of ethoxy and formation of hydrocarbon-like or graphitic species are evident even at room temperature. At elevated temperatures this transformation becomes faster, accompanied by only limited desorption. Above 470 K only graphitic surface carbon species can be identified; complete carbon removal accompanied by heavy reduction of the ceria requires temperatures as high as 620 K.

The surface adsorbates behave very similarly if the ethoxy-covered Ni/CeO2 surface is annealed in water vapour. The main difference with respect to the vacuum annealing is that the cerium oxide becomes reduced to a much smaller extent and is covered by hydroxyl groups, while no oxidation of the Ni occurs, demonstrating that water plays an important role in stabilizing the oxidation state of the catalyst at working temperature. Thanks This project has been partly supported by the National Development Agency (Hungary), grant No. KTIA_AIK_12-1-2012-0014. Financial support by the National Scientific Research Grant (Hungary), grant No. K100793 (Zoltán Pászti) is gratefully acknowledged.

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O7-CAT _126 MODEL CU/AU CATALYTIC SURFACES FOR COUPLED DEHYDROGENATION/HYDROGENATION REACTIONS

CAT - Catalysis under ideal and real conditions F. Grillo *, R. Megginson, C.J. Baddeley EaStCHEM School of Chemistry - University of St Andrews - St Andrews (United Kingdom) Supported Au can operate as a catalyst for furfural hydrogenation to furfuryl alcohol with a very high selectivity [1], however the high activation barrier for H2 dissociative adsorption limits the rate of hydrogenation. A way to supply reactive hydrogen to the system is its generation in situ via a parallel dehydrogenation reaction [2]. Hydrogen-free hydrogenation of nitrobenzene coupled with butan-2-ol dehydrogenation over supported Cu has been successfully demonstrated [3]. These suggest the possibility of using bimetallic Cu/Au systems as catalysts for coupled dehydrogenation/hydrogenation reactions. In this study, a making prototype butan-2-ol/furfural system is investigated with the focus being on the characterisation of the adsorption behaviour of each molecular species as functions of surface morphology and composition of the Cu/Au system. STM studies show that 2D Cu particles nucleate at specific places within the Au(111) herringbone reconstruction elbows [4]. In the high coverage regime, ordered Cu-Au surface alloys are characterised by regular successions of distinct Cu and Au rows. The adsorption of furfural and butan-2-ol have been investigated with TPD and HREELS on Cu(111), Au(111) and on Cu/Au(111) surfaces, at different Cu loadings. The nature of the adsorbed species has been found to be strongly dependent on both surface composition and morphology. Thanks The Engineering and Physical Sciences Research Council (EPSRC) is acknowledged for funding (EP/M029077/1). References [1] M. Li, Y. Hao, F. Cárdenas-Lizana, M. A. Keane, Catal. Commun. 2015, 69, 119 – 122. [2] A. Javaid, C. S. Bildea, Chem. Eng. & Technol. 2014, 37, 1515 – 1524. [3] M. Li, Y. Hao, F. Cárdenas-Lizana, H. H. P. Yiu, M. A. Keane, Top. Catal. 2015, 58, 149 – 158. [4] F. Grillo, H. Früchtl, S. M. Francis, N. V. Richardson, New J. Phys. 2011, 13, 013044.

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P1-CAT_6 PREPARATION OF NANOMETER COFE2O4 BY CO-PRECIPITATION USING DIFFERENT PRECIPITANTS AND ITS CHARACTERIZATION

CAT - Catalysis under ideal and real conditions L. Meddour-Boukhobza 1,*, Y. Hammiche-Bellal 1,*, A. Djadoun 2, N. Henda 3, A. Hassanine 3, F. Merneche 4, M. Sennour 5, M.H. Berger 5, A. Meddour 5, A. Auroux 6 1Faculté de Chimie, USTHB, Babezzouar - Alger (Algeria), 2Laboratoire de Géophysique, Fstgat, USTHB, Babezzouar - Alger (Algeria), 3Dcemp, Credec, Rue de Ouled Fayet - Alger (Algeria), 4Udec, Crnd, Comena, Rue Sébala, Draria - Alger (Algeria), 5Mat, Centre des Matériaux, MINES-ParisTech, - Paris (France), 6Cnrs, Université Claude Bernard, - Lyon (France) This work is devoted to the investigation of the influence of the preparation process on the physical–chemical properties of a cobalt ferrite spinel applied. Samples of CoFe2O4 mixed oxide belonging to the inverted spinel type structure have been obtained by co-precipitation method using chloride, nitrate and citrate precursor procedures at 70°C. The obtained materials are calcined at 500°C. The bulk catalysts were characterized by ATG/ATD, FTIR, XRD, MEB, TEM-EDX, BET and TPR. In this work it is demonstrated that the chemical synthesis affect the crystal properties and cation distribution in the spinel structure, microstructure, surface area and reducibility; which are among the most relevant physical chemical properties for the catalytic activity. The infrared spectra of precursors, based on co-precipitated chloride salts at 70 ° C shows the presence of common bands at about 3500 cm -1, 1380 and 1632 cm-1 related to different water molecules of the vibration modes physisorbed adsorbed to the surface of solids. These bands are wider for the oxalate based precursor since the formed salt is in hydrate form . The EDX analysis shows that the catalysts are composed only of the elements cobalt, iron and oxygen, no impurity was detected. However, atomic percentages were determined only in one point, which does not reflect the average stoichiometry of each sample. Thanks We thank Aline Auroux for analysis TPR and the team of the School of Mines of Paris: Marie- Hélène Berger, Mohamed Sennour and Abdennour Meddour for MET / EDAX analysis. References Y. Hammiche-Bellal, A. Benadda, L. Meddour-Boukhobza, S. Barama, A. Djadoun, A. Barama, Catal. Commun. 42 (2013) 62–67.

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P2-CAT_9 PHOTO-OXIDATION ACTIVITIES DEPENDING ON METAL-DOPED TIO2 NANOPARTICLES

CAT - Catalysis under ideal and real conditions H. Lee * Sookmyung Women's University - Seoul (Korea, republic of) The reduction of the band gap to the visible range was investigated with reference to the surface distortion of anatase TiO2 nanoparticles induced by varying Fe doping concentrations. Fe-doped TiO2 nanoparticles (Fe@TiO2) were synthesized by a hydrothermal method and analyzed by various surface analysis techniques such as transmission electron microscopy, Raman spectroscopy, X-ray diffraction, scanning transmission X-ray microscopy, and high-resolution photoemission spectroscopy. We observed that The Ti3+ sites act as an electron trap sites to deliver the electron to O2 as well as introduce the dopants level inside the band gap, resulting in a significant increase in the photocatalytic oxidation reaction of thiol (–SH) of 2-aminothiophenol to sulfonic acid (– SO3H) under ultraviolet and visible light illumination.

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P3-CAT_65 PHENOL PEROXIDE OXIDATION OVER FE-FSM-16

CAT - Catalysis under ideal and real conditions K. Chellal 1,*, F. Sadi 1, K. Bachari 2 1Universityof Science an d Technology Houari Boumediène. Faculty of Chemistry - Algiers (Algeria), 2Centre de Recherche Scientifique et Technique en Analyses Physico-Chimiques (C.R.A.P.C.) - Algiers (Algeria) 1 Introduction Fe-FSM-16 with a Si/Fe ratio equal to 60 have been synthesized by microwave- hydrothermal (M-H) process and characterized by chemical analysis, XRD and N2 adsorption measurements and tested in the phenol hydroxylation and catalytic wet peroxide oxidation (CWPO) under mild reaction conditions (1atm, 313K). 2 Results The characterisation by several techniques of materials prepared by microwave- hydrothermal synthesis has shown that several iron species could be identified at the surface of the pore walls of the mesoporous silica. The surface area and pore volume of the Fe-FSM-16 are lower than those reported for FSM- 16 materials prepared by conventional-hydrothermal synthesis; this can be explained by the fact that the pore walls of the Fe-FSM-16 prepared by microwave-hydrothermal (M-H) process are thicker than those prepared by the conventional hydrothermal synthesis [1]. The X-ray powder diffraction patterns of these materials showed three peaks indexed as (1 0 0), (1 1 0) and (2 0 0) reflections in the range of 2θ=2-5°, which are corresponding to the well ordered hexagonal mesoporous structure. At the same time, small peaks corresponding to α-Fe2O3 (hematite form) appeared in the 10-80° (2θ) range. 3 Conclusion The catalytic test show that iron incorporated mesoporous materials can efficiently catalyse the oxidation of phenol in water in mild reaction conditions using hydrogen peroxide as an oxidant. In the phenol hydroxylation, Fe-FSM-16 has shown high catalytic activity and selectivity to dihydroxybenzene. Using a molar ratio phenol: H2O2 = 1:2 at 313 K, hydroquinone (HQ) was found to be the predominant product (CAT/HQ = 0.4). The slow decomposition of H2O2 is due probably to the softer operating conditions. The temperature up to 353 K is beneficial for the hydroxylation of phenol due to the rapid decomposition of H2O2 [2]. However, higher reaction temperatures may result in tar formation due to the side reaction of benzoquinone oxidation [3]. References [1] K. Bachari, R.M. Guerroudj, M. Lamouchi. Mater . Chem. Physic. 124 (2010) 994. [2] K.M. Parida, S. Mallick. J. Mol. Catal. A: Chem. 124 (2008) 104 [3] C.B. Liu, Z. Zhao, X.G. Yang, X.K. Ye, Y. Wu. Chem. Commun. (1996) 1019.

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P4-CAT_81 VARYING THE DEGREE OF REDUCTION OF CERIA LAYERS BY ANION DOPING WITH FLUORINE

CAT - Catalysis under ideal and real conditions M. Kettner 1,*, K. Ševcíková 2, Z. Rafaj 1, V. Nehasil 1 1Department of Surface and Plasma Science, Charles University in Prague - Prague (Czech republic), 2Material Science Beamline, Elettra Sincrotrone Trieste - Trieste (Italy)

CeO2 or so-called ceria is widely used material in the field of catalysis. The range of application varies from the three-way catalysis in car catalysts to utilization in wastewater treatments [1] or in fuel cells [2]. Cerium oxide is employed due to its capability to change its oxidation state reversibly between Ce4+ and Ce3+ without transforming its structure. Therefore, ceria serves as an oxygen buffer layer, which provides oxygen in oxygen-lean conditions and accepts oxygen during its excess. Reduction of the ceria substrate influences also the active metals on top causing a charge transfer and, in this way, altering the chemical properties of the catalyst [3]. From other point of view, fluorine lately showed to be quite a common pollutant in the ceria [4]. We prepared the fluorine doped ceria by exposing it in HF vapors prior the inserting into the evaporator that we use for preparing the cerium oxide layers. As a substrate, we use the Rh (111) single crystal. We examined the influence of fluorine on the electronic structure and morphology of the cerium oxy-fluorite. We observed and evaluated a strong influence on the shape of Ce 3d spectra measured by X-ray Photoelectron Spectroscopy. As it seems, the presence of fluorine changes also the growth mode of the ceria layers from 2D layer to 3D island growth. The Low Electron Energy Diffraction showed disruption of the regular CeO2 pattern induced by fluorine. We also studied the impact of fluorine dopants on chemical properties of cerium layers and, especially, on the ability of ceria to change its 4+ degree of reduction (i.e. the amount of Ce ions) after the exposures with O2 and H2 gases. We observed no substantial change in this reduction ability between fluorine-free and fluorine-doped cerium oxide layers under the ultrahigh vacuum conditions, but the overall concentration of Ce4+ ions was much lower in the case of fluorine-doped samples. Thus, anion doping with fluorine seems to be a promising way for intentional modification of the reduction level of cerium oxide layers without affecting its oxygen-storage capabilities. Thanks The research was supported by the Charles University in Prague, project GA UK No. 897316. References [1] A. Trovarelli, et al., Catal. Today. 50 (1999) 353–367. [2] R. Fiala, et al., Catal. Today. 240 (2015) 236–241. [3] G. Pacchioni, Phys. Chem. Chem. Phys. 15 (2013) 1737. [4] H.H. Pieper, et al., Phys. Chem. Chem. Phys. 14 (2012) 15361.

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P5-CAT_142 SYNCHROTRON-RADIATION-INDUCED FORMATION OF SURFACE OXIDES ON AG(111) IN A HIGH-PRESSURE FLOW REACTOR.

CAT - Catalysis under ideal and real conditions M. Mirolo 1,*, M. Jankowski 1,*, A. Leone 1, Y. Birkhölzer 2, K. Hofhuis 2, H. Isern 1, R. Felici 1, J. Drnec 1, H. Wormeester 2 1ESRF - The European Synchrotron - Grenoble (France), 2University of Twente - Twente (Netherlands) Formation of surface oxides on Ag(111) has been studied with operando surface x-ray diffraction (SXRD). We report the rapid oxidation of the Ag(111) surface at near atmospheric oxygen pressure induced by the x-ray beam. The initial surface oxidation results in formation of epitaxial layers of surface oxides with 4x4 and 7x7 structure, and domains of silver oxide with 7x7 structure azimuthally rotated relative to the substrate. Subsequently, prolonged oxidation leads to the growth of thick Ag2O bulk oxide and continuous roughening of the surface. These results show that structure, growth rate and stability of surface oxides on Ag(111) formed during operando SXRD experiments does not only depend on the oxygen pressure and temperature but the main cause of the rapid surface oxidation is an exposure to te synchrotron x-ray beam.

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P6-CAT_169 DISSOCIATION OF WATER MOLECULES ON CLEAVED GAN(1-100)

CAT - Catalysis under ideal and real conditions M. Luo *, Y.Y. Hsia * National Central University - Taoyuan (Taiwan, republic of china) The dissociation of water molecules adsorbed on a cleaved non-polar GaN(1-100) surface was studied with synchrotron-based photoelectron spectroscopy (PES), X-ray absorption spectroscopy (XAS), and calculations with density-functional-theory (DFT). Use of semiconductors as a catalyst to dissociate water attracts interests for years because the reaction can serve as a potential clean source of hydrogen. GaN is of interest because of its tremendous carrier-photon transfer properties that have been widely used for optoelectronics. The band gap tunable from the ultraviolet to the near-infrared region makes possible utilizing the full solar spectrum. The theoretical calculations even indicated that the dissociative adsorption of H2O on the non-polar GaN(1-100) surface can occur at room temperature. Our results show that the adsorbed water molecules dissociated into hydrogen atoms (H) and hydroxyl groups (OH) at either 300 or 130 K, which implies a negligible activation energy (smaller than 11 eV) for the dissociation. The H and OH were bonded to the surface nitrogen and gallium on GaN(1-100) respectively. The bonding configuration of N-H bond was also found according to the XAS spectra. These results highlight promising applications of the non-polar GaN(1-100) surface in water dissociation and the generation of hydrogen.

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P7-CAT_262 SURFACE CHARACTERIZATION OF SUPPORTED CATALYSTS.

CAT - Catalysis under ideal and real conditions V. D'anna *, C. Michel, S. Philippe ENS-Lyon (France) Nowadays, an important portion of industrial processes involves the use of a catalyst. There are several reasons behind the choice of a catalytic reaction; few examples are the improvement of the reaction rate, the reduction of the energy investment to perform the reaction, the purity of the product obtained. The supported catalysts are largely used since they combine the advantages of homogeneous and heterogeneous catalysts. In a supported catalyst the active species is anchored on a support, that can be inert or catalytically active. In any case, the support should bound the active centers and disperse them, allowing to easily separate the catalyst from the reaction products. The surface characterization of supported catalysts is of crucial importance since it provides information regarding the structure of the active species, giving hints for improving the catalyst. Several methods of analysis are exploited to study these kinds of system; due to their complexity, often combinations of several methods are required. In this work two examples of supported catalysts composed by metal complexes anchored on insulator surfaces are considered. The first example is the Ziegler-Natta polymerization catalyst[1,2]; the second is inherent to the reaction of metathesis of olefins[3]. Figure 1 represents the the model chosen to study the Ziegler-Natta catalyst. In both cases atomic-level studies are performed at the Density Functional Theory (DFT) level, using both periodic and cluster, tuned according to the kind of system and the observables computed. The theoretical results will be tightly compared with the experiment (as NMR), in order to both validate the model and interpret the experimental data. References [1] L. Lyod, Handbook of Industrial Catalysts, Springer, 2011, ch. 8 [2] E. Albizzati, U. Giannini, G. Collina, L. Noristi and L. Resconi, Catalysis and polymerizations, in Popypropylene Handbook, ed. E. P.J. Moore, Hanser-Gardner Publications. Cincinnati, OH, 1996, ch. 2 [3] K. Ivin, H. Mol, In Olefin Metathesis and Metathesis Polymerization, Eds. Academic Press: London, 1997

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ELC - Electrochemistry at surfaces

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O1-ELC_426 THE GITSAXS-BASED STUDY OF OPERANDO AL ANODIZATION

ELC - Electrochemistry at surfaces N. Vinogradov 1,*, F. Carlà 2, J. Evertsson 1, L. Rullik 1, R. Felici 3, E. Lundgren 1 1Lund University - Lund (Sweden), 2ESRF - Grenoble (France), 3SPIN-CNR - Rome (Italy) For their fascinating properties, nanoporous materials are of high demand in the various industrial processes and academic research. Nanoporous anodic aluminium oxide (NP- AAO) is a very special case of such materials, due to the remarkably narrow pore size distribution, self-ordering of the pores and giant aspect ratios of those, developed under certain anodization conditions. For these properties NP-AAO are vastly used as templates and supports/carriers in engineering various types of hierarchical materials. As of now, a general understanding of Al anodization process has been developed. This resulted in a number of empirically-derived formulae relating the anodization parameters, such as anodization time, voltage, electrolyte type, etc. to the structure and properties of the anodic oxide. However, this knowledge has been based mostly on the scanning electron microscopy (SEM) studies of the NP-AAO performed ex-situ. However, using this approach the changes in sample structure can only be related post-factum to the variation of the anodization conditions. This significantly complicates studying of dynamical processes in NP-AAO and may lead to uncertainties in results interpretation. Here we present a different approach to the problem. Making use of high penetration ability of hard X-rays, we were able to observe a striking evolution of the X-ray scattering pattern, generated by growing NP-AAO film, in operando. The clear changes in this pattern arise from the changes in the NP-AAO, and the structural parameters of the latter can be easily calculated at any stage of anodization, with high precision. Using this approach we have performed a comparative study of NP-AAO structural parameters evolution upon anodization with three most common electrolytes. Our approach is neither limited to aluminum only, nor to studying porous structures solely, but can be applied to a number of other elements and materials.

Fig.1 Experiment schematics and typical scattering pattern. X-rays that impinge on the sample surface at a grazing incidence (>0.5 deg), are scattered by the electron density variation (pore- electrolyte interfaces) and captured by the detector. Analysis of the scattering pattern allows for determination of the structural parameters of the pores: pore separation L, pore diameter D, and pore height H.

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O2-ELC_74 ACTIVE SITES OF NITROGEN-DOPED CARBON MATERIALS FOR OXYGEN REDUCTION REACTION

ELC - Electrochemistry at surfaces J. Nakamura *, D. Guo *, T. Kondo University of Tsukuba - Tsukuba (Japan) Nitrogen-doped carbon materials exhibit high electrocatalytic activity for the oxygen reduction reaction (ORR), which is essential for several renewable energy systems. However, the ORR active site(s) is unclear, which retards further developments of high- performance catalysts. We have conclusively characterized the ORR active site by using newly designed graphite (HOPG) model catalysts with well-defined π-conjugation and well- controlled doping of nitrogen species [1]. As shown in Fig.1, the ORR active site is created by pyridinic N, while graphitic N-doped HOPG surfaces show no catalytic activity for ORR. CO2 adsorption experiments indicated that pyridinic N also creates Lewis basic sites. The specific activities per pyridinic N in the HOPG model catalysts are comparable with those of N-doped graphene powder catalysts. It is thus concluded that the ORR active sites in nitrogen-doped carbon materials are carbon atoms with Lewis basicity next to pyridinic N. We have further examined the local electronic structure of the pyridinic N-doped HOPG surface by scanning tunneling spectroscopy (STS). As a result, a non-bonding pz state or edge state was observed by STS in the vicinity of the nitrogen atom, which is ascribed to the origin of the ORR activity.

Thanks This study is partially supported by JST PRESTO and NEDO projects. References [1] D. Guo, R. Shibuyaa, C. Akiba, S. Saji, T. Kondo, J. Nakamura, Science , 351 (2016)1,361.

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I02_ELC_435 ELECTROCATALYSTS AND "ANTI-ELECTROCATALYSTS" FOR ENERGY APPLICATIONS

ELC - Electrochemistry at surfaces A. Bandarenka * Physics of Energy Conversion and Storage - ECS, Physik-Department, Technische Universität München - Garching (Germany) Electrocatalysis will play an increasingly important role to overcome challenges associated with efficient generation and conversion of so-called “solar fuels”. The catalytic properties of the electrode surface are primarily determined by its electronic structure, which, in turn, influences adsorption and desorption of reaction intermediates. It is well known through the Sabatier principle that the ideal catalytic surface sites should neither bind them too strongly nor too weakly. Indeed, the strength of the binding of an adsorbed species to the catalytic centers has been shown to play a key role in the activity of electrocatalysts, as activation energies for elementary surface reactions are strongly correlated with the adsorption energies. In many cases it is possible to optimize the binding energies of the adsorbed intermediates by changing the atomic composition and/or structure at the catalytic sites. For instance, the common way of improving the activity of metal electrodes is a modification of the electronic properties of the surface through alloying it with other metals. One can distinguish approaches which are based on “bulk”, “sub-surface” and “surface” alloying. Additionally, introduction of specific (often quasi-periodic) defects can also result in a drastic increase in the catalyst activity. In the presentation, examples will be given of how the above- mentioned approaches can be used to design active surfaces rationally; and how the model electrodes can help in better understanding of the performance of electrocatalytic systems. While for the fuel cells, electrolysers, metal air batteries and many other energy conversion and storage devices the design of the most active electrocatalysts is one of the primary tasks, many batteries (which use the phenomenon of intercalation) and supercapacitors require the electrode surfaces and systems in which no catalytic reactions should take place. For instance, in aqueous Na-ion batteries in order to extend the operational potential window, the oxygen evolution reaction and hydrogen evolution reactions at the electrode surfaces must be prohibited. It can be done by several ways. One can optimize the electrolyte composition. Namely, it is important to identify inhibitors (molecules or ions), which adsorb at the surface and selectively poison the catalytic centers, but do not interrupt intercalation and de-intercalation of cations. Another approach would involve the development of the thinnest possible layers of a non-active material which can still conduct cations. Finally, one can identify an electrode material which is both inactive towards the side reactions and good in terms of intercalation properties. A set of various approaches aiming to suppress side electrocatalytic reactions in many energy storage devices can be arbitrarily called “anti-electrocatalysis”. In the presentation, several examples involving electrode materials for Na-ion batteries operating in aqueous media will be presented.

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I25_ELC_436 ADVANCING OXYGEN ELECTROREDUCTION ON THE BASIS OF MODEL INVESTIGATIONS OF PT-ALLOY SURFACES

ELC - Electrochemistry at surfaces I.E.L. Stephens * Technical University of Denmark (DTU), Department of Physics (Denmark) Low temperature fuel cells, could provide a potentially zero emission source of power for automotive vehicles. However, they are limited by the slow kinetics of oxygen reduction. High loadings of platinum are required to catalyse the reaction; its short supply limits the extent to which fuel cell technology could be scaled up. The most widely used strategy to decrease the Pt loading is to enhance the catalytic activity of Pt by alloying it with late transition metals, in particular Ni or Co. However, these materials typically degrade via dealloying. At our laboratory, we have developed a different class of oxygen reduction catalyst: alloys of Pt with rare earths, including Y and Gd. The strong interaction between Pt and the rare earth elements should make these compounds inherently less prone towards dealloying. These catalysts exhibit high activity, both on extended surfaces and in the nanoparticulate form.[1-3] Our efforts are now aimed towards the large scale synthesis of these catalysts, so that they can be implemented in fuel cells and tested for their long term stability. It turns out that that both the activity and stability are a function of the bulk Pt-Pt distance. Bulk compression brings about a strain onto the pure Pt overlayer. Thus changing the rare earth element provides us with a lever to control the catalytic performance, via the “lanthanide contraction”. [4] We have investigated well defined Pt-rare earth alloy catalysts in the form of mass-selected nanoparticles,[3] smooth polycrystalline surfaces[1,2,4] and single crystals.[5] Our studies incorporate electrochemical measurements, ultra-high vacuum based surface science methods, electron microscopy, synchrotron-based X-ray spectroscopy and density functional theory calculations. References [1] J. Greeley, I.E.L. Stephens, A.S. Bondarenko, T.P. Johansson, H.A. Hansen, T.F. Jaramillo, J. Rossmeisl, I. Chorkendorff, J.K. Nørskov, Nature Chemistry, 1 (2009) 552-556. [2] I.E.L. Stephens, A.S. Bondarenko, U. Gronbjerg, J. Rossmeisl, I. Chorkendorff, Energy & Environmental Science, 5 (2012) 6744-6762. [3] P. Hernandez-Fernandez, F. Masini, D.N. McCarthy, C.E. Strebel, D. Friebel, D. Deiana, P. Malacrida, A. Nierhoff, A. Bodin, A.M. Wise, J.H. Nielsen, T.W. Hansen, A. Nilsson, I.E.L. Stephens, I. Chorkendorff Nature Chemistry, 6 (2014) 732-738. [4] M. Escudero Escribano, P. Malacrida, M.H. Hansen, U.G. Vej-Hansen, A. Velazquez-Palenzuela, V. Tripkovic, J. Schiøtz, J. Rossmeisl, I.E.L. Stephens, I. Chorkendorff, Science, 352 (2016) 73-76. [5] Pedersen, A. F., Ulrikkeholm, E. T., Escudero-Escribano, M., Johannson, T. P., Malacrida, P., Pedersen, C. M., Hansen, M. H., Jensen, K. D., Rossmeisl, J., Friebel, D., Nilsson, A., Chorkendorff,I., Stephens, I. E. L. Nano Energy (2016) in press.

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O3-ELC_365 COUPLING BETWEEN ELECTROCHEMISTRY AND SURFACE X-RAY DIFFRACTION FOR A MULTISCALE ANALYSIS OF THE PD/M(111°)-H SYSTEM (M=PT,AU)

ELC - Electrochemistry at surfaces Y. Soldo-Olivier 1,*, M. De Santis 1, L. Wang 2, B. Previdello 2, E. Sibert 2 1Institut Néel - CNRS - Grenoble (France), 2LEPMI - Grenoble (France) Palladium presents remarkable properties as a catalyst for hydrogen dissociation and is characterized by a high insertion/desorption kinetic. Compared to bulk Pd, the nanometric size of ultra-thin films is expected to induce deep modifications on the thermodynamic properties. This is the case for Pd nanoparticles, which present reduced hydrogen solubility. In order to get a thorough comprehension of the mechanisms governing the hydrogen insertion into Pd ultra-thin films, we have studied the influence of the film nanometric size and of the substrate on the electrochemical isotherms. In our approach, the global behavior of this electrochemical system (macroscopic characterization) is elucidated by its structural characterization at the atomic scale. For Pd/Pt(111) and Pd/Au(111) films of different equivalent thicknesses up to about 20 monolayers, the original behavior of the different thermodynamic parameters, like the maximal hydrogen insertion rate, has been pointed out. The large effect of the substrate has been revealed, as well. Thanks to the powerful approach coupling electrochemistry with in situ Surface X-ray Diffraction, we have been able to give a deep insight into the strong relationship between the detailed description at the atomic level of the films structure and the corresponding isotherms behavior. In particular, we propose a model where the hydrogen insertion rate into the Pd deposit is deeply correlated with the film constraints induced by the substrate.

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O4-ELC_315 OPERANDO SXRD OF E-ALD DEPOSITED SULPHIDES ULTRA-THIN FILMS: CRYSTALLITE STRAIN AND SIZE.

ELC - Electrochemistry at surfaces A. Giaccherini 1,*, F. Carlà 2, M. Giordano 3, I. Massimo 1, F. Roberto 4, D.B. Francesco 5 1Department of chemistry - Università degli Studi di Firenze (Italy), 2ESRF (Italy), 3IGG - CNR (Italy), 4SPIN - CNR (Italy), 5Department of earth sciences - Università degli Studi di Firenze (Italy) In the last year scientific community manifested a growing interest for cheaper, more productive and greener methods of deposition for highly ordered ultra-thin films and 2D structures. Electrochemical Atomic Layer Deposition (E-ALD), exploiting surface limited electrodeposition of atomic layers, proved to be easily implemented to deposit such systems. Among the first technologically interesting materials deposited by means of E-ALD are chalcogenides such as CdSe and CdTe thin-films. On the other hand, toxicity and shortage of the involved elements, must be considered. Hence scientific community is focusing attention on new compounds based on economic and low-environmental impact elements such as Cu, Sn, Fe and Zn. In particular, quaternary semiconducting materials based on the kesterite (Cu2ZnSnS4) mineral structure are the most promising candidates to overtake the current generation of light-absorbing materials for thin-film solar cells. On this ground, an assesment of the structural ordering and growth mechanism investigation on ultra-thin films of Cu, Zn and Cd bearing sulphides has been performed by means of SXRD. The experiments were performed at ESRF (Grenoble) and focused on Cu2S, CuxZnyS and CuxZnyS/CdS ultra-thin films on the Ag(111) crystal plane. The growth of the films were monitored by following the evolution of the Bragg peaks after a certain number of E-ALD steps. Pseudo single crystal pattern emerges for each film and in some cases a powder pattern can also be obtained. Usually, after the Bragg reflections are observed for the first time, only minor changes of the structural arrangement are registered for the pseudo single crystal patterns. Breadth and profile analysis of the Bragg peaks lead to a qualitative interpretation of the growth mechanism, in the normal and in-plane directions, with respect to the Ag surface. Namely, the contribution of crystallite’s strain and size were identified in the width of the Bragg reflections. The crystal structure of the electro-deposited Cu2S phase, identified in the three films, could be related to that of chalcocite, in particular considering the layering of triangular Cu sites and octahedral Cu sites. Eventually, the influence of the applied electric potential on the stability of the electro-deposited crystal structure has been monitored by means of SXRD measurements performed during the switch off of the potential. A structural change was, in fact, registered, and correlated to the occurrence of the stable phases under conventional laboratory conditions.

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O5-ELC_202 ELECTROCHEMICAL LAYER BY LAYER DEPOSITION: AN IN-SITU SXRD STUDY

ELC - Electrochemistry at surfaces F. Carlà 1,*, A. Magrini 2, R. Felici 3 1ESRF - Grenoble (France), 2Universita degli Studi di Firenze - Firenze (Italy), 3SPIN-CNR - Roma (Italy) The electrochemical synthesis of thin films of semiconductor materials with well defined crystalline structure and physical properties has been attempted using different approaches during the past. Among the methods developed, the Electrochemical Atomic Layer Deposition (EC-ALD) [1] seems to be an extremely promising as it allows for a strict control on film thickness and composition. The EC-ALD method is based on the alternate Under Potential Deposition (UPD) of different elements. UPD is a surface limited phenomenon and in electrochemical environment can be easily exploited for the sequential deposition of elemental layers which leads to the layer by layer growth of thin films of compounds on single crystal substrates. The method has been demonstrated very effective for the production of thin films of semiconductor compounds with high grade of crystallinity by post- growth Surface X-ray Diffraction experiments. Even if it's well established that the sequential deposition of UPD layers results in an ordered multilayer structure many aspects of the growth process are not clear yet. It appears in fact that several experimental parameters such as substrate structure, chemical environment and applied potential may affect the mechanism of the ECALE growth [2]. In this contribution we will report the results of a series of in-situ Surface X-ray Diffraction (SXRD) experiments devoted to the investigation of the ECALE deposition of CdS multilayers on Ag(111). The experiments were carried on the ID03 beamline at ESRF (Grenoble) using electrochemical flow cell specifically designed for this purpose. In-situ experiments allowed to record the structural changes of the in-plane order and details of the out-of-plane relaxation of the film during the growth. Moreover the dependency of the epitaxial order on the potential used for the UPD deposition process was also observed. References 1. B. W. Gregory et al. , J. Electroanal. Chem. 300, 543 (1991) 2. F. Carla' et al., J. Phys. Chem. C 12, 6132 (2014)

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O6-ELC_309 ELECTROCHEMICAL MODIFICATION OF INDIUM PHOSPHIDE INDUCED BY IONIC BOMBARDMENT

ELC - Electrochemistry at surfaces D. Aureau *, A.M. Gonçalves, A. Etcheberry Institut Lavoisier-UMR 8180 CNRS-UVSQ - Versailles (France) When XPS profiling of crystalline materials by ionic bombardment is performed, a peak broadening is generally observed. In case of alloys, changes in the atomic ratios may also appear. These effects can be interpreted as the appearance of disorder in a crystalline structure and a preferential etching. The purpose of this work is to study in detail the effects of monoatomic projectiles and clusters on indium phosphide. The objective here is the correlation between XPS and interfacial electrochemistry. Such approach allows to know the overall change in the properties of the electrode induced by various bombings and therefore highlights the limits of interpretations in XPS profiling study and the possible reorganizations when delivered to the air. Deoxidized InP has typical and reproducible electrochemical signatures, both in the darkness and under illumination where a photocurrent appears at a specific potential whose intensity is directly proportional to the incident photon flux. Modifications of the electrode could be followed by its electrochemical behavior during for hydrogen evolution leading to the cathodic decomposition of the material (appearance of metallic indium). After monoatomic bombardment, indium enrichment (figure 1) and electrochemical modification are observed. The photocurrent is no longer detectable, showing formation of a film hiding the semiconductor. The Mott-Schottky plot strongly flattens over the entire potential gap of InP. Nyquist plots also show (Figure 2) an increase in the charge transfer resistance at the open circuit potential. Using cluster of thousands of atoms of argon (lower energy per atom) allows better control of the induced modifications and a regime where the characteristics of the semiconductor can be retrieved by anodic dissolution.

Figure 1: Evolution of the atomic percentage of indium and phosphorus during abrasion (argon ions, 180 s, 4 keV). inset: P2p spectra before and after bombardment.

Figure 2: Nyquist plots before and after bombardment.

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O7-ELC_323 UNDERSTANDING CORROSION INHIBITION WITH DFT METHODS: THE CASE OF BENZOTRIAZOLE

ELC - Electrochemistry at surfaces C. Gattinoni * University College London - London (United Kingdom) The adsorption of benzotriazole (BTAH), an effective corrosion inhibitor for copper, has been a matter of debate for more than sixty years. The use of computer simulation approaches based on density functional theory (DFT) has allowed us to establish the nature of BTAH adsorption on copper and copper oxide, and to contribute to explain its efficacy as an inhibitor. The atomistic understanding of the processes underlying corrosion and corrosion inhibition is of paramount importance towards the treatment of this undesirable and costly process. In particular, the development of novel, improved organic molecule based inhibitors depends on understanding the corrosion reduction mechanism of current ones. Benzotriazole is the most widely used and studied corrosion inhibitor for copper, and a molecule of great industrial relevance. However, conflicting experimental results have been obtained over the years regarding its adsorption mechanism on metal and oxide surfaces. In this work, the systems formed by intact and dissociated BTAH molecules on Cu(111) and Cu2O(111) have been determined and linked to their inhibiting properties. Moreover, simulated NEXAFS and XPS spectra directly link the proposed DFT-calculated structures to experimental data. It is found1 that hydrogen bonding, van der Waals interactions and steric repulsions all contribute in shaping how BTAH molecules adsorb, with flat-lying structures preferred at low coverage and upright configurations preferred at high coverage. The interaction of dissociated benzotriazole (BTA) with the copper and oxide surfaces is instead dominated by strong chemisorption via the azole moiety with the aid of copper adatoms. Structures of dimers or chains are found to be the most stable structures at all coverages, in good agreement with STM, NEXAFS and XPS experimental results. Benzotriazole thus shows a complex phase behaviour in which van der Waals forces play an important role, and which depends on coverage and on its protonation state and all of these factors feasibly contribute to its effectiveness as a corrosion inhibitor. The importance of external conditions when dealing with complex oxide surfaces is also highlighted, via the use of ab initio thermodynamics. The adsorbed complexes were found to be strongly dependent on external factors, e.g. on the O2 partial pressure. Indeed, different pressure conditions lead to strikingly different adsorption structure and adsorption energies. The strong dependence of BTAH and BTA adsorption structures on environmental factors also explain the wide range of results from experiments performed under different conditions. References C. Gattinoni and A. Michaelides, Faraday Discuss., 180, 439 (2015)

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O8-ELC_128 A NEW PROBE OF THE ELECTROCHEMICAL INTERFACE: SURFACE MAGNETISM

ELC - Electrochemistry at surfaces F. Maroun *, N. Tournerie *, A. Engelhardt, P. Allongue Physique de la Matière Condensée, CNRS, Ecole Polytechnique - Palaiseau (France) In this presentation, we present a new method to probe electrode surface chemistry and double layer structure at the electrochemical interface [1]. This method is based on the high sensitivity of the magnetism to the surface chemistry of magnetic electrodes. For this purpose, we designed a new setup where the magnetic properties (magnetization amplitude and orientation) can be measured in-situ on electrodes in an electrochemical flow cell. The measurement time resolution is ~0.5 s and its sensitivity is a small fraction of chemically modified electrode surface. In this presentation, we will give several examples in the case of Co/Au(111) electrodes showing the insights into the electrochemical interface provided by this powerful probe. In the first example, we probe the adsorption of CO on Co. Since CO adsorption induce a 90° change of the magnetization orientation of the Co electrode, the CO adsorption kinetic could be measured as shown in the plot of the Figure below. We will also show that this probe is sensitive to the initial step of Co oxidation in alkaline electrolytes [2]. In the second example, we demonstrate that the magnetic properties are strongly modified by the hydrogen evolution reaction (HER) at CO- covered Co electrodes. We exploit this correlation to study the HER reaction mechanism. In the third example, we take advantage of the sensitivity of this probe to the electric field present at the electrochemical interface to unravel the structure of the double layer at H- and CO-covered Co electrodes (see drawing below) [3]. References [1] N Tournerie, A Engelhardt, F Maroun, and P Allongue, Surf. Sci. 631 (2015) 88. [2] N Di, J Kubal, Z Zeng, J Greeley, F Maroun, and P Allongue, Appl. Phys. Lett. 106 (2015) 122405. [3] N Tournerie, A P Engelhardt, F Maroun, and P Allongue, Phys. Rev. B 86 (2012) 104434.

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O9-ELC_227 STRUCTURAL DYNAMICS OF METAL DEPOSITION ON AU(111) ELECTRODE

ELC - Electrochemistry at surfaces M. Nakamura 1,*, T. Banzai 1, Y. Maehata 1, H. Tajiri 2, O. Sakata 3, N. Hoshi 1 1Chiba University (Japan), 2Japan Synchrotron Radiation Research Institute (Japan), 3National Institute for Materials Science (Japan) Underpotential deposition (upd) of metal cations has been investigated by using scanning tunneling microscopy, X-ray diffraction and spectroscopic techniques because the understanding of upd processes is useful for fundamental research as an initial model of metal deposition. The understanding of transient structure is also necessary to elucidate deposition/dissolution processes. In this study, deposition process of various metal cations on Au(111) was studied by using time resolved X-ray diffraction and time resolved infrared spectroscopy. Transient structures of metal cations in the electrical double layer were captured by time resolved techniques. X-ray diffraction measurements were performed with a multi-axis diffractometer at BL13XU (SPring-8). Diffracted X-ray was counted by the multichannel scaler synchronized with the function generator [1]. The upd metal used were Ag+, Cu2+, and Bi3+. After the potential is stepped from non-upd potential to upd potential, the CTR intensity between Bragg peaks is reduced because of the interference between the Au substrate and the upd layer. However, the intensity between Bragg peaks increases within a few ms and then decreases over the next 200 - 400 ms in Cu2+ and Bi3+ containing solutions. Structural analysis was performed from time-resolved measurements at the peak positions along the CTR. Intensity increase at the initial step suggests the presence of the outer layer species in the electrical double layer, and we assigned to the hydrated metal ion. During Cu2+ and Bi3+ deposition, hydrated metal cations approach to the outer layer and then metal ions are deposited on Au(111) with the destruction of hydration shell. References [1] M. Nakamura, H. Kaminaga, O. Endo, H. Tajiri, O. Sakata, N. Hoshi, J. Phys. Chem. C, 118, 22136 (2014).

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P1-ELC_127 IN VITRO ELECTROCHEMICAL AND ANTIBACTERIAL PERFORMANCE OF P(ACRYLIC ACID-CO- 2-ETHYLHEXYL ACRYLATE)/SILICA NANOHYBRIDS

ELC - Electrochemistry at surfaces M. Mohamadpour Nazarabady *, G.A. Farzi * Department of Materials and Polymer Engineering, Faculty of Engineering, Hakim Sabzevari University - , Sabzevar (Iran, islamic republic of) A facile one-pot synthesis for the preparation of acrylate copolymers/silica nanohybrids particles is described, see Figure 1. This can be effectively accomplished through a simultaneous radical polymerization of acrylic monomers and sol-gel process of silica precursor. Silane coupling agents, 3- methacryloxy propyltrimethoxysilane (γ-MPS) and 3- aminopropyltriethoxysilane (APTS), here also serve to enhance chemically linking as revealed by Fourier transform infrared spectroscopy, X-ray diffractometer and scanning electron microscopy and is beneficial to electrical communication, leading to the formation of well-defined nanohybrids. The prepared nanomaterial showed the electrochemical discrimination as a result of polymer/silica rational conjunction in their nanostructures. Moreover, the result of plate- counting method reveals the effective antibacterial properties of the nanohybrids. Thus, it can be concluded that the present method is simple and holds potential for electroanalytical and antibacterial applications. Keywords: P(acrylic acid-co- 2-ethylhexyl acrylate)/silica, Nanohybrids, One-pot synthesis, Antibacterial activity, Electrochemical analysis.

Figure 1. Schematic of the procedure for preparation of P(acrylic acid-co- 2-ethylhexyl acrylate)/silica nanohybrids.

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P2-ELC_136 IN-SITU STUDIES OF THE LITHIUM INCORPORATION INTO SILICON AS AN LITHIUM-ION BATTERY MODEL SYSTEM

ELC - Electrochemistry at surfaces B. Seidlhofer 1,*, B. Jerliu 2, E. Hüger 2, M. Trapp 1,*, S. Risse 1, A. Ronneburg 1, H. Schmidt 2, R. Steitz 1, M. Ballauff 1 1Helmholtz-Zentrum Berlin für Materialien und Energie GmbH - Berlin (Germany), 2Technische Universität Clausthal - Clausthal-Zellerfeld (Germany) Lithium-ion batteries are widely developed and used as rechargeable power sources for several portable devices but will also be essential in the field of automotive transportation. For the latter improvements in cycling and life time, driving range, power density, safety and costs are required. The limiting factors of these properties are the processes taking place at the electrodes during lithiation. Therefore their investigation and the determination of lithiation kinetics and pathways are essential. In situ neutron reflectivity studies are ideally suited to investigate the processes occuring during cycling directly at the electrode/electrolyte interface. With this method it is possible to monitor the concentration gradient of lithium and the volume changes inside of the working electrode and to gain important information on the lithiation/delithiation mechanisms and kinetics.1 Measurements were performed using a three electrode electrochemical cell setup with a crystalline silicon working electrode. Counter and reference electrode were composed of pure lithium. A liquid electrolyte and a housing made of high density polyethylene were used. Crystalline silicon was chosen as negative electrode material as it provides a very simple and well suited model system. In situ investigations of the lithiation/delithiation processes of this battery model system indicate that a lithium concentration gradient is formed during cycling in an interfacial zone with total thickness of about 500 Å (Figure 1) and an amount of Li ions of about x ~ 2.5 in LixSi next to the silicon electrode. After the first cycle a rest amount of Li rich material remains adjacent to the silicon electrode (x ~ 1.1 in LixSi).The total thickness of the lithiated phase increases to about 900 Å after the second lithiation. Moreover, a solid electrolyte interface is formed and dissolved during the entire cycling. The findings indicate an irreversible degradation of the silicon electrode. Further in- operando measurements are shown and discussed in the context of lithiation mechanisms and kinetics with unprecedented spatial and temporal resolution.

References 1 B. Jerliu, L. Dörrer, E. Hüger, G. Borchardt, R. Steitz, U. Geckle, V. Oberst, M. Bruns, O. Schneider, H. Schmidt, Phys. Chem. Chem. Phys. 2013, 15, 7777.

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P3-ELC_205 ELECTROLESS DEPOSITION OF NANOSTRUCTURES ON MICROPATTERNED SUBSTRATES: FROM NANOWIRES TO NANOPORES

ELC - Electrochemistry at surfaces A. Ellsworth 1,*, A. Walker 2,* 1University of Texas at Dallas, Department of Chemistry - Richardson (United States of America), 2University of Texas at Dallas, Department of Chemistry, Department of Materials Science & Engineering - Richardson (United States of America) One of the most significant challenges in nanoscience is the precise placement and orientation of nano-objects in situ over the mesoscale on technologically relevant substrates. Electroless deposition on micropatterned substrates (ENDOM) allows for the simultaneous synthesis and placement of a variety of nano-objects in a fast, flexible, parallel, and highly controllable method. These nano-objects have a wide range of applications from electronics to sensing. The shape of the deposit is controlled by the substrate pattern, resulting in nanowires (width <100 nm) which can follow arbitrary shapes such as around a right angle bend or in an arc. The width of the nanowire can be precisely controlled by monitoring the deposition time, leading to the formation of mesowires (100 nm < width < ~3000 nm) at intermediate times, and at later times nanopores and nanochannels. We have observed that the nanostructure adhesion to the surface is dependent upon the reagent concentrations within the deposition bath. For example in Cu ENDOM, upon reduction of the triethanolamine (complexing agent and buffer) concentration, nanowires no longer adhere strongly to the substrate and can be transferred to other substrates, such as silicon and poly(methyl methacrylate). The ENDOM process can also be used to create more complex nanostructures. We have demonstrated the synthesis of crossbar nanowire structures over large areas (millimeters) in parallel in as few as 6 steps.

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P4-ELC_288 ELECTROCHEMICAL STUDY OF A COPPER SEED-LAYER DISSOLUTION FOR 3D INTERCONNECTIONS

ELC - Electrochemistry at surfaces E. Delbos 1,*, H. El Belghiti 1,*, A.M. Gonçalves 2, M. Bouttemy 2, A. Etcheberry 2 1KMG Ultra Pure Chemicals - Saint-Fromond (France), 2Institut Lavoisier de Versailles - Versailles (France) In microelectronic area, the interconnections between different microprocessor levels are currently made by 3D contacts from Damascene (nanometric scale) or Through Silicon Vias (TSV) (micrometric scale) processes. These trenches or vias are filled by copper electrodeposition to ensure a performing electrical transfer. From these processes, the substrates are constituted by a silicon wafer, where the contact cavities are etched (mainly by the Bosch process). Then, a silicon oxide is generated to create a dielectric component. A diffusion barrier is next deposited by PVC, CVD or ALD process to provide the copper diffusion throughout the silicon substrate, followed by a copper seed-layer made also classically by a physical process. Thanks to this copper seed-layer, electrochemical deposition can be used as fast method to fill the cavities. Several parameters govern the electrodeposition [1,2], as the bath chemical composition, the applied current density or potential, the nature of the substrate… and it is necessary to well understand the nucleation-growth mechanisms to guarantee free-defect fillings. One of scientific key points is the determination of the seed-layer evolution during its immersion in the plating bath, just before the application of a current density or a potential. Therefore the aim of this study is to determine the behaviour of the seed-layer by electrochemical methods: open circuit potential tracking and evolution of the copper content on the sample surface by quartz crystal microbalance [3]. The copper bath is mainly constituted by copper sulphate and sulphuric acid. So, experiments were done both in the copper bath (with and without the addition of organic additives) and in H2SO4 solution [4]. The sample surfaces were characterised by SEM-EDS analyses before and after immersion. To complement the study, some experiments using atomic adsorption spectroscopy were performed to determine the variation of the copper content in solution, to confirm the dissolution of the seed-layer. References [1] E. Delbos, L. Omnès, A. Etcheberry, Copper electrodeposition parameters optimization for through- silicon vias filling, ECS Trans., 25-38, 109, (2010) [2] E. Delbos, L. Omnès, A. Etcheberry, Bottom-up filling optimization for efficient TSV metallization, Microelectronic Engineering, 514-516, 87(3), (2010) [3] A.G. Zelinsky, B.Ya. Pirogov, O.A. Yurjev, Open circuit potential transients and electrochemical quartz crystal microgravimetry measurements of dissolution of copper in acidic sulfate solutions, Corrosion Science,1083-1093, 46, (2004) [4] D.K.Y. Wong, B.A.W. Coller and D.R. MacFarlane, A kinetic model for the dissolution mechanism of copper in acidic sulfate solutions, Electrochimica Acta, Vol. 38, No. 14,2121-2127, 38 (14), (1993)

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P5-ELC_307 ELECTROLEACHING PROCESS, TECHNIQUE IMPROVED BY ADDITION OF NANOPARTICLES

ELC - Electrochemistry at surfaces N. Sabba *, M. Taleb USTHB - Bab Ezzouar (Algeria) This work has concerned the study of the effectiveness of electroleaching process applied in batch using selective membrane, for the treatment of five synthetic solution of pure hues of different colors and for real discharge painting water from (ENAP / Algeria). Its efficiency is evaluated by measurement of indicators of pollution, concentration and COD (for the actual discharge). This process was developed to overcome the disadvantages of industrial water treatment technologies. Electroleaching is very efficient in the removal of heavy metals, suspended particles, and organic matter. To improve this process, we have introduced a nonopaticles into solution. Parametric study was followed including: pH of the medium concentration of the pollutant load processing time, current density on the electrochemical treatment process.

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P6-ELC_376 EFFECT OF TEMPERATURE ON THE CORROSION BEHAVIOUR OF ZN AND ZN- 0.2AL ALLOY IN 3% NACL

ELC - Electrochemistry at surfaces S. Moussaoui 1,*, A. Benchettara 2 1Laboratoire d’Electrochimie Corrosion -Métallurgie et Chimie Minérale, Faculté de Chimie BP32 El Alia Bab Ezzouar 16111 - Boumerdes (Algeria), 2Laboratoire d’Electrochimie Corrosion -Métallurgie et Chimie Minérale, Faculté de Chimie BP32 El Alia Bab Ezzouar 16111 - Bab Ezzouar (Algeria) Iron and steel of buried pipe lines in maritime structures is exposed at a severe corrosion. To avoid this problem, cathodic protection with sacrificial anodes is generally used, in order to shift corrosion potential of the materials towards cathodic values and make them cathodically protected. Zinc remains the most widely adopted anode materiel for cathodic protection in the conductive environments [1- 3]. The behaviour of Zn and Zn-0.2Al alloy sacrificial anodes was studied, in 3% NaCl solution at different temperatures (15, 25, 35 and 45°C), by the electrochemical techniques such as potentiodynamic polarization and linear polarization resistance. The results obtained, by potentiodynamic polarization, show that the addition of 0.2 wt % in Al to Zn pure slowed down the corrosion current value at different temperature. With the method of linear polarization resistance, it reveals a substantial improvement of the charge transfer resistance for zinc-aluminium alloy with respect to pure zinc. These results show that Zn-0.2Al alloy shows a better corrosion resistance at different temperature. Thanks Thank you for allowing us to participate in this scientific pole References [1] Bounoughaz M., Salhi E., Benzine K. and Dalard F., J. Mater. Sci., 38 (2003) 1139. [2] Rabiot D., Dalard F., Rameau J.-J. and Boyer S., J. Appl. Electrochem., 29 (1999) 541. [3] Marder A.R., Prog. Mater. Sci., 45 (2000) 191.

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P7-ELC_403 PHOTO-ELECTROCHEMICAL STUDY OF: ANTIMONY DOPED SNO2 FILM/ CHROMATE SOLUTION

ELC - Electrochemistry at surfaces H. Ali *, R. Outemzabet, M. Trari, R. Brahimi University of Sciences and Technology Houari Boumediene - Algiers (Algeria) Tin dioxide SnO2 is a widely used material in various fields of applications because of its special properties. It is found in the design of gas sensors, photovoltaic cells dye-based nanocrystalline. It has been used as electrodes in solar cells and fuel cells, liquid crystal displays, infrared reflectors, plasma display panels (PDPs), transistors, etc .... [1]. In addition, SnO2 has environmental friendly characteristics and it is chemically stable and low cost. When doped with antimony (ATO), indium (ITO) or fluorine (FTO), it behaves like a metal. The Sb doping generates free electrons, responsible of the enhanced transport properties. The main objective of this work is to correlate the structural properties with the electrochemical and photo-electrochemical behavior of pure and doped thin layers of tin dioxide. The layers were developed by the CVD method (chemical vapor deposition) in the configuration of a horizontal reactor then characterized by X-ray diffraction and SEM analysis. The results indicate a rutile phase and a growth of pyramidal grains. Firstly we show that material properties are strongly influenced by their microstructures such as texture and crystallography. To study the phenomena of interfaces and to better understand the processes involved, we characterize the layers deposited on various substrates by electrochemical techniques such as electrochemical impedance spectroscopy (EIS) and Mott Schottky C-2 (V) [2] in the second part. In this study, we found that antimony doped tin dioxide structures / chromate solution provides variable electrochemical properties, as well as appreciable difference in the absorbance under light confirming the reduction of chromate. We also show by using Nyquist plot (experimental measures EIS) on these structures that the values of relaxation electrical components, conductivity, dielectric constant of the system are reduced. The n type character induced by the charge compensation mechanism is confirmed by the capacitance measurements (Mott-Schottky). The photocatalytic activity was predicted from the energy diagram and the chromate removal is used as reaction test. References [1] Zhen Zhu, Jin Ma, Caina Luan, Lingyi Kong, Qiaoqun Yu, Applied Surface Science 257 (2011) 2516– 2519. [2] J. Ross. Mac Donald, Impedance spectroscopy; John Wiley & Sons New York (1987).

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P8-ELC_330 IN-SITU X-RAY DIFFRACTION STUDY OF PT(111) OXIDATION DURING OXYGEN REDUCTION REACTION

ELC - Electrochemistry at surfaces J. Drnec 1,*, M. Ruge 2, F. Reikowski 2, B. Rahn 2, F. Carlà 1, R. Felici 3, O.M. Magnussen 2, D.A. Harrington 4 1ESRF - Grenoble (France), 2Institute of Experimental and Applied Physics, Kiel University - Kiel (Germany), 3CNR-SPIN - Roma (Italy), 4University of Victoria - Victoria (Canada) ORR is one of the most studied electrochemical reactions due to its tremendous fundamental and practical importance. Oxygen is a common, readily accessible oxidizing agent and, therefore, the Pt ORR cathode is part of many energy conversion devices, e.g. fuel cells. Unfortunately, the slow kinetics of ORR negatively affects the performance and is currently one of the main bottleneck in large scale fuel cell commercialization. It has been suggested that this is partly caused by the presence of surface Pt oxides, which slow the reaction rate and trap reaction intermediates on the surface. The oxide formation and dissolution is also known to cause dissolution of Pt catalyst, which further degrades the performance. Even though the electrochemical formation of surface oxides on platinum surface has been extensively studied in the past, there are still many questions unanswered, mainly regarding the detailed structure of the oxide and its growth mechanism [1 and references therein]. Most of the studies were performed in the absence of O2, the fuel cell oxidant, and therefore they are less relevant to the fuel cell operation as gaseous O2 can modify the oxidation potentials and mechanism. Here we show the results of an in-situ surface X-ray diffraction (SXRD) study of electrochemical oxide formation on Pt(111) and how it is influenced by the presence of O2 during ORR. The place exchange process associated with the initial stages of oxidation is followed dynamically by parallel SXRD and electrochemical measurements during cyclic voltammetry (CV) and potential step experiments in the presence and absence of oxygen. Detailed analysis at two potentials shows that the structural changes are consistent with a place exchange between Pt and O atoms, in which the exchanged Pt atoms are located directly above their original positions in the Pt(111) lattice. Adding O2 to the electrolyte does not have any significant effect on the oxidation behavior, in contrast to some literature reports, and the O2 -accelerated Pt dissolution is not caused by the negative shift in the oxidation potential. Furthermore, the ORR current decreases before oxidation, implying that the presence of the surface oxide is not the limiting factor in the ORR and the high ORR overpotential is solely due to the slow ORR mechanism on an unreconstructed surface. References [1] Kongkanand and Ziegelbauer, J. Phys. Chem. C, 2012, 116, 3684-3693

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P9-ELC_411 ONE-POT SYNTHESIZED P(ACRYLIC ACID)/SILICA NANOHYBRIDS COATINGS FOR PROTECTIVE APPLICATIONS

ELC - Electrochemistry at surfaces M. Mohamadpour Nazarabady *, G.A. Farzi * Hakim Sabzevary university - Sabzevar (Iran, islamic republic of) A series of p(acrylic acid)/silica nanohybrid coatings (P(AA)/SiO2) consisting of two different silane coupling agents, i.e. 3- methacryloxy propyltrimethoxysilane (γ-MPS) and 3- aminopropyltriethoxysilane (APTS), were developed for antibacterial and corrosion protection. As it was revealed by Fourier transform infrared spectroscopy, X-ray diffractometry and transmission and scanning electron microscopy, the two coupling agents not only serve to enhance chemically linking but also play a significant role in the morphology conduction of the well-defined nanostructures. The effect of silica content and morphology of the P(AA)/SiO2 nanohybrid coatings were investigated by electrochemical and optical density at 600 nm (O.D. 600) measurements. The electrochemical potentiodynamic measurements in Harrison’s solution, which simulates aircraft conditions, suggested that the nanohybrids deposited as coatings on aluminum (Al) substrates improved the corrosion resistance of Al. Finally, the result of antibacterial test demonstrates the effective antibacterial properties of the nanohybrids. Thus, it can be concluded that the facile one-pot rout reported here is a versatile approach to develop antibacterial and anticorrosion coatings. Keywords: P(acrylic acid) /silica nanohybrids coating, Morphology conduction, One-pot synthesis, Antibacterial protection, Corrosion resistance.

Figure 1: Schematic of the procedure for preparation of p (acrylic acid)/silica nanohybrids. Changing the coupling agents affects the morphology, anticorrosion and antibacterial properties of the nanohybrids.

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ELPS - Electronic properties of strong correlations systems

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I06_ELPS_437 1D AND 2D MATERIALS CHARACTERIZATION USING COMBINED STM & NC-AFM

ELPS - Electronic properties of strong correlations systems T. Dienel * nanotech@surfaces Lab, Empa – Swiss Federal Laboratories for Materials Science and Technolgy - Duebendorf (Switzerland) Physical properties of low-dimensional materials sensitively depend on subtle details of their atomic structure. The newly developed on-surface synthesis approach takes advantage of rationally designed precursor molecules to create atomically precise graphene-related nanomaterials, including graphene nanoribbons (GNRs), conjugated polymers, or atomically-thin hexagonal boron nitride sheets (h-BN). Scanning tunneling microscopy (STM) and non-contact atomic force microscopy (nc-AFM) under ultrahigh vacuum conditions are methods of choice to resolve the intra- and intermolecular structural changes and bond rearrangements associated with surface-based chemical reactions. In the first part of this presentation, I will review recent developments in bottom-up synthesis and characterization of atomically precise GNRs [1], whose electronic states mainly depend on their width and edge structure. The ultrahigh resolution achievable by nc-AFM with CO- sensitized tips [2] allows to directly identify the bond configurations and terminations of the formed GNRs: the growing family of armchair GNRs [1,3] and junctions thereof [4], emergent zigzag GNRs [5], and metalated carbyne [6]. In the second part, I will report on atom-thin h-BN monolayers on metal substrates, where the h-BN layer forms a distinctive superstructure due to the interaction with the underlying metal atoms [7]. The comparison between STM and nc-AFM data provides new insights on the three-dimensional corrugation of the h-BN superstructure. References [1] Cai, J. et al., Nature 466, 470 (2010). [2] Gross, L.et al., Science 325, 1110 (2009). [3] Talirz, L. et al., Adv. Mater., doi: 10.1002/adma.201505738 (2016). [4] Dienel, T. et al., Nano Letters 15, 5185-5190 (2015). [5] Ruffieux, P. et al., Nature 531, 489-492 (2016). [6] Sun, Q. et al., J. Am. Chem. Soc. 138, 1106–1109 (2016) [7] Goméz-Diáz, J. et al., Theor. Chem. Acc. 132, 1350 (2013).

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O1-ELPS_10 HOW ATOMIC DEFECTS MODIFY THE ELECTRONIC STRUCTURE IN 2-D TRANSITION METAL DICHALCOGENIDES AND LEAD TO NOVEL PROPERTIES

ELPS - Electronic properties of strong correlations systems A. Weber-Bargioni * Lawrence Berkeley National Laboratory - Berkley (United States of America) In this presentation we show how individual atomic defects and linear mirror twin boundaries in 2-D MoSe2, identified with super resolution atomic force microscopy, alter the electronic wave function, imaged via Scanning Tunneling Spectroscopic mapping, leading along mirror twin boundaries to charge density waves and solitons. Hierarchically ordered defects or adsorbents in two dimensional transition metal dichalcogenides (TMDs) enable the direct visualization of electron wave tuning using heterostructures of comparable length scale as the electronic wave function. We identify individual Se vacancies – on both, the SPM facing and the substrate facing surface. Both result in particular electronic wave function related to states located at the atomic defect. These defect states form atomically sharp type 1 heterojunctions with the surrounding pristine MoSe2, and form an excellent test bed to study catalytic activity with atomic precision. We also identified hierarchically ordered defects in from of Mirror Twin Boundaries (MTB) in MoSe2, which form truly 1-D metal channels embedded in the surrounding semiconductor. At low temperatures these 1-D metallic states open a band gap at Fermi of 100meV. The new band gap frontier states exhibit a preiodic modulation of three times the lattice constant along the channels. Density Functional Theory calculation confirm that the observed charge modulation is a result of the formation of a charge density wave. By charging up the charge density wave we observe the creation of solitons – a self-reinforcing wave - and are able to measure its’ energetic dispersion. References Maps of Electronic Wave functions associated with various atomic defects in MoSe2, S. Barja, et al. submitted Charge density wave order in 1D mirror twin boundaries of single-layer MoSe2, S. Barja, et al. accepted in nature physics Formation of Charge Density Wave Solitons in Mirror Twin Boundaries embedded in MoSe2, S. Wickenburg, et al. in preparation

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O2-ELPS_332 STM STUDY OF LOCAL BAND OFFSETS IN TUNGSTEN DISELINIDE FLAKES TRANSFERRED ON GRAPHENE

ELPS - Electronic properties of strong correlations systems J. Veuillen 1,*, V. Cherkez 1, P. Mallet 1, K. Nogajewski 2, M. Potemski 2 1Institut NEEL, CNRS et Université Grenoble Alpes - Grenoble (France), 2LNCMI, CNRS et Université Grenoble Alpes - Grenoble (France) Thin layers of semiconducting transition metal dichalcogenides (TMDs), especially in the monolayer range, are attracting increasing interest for their use in stacked van der Waals heterostructures [1]. In this perspective, the band offset between TMDs and other two dimensional materials, e.g. graphene, is a central issue. We have adressed this question by means of scanning tunneling microscopy (STM) and spectroscopy (STS) for tungsten diselenide (WSe2) flakes reported on epitaxial graphene (EG) grown on 6H-SiC(0001). Large scale images show that, except for some “bubbles”, the TMD flake conforms to the EG substrate, which indicates a clean interface between them [1]. Atomic resolution images reveal a significant density (a few 1012 cm-2) of point defects (including Se vacancies) which seem to have only a weak influence on the local electronic structure. WSe2 is found to be (slightly) n type from STS spectra taken away from defects and boundaries [2]. We have identified different sources of shifts of the band onsets in our samples: edges, charged defects and changes in the EG thickness. All of them cause an upwards energy shift (by +0.1 to +0.5 eV) of the TMD bands, extending over several nanometres. As an example, the figure shows the conduction (CB) and valence (VB) band bending at a flake edge (pink arrow), induced by in-gap states at the boundary. More relevant for the charge transport across TMD layers, we have observed a local band bending (by +0.2eV) around stable negatively charged defects in a trilayer WSe2 flake. The shift in the band edges of the TMD flake between monolayer and bilayer (graphene) terraces of the substrate is consistent in sign and magnitude (≈0.1eV) with the measured differences of their work functions [3], resembling the “Schottky-Mott” rule for (weakly interacting) metal-semiconductor junctions. Thanks This work was supported by the European Union “Graphene Flagship“ project n° 604391 References [1] A. K. Geim et al., Nature 499, 419 (2013) [2] M. M. Ugeda et al., Nature Materials 13, 1091 (2014) [3] T. Filleter et al., Appl. Phys. Lett. 93, 133117 (2008)

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O3-ELPS_61 TUNING THE ELECTRONIC STRUCTURE OF AU(111) AND GRAPHENE BY MOLECULAR PATTERNING

ELPS - Electronic properties of strong correlations systems J. Li *, G. Stefano, J.C. Moreno-Lopez, L. Solianyk, M. Stöhr University of Groningen (Netherlands) The controlled tuning of material properties on the nanometer scale is a central goal in nanoscience. Artificial nanostructures can be built by STM in an atom by atom fashion. Corral structures built in this way were shown to confine the surface state electrons and locally modify the electronic properties of surface state electrons[1]. However, the manipulation process is impractical to change the electronic properties of the entire surface. On the other hand, molecular self-assembly offers the possibility to build well-ordered and defect-free nanostructures due to its intrinsic error-correction nature. By using different molecular building blocks, networks of different sizes and symmetries can be formed, which allows for tuning the electronic structure not only locally but also surface wide[2]. Here, we report on tuning the electronic structures of Au(111) as well as graphene by a supramolecular porous network, which is formed from 1,3,5-benzenetribenzoic acid molecules. STM and LEED measurements were performed to obtain structural information while STS and ARPES measurements revealed that the surface state electrons of Au(111) were confined in the pores of the molecular network. References [1] Crommie, Michael F., et al. "Confinement of electrons to quantum corrals on a metal surface." Science 262.5131 (1993): 218-220. [2] Lobo-Checa, Jorge, et al. "Band formation from coupled quantum dots formed by a nanoporous network on a copper surface." Science 325.5938 (2009): 300-303.

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O4-ELPS_91 CORRELATION BETWEEN MORPHOLOGY AND TRANSPORT PROPERTIES OF QUASI-FREE-STANDING MONOLAYER GRAPHENE (QFMLG)

ELPS - Electronic properties of strong correlations systems Y. Murata 1,*, T. Mashoff 2, N. Pavlicek 3, G. Meyer 3, M. Takamura 4, H. Hibino 4, F. Beltram 1, S. Heun 1,* 1NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore - Pisa (Italy), 2Center for Nanotechnology Innovation @ NEST, Istituto Italiano di Tecnologia - Pisa (Italy), 3IBM Zurich Research Laboratory - Zurich (Switzerland), 4NTT Basic Research Laboratories, NTT Corporation, Japan - Atsugi (Japan) Quasi-free-standing monolayer graphene (QFMLG), obtained by intercalating hydrogen at the interface of buffer layer and SiC(0001), is efficiently decoupled from the substrate and a promising material for wafer-scale graphene-based nanoelectronics [1,2]. However, the mobility of QFMLG (~3000 cm2V-1s-1) is limited to a value lower than that of exfoliated graphene on SiO2, and the carrier scattering has not been fully understood. Recently it has been reported that the mobility of QFMLG depends on the substrate temperature during the hydrogen intercalation process, and the highest mobility is obtained at 700-800°C [3]. These measurements suggested that the mobility is mainly limited by charged impurities. We have used scanning tunneling microscopy (STM) and spectroscopy (STS) to study the surface structure of QFMLG formed at several hydrogen intercalation temperatures, and investigated the relationship with transport measurements [4]. Our STM observations reveal that the QFMLG shows features with a diameter of 1.5 nm (see Fig. 1, left). They partially align with a periodicity of 1.8 nm, corresponding to the quasi-(6x6) reconstruction of the buffer layer [4]. This implies that hydrogen intercalation in our samples is not complete and suggests that Si dangling bonds due to incomplete hydrogen intercalation scatter carriers as charged impurities, consistent with transport measurements. Our interpretation is further substantiated by low-temperature STM and STS. Spectra taken at the position of dangling bonds show a characteristic peak at 1.1 to 1.4 eV, not observed otherwise (see Fig. 1, right). A similar adatom resonance has been observed for dangling bonds at the interface between graphene and C-face SiC [5]. References [1] C. Riedl et al., Phys. Rev. Lett. 103, 246804 (2009). [2] S. Goler et al., Carbon 51, 249 (2013). [3] S. Tanabe et al., Jpn. J. Appl. Phys. 53, 04EN01 (2014). [4] Y. Murata et al., Appl. Phys. Lett. 105, 221604 (2014). [5] F. Hiebel et al., Phys. Rev. B 86, 205421 (2012).

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O5-ELPS_214 SECONDARY ELECTRON EMISSION FROM NANOGRAPHENE: A REAL-TIME FIRST- PRINCIPLES SIMULATION

ELPS - Electronic properties of strong correlations systems K. Watanabe *, Y. Ueda *, Y. Suzuki Tokyo University of Science - Tokyo (Japan) Secondary electron emission (SEE) [1] is a well-known phenomenon and has been utilized as a practical and useful probe for surface analyses. In particular, scanning electron microscopy (SEM), which is a useful and popular technique that applies SEE to obtain information about surface structures, has been applied recently to observe nano-scale atomic structures. Monte-Carlo (MC) simulations with empirical models are used widely for the theoretical study of SEE and explain well the incident-energy and angle dependence of secondary electron yields. The MC simulations, however, were performed with various approximations, such as the first-Born approximation for electron scattering at jellium surfaces instead of crystal surfaces. The jellium model neglects atomic structures, and the first-Born approximation is not suitable for simulations of low-energy electron scattering. Thus, we have carried out a real-time time-dependent density functional theory simulation of SEE that fully takes account of target atomic structures and electron scattering processes. We chose nanographene as a target material in the present study, because graphene has attracted considerable interest for its unique properties, and also because graphene is a simple and ideal target to elucidate the mechanism underlying SEE. We have demonstrated the SEE dynamics upon electron scattering with a target graphene flake [2] (figure), and obtained the incident-electron energy dependence and bilayer effect on SEE, which are interpreted by the electron scattering processes in real time. We also found that the collective electron-density oscillation of the target flake that emerges after SEE has a frequency specific to the target and independent of the kinetic energy of incident electron. The important findings in our study are that the excitation dynamics responsible for SEE has been elucidated, and that the energy spectrum, which is consistent with typical properties observed in experiments, has been determined from first principles for the first time by utilizing the time-dependent Kohn-Sham decomposition scheme. In spite of the small target, our simulation revealed the essence and general features of SEE experiment.

References 1. A. Modinos: Field, Thermionic, and Secondary Electron Emission Spectroscopy (Springer US, 1984). 2. K. Tsubonoya, C. Hu, and K. Watanabe: Phys. Rev. B 90, 035416 (2014).

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O6-ELPS_272 ATOMIC SIZE EFFECTS STUDIED BY TRANSPORT IN SINGLE SILICIDE NANOWIRES

ELPS - Electronic properties of strong correlations systems F. Edler 1,*, I. Miccoli 1, H. Pfnür 1, S. Appelfeller 2, M. Dähne 2, K. Holtgreve 3, S. Sanna 3, W.G. Schmidt 3, C. Tegenkamp 1 1Institut für Festkörperphysik, Leibniz Universität Hannover - Hannover (Germany), 2Institut für Festkörperphysik, Technische Universität Berlin - Berlin (Germany), 3Lehrstuhl für Theoretische Physik, Universität Paderborn - Paderborn (Germany) Silicide nanowires (NWs) currently play a pivotal role in fundamental research beyond opening intriguing perspectives for CMOS applications as ohmic contacts and gate electrodes, due to their very low resistivity and appropriate Schottky barrier heights. In particular, novel rare-earth metals (e.g. Tb, Dy, Er, Y) can be adopted for the strain-mediated self-assembly of ultrathin silicide NWs with extremely high aspect ratios triggered by uniaxial lattice matching with the Si substrate, which paves the way to the sub-10nm nodes CMOS technique. However, the gradual reduction in size towards the atomic scale comes inevitably along with the increasing importance of atomic defects and interaction with the substrate [1]. The transport properties of TbSi-NWs grown on vicinal (001)Si substrates were studied via a 4-tip STM/SEM system. The system allows the direct measurement of the NW resistance profile without any additional sample processing. Thereby, the SEM was used for the fast characterization of sample quality and precise positioning of feedback controlled STM tips, enabling gentle contacts and transport measurements on a nm-scale. STS measurements reveal that the wires are metallic as well as electronically decoupled from the Si substrate in agreement with DFT calculations and transport measurements. Our transport measurements reveal three types of metallic wires, mainly depending on the growth parameters. The data can be perfectly described by a theoretical quantum model taking into account details of the surface roughness and the lateral surface correlation length which were determined on the same wires with STM [2,3]. References [1] Zeng et al. Nat. Mater.7 539 (2008) [2] Chatterjee et Meyerovich, Phys. Rev. B 81, 245409 (2010) [3] Miccoli, Edler et.al. Phys. Rev. B 93, 125412 (2016)

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O7-ELPS_135 DETERMINING THE CRITICAL JOSEPHSON CURRENT IN STM JUNCTIONS

ELPS - Electronic properties of strong correlations systems M. Etzkorn *, B. Jaeck *, M. Eltschka, M. Assig, C. Ast, K. Kern Max Planck Institute for Solid State Research - Stuttgart (Germany) Combining the Josephson effect, i.e. the tunneling of Cooper pairs, and scanning tunneling microscopy (STM) allows to directly access the superconducting condensate with atomic resolution. However, an STM junction is characterized by a small capacitance between tip and sample. The resulting charging energy (EC) can easily exceed typical Josephson coupling energies (EJ) and therefore leads to dynamical coulomb blockade effects in the Cooper pair tunneling. Even at ultra-low temperatures the Cooper pair transport is then dominated by phase fluctuations that prevent a direct experimental determination of the Josephson critical current from which the superconducting pairing amplitude can be extracted. Therefore, the capacitance and the entire local electromagnetic environment of the junction have to be considered in order to extract quantitative information for example on the critical current from such STM measurements. We have studied the current-voltage characteristics of a voltage-biased Josephson junction in the low conductance regime of an ultra-low temperature STM working at 15 milli-Kelvin [1]. We describe our results and the impact of the local environment using the P(E) theory. Within this description the critical current enters as a scaling factor and thus can be determined precisely even when considering the uncertainties in the description of the local impedance. We can therefore determine the absolute value of the critical current of a Josephson junction in STM measurements performed in the dynamical Coulomb blockade regime. The Josephson critical current, experimentally determined in this regime, is in good agreement with the critical current calculated from the Ambegaokar-Baratoff formula. Furthermore, we experimentally determine a range of validity for P(E) theory, which is in accordance with theoretical predictions. In this way, we establish an optimal parameter range, in which Josephson STM can be performed. References [1] B. Jäck, et al., PHYSICAL REVIEW B 93, 020504(R) (2016).

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O8-ELPS_42 ELECTRONIC PROPERTIES OF CR ATOMS INSERTED IN THE FIRST LAYERS OF GAAS(110) SURFACE PROBED BY STM/STS

ELPS - Electronic properties of strong correlations systems K. Badiane *, G. Rodary *, J.C. Girard, C. David Laboratoire de Photonique et de Nanostructures - Marcoussis (France) Electronic properties of single Cr atoms in the p-type GaAs(110) surface are investigated by Scanning Tunneling Microscopy and Spectroscopy (STM/STS) in order to understand the ferromagnetism of the dilute magnetic semiconductors (DMS) [1][2][3] at the atomic scale. By STM tip manipulation we succeed to substitute Ga atoms by Cr surface adatoms by sweeping the voltage from a negative voltage to a positive voltage. The inserted Cr appear in two different forms giving rise to extended and anisotropic electronic wave functions. With a cristallographic approach we associate these forms to Cr atoms in subtitution to Ga atoms in the first and the second layer of the surface (see figures (a) and (b) respectively). dI/dV spectra on the inserted Cr reveal several distinct peaks. These peaks are discussed in the context of electronics states that originate from hybridization between d orbitals of the Cr atom and p-like orbitals of neighboring As atoms [4].

Figures (a) and (b): STM topographic images of inserted Cr atoms in the GaAs(110) surface: 3nm x 3nm; +1.5V; 100pA; 5K. A ball-and-stick atomic model of this surface is shown to localise the Ga atoms substituted by the Cr atoms: the Ga atoms (red) and the As atoms (black) in the first and the second layer are represented by big and small balls respectively. The circles show the Ga atoms substituted by the Cr atoms in the first layer (a) and in the second layer (b) of GaAs(110) surface. References [1] H.Ohno and al., APL 69, 393(1996) [2] H. Wu and al., Solid State Communications 151, 456(2011) [3] D. Kitchen and al., Nature 442, 436(2006) [4] P. Mahadevan and A. Zunger, PRB 69, 115211(2004).

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O9-ELPS_306 CONTROLLING THE FORMATION OF SPIN CHAINS AT STEPPED SILICON SURFACES

ELPS - Electronic properties of strong correlations systems J. Aulbach 1,*, S.C. Erwin 2, R. Claessen 1, J. Schaefer 1 1Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Wuerzburg - Wuerzburg (Germany), 2Center for Computational Materials Science, Naval Research Laboratory - Washington D. C. (United States of America) Adsorption of a submonolayer of gold on various stepped Si(hhk) substrates yield the formation of atomic wire arrays with rather perfect structural order. As a specific representative, stabilization of the Si(553) surface by Au adsorption results in two different atomically defined chain types, one made of Au atoms and one of Si. The latter, situated at the step edges, forms a honeycomb nanoribbon. The silicon atoms at the exposed edges of this graphitic stripe are known to be spin- polarized and charge ordered along the edge [1, 2]. However, the extent to which these so- called “spin chains” can be modified, or suppressed, has remained unexplored. Here our approach is to exploit the tunability offered by the Si(hhk)-Au family, which exhibits not only varied terrace widths but also different bonding networks (see figure below). Based on scanning tunneling microscopy and density- functional theory we reveal why spin chains form on particular Si(hhk) surfaces but not on others. Moreover, we predict that unintentional defects and intentional dopants can create or suppress local magnetic moments at Si(hhk)- Au step edges and verify this prediction experimentally [3]. References [1] S. C. Erwin and F. J. Himpsel, Nature Commun. 1, 58 (2010). [2] J. Aulbach et al., Phys. Rev. Lett. 111, 137203 (2013). [3] J. Aulbach et al., Nano Lett. 16, 2698 (2016).

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O10-ELPS_196 CALCULATING THE REACTIVITY OF METAL SURFACES

ELPS - Electronic properties of strong correlations systems A. Miller *, S.J. Jenkins University of Cambridge - Cambridge (United Kingdom) Understanding trends in the reactivity of metal surfaces is desirable in order to understand heterogeneous catalysis and corrosion. There is a need for a reactivity index which can be used for both metal atoms and adsorbates. In addition it would be highly desirable to be able to compare reactivity between sites on different surfaces.1,2 The local softness is a reactivity index which meets both these criteria. A method is presented for calculating the local softness of surfaces using DFT. This has been used to explain reactivity trends for sites on a range of metal surfaces. Potential applications include the identification of active sites in catalytic systems. Ultimately the identification of active sites may enable the systematic design of new heterogeneous catalysts. References 1. B. Hammer and J. K. Nørskov, Adv. Catal., 2000, 45, 71-129. 2. S. Wilke, M. Cohen and M. Scheffler, Phys. Rev. Lett., 1996, 77, 1560-1563.

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O11-ELPS_138 SCANNING TUNNELING MICROSCOPY ON BULK FESE

ELPS - Electronic properties of strong correlations systems J. Jandke 1,*, J. Dressner 1, T. Wolf 2, W. Wulfhekel 1 1Physikalisches Institut, Karlsruher Institut für Technologie - Karlsruhe (Germany), 2Institut für Festkörperphysik, Karlsruher Institut für Technologie - Karlsruhe (Germany) Scanning tunneling microscopy (STM) is a suitable tool to not only investigate the topography or spatially resolved density of state (DOS) but inelastic excitations as well. Furthermore, it is possible to gain insight into reziprocal space, even though STM is a real space technique. This can be done by performing Fourier-transformation on spatially resolved DOS maps. Hence, this method is called FT- STM. We use high-resolution scanning tunneling spectroscopy to study single crystal FeSe at temperatures down to 30mK. Highly resolved spectra of the quasiparticle density of states show multiple superconducting gaps. This is in agreement with the multiband character of this system and confirms previous investigations [1,2]. Besides the superconducting gap, there is evidence of bosonic excitations in the measured quasiparticle density of states as will be discussed. Finally, the results of the quasiparticle interference measurements are presented indicating dispersing features which could originate from inter/intra-band scattering. References [1] C. Song et al., Science 332, 1410 (2011) [2] S. Kasahara et al., PNAS 111, 16309 (2014)

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O12-ELPS_111 SURFACE POLARIZATION ON A SI(111) RECONSTRUCTED SURFACE MEASURED BY NONCONTACT SCANNING NONLINEAR DIELECTRIC POTENTIOMETRY

ELPS - Electronic properties of strong correlations systems K. Yamasue *, Y. Cho Tohoku University - Sendai (Japan) Spontaneous polarization on surfaces and interfaces plays an important role in modern electronic materials and devices. However, the measurement of spontaneous polarization is difficult at a nanoscale. Here we present a novel method that can quantitatively measure spontaneous polarization, or polarization charge density. Our method is based on a recently proposed scanning probe technique called noncontact scanning nonlinear dielectric potentiometry (NC-SNDP) [1, 2]. NC-SNDP measures local electric potentials governed by spontaneous polarization. This method is distinguished from Kelvin probe force microscopy, an existing method to measure potentials, in that NC-SNDP is insensitive to monopole charge or contact potential differences. The difference comes from the underlying principle. NC-SNDP detects the second order nonlinearity in a dielectric response of a sample rather than an electrostatic force. The key to measuring polarization is to use the dependence of the measured potential on tip-sample distance. If we model a tip and sample using a parallel plate capacitor, the dependence is described by. Here, is spontaneous polarization and is the thickness of the sample with relative permittivity . denotes the vacuum permittivity. If is sufficiently large, the measured potential is approximated by . Thus, can be estimated from the slope of the distance dependence, which can also be measured using lock-in amplifier under the distance modulation. We demonstrate the capability of our technique on a reconstructed Si(111) surface. Figure shows NC- SNDP images of (a) topography (b) potential, and (c) polarization charge density on the surface. The tip-sample distance was modulated at 125 Hz. The images were simultaneously acquired using the main feedback, bias feedback, and slope detection. The observed potentials were basically positive on the surface and polarization charge density was here estimated to be about 4 mC/m2. Our technique thus can provide quantitative insights on polarization in a nanoscale. Thanks This work was partly supported by a Grant-in-Aid for Scientific Research (Nos. 23226008, 15K04673, 16H02330) from the Japan Society for the Promotion of Science. References [1] K.Yamasue and Y. Cho, Rev. Sci. Instrum. 86, 093704 (2015). [2] K. Yamasue, H. Fukidome, K. Funakubo, M. Suemitsu, and Y. Cho, Phys. Rev. Lett. 114(22), 226103 (2015).

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O13-ELPS_193 DETECTING ELECTRONEGATIVITY VARIATION AT THE ATOMIC SCALE WITH THE ATOMIC FORCE MICROSCOPE

ELPS - Electronic properties of strong correlations systems M. Ondrácek 1,*, J. Onoda 2,*, P. Jelinek 1, Y. Sugimoto 3 1Institute of Physics, Czech Academy of Sciences, Cukrovarnicka 10/112 - Prague (Czech republic), 2Graduate School of Engineering, Osaka University, 2-1 Yamada-Oka, Suita - Osaka (Japan), 3Department of Advanced Materials Science, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa - Chiba (Japan) Electronegativity is an important concept in chemistry, originally defined by Linus Pauling as “the power of an atom in a molecule to attract electrons to itself” [1]. We propose a new methodology to probe the electronegativity of individual atoms on surfaces by atomic force microscopy (AFM). We repeatedly measured bond energies between the AFM tip and a chosen atom adsorbed on the Si(111)-7x7 surface using a large variety of tips which exhibited various degrees of reactivity. We found linear relations between the bond energies of different chemical species. We interpret the linear relations in terms of Pauling’s equation for polar covalent bond. In particular, we relate the slope of the linear dependence to the energy of a homonuclear bond for a given species while we associate the intercept with the ionic component of the bond energy for bonds between the probed atom and Si. The covalent bond energy terms revealed by the slopes correlate to the chemical identity of individual atoms. On the other hand, using the ionic energies from the intercepts, we successfully recover electronegativity values for the Ge, Sn, Al, and O atoms. Moreover, we determined subtle differences in Si atom electronegativity associated with local oxide or oxynitride groups compared to pure Si atoms. The figure below illustrates the empirical relations found among the bond energies derived from AFM. Bond energies of native Si atoms (horizontal axis) are plotted against bond energies of some different atom (vertical axis). Left panel: an Al atom replacing the Si adatom. Right panel: Si atom in an SiO2 adatom structure. Open squares with error bars show measured data, solid line represents a linear fit, full squares denote results of DFT simulations with model tips. Our findings demonstrate that AFM is sensitive to the “group” electronegativity of individual surface atoms whose electronic structure is modified by surrounding environment consisting of different chemical and atomic configurations. References [1] Pauling, L. The Nature of the Chemical Bond, Cornell University Press, Ithaca, New York, 1960, 3rd, 13th printing 1995 ed.

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P1-ELPS_51 SINGLE TRIPYRIDYL−TRIAZINE MOLECULAR JUNCTION WITH MULTIPLE BINDING SITES

ELPS - Electronic properties of strong correlations systems M. Iwane *, S. Fujii, M. Kiguchi Department of Chemistry, Tokyo Institute of Technology - Tokyo (Japan) An understanding of the charge transport through single molecular junctions is of considerable fundamental interest in molecular electronics. Recently, multiterminal molecular junctions have attracted increasing interest because the multiple anchoring groups offer higher junction stability and higher electronic conductance. In this study, we have investigated the single molecular junction of 2,4,6-tris(2′,2″,2‴-pyridyl)-1,3,5-triazine (TPTZ) with multiple metal−molecule binding sites using scanning tunneling microscopy- based break junction (STM-BJ) method under ambient conditions [1]. The single TPTZ molecular junction showed three conductance states of ca. 10−1, 10−2, and −4 2 10 G0 (G0=2e /h), which suggests that the single TPTZ molecular junction has three charge transport paths depending on the molecular anchoring sites on the Au electrodes. Analysis of electrode−gap distance in the molecular junction revealed that effective gap length is 0.5, 0.9 and 1.2 nm for the high, medium and low conductance states, respectively. By combining the results of the measured conductance and the estimated electrode−gap distance, we proposed models of junction-structures for the observed three conductance states. This study demonstrates that a molecular junction consisting of multiple metal−π binding sites provides high and tunable conductance behavior based on the multiple charge transport paths within a molecule. References [1] M. Iwane, M. Kiguchi et al., J. Phys. Chem. C (2016), in press.

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P2-ELPS_92 ELECTRONIC STATES OF TERMINATION-CONTROLLED SURFACES OF SRTIO3(001)

ELPS - Electronic properties of strong correlations systems S. Ogawa *, N. Nagatsuka, S. Ogura, K. Fukutani Institute of Industrial Science, The University of Tokyo - Tokyo (Japan) SrTiO3 consists of alternately stacked layers of SrO and TiO2.The SrTiO3(001) surface therefore has two types of terminations. The TiO2-terminated surface, which can be prepared by chemical etching[1], has been studied in detail to date. Although the SrO- terminated surface is theoretically predicted to have particular electronic states[2], because of the difficulty of the preparation, it has not been well understood and investigated. In the present paper, we have prepared the TiO2- and SrO-terminated surfaces and investigated the electronic states by photoemission spectroscopy. Based on a previous study[3], we prepared the SrO-terminated surface by annealing the sample at 1550 K for 72 h in air, we confirmed that the surface is flat by AFM. From the analysis of the AES intensities, it is considered that 85% of the surface is SrO-terminated. We measured the photoemission spectroscopy for both terminated samples with the HeI source. We found that the shape of the O2p band is different between the two surfaces as shown in Fig. 1. We discuss that the spectrum difference originates from the symmetry difference of the Ti ions. References [1] M. Kawasaki et al., Science 266, 1540 (1994). [2] P. Delugas et al., Phys. Rev. B 91, 115315 (2015). [3] R. Bachelet et al., Appl. Phys. Lett. 95, 141915 (2009).

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P3-ELPS_185 AUGER AND X-RAY PHOTOEMISSION SPECTROSCOPY OF PLANAR AND NANOSTRUCTURED SURFACES

ELPS - Electronic properties of strong correlations systems J. Gervasoni 1,*, J. Gallardo 2,*, L. Kover 3 1CNEA-CONICET - Bariloche (Argentina), 2CNEA - Bariloche (Argentina), 3ATOMKI - Debrecen (Hungary) In this communication, we study the process of excitation of bulk and surface plasmons during the emission of electrons in the proximity of surfaces of different shapes and dimensions.We investigate in detail the effects due to the interaction between an electron and a stationary positive ion (or atomic hole) in the neighborhood of a metallic surface. We take into account the effects due to the sudden creation of an electron and the residual holes, one in the case of X-ray Photoemission Spectroscopy (XPS) and two in the case of Auger Electron Spectroscopy (AES). We use the dielectric response of the metal and the specular reflection model. The results illustrate the differences between XPS and AES plasmon excitations [1, 2]. In particular, we study how the electron-hole pair interaction can influence the energy loss of the emerging electron. In particular, we show that the plasmons leave a mark in the X-ray Photoelectron and Auger Electron Spectrum (XPS and AES), which poses a challenge to the automatic techniques of spectra analysis. We compare our results with experimental data and investigate the importance of surface effects in the analysis of photoelectron spectroscopy. The method described here is useful for studying multiple plasmon excitations in nanostructures and for understanding the excited electron spectra of these nanostructures (different from those of the same bulk material) [3-6]. References [1] J. L. Gervasoni and F. Yubero, Nucl. Instr. Meth. B 182 (2001) 96. [2] J. L. Gervasoni and L. Kövér, J. Electron Spectrosc. 161 (2007) 134. [3] J. L. Gervasoni and L. Kövér, Vacuum 83 (2009) 1049. [4] J. A. García Gallardo, J. L. Gervasoni and L. Kövér, Vacuum 84 (2010) 258. [5] J. A. García Gallardo, J. L. Gervasoni and L. Kövér, J. Nanosci. Nanotechnol. 12 (2012) 9271. [6] J. A. García Galardo, J. L. Gervasoni, L. Kövér, Vacuum 107 (2014) 316.

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P4-ELPS_209 ASYMMETRY IN THE EXCITATION OF PLASMONS BY SWIFT PARTICLES TRAVERSING A SURFACE AT OBLIQUE INCIDENCE

ELPS - Electronic properties of strong correlations systems J. Gervasoni 1,*, F. Navarrete 2, S. Segui 2, N. Arista 3 1CNEA-CONICET - Bariloche (Argentina), 2CONICET - Bariloche (Argentina), 3CNEA - Bariloche (Argentina) Asymmetry in the excitation of plasmons by swift particles traversing a surface at oblique incidence The study of plasmon excitation is of great relevance for the characterisation of surfaces, thin films, and nanoparticles using different charged-particles spectroscopic techniques. In this work we are interested in analyzing the asymmetry found in the production of plasmons by fast charged particles entering or leaving a semi-infinite material through a planar surface. We employ the specular reflection model and the extended pseudo-medium method [1] in order to assess the energy loss rate due to plasmon excitation along the projectile's trajectory. In particular, we analyze the integration conditions of the transferred momentum, showing that an approximation usually applied in the literature drives to unconsistent results. We obtain results for a variety of experimental settings, spanning a range of velocities and incidence angles to study how the observed asymmetry between incoming and outgoing trajectories depend on these variables. References J. L. Gervasoni, N. R. Arista 1992 Surf. Sci. 260, p. 329

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P5-ELPS_257 EFFECTS OF CHARGE DYNAMICS IN ELECTROSTATIC FORCE MICROSCOPY

ELPS - Electronic properties of strong correlations systems M. Ondrácek *, P. Hapala, P. Jelinek Institute of Physics, Czech Academy of Sciences, Cukrovarnicka 10/112 - Prague (Czech republic) Atoms, molecules, clusters or other structures on surfaces which can switch between two or several different charge states, attract a lot of interest because of their potential applications in nanoelectronics. Single-electron sensitive electrostatic force microscopy (e- EFM) [1,2] is an convenient tool for probing such structures locally. The interpretation of the measured signal is relatively straightforward if the probed structure remains in one state for a long time compared to the time resolution of the experiment [3] or if the dynamics fast enough so that the charge reacts to the applied voltage virtually immediately. However, the interpretation becomes more complicated if the time scale of charge switching is comparable to the oscillations frequency of the e-EFM probe [2,4]. We present a numerical model which allows us to study the response of an oscillating probe in electrostatic force spectroscopy to the charge switching in chargeable structures at various time scales. We analyze the dependence of the frequency shift, the dissipated energy, and fluctuations in both these quantities, on the tip oscillation frequency and the relevant tunneling rates. We compare two complementary approaches to simulating the charge dynamics, a stochastic and a deterministic one. In addition, we derive analytic formulas valid for small amplitudes, describing relations between the frequency shift, dissipated energy, and the characteristic rates driving the charging and discharging process. The figure below shows simulated bias dependence of the frequency shift, in a wider voltage range (left) and around resonance for various discharging rates (right). References [1] M.T. Woodside & P.L. McEuen, Scanning probe Imaging of Single Electron Charge States in Nanotube Quantum Dots, Science 296, 1098-1101 (2002). [2] A. Roy-Gobeil, Y. Miyahara & P. Grutter, Revealing Energy Level Structure of Individual Quantum Dots by Tunneling Rate Measure by Single-electron Sensitive Electrostatic Force Spectroscopy, Nano Letters 15, 2324-2328 (2015). [3] J. Repp & al., Controlling the Charge State of Individual Gold Atoms, Science 305, 493-495 (2004). [4] R. Stomp & al., Detection of Single-Electron Charging in an Individual InAs Quantum Dot by Noncontact Atomic-Force Microscopy, Phys. Rev. Lett. 94, 056802 (2005).

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P6-ELPS_274 THE EFFECT OF ADSORBATES ON THE TRANSPORT CHARACTERISTICS OF AU CHAINS ON VICINAL SI(HHK) SURFACES

ELPS - Electronic properties of strong correlations systems F. Edler *, I. Miccoli, J.P. Stöckmann, H. Pfnür, C. Tegenkamp Institut für Festkörperphysik, Leibniz Universität Hannover - Hannover (Germany) Atomic chain ensembles grown by self-assembly are prototype 1D systems with outstanding electronic properties for fundamental research studies such as Peierls driven metal to insulator phase transition (MIT) or dimensional crossover from Fermi to Luttinger liquid behavior. However, it is well know that these properties are strongly affected by imperfections or near surface modifications, e.g. the interwire coupling as well as MIT temperature of indium chains on the Si(111)-4x1 surface is strongly dependent on the presence of oxygen-mediated defects [1]. Here, we present a systematic study on the transport properties of chains of gold atoms self- assembled on vicinal Si(hhk) surfaces via a multi-tip STM/SEM system and the rotational four-point-probe square method [2]. The transport characteristics of various Au/Si(hhk) systems, i.e. conductivity values along and perpendicular to the chains as well as the anisotropy ratio, were carefully studied and correlated with the miscut-angle of the substrate, the gold coverage and the Au-induced surface refaceting (investigated by LEED). In addition, in-situ adsorption experiments with molecular and atomic species (i.e. O2, H+) were performed to tune and modify the intra- and interwire couplings within the ensemble. Most strikingly, the Au/Si(553) system showed for Au chain ensembles prepared with different Au coverages very different transport characteristics as exposed to oxygen. While the 0.48 ML Au on Si(553) turns out to be extremely robust and almost unaffected (up to 60 Langmuir), the 0.19 ML phase, where Au adsorbs on every next but Si terrace [3], reacts strongly as seen by the exponential decrease and cross-over of its conductivity components. We will discuss the different transport findings in terms of the different building blocks (Au chains, Si-adatom chain, Si edge) found for the Au/Si(hhk) systems [4]. References [1] F. Edler et al., Phys. Rev. B 92, 085426 (2015) [2] I. Miccoli et al., JPCM 27, 223201 (2015) [3] I. Song et al., ACS Nano 9, 10621 (2015) [4] J. Aulbach et.al., Nano Letters 16, 2698 (2016)

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P7-ELPS_297 PLASMON PEAKS IN FE-SI ALLOYS IN AUGER AND X-RAY PHOTOEMISSION SPECTROSCOPY

ELPS - Electronic properties of strong correlations systems J. Gervasoni 1,*, M. Jenko 2, M. Godec 2, A. Juan 3 1CNEA-CONICET - Bariloche (Argentina), 2Institute of Metals and Technology - Ljubljana (Slovenia), 3CONICET - Bahia Blanca (Argentina) Fe-Si has been the subject of experimental and theoretical interest for over fifty years [1]. The most direct way to shed light on the electronic structure, including many-body effects of a material is the resolved photoemis-sion spectroscopy angle technique (ARPES, or AES). Furthermore, the energy resolution is not sufficient, in some cases, to give clear answers to the issue of the electronic nature of these states [2]. Therefore, highly resolved AES is used to study in detail the performance of sin-gle crystals of Fe-Si with a very low concentra-tion of the impurity. We investigate in detail the effects due to the interaction between an electron and a stationary positive ion (or atomic hole) in the neighborhood of a surface of Fe-Si, having a strong plasmon peak in their electron energy loss spectra. The plasmons leave a mark in the Auger and XPS spectrum which poses a challenge to the spectra analysis. The method described here is useful for studying multiple plasmon excitations and for under-standing the electron spectra excited from these alloys. In this work we describe in detail the contribution to the energy loss of the external particles (electron plus holes) in the sample and the plasmon excitation due to this process. We treat the Auger electron emission in a very simplified manner in order to be able to develop analytical expressions accounting for surface and bulk plasmon excitations. A de- tailed description of the photoelectron process was done in ref. [3]. References [1] Riseborough P S 2000, Adv. Phys. 49, 257–320. [2] Jaccarino V, Wertheim G K, Wernick J H, Walk-er L R and Arajs S 1967, Phys. Rev. 160, 476–82. [3] J. L. Gervasoni and N. R. Arista, Surf. Sci. 260, 329 (1992).

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P8-ELPS_331 FORMATION OF SINGLE-ELECTRON TRANSISTOR ARRAYS BY FIELD-EMISSION- INDUCED ELECTROMIGRATION

ELPS - Electronic properties of strong correlations systems M. Ito *, K. Okada, K. Inoue, T. Ito, J. Shirakashi * Tokyo University of Agriculture and Technology - Koganei (Japan) We have studied simple and easy technique for the fabrication of planar-type nanogap- based single-electron transistors (SETs). In this method, electromigration is induced across the nanogap by a field emission current, and then the island structure is formed in the nanogap. We call this method “activation” [1, 2]. The activation scheme can control the tunnel resistance of nanogaps and fabricate the Ni-based SETs with multiple islands [3, 4]. Here, in order to integrate SETs, a field emission current was simultaneously applied to the ten series-connected initial nanogaps. This procedure was repeated several times while preset current Is was increased from 1 nA (1st activation) to 1 μA (10th activation). When preset current Is was set to 1 nA (1st), the current-voltage characteristics showed insulation- like properties. Then, in simultaneously activated devices after performing the activation with preset current Is ranging from 100 nA (3rd) to 200 nA (5th), current-voltage curves displayed Coulomb blockade properties, and Coulomb blockade voltage was also modulated by the gate voltage at room temperature. In addition, the nonlinear properties without Coulomb blockade properties were obtained, as the preset current Is was set to 300 nA (7th). Consequently, the current-voltage properties of the devices were simultaneously varied from “insulating” to “nonlinear” through “SET” properties with increasing the preset current. These results suggest that the accumulation of atoms within the gap was significantly increased due to the higher preset currents. Therefore, it is expected that as the preset current Is increases, the size of the islands is increased and the number of the islands is decreased. These results imply that the integration of SETs and precise tuning of SET properties can be successfully achieved by the activation method. References [1] S. Kayashima, K. Takahashi, M. Motoyama, and J. Shirakashi, Jpn. J. Appl. Phys., Part 2 46, L907 (2007). [2] Y. Tomoda, K. Takahashi, M. Hanada, W. Kume, and J. Shirakashi, J. Vac. Sci. Technol., B 27, 813 (2009). [3] W. Kume, Y. Tomoda, M. Hanada, and J. Shirakashi, J. Nanosci. Nanotechnol., 10, 7239 (2010). [4] S. Akimoto, M. Ito, S. Ueno, and J. Shirakashi, J. Nanosci. Nanotechnol., 13, 993 (2013).

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P9-ELPS_412 UNOCCUPIED ELECTRONIC STATES IN RU(0001)

ELPS - Electronic properties of strong correlations systems P. Häberle 1,*, V. Del Campo 1,*, J. Correa 2, J. Correa-Puerta 3, D. Kroeger 4 1Universidad Técnica Federico Santa María - Valparaíso (Chile), 2Universidad de Medellin - Medellín (Colombia), 3Pontificia Universidad Católica de Valparaíso - Valparaiso (Chile), 4Universidad Técnica Federico Santa María - Valparaiso (Chile) A combined theoretical and experimental description of the unoccupied electronic states of Ru(0001) is presented. A renewed interest in this surface derives from its current use as substrate to grow graphene by low pressure CVD [1]. We have used angle-resolved inverse photoemission spectroscopy (IPES) and an Ab initio calculations of the electronic structure of Ru(0001), to determine the energy dispersion of the different bulk derived states and surface resonances. Through the calculations we can identify the origin of most experimentally detected features. Both, measurements and calculations, represent a significant complement to previous reports [2] regarding ruthenium´s conduction band structure. The figure below shows the main results of both calculation and IPES measurements in an energy dispersion diagram. The blue markers indicate possible 9.5 eV optical transitions of surface derived resonances among calculated unoccupied bands. Black markers correspond to transitions between bulk electronic bands. The rest of the color markers describe the dispersion of the experimentally detected resonances. The spectral response is dominated by resonances with energies within 2 eV above the Fermi level. References 1.- Effects of surface impurities on epitaxial graphene growth, V. del Campo et al, App.Surf.Sci. vol. 264, 727 (2013). 2.- W. K. Siu and R. A. Bartynski, Phys. Rev. B. 75, 235427 (2007).

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GRA - Graphene and carbon-based nanomaterials

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I15_GRA_438 SELF-ASSEMBLED SEALED GRAPHENE NANOBLISTERS AS CAGES FOR SQUEEZED RARE GAS ATOMS

GRA - Graphene and carbon-based nanomaterials R. Larciprete 1,*, S. Colonna 2, F. Ronci 2, R. Flammini 2, P. Lacovig 3, N. Apostol 4, A. Politano 5, P. Feulner 6, D. Menzel 6, D. Menzel 7, S. Lizzit 3 1CNR-ISC Istituto dei Sistemi Complessi - Roma (Italy), 2CNR-ISM Istituto di Struttura della Materia - Roma (Italy), 3Elettra-Sincrotrone Trieste S.C.p.A. - Trieste (Italy), 4National Institute of Materials Physics - Magurele-Ilfov (Romania), 5Department of Physics, University of Calabria - Rende (cs) (Italy), 6Physikdepartment E20, Technische Universita¨t Mu¨nchen - Garching (Germany), 7Department of Chemical Physics, Fritz-Haber Institut - Berlin (Germany) In the last years, several methodologies based on chemical routes, lithographic patterning and block copolymer self-assembling have been envisaged to nanostructure graphene at the atomic level. Although these fabrication strategies have the potential to be eligible for several applications, issues might arise when chemical state and defect type in the quantum dots need to be known at the atomic level. A possible way to face this need is to turn to bottom-up strategies carried out in vacuum. We have shown that it is possible to profit from the extraordinary flexibility and mechanical strength of graphene coupled with its thermal instability on the surface of certain metals such as nickel to promote the dissolution of graphene in the substrate while forcing a small portion of it to keep afloat, owing to the presence of rare gas atoms intercalated underneath. The irradiation of epitaxial graphene monolayers on Ni(111) with low energy rare gas ions allows remarkable quantities of such atoms to remain trapped below graphene and once heated, to assemble into solid clusters. At higher temperature (above 900 K), while graphene in direct contact with the Ni surface decomposes, the floating regions encase the rare gas aggregates forming graphene nanosized blisters (GNBs), evenly distributed on the bare substrate surface and stable in a wide temperature range. We have followed [1] in real time, by X-ray photoelectron spectroscopy with synchrotron radiation, the self-assembling of the GNBs during the thermal annealing of the Gr/Ni(111) interface loaded with Ar and Ne and characterized their morphology and structure at the atomic scale by scanning tunneling microscopy (Fig.1). The GNBs contain the rare gas aggregates compressed at high pressure arranged below the graphene monolayer skin that is decoupled from the Ni substrate and sealed only at the periphery through stable C−Ni bonds. The integrity of the graphene lattice in the air-exposed GNBs has revealed their stability in atmosphere. They exhibit in-plane truncated triangular shapes driven by the crystallographic directions of the Ni surface and non-uniform strain along their profile, attributed to the inhomogeneous expansion of the flexible graphene lattice to envelop the rare gas atoms. The possibility to intentionally modify the termination of the bare metal surface surrounding the GNBs by chemical treatments and the known thermal instability of graphene on several transition metals and probably on their alloys prefigures the expansion of this method to a variety of GNBs/support systems. Finally, it is noteworthy to mention that the encapsulation of rare gas atoms in the GNBs provides at hand at room temperature a solid rare gas target ready to be probed with spectroscopic and structural tools. We have used the so-called core hole clock method [2] to characterize the Ar species in the various stages of GNB formation, in terms of their state of coupling or decoupling to their surroundings. The different behaviors observed for Ar pressed into the Ni substrate, Ar in contact with graphene, and Ar in the GNB interior shielded from both interfaces contribute to understand the physics of excitation decay in strongly coupled systems.

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Fig.1 (left) Side-view 3D rendering of the STM image taken on the Gr/Ni(111) surface dosed with 0.6 equivalent monolayers of Ar+ ions and annealed for 10 min at 1000 K and (right) GNB profiles taken along the indicated lines. References [1] R. Larciprete et al., Nano Lett. 16 (2016) 1808−1817 [2] Wurth et al., Chem.Phys. 251 (2000) 141–149

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O1-GRA_296 MOVING TOWARDS CHEMICALLY PATTERNED GRAPHENE; CONTROLLED FORMATION OF NEW BONDS AT THE GRAPHENE BASAL PLANE

GRA - Graphene and carbon-based nanomaterials A. Cassidy 1,*, J. Jørgensen 1, M. Kongsfelt 1, S. Pedersen 1, M.A. Arman 2, J. Knudsen 2, K. Daasbjerg 1, L. Hornekær 1 1Aarhus University - Aarhus (Denmark), 2Lund University - Lund (Sweden) Creating sp3 defect sites in an otherwise perfect sp2 graphene lattice, in a controlled manner, has been shown to introduce a band gap in the electronic structure of graphene [1]. Here, we exploit the Moire lattice which emerges following the epitaxial growth of graphene on an Ir(111) surface to create sp3 defect sites, in patterned formation, on the graphene basal plane. The barrier to bond formation is lowered in regions where the carbon atoms lie in a graphene-like configuration above Ir atoms and we use this phenomenon to guide the formation of new chemical bonds. This allows for the creation of sp3 defects, created by forming new bonds to C atoms in the graphene lattice, and introduces new chemical functional groups to the graphene surface. The aromatic sp2 C- bonds in the graphene lattice are thermodynamically stable and it requires highly reactive species to break the aromatic system and form new C-C bonds. This has directed research efforts towards the generation of reactive radical species in the vicinity of the graphene layer.[2] Typically, therefore, reaction pathways rely on electron transfer between the graphene sheet and the reactant molecule to generate radicals, with reactions taking place in conducting solvents. The uneven distribution of electron-hole puddles in graphene has been shown to have a large effect on the success of many of these reactions, in particular reactions involving diazonium salts to form new C-C bonds or strong oxidising agents to form graphene oxide.[3] We use a clean, surface science approach to functionalizing the graphene basal plane which allows us to follow the reaction with cryo- scanning tunnelling microscopy, x-ray photoelectron spectroscopy and mass spectrometry. We have used the thermal decomposition of molecular moieties, in some cases adsorbed as a molecular monolayer on a graphene sheet, under ultra-high vacuum conditions, to produce radicals which subsequently react with and bind to the underlying graphene sheet. The results provide a detailed spatial and electronic profile of the chemically functionalised graphene sheet. X-ray photoemission spectroscopy confirms that new bonds are formed at tne graphene basal plane while scanning tunnelling microscopy data shows that these bonds are selectively formed at preferred sites on the Moire pattern. References [1] R. Balog. et al., Nat. Mater. 2010, 9, 315. [2] G. L. C. Paulus, et al., Acc. Chem. Res. 2013, 46, 160. [3] M. Lillethorup et al., Small 2014, 10, 922.

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O2-GRA_178 GRAPHENE BAND GAP TAILORING BY SUBSTRATE NANOSTRUCTURATION

GRA - Graphene and carbon-based nanomaterials A. Celis 1,*, M. Narayanan 2, A. Taleb-Ibrahimi 2, A. Tejeda 1 1Laboratoire de Physique des Solides - Orsay (France), 2Synchrotron SOLEIL - Gif-Sur-Yvette (France) Nanostructuration is a successful way of tailoring the electronic properties of materials for devices [1]. One way of tuning electronic properties consists of exploiting the electronic confinement in artificial structures of nanometric size. Electronic confinement of metallic Shockley states has been demonstrated on noble metal surfaces by superperiodic potentials [2, 3]. Likewise, electronic confinement gaps have been observed on graphene nanoribbons of 1-2 nm width [4]. Here, we show two examples on how periodic nanostructures modify graphene’s electronic properties. By using a vicinal Ir and a nanostructured Pt substrate, we induce different superperiodicities on graphene triggering a band-gap opening in different energies and different regions of the reciprocal space. Our study correlates the mini gaps observed in Angle-Resolved Photoemission to the atomic structure observed by Scanning Tunneling Microscopy (STM). A Kronig-Penney model describes the graphene band structure and the induced band gap openings [5]. References 1. P. Lodahl, S. Mahmoodian and Soren Stobbe. Reviews of Modern Physics, 87, 347 (2015) 2. A. Mugarza, A. Mascaraque, V. Pérez-Dieste, V. Repain, S. Rousset, F.J. Garcia de Abajo, and J.E. Ortega. Physical Review Letters, 87, 107601 (2001) 3. C. Didiot, A. Tejeda, Y. Fagot-Revurat, V. Repain, B. Kierren, S. Rousset and D. Malterre. Physical Review B, 76, 081404(R) (2007) 4. I. Palacio, A. Celis, M. N. Nair, A. Gloter, A. Zobelli, M. Sicot, D. Malterre, M.S. Nevius, W.A. de Heer, C. Berger, E. Conrad, A. Taleb-Ibrahimi and A. Tejeda. Nanoletters, 15, 182 (2015) 5. J. Lima. Physics Letters A, 379, 1372 (2015)

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O4-GRA_313 TAILORING ELECTRONIC PROPERTIES IN LONG RANGE ORDERED ON SURFACE SYNTHETIZED POLYMERS

GRA - Graphene and carbon-based nanomaterials Y. Fagot-Revurat 1,*, S. Xing 1, G. Vasseur 1, M. Sicot 1, B. Kierren 1, D. Malterre 1, L. Moreau 1, L. Cardenas 2, G. Galeotti 2, J. Lipton-Duffin 2, F. Rosei 2, M. Di Giovannantonio 3, G. Contini 3, P. Le Fevre 4, F. Bertran 4, L. Liang 5, V. Meunier 5, P. Dmitrii F. 6 1Institut Jean Lamour - Vandoeuvre-Les-Nancy (France), 2INRS - Varennes (Canada), 3Instituto di Struttura della Materia, CNR - Roma (Italy), 4Synchrotron SOLEIL - Saint Aubin (France), 5Rensselaer Polytechnic Institut - New York (United States of America), 6Mc Gill University - Montreal (Canada) On-surface covalent self-assembly of organic molecules is a very promising bottom–up approach for producing atomically controlled nanostructures. Due to their highly tuneable properties, these structures may be used as building blocks in electronic carbon-based molecular devices. Following this idea, we report on the electronic structure of an ordered array of poly(para-phenylene) i.e. 3-AGNR nanowires produced by surface-catalysed dehalogenative reaction of dBB precursor on a Cu(110) surface [1]. By scanning tunnelling spectroscopy (STS) we follow the quantization of unoccupied molecular states as a function of oligomer length, with Fermi level crossing observed for long chains. Angle-resolved photoelectron spectroscopy (ARPES) reveals a quasi-1D valence band as well as a direct gap of 1.15 eV, as the conduction band is partially filled through adsorption on the surface (figure 1a). Tight-binding modelling and ab initio density functional theory calculations lead to a full description of the band structure, including the gap size and charge transfer mechanisms, highlighting a strong substrate–molecule interaction that drives the system into a metallic behaviour. Moreover, changing the precursor from dBB to dIB is shown to substantially increase the PPP HOMO- LUMO band gap approaching the metal-insulator transition. Finally, we recently succeed to grow quasi-infinite PPP chains on Cu(775) vicinal surfaces showing a long range ordering never observed before for polymers at surface (figure 1b, [2]). An original growth mechanism is emphasized and consequences on electronic properties will be discussed in the light of N- EXAFS and ARPES measurements. References [1] G. Vasseur et al., Nat. Comm. 7, 10235 (2016); [2] S. Xing et al.,to be published (2016).

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I05_GRA_439 DEFORMATIONS IN GRAPHENE ON A METAL

GRA - Graphene and carbon-based nanomaterials J. Coraux * Institut Néel (France) Much like every membrane, graphene is prone to deformations – rippling and wrinkling for instance. Being a crystalline membrane, it can also host more subtle deformations, some of which are periodic at nanometer scale, especially if graphene is contacted with a crystalline support. All these deformations influence the electronic and chemical properties of graphene, noteworthy giving rise to magnetic gauge fields, exotic quantum phases, or efficient patterns driving the nanoscale organization of a variety of species. I will first carefully introduce the crystallographic relationships between graphene and a crystalline support (here a metal), which will lead me to consider the concepts of commensurability and (an)isotropic in-plane strains, as well as the analogy with the optical moiré effect used to describe the superstructure between graphene and its support [1]. I will then briefly discuss the nanorippling of the graphene membrane under the influence of the interaction with the support [2,3,4]. Finally, I will present instances of in-plane strains locally induced by graphene wrinkles [5], edges [5] and vacancies [6], which in the latter case can yield global strains translating into a phase transition between two commensurate graphene/metal superstructures. References [1] A. Artaud et al. Universal classification of twisted, strained and sheared moiré superlattices. Sci. Rep. 6, 25670 (2016) [2] C. Busse et al. Graphene on Ir(111): physisorption with chemical modulation. Phys. Rev. Lett. 107, 036101 (2011) [3] S. Runte et al. Graphene buckles under stress: an X-ray standing wave and scanning tunneling microscopy study. Phys. Rev. B 89, 155427 (2014) [4] F. Jean et al. Topography of the graphene/Ir(111) moiré studied by surface X-ray diffraction. Phys. Rev. B 91, 245424 (2015) [5] M. S. Bronsgeest et al. Strain relaxation in CVD graphene: wrinkling with shear lag. Nano Lett. 15, 5098 (2015) [6] N. Blanc et al. Strains induced by point defects in graphene on a metal. Phys. Rev. Lett. 111, 085501 (2013)

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O5-GRA_368 FEMTOMAGNETISM IN GRAPHENE INDUCED BY CORE LEVEL EXCITATION OF ORGANIC ADSORBATES

GRA - Graphene and carbon-based nanomaterials A. Ravikumar 1,*, A. Baby 1, H. Lin 1, G.P. Brivio 1, G. Fratesi 2 1Università di Milano-Bicocca - Milano (Italy), 2Università degli Studi di Milano - Milano (Italy) We predict the induction or suppression of magnetism in the valence shell of physisorbed and chemisorbed organic molecules on graphene occurring on the femtosecond time scale as a result of core level excitations [1]. For physisorbed molecules, where the interaction with graphene is dominated by van der Waals forces and the system is non-magnetic in the ground state, numerical simulations based on density functional theory show that the valence electrons relax towards a spin polarized configuration upon excitation of a core-level electron. The system is magnetic until the core electron de-excites via one of the several electronic decay channels [2,3]. The magnetism depends on efficient electron transfer from graphene on the femtosecond time scale. On the other hand, when graphene is covalently functionalized, the system is magnetic in the ground state showing two spin dependent mid gap states localized around the adsorption site [4]. At variance with the physisorbed case upon core- level excitation, the LUMO of the molecule and the mid gap states of graphene hybridize and the relaxed valence shell is not magnetic anymore. Thanks This project has received funding from the European Union Seventh Framework Programme under grant agreement no. 607232 [THINFACE] and A.R. is grateful for this. We thank D. Sánchez-Portal, R. Martinazzo and A. Morgante for their useful comments. The work is performed within the PCAM European doctorate. References [1] Ravikumar, A. et al. Femtomagnetism in graphene induced by core level excitation of organic adsorbates. Sci. Rep. 6, 24603; doi: 10.1038/srep24603 (2016). [2] Adak, O. et al. Ultrafast Bidirectional Charge Transport and Electron Decoherence at Molecule/Surface Interfaces: A Comparison of Gold, Graphene, and Graphene Nanoribbon Surfaces. Nano Letters 15, 8316–8321 (2015). [3] Fratesi, G., Motta, C., Trioni, M. I., Brivio, G. P. & Sánchez-Portal, D. Resonant Lifetime of Core-Excited Organic Adsorbates from First Principles. The Journal of Physical Chemistry C 118, 8775–8782 (2014). [4] Santos, E. J. G., Ayuela, A. & Sánchez-Portal, D. Universal magnetic properties of sp 3 -type defects in covalently functionalized graphene. New Journal of Physics 14, 043022 (2012).

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O6-GRA_248 ELECTRONIC STRUCTURE OF LOW-ANGLE DISORDERED ROTATED GRAPHENE LAYERS

GRA - Graphene and carbon-based nanomaterials T. Le Quang 1,*, G. Trambly De Laissardière 2, D. Mayou 3, L. Magaud 3, C. Chapelier 1, V. Renard 1 1Université Grenoble-Alpes/CEA,INAC-PHELIQS, F-38000 Grenoble, France - Grenoble (France), 2Laboratoire de Physique Théorique et Modélisation, Université de Cergy-Pontoise-CNRS, F-95302 Cergy-Pontoise - Paris (France), 3Institut Néel, CNRS-Université Joseph Fourier, F-38042 Grenoble, France D’Hères, France - Grenoble (France) We have studied the local density of states (LDOS) of low-angle rotated graphene layers grown on C-face of SiC substrates by cryogenic scanning tunneling microscope (STM) and by tight- binding calculations. For the rotation angle (θ=2.2°), the calculations for disorder-free rotated layers with the same angle agrees well with our measurement by showing van Hove singularity peaks, whose separation is similar to ones reported previously (left figure and ref.). On the contrary, the measured LDOS of a system with a smaller rotation angle (θ=1.35°) is not reproduced by the disorder-free model. Instead of having two peaks laying in proximity of the Dirac point, several peaks are observed in the low-energy region (the blue curve in the right figure). A qualitative agreement with the low-energy peaks observed in our experiment is obtained by introducing disorder (either Anderson one, or vacancies) into the model of rotated graphene layers with a similar rotation angle. However, since we were unable to find any vacancy in our STM images, we believed that Anderson disorder induces low-energy features observed in our experiments. Thanks Toai Le Quang was supported by a CIBLE fellowship from Region Rhône-Alpes References I. Brihuega, P. Mallet, H. González-Herrero, G. Trambly de Laissardière, M. M. Ugeda, L. Magaud, J. M. Gómez-Rodríguez, F. Ynduráin, and J.-Y. Veuillen, PRL, 109, 196802, (2012).

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O7-GRA_117 FIRST PRINCIPLES STUDY OF CO ADSORPTION ON PT CLUSTERS DEPOSITED ON DEFECTIVE GRAPHENE

GRA - Graphene and carbon-based nanomaterials Y. Hamamoto *, S.A. Wella, K. Inagaki, Y. Morikawa Department of Precision Science and Technology, Graduate School of Engineering, Osaka University - Suita (Japan) Graphene, atomically thin two-dimensional material composed of a honeycomb lattice of carbon atoms, has drawn keen attention since its experimental realization, due to the peculiar electronic and structural properties. Nowadays, the applications of graphene to various industries have been explored extensively, among which one of the most promising candidates is the usage of graphene as a support material of metallic cluster catalysts. Experiments have demonstrated that Pt clusters deposited on graphene exhibit higher catalytic activity than on other carbon substrates such as carbon black and carbon nanotubes [1]. Similar phenomena can be found for Pt clusters supported on highly oriented pyrolytic graphite (HOPG), in which reduction of CO desorption temperature from the Pt clusters has been observed with temperature programmed desorption measurements [2,3]. The analogy between the HOPG surface and graphene suggests that CO poisoning tolerance plays an essential role also for Pt clusters on graphene. Despite these experimental evidences, however, little has been understood about the microscopic mechanism of the enhanced catalytic activity of Pt clusters on graphene. To gain theoretical understanding of these phenomena, we here investigate CO adsorption on Pt clusters on defective graphene as shown in the figure below. We show [4] that, unlike Pt clusters on pristine graphene, those deposited on graphene vacancies induce large electron transfer form Pt clusters to graphene, which is accompanied by a significant change in the electronic states of the Pt clusters. As a result, CO adsorption energies on these Pt clusters become much smaller than those on isolated Pt clusters and Pt surfaces, which can be a possible scenario for the enhanced catalytic activity observed experimentally. References [1] E. Yoo, T. Okata, T. Akita, M. Kohyama, J. Nakamura, and I. Honma, Nano Lett. 9, 2255 (2009). [2] T. Kondo, K. Izumi, K. Watahiki, Y. Iwasaki, T. Suzuki, and J. Nakamura, J. Phys. Chem. C, 112, 15607 (2008). [3] J. Oh, T. Kondo, D. Hatake, Y. Iwasaki, Y. Honma, Y. Suda, D. Sekiba, H. Kudo, and J. Nakamura, Phys. Chem. Lett. 1, 463 (2010). [4] Y. Hamamoto, S. A. Wella, K. Inagaki, and Y. Morikawa, in preparation.

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O8-GRA_355 TAILORING GRAPHENE CORRUGATION AND ELECTRONIC PROPERTIES ON METALLIC SUBSTRATES VIA ATOMIC OXYGEN INTERCALATION

GRA - Graphene and carbon-based nanomaterials R. Perez *, C. Romero-Muniz *, A. Martin-Recio, P. Pou, J.M. Gomez-Rodriguez Universidad Autonoma de Madrid - Madrid (Spain) Deposition of large areas of graphene on metallic substrates is now an important topic in surface physics because of the possibility of tuning electronic properties of the graphene monolayer through substrate interaction. More precisely the growth of graphene on Rh(111) lead to the formation of different rotational highly-corrugated domains with a strong dependence on the lattice parameter of the moiré unit cell [1]. These moiré patterns, where no Dirac cone in the graphene is found, have been extensively studied by means of STM experiments and DFT calculations. In this kind of strongly- interacting systems we can recover the original electronic properties of pristine flat graphene by intercalating atomic oxygen with a O-(2x1)-Rh(111) reconstruction under the graphene monolayer. A careful control of the experimental conditions together with theoretical calculations allowed us to track the whole process of the step-by-step decoupling of the layer.This process, that is not a simple linear function of the oxygen coverage [2], is illustrated in Fig. 1a, that shows the evolution of the electronic properties through the graphene PDOS for three stages of the oxygen intercalation process corresponding to different oxygen coverage (θO), leading to a totally-decoupled final stage. We have determined the atomistic mechanisms involved in the intercalation process: (1) Molecular oxygen dissociation; (2) penetration through extended defects and (3) diffusion of atomic oxygen under the graphene [3]. In particular, we have characterized (Fig. 1b) the possible paths for the underneath diffusion of atomic oxygen occupying the highest parts of the moiré pattern. The energy barrier for the diffusion path between adjacent hollow sites is shown in the inset. References [1] A. Martín-Recio, et al.: Nanoscale 7, 11300 (2015) [2] C. Romero-Muniz, et al.: Carbon 101, 129 (2016) [3] A. Martín-Recio, et al.: (2016) submitted

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I24_GRA_440 SURFACE ASSISTED SYNTHESIS OF GRAPHENE NANOSTRUCTURES ON SILVER

GRA - Graphene and carbon-based nanomaterials L. Savio * IMEM-CNR, UOS Genova - Genova (Italy) In this talk I will discuss our recent results on the formation of low dimensional graphene nanostructures on Ag(110) [1]. By a combination of scanning tunneling microscopy, spectroscopic techniques and density functional theory calculations, we demonstrate the formation of extended, chiral patterns of parallel graphene nanoribbons (GNR) by surface assisted Ullmann coupling and de-hydrogenation [2] of 1,6-dibromo-pyrene. The so-formed polymers are monodispersed in width and show alternated zig-zag and armchair sites at the edges. It’is well known that graphene is a material of exceptional properties, but its intrinsic zero-energy gap reduces the impact for applications in nanoelectronics. On the contrary, GNRs narrower than 10 nm are semiconductors, due to the electron confinement in one dimension and to edge effects [3]. The ability to grow highly ordered nano-ribbons is therefore of relevance for possible applications in nanodevices. Besides that, our result demonstrates the peculiarity of pyrene derivatives for the formation of GNRs on coinage metals, in particular on Ag(110). These results open the possibility of engineering nanostructures of particular shape and dimension (and hence with tailored electronic properties) by choosing suitable molecular precursors. The last part of the presentation will focus on studies of the chemical activity of supported graphene films. The role of a strongly interactive substrate like Ni in determining the adsorption properties and reactivity of supported graphene films, either pristine or defected [3,4], will be shown and implications in the use of graphene based materials for sensoristic applications will be discussed. References [1] M. Smerieri, I. Píš, S. Nappini, A. Lusuan, L. Ferrighi, C. Di Valentin, L. Vaghi, A. Papagni, M. Cattelan, S. Agnoli, E. Magnano, F. Bondino, L. Savio, in preparation. [2] C. Zhang, Q. Sun, H. Chen, Q. Tan, W. Xu, ChemComm 51, 495 (2015). [3] X. Li, X. Wang, L.Zhang, S. Lee, H. Dai, Science 319, 1229 (2008). [4] M. Smerieri, E. Celasco, G. Carraro, A. Lusuan, J. Pal, G. Bracco, M. Rocca, L. Savio, L. Vattuone, ChemCatChem 7, 2328 (2015) and in preparation. [5] E. Celasco, G. Carraro, A. Lusuan, M. Smerieri, J. Pal, M. Rocca, L. Savio, L. Vattuone, submitted.

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O9-GRA_208 GRAPHENE FORMATION IN TRANSMISSION ELECTRON MICROSCOPE (TEM)

GRA - Graphene and carbon-based nanomaterials M. Tanemura 1,*, M.S. Rosmi 1, Y. Yaakob 2, S. Sharma 1, G. Kalita 1, C. Takahashi 3, M.Z. Yusop 4 1Nagoya Institute of Technology - Nagoya (Japan), 2Universiti Putra Malaysia - Selangor (Malaysia), 3Aichi Gakuin University - Nagoya (Japan), 4Universiti Teknologi Malaysia - Johor (Malaysia) Graphene is one of the hottest materials in nanotechnology and nanomaterials science, thus a variety of applications is expected. The subjects to be solved for realizing those applications include the controllable synthesis of graphene. In this talk, in situ dynamic TEM observation of the graphene synthesis with various catalyst by solid phase reaction will be dealt with. For this purpose, 1-dimensional amorphous carbon nanofibers (CNFs) with a metal inclusion were fabricated on an edge of a graphite foil by Ar ion irradiation with a simultaneous supply of various kinds of metals at room temperature. CNFs without metal inclusion (pristine CNFs) were also prepared. The current-voltage (I-V) characteristics were measured in TEM equipped with a piezo-controlled nanoprobe electrode. For metal-included CNFs, metal nanoparticles were dispersed in amorphous CNF matrix, and depending on the catalytic property of the included metal, different types of nanocarbons formed during the electron current flow, such as carbon nanotubes and mixture of ring- shaped graphene and amorphous carbon for Fe-included [1] and Au- and Ag-included [2, 3] CNFs, respectively. By contrast, as shown in the present work, for Pd-included CNFs, graphene nanowire formed during I-V measurement. Different from Au and Ag cases, all the C around the Pd nanoparticles transformed into graphitic layers. It should be noted that agglomeration and migration of Pd nanoparticles occurred after the graphitization was almost completed (Fig. 1). In this graphitization process, current as high as ~4.5 uA was achieved for the graphene nanowire of ~10 and ~300 nm in width and length, respectively. In the talk, a comparison between the Pd-included CNF and a Cu-coated pristine CNF [4] will be also made. Thus, it is believed that the graphene formation by solid phase reaction is essential also for the growth area (position) control of graphene. Fig. 1 TEM images of a Pd-included CNF during I-V measurement. Inset: Enlarged image of graphene formed. References [1] M. Zamri Yusop, et al., ACS Nano 6 (2012) 9567. [2] C. Takahashi, et al., Carbon 75 (2014) 277. [3] Y. Yaakob, et al., RSC Advances, 5 (2015) 5647. [4] M. Rosmi, et al., Scientific Reports, 4 (2014) 7563.

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O10-GRA_180 MOLECULAR DYNAMICS SIMULATION OF GRAPHENE ON CU(111) WITH DIFFERENT LENNARD-JONES PARAMETERS.

GRA - Graphene and carbon-based nanomaterials S. Kolesnikov *, A. Sidorenkov, A. Saletsky Lomonosov Moscow State University - Moscow (Russian federation) The catalytic chemical vapor deposition (CVD) of carbon precursors is one of the most widespread methods that have been used to grow wafer-scale grapheme [1]. CVD is widely known to involve the decomposition of a carbon feedstock, either hydrocarbons or polymers, with the aid of heat and metal catalysts. Various metals, such as Cu, Ni, Pt, Ru, and Ir, have been proven to catalyse the growth of graphene. The growth mechanism of graphene on Cu is quite different from the others, because the solubility of carbon in the Cu bulk is very low, and the mobility of carbon can be concluded to be a purely surface-based process [2]. Graphene can be nucleated on various crystal facets on Cu, however, the Cu(111) surface is more preferable for synthesis of high quality monolayer graphene. Two predominant graphene orientations on Cu(111) have been observed [3]: one with zero rotational angle Θ and large Moiré pattern (6.6 nm periodicity) and another with Θ =7° and smaller Moiré pattern (2 nm periodicity). Moiré superstructures with another rotational angle (Θ =10.4°) are also observed [4]. MD simulations of graphene on Cu surfaces allow to investigate such interesting phenomena as the formation of Moiré superlattices, peeling and folding of graphene, interaction of graphene with metal clusters, and also jumping of metal nanodroplets. Usually, the Lennard-Jones potential is used to describe van der Waals interaction between carbon and Cu atoms. However, the investigation [5] showed that the binding energy of graphene on Cu(111) surface has only one minimum at zero rotational angle Θ. In this work we show that it is possible to fit Lennard-Jones potential which leads to the correct values of binding energies and binding distances and, at the same time, gives two (or three) different Moiré superstructures with rotational angles Θ =0° and Θ =7° (or Θ =0°,7°,10°). Thanks Computational resources were provided by the Research Computing Center of the Moscow State University (MSU NIVC). References [1] H. Tetlow, J. Posthuma de Boer, I.J. Ford, D.D. Vvedensky, J. Coraux, and L. Kantorovich, Phys. Rep. 542, 195 (2014). [2] H. Shu, X. Chen, X. Tao, and F. Ding, ACS Nano 6, 3243 (2012). [3] L. Gao, J.R. Guest, and N.P. Guisinger, Nano Lett. 10, 3512 (2010). [4] P. Süle, M. Szendrö, C. Hwang, L. Tapasztó, Carbon 77, 1082 (2014). [5] X. Shi, Q. Yin, and Y. Wei, Carbon 50, 3055 (2012).

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I12_GRA_441 PROBING AND MODIFYING GRAPHENE AT THE ATOMIC SCALE WITH STM AND NCAFM

GRA - Graphene and carbon-based nanomaterials J.M. Gomez-Rodriguez * Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid (Spain) Graphene, a single layer of carbon atoms in a honeycomb arrangement, is revealing, in the last few years, its high potential. Many extraordinary properties have been discovered and many other are emerging as a result of the huge experimental and theoretical effort devoted to this material. In this talk I will present some of our recent work [1-2] on the investigation of graphene at the atomic scale by means of scanning tunneling microscopy (STM) and non- contact atomic force microscopy (NCAFM) under ultra-high vacuum and at low temperature. First, it will be shown [1] that NCAFM is sensitive to the local stiffness in the atomic-scale limit on weakly coupled 2D materials, as graphene on metals. Our large amplitude NCAFM topography and dissipation images resolve the atomic and moiré patterns in graphene on Pt(111), despite its extremely low geometric corrugation. The imaging mechanisms are identified with a multiscale model based on density-functional theory calculations, where the energy cost of global and local deformations of graphene competes with short-range chemical and long-range van der Waals interactions. Atomic contrast is related with short- range tip-sample interactions, while the dissipation can be understood in terms of global deformations in the weakly coupled graphene layer. Remarkably, the observed moiré modulation is linked with the subtle variations of the local interplanar graphene-substrate interaction, opening a new route to explore the local mechanical properties of 2D materials at the atomic scale. In the second part of the talk, I will discuss our recent low temperature STM experiments, supported by ab initio calculations, that provide a comprehensive picture of the origin, coupling, and manipulation of the magnetism induced by H atoms on graphene layers. Here [2] we demonstrate that the adsorption of a single hydrogen atom on graphene induces a magnetic moment characterized by a 20 meV spin-split state at the Fermi energy. Our STM experiments show that such a spin-polarized state is essentially localized on the carbon sublattice complementary to the one where H is chemisorbed. This atomically modulated spin-texture, which extends several nanometers away from the H atom, drives the direct coupling between the magnetic moments at unusually long distances. The magnetic nature of the H induced graphene state is confirmed by external electronic doping. Using the STM tip to manipulate H atoms with atomic precision, we demonstrate the possibility to tailor the magnetism of selected graphene regions. References [1] B. de la Torre, M. Ellner, P. Pou, N. Nicoara, R. Pérez, and J. M. Gómez-Rodríguez. Phys. Rev. Lett. 116, 245502 (2016). [2] H. González-Herrero, J. M. Gómez-Rodríguez, P. Mallet, M. Moaied, J. J. Palacios, C. Salgado, M. M. Ugeda, J.-Y. Veuillen, F. Yndurain, I. Brihuega. Science 352, 437 (2016).

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O11-GRA_391 MOLECULAR HYDROGEN FOR GRAPHENE FUNCTIONALIZATION

GRA - Graphene and carbon-based nanomaterials L. Kyhl 1,*, R. Bisson 2, R. Balog 3, M. Groves 3, A. Cassidy 3, J. Jørgensen 1, S. Halkjær 3, J. Miwa 3, A.G. Cabo 1, T. Angot 2, P. Hofmann 3, M.A. Arman 4, S. Urpelainen 5, H. Bluhm 6, J. Knudsen 4, B. Hammer 3, L. Hornekær 3 1iNANO, University of Aarhus - Aarhus (Denmark), 2Aix-Marseille Université, CNRS, PIIM - Marseille (France), 3Department of Physics and Astronomy, University of Aarhus - Aarhus (Denmark), 4Division of Synchrotron Radiation Research, Lund University - Lund (Sweden), 5The MAX IV Laboratory, Lund University - Lund (Sweden), 6Chemical Sciences Division, Lawrence Berkeley National Lab - Berkeley (United States of America)

1 Previous studies have shown that H2 molecules do not dissociate on graphene on Ir(111) (gr/Ir(111)) and exposure to hydrogen radicals has therefore been the preferred method for hydrogenating gr/Ir(111).2-4 Here we present a new method for hydrogenation using vibrationally excited H2 molecules. We demonstrate that this new hydrogenation method is based on a domino effect: The barrier for the first H2 molecule to dissociate on gr/Ir(111) is found theoretically to ~3 eV, while the barrier decreases substantially for the subsequent impinging molecules yielding the proposed domino effect for the chemisorption reaction. Our study is based on results obtained by scanning tunneling microscopy (STM), high- resolution electron energy loss spectroscopy (HREELS), x-ray photoemission spectroscopy (XPS) and density functional theory (DFT) calculations. Our new hydrogenation method provides a new route for obtaining chemically functionalized graphene, but it is also very likely that the method could be used for hydroxylation of surface oxides. Thanks We would like to acknowledge support from the Danish Council for Independent Research and Innovation Fund Denmark (under the National Initiative for Advanced Graphene Coatings and Composites). References 1 E. Grånäs, T. Gerber, U. A. Schröder, K. Schulte, J. N. Andersen, T. Michely, and J. Knudsen, Surface Science 651, 57 (2016). 2 R. Balog, et al., Nature Materials 9, 315 (2010). 3 R. Balog, et al., Acs Nano 7, 3823 (2013). 4 L. Kyhl, R. Balog, T. Angot, L. Hornekaer, and R. Bisson, Physical Review B 93, 115403 (2016).

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I18_GRA_442 ATOMICALLY PRECISE GRAPHENE NANORIBBONS THROUGH ON-SURFACE SYNTHESIS

GRA - Graphene and carbon-based nanomaterials P. Liljeroth * Department of Applied Physics, Aalto University School of Science - Aalto (Finland) Graphene nanoribbons (GNRs) are a new class of materials that have promising applications in next-generation nanoelectronic, photonic and spintronic devices. GNRs have been predicted to show interesting electronic properties that depend strongly on their width and edge structure. However, the required precision cannot be achieved by top-down approaches, including e-beam lithography on a sheet of graphene or unzipping carbon nanotubes. Recently, bottom-up synthesis using molecular precursors has been shown to provide precise control over the width and edge geometry of GNRs [1]. By changing the monomer design, fabrication of a wide range of different GNRs can be achieved with engineered chemical and electronic properties. I will discuss the different GNRs that can be synthesized through the on-surface route. The armchair GNRs can be divided into three families based on their width N: GNRs with N = 3m or N=3m+1, where m is an integer, are semiconducting. On the other hand, GNRs with a width of N=3m+2 are predicted to be metallic within a nearest-neighbor tight-binding model. While more accurate calculations predict a presence of a bandgap, it should remain much smaller than those in the other armchair GNRs. We have synthesized N=5 armchair GNRs and studied their electronic properties in detail using low-temperature scanning probe techniques [2]. Scanning tunneling spectroscopy demonstrates that N=5 ribbons show nearly metallic behavior with much smaller bandgap than the wider N=7 GNRs belonging to the N=3m+1 family [3]. These narrow armchair GNRs with a small bandgap would form ideal molecular wires to be used as interconnects in molecular scale circuitry. In the typical picture of the on-surface synthesis, the substrate does not play a big role in the chemical reaction. In the second part of the talk, I will show that the substrate is not always an innocent bystander in these reactions. On Au(111) surface, the prototypical precursor dibromo- bianthryl (DBBA) polymerizes via an Ullmann route to form straight GNRs with armchair edges. However, on Cu(111), the DBBA precursor forms chiral (3,1)GNRs [4]. In contrast, dibromo-perylene (DBP) precursors do form armchair GNRs via Ullmann coupling, in close analogy to recent results on Au(111) [2]. The reaction intermediates highlight the role of the precursor shape, molecule- molecule interactions and substrate reactivity as decisive factors in determining the reaction pathway. Our findings help to realize new routes for previously unattainable covalently bonded nanostructures. References [1] L. Talirz, P. Ruffieux, R. Fasel, Adv. Mater. doi: 10.1002/adma.201505738. [2] A. Kimouche et al. Nat. Commun.6, 10177 (2015). [3] J. van der Lit et al. Nat. Commun. 4, 2023 (2013). [4] F. Schulz et al. submitted.

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O12-GRA_316 ELECTRONIC INTERACTION BETWEEN ORGANIC MOLECULES AND NITROGEN- DOPED GRAPHENE

GRA - Graphene and carbon-based nanomaterials V. Pham 1,*, C. Chacon 1, V. Repain 1, A. Bellec 1, Y. Girard 1, S. Rousset 2, M.C. Dos Santos 3, F. Joucken 4 1Matériaux et Phénomènes Quantiques, France (France), 2Matériaux et Phénomènes Quantiques, Paris, France (France), 3Instituto de Fésica Universidade de Sao Paulo, Brazil (Brazil), 4Physics department, University of Namur, Belgium (Brazil) Interaction between donor and acceptor molecules with graphene is key strategy for tuning and exploiting the unique properties of graphene in coupling with the unique properties of molecular building block in molecular electronics. Scanning tunneling microscopy/spectroscopy (STM/STS) offers unique surface investigation technique that provide both topography and electronic properties at atomic spatial resolution of the interacting systems. Here, we show the electronic interaction between porphyrins – a donor molecule and another type of acceptor molecule adsorbed on both pristine and nitrogen- doped graphene. We focus on the electronic interaction between these molecules with graphene, particularly, on nitrogen defect site of doped graphene. The STM results show that on graphene, these molecules form self-assembled molecular island. Strikingly, the molecules adsorbed above nitrogen doping sites are distinctively different (as bright molecules in Figure 1) as compared to those adsorbed on pristine graphene area. This effect is both originated from (i) different polarizability [1] and (ii) small charge transfer [2] of doped graphene that is locally different at nitrogen doping site more than the bare graphene area. As a consequence, the STS taken on these bright molecules revealed a downshift of HOMO- LUMO gap. Then, tip manipulation was used to remove the molecular self-assembly, that finally discovered the underlying nitrogen dopants in order to determine their relative position to the molecules with atomic precision. Our current results offer a basic understanding of the electronic interaction between different types of molecule (donor and acceptor) with graphene, particularly with atomic defect site on graphene (nitrogen doping). This work help better understand on the future fabrication of graphene-related electronic devices, for example, graphene sensor.

Figure 1: STM image of self-assembled porphyrin molecules adsorbed on nitrogen-doped graphene. The bright molecules are sitting above the nitrogen dopants and induced by nitrogen sites. Thanks This work was supported by the Labex SEAM. References [1] Pham V. D. et al. Accepted in Scientific Report. (srep24796, 2016). [2] Pham V. D. et al. ACS Nano, 8 (2014) 9403-9409.

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O13-GRA_289 FOURIER TRANSFORM MICROSCOPY-BASED UNIVERSAL CLASSIFICATION OF TWISTED AND SHEARED GRAPHENE MOIRÉ SUPERLATTICES

GRA - Graphene and carbon-based nanomaterials A. Artaud *, L. Magaud, T. Le Quang, V. Guisset, P. David, C. Chapelier, J. Coraux Univ. Grenoble Alpes, F-38000 - Grenoble (France) A prototypical example of a moiré pattern is that found between two twisted graphene layers in graphite, which is frequently observed in transmission electron microscopy experiments. The effect is reminiscent of the optical beating effect observed through two thin tissue veils, and translates the locally varying nature of the approximate coincidence between two crystal lattices of different structure or orientation. Similar patterns are ubiquitous at the interface between an ultra-thin layer – a metallic atomic layer, an oxide film, graphene, boron nitride, a transition metal dichalcogenide layer, etc – and a substrate. In the context of graphene, moiré patterns have received considerable interest as they allow for enriching the properties of graphene. The description of moiré superlattices however remains incomplete, and a unifying geometric description is still missing. Using a consistent direct and Fourier analysis of scanning tunneling microscopy (STM) images, we achieve an accurate assignment of the atomic structure underlying moiré superlattices with precision better than 0.001Å. We reveal commensurate superlattices with unit cells of few 1,000 atoms and show that besides the well-known biaxial strains and small- angle twins, shears characterize the fine structure of graphene on a substrate, as exemplified for Re(0001) (see Figure). Our analysis is illustrated on different graphene- based systems [1] and holds generality for other ultra-thin films or atomic layers on substrates.

Figure: (a) STM topograph (5.6 x 5.2 nm²) of graphene on Re(0001). The graphene lattice is highlighted (black), so the moiré periodicity (blue), though commensurate with that of graphene (red), proves twisted and sheared. (b) Corresponding FFT-image with extrapolated moiré reciprocal lattice (black) and consistently interpreted graphene periodicity. Inset: moiré spots surrounding the central spot of the FFT-image with improved contrast. References [1] A. Artaud, L. Magaud, T. Le Quang, V. Guisset, P. David, C. Chapelier, J. Coraux, Universal classification of twisted, strained and sheared graphene moiré superlattices, Scientific Reports (accepted)

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P1-GRA_58 EFFECT OF ADVANCING LIQUID CONTACT LINE ON DEPOSITS OF ARC- DISCHARGE MULTIWALLED CARBON NANOTUBES

GRA - Graphene and carbon-based nanomaterials M. Ahlskog *, M. Hokkanen * University of Jyväskylä - Jyväskylä (Finland) We studied spreading of drops of water on multiwall carbon nanotube (MWNT) depositions [1]. These deposits consisted of individual arc-discharge synthesized MWNTs and irregular amorphous carbon nanoparticles on hydrophilically rendered silicon substrates. The mobile circular contact line of a spreading drop created an annular shape on the deposit (Fig. 1), where some of the MWNTs and the amorphous nanoparticles in particular were largely depleted. The effect was strongly dependent on the hydrophilicity of the substrate. Most of the MWNTs were not only left within the annuli, but were also apparently reoriented by their interaction with the passing contact line (Fig. 2). Arc-discharge synthesized MWNTs have been proven to be of high quality [2], but their use is very limited due to difficulties in obtaining them in a clean and undamaged form. Our results imply the possibility of applications in improvement of nanotube depositions in terms of both tube orientation and cleanliness, and in a way that preserves the high intrinsic quality of arc-discharge MWNTs. References [1] M.J. Hokkanen, R. Lehto, J. Takalo, J. Salmela, S. Haavisto, A. Bykov, R. Myllylä, J. Timonen, M. Ahlskog, Colloids and Surfaces A, 482, 624 (2015). [2] S.N. Bokova, E.D. Obraztsova, V.V. Grebenyukov, K.V. Elumeeva, A.V. Ishchenko, V.L. Kuznetsov. Phys. Status Solidi B, 247, 2827 (2010).

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P2-GRA_93 APPLICATION OF NANODIAMONDS FOR DEVELOPMENT OF COMPOSITES WITH REINFORCING TIC NANOPARTICLES.

GRA - Graphene and carbon-based nanomaterials V. Popov * National University of Science and Technology "MISIS" - Moscow (Russian federation) One of the problems impeding the wide application of TiC nanoparticles for reinforcing metal matrix in composites is the presence of foreign inclusions and contaminants on the nanoparticle surface because the surface corresponds to the interface between the reinforcing particles and the metal matrix. The goal of this study is to develop an “in-situ” method for the synthesis of TiC reinforcing nanoparticles directly inside the metal matrix, thus avoiding contamination at the matrix-reinforcements interface. TiC synthesis was executed by mechanical alloying during 8 h. Nanodiamonds [1-4], carbon black and graphite were used as carbon materials for synthesis. The following ratios of starting materials were employed: Al – 30 g, Ti – 31.98 g, carbon materials – 8.02 g. The XRD investigation indicated that these technological conditions lead to the complete “in-situ” synthesis of the TiC nanoparticles for all kinds of the carbon materials. The XRD patterns showed only aluminum and titanium carbide peaks. The results of the granule structure investigation using scanning electron microscopy (SEM) reveal that TiC particles have sizes range from 10 to 30 nm for nanodiamonds use only; for other cases, TiC reinforcing particles have size up to micrometres. The differential scanning callorimetry (DSC) is considered a significant part of the study because it is used to obtain data on the functional capability of the composite under high-temperature conditions. The DSC curve shows that chemical reactions between the titanium carbide nanoparticles and the aluminum alloy start at temperatures higher than 750 °С. Thus, the composite synthesized in this study can be used as a master alloy in casting technologies without the occurrence of unwanted chemical reactions. Thanks The author is grateful to A. Prosviryakov, E. Shelekhov, T. Sagalova, B.Senatulin and N. Dremova for assistance in investigation. References 1.Kuznetsov VL, Aleksandrov MN, Zagoruiko IV, Chuvilin AL, Moroz EM, Kolomiichuk VN et al. Carbon 1991; 29 (4-5): 665–668 2.Popov VA, Shelekhov EV, Vershinina EV. Eur J Inorganic Chem 2015; DOI: 10.1002/ejic.201501149 3.Popov V. Phys Status Solidi A 2015; 212: 2722–2726 4.Popov VA. Metal matrix composites with non-agglomerated nanodiamond reinforcing particles. In: Xiaoying Wang (Ed.), Nanocomposites: Synthesis, Characterization and Applications, Nova Science Publishers, New York, 2013, 369-401.

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P3-GRA_120 INFLUENCE OF THE GRAPHENE BUFFER LAYERS ON THE MOLECULAR FE COMPLEXES DEPOSITED ON NI(111)

GRA - Graphene and carbon-based nanomaterials M. Pedio 1,*, A. Kumar 1,*, A. Goldoni 2, M. Panighel 2, A. Nefedov 3, C. Cepek 2 1CNR-IOM lab TASC - Trieste (Italy), 2Sincrotrone Trieste - Trieste (Italy), 3Sincrotrone Trieste - Karlsruhe (Germany) Research on graphene (GR) has experienced an explosive growth in the last few years. When associated with magnetic nanostructures, hybrid systems are expected with a variety of magnetic functionalities. Metal complexes adsorption on surfaces with and without GR buffer layers and the resulting electronic and magnetic properties are a crucial issue and a fine characterization of these interfaces is mandatory. Recent results of phthalocyanines deposited on ferromagnetic metallic surfaces and GR buffer layers have revealed a substrate-molecule coupling mechanism, showing a delicate interplay between long-range interactions, local chemical bonding and magnetic moment. We present a combination of NEXAFS and XPS measurements employed to study the adsorption of molecular Fe-complexes (ferrocene Fe(C5H5)2 and Fe(III)tetraphenylporphyrin chloride, FeTPP-Cl) deposited on well characterized graphene supported by Ni(111) and compared with the adsorption on HOPG substrate. The two set of molecules have been chosen for their different structural surrounding of the Fe ion and the different distance between Fe in the adsorbed molecules and the substrate. Physisorbed Ferrocene on HOPG presents its 5-fold symmetric molecular axis oriented approximately perpendicularly to the surface and the Fe L3 XAS lineshape is similar to that of the multilayer Ferrocene Thin Film. Though the molecular orientation on GR/Ni(111) results similar to the HOPG case, the Fe L3 features result broader and slightly shifted. GR layers covered homogeneously the Ni(111) substrate andbare areas were absent as imaged by STM [1]. FeTPP-Cl on GR/Ni(111) shows a flat laying orientation and, up to 1 monolayer, an altered Fe L3 lineshape in a Fe(II) configuration and the loss of the Cl atom. For higher coverages the Cl is present in the detected spectra together with a Fe(III) ion. Our findings indicate that the coupling is mediated via the π electronic states of the substrate, while no covalent bonds between the molecule and the substrate are established. Similar results are found also in the case of HOPG substrate for FeTPP up to 1 ML. The differences in the organic electronic properties found in the two Fe complexes deposited layers onto the two HOPG and GR/Ni(111) substrates will be discussed. Thanks This research was supported by the GRAF PRIN project and the CALYPSO Program to access the BESSY II facility References [1] L. L. Patera, C. Africh,, R. S. Weatherup, R. Blume, S. Bhardwaj, C. Castellarin-Cudia, A. Knop- Gericke, R. Schloegl, G. Comelli, S. Hofmann, C. Cepek ACS Nano 7, (2013) 7901-7912.

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P4-GRA_199 TIP-INDUCED INTERACTION EFFECTS IN STM STUDIES OF MOIRÉS ON GRAPHENE ON SIC(000-1)

GRA - Graphene and carbon-based nanomaterials L. Huder *, V.T. Renard, C. Chapelier, L. Jansen INAC/PHELIQS, CEA Grenoble, UGA - Grenoble (France) Graphene consists of a 2D honeycomb lattice of carbon atoms with a unique electronic band structure (Dirac cones). Multilayers of graphene grown on carbon-faced silicon carbide (SiC(000-1)) is known to stack with a rotational disorder1 inducing the superposition of atomic lattices with one rotated with respect to the other giving rise to a moiré pattern that can be observed by Scanning Tunnelling Microscopy (STM). The electronic density of states (DOS) of rotated graphene bilayers is known to display van Hove singularities (vHs) due to the crossing of the Dirac cones in the reciprocal space of each layer2. The corresponding peaks in the DOS can be locally probed by Scanning Tunnelling Spectroscopy. However, recent experiments in our group3 showed that reproducible multiple peaks arise and a possible explanation could be the strain-induced lifting of the vHs degeneracy due to the tip-sample interaction. To check whether or not the tip can interact enough with the graphene to induce changes in the corrugations and the spectroscopy of moiré patterns of graphene, extensive STM studies were conducted in a home-made STM apparatus working at 50mK. Topography images and spectroscopies have been done at different tunnelling conditions (bias and current). This poster will show that the presence of tip-induced interaction effects lead to strong deformations of the STM images under harsh tunnelling conditions. The observed corrugation is abnormally important and may eventually give rise to abrupt local jumps in the topography. The tunnel junction has also been characterized by I(z) measurements. The very low apparent work function demonstrates that tip contamination is at the origin of an interaction-enhanced corrugation4. This interaction appears to be spatially modulated by the local stacking at the moiré scale as recently shown for graphene on hBN5. References 1J. Hass, W. A. de Heer and E. H. Conrad, The growth and morphology of epitaxial multilayer graphene, J. Phys.: Condens. Matter 20 (2008) 2G. Trambly de Laissardière, D. Mayou, and L. Magaud, Numerical studies of confined states in rotated bilayers of graphene, Physical Review B 86 (2012) 3Toai Le Quang, Microscopie et spectroscopie tunnel à très basse température de graphène épitaxié sur SiC, PhD thesis, Université Grenoble Alpes, (2016). 4H.J. Mamin et al., Contamination-mediated deformation of graphite by the scanning tunneling microscope, Physical Review B 20, (1986). 5M. Yankowitz et al., Pressure-induced commensurate stacking of graphene on boron nitride, arXiv:1603.03244, (2016).

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P5-GRA_210 ENERGY DISSIPATION AND TRANSITION RADIATION PRODUCED BY THE INTERACTION OF CHARGED PARTICLES WITH A GRAPHENE SHEET

GRA - Graphene and carbon-based nanomaterials J. Gervasoni 1,*, S. Segui 2, N. Arista 3, Z. Miskovic 4 1CNEA-CONICET - Bariloche (Argentina), 2CONICET - Bariloche (Argentina), 3CNEA - Bariloche (Argentina), 4CNEA - Waterloo (Canada) As a fundamental technique to study the electronic and optical properties of nanostructures, electron energy loss spectroscopy (EELS) has been extensively used to characterize single- and multi-layer graphene. This technique is performed in transmission electron microscopes (TEM) with high energy electron beams (around 100 keV), for which relativistic effects could be important. Although non-retarded calculations have reproduced experimental spectra quite succesfully, some aspects of the radiation processes induced by the incident particle remain unclear, such as the transition radiation patterns in the presence of plasmon fields. Also, in order to evaluate its importance in TEM experiments, a quantitative assessment of the relativistic correction to the energy loss spectra is necessary. This work addresses these issues by using a relativistic formulation of the electromagnetic fields, and modeling the conductivity with the well-known dielectric response with adequate parameters to describe the electronic properties of graphene. We start with a thorough description of the theory used. In particular, we present detailed expressions for the electromagnetic fields, the energy loss formulas used to calculate the spectra, and the models of conductivity applied in different regimes. We show and discuss the principal results obtained for doped and neutral graphene monolayers.

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P6-GRA_212 SILICENE AND FEW-LAYER SILICON FILMS ON METAL SURFACES

GRA - Graphene and carbon-based nanomaterials D. Lin *, H.D. Chen *, C.Y. Lin National Tsing Hua University - Hsinchu (Taiwan, republic of china) Growth by molecular beam epitaxy (MBE) of Si on Ag(111) results in 2D silicene islands at sub-monolayer coverages and a two-dimensional film with surface structure at near monolayer (ML) coverage. The same pattern persists for coverages of Si up to several MLs. The atomic structure of the resulting Si film has posed an intriguing question. One possible scenario is that Ag acts as a surfactant to foster the low-temperature growth of metastable silicene mulitlayers, which would be an analogue of graphite and a new state of Si. Yet another possibility is the formation of diamond- structured Si. In our experiment, we use low- temperature scanning tunneling microscopy (LT-STM) to observe the chemical response of the film surface exposed to an atomic deuterium (D) beam. We find D displaces the Ag surfactant adatoms, resulting in a D-terminated surface. The displaced Ag atoms migrate on the surface to form Ag(111) crystallites as shown in Fig. 1. The same reactions have been observed for a Si(111) bulk single-crystal surface decorated by Ag. The results confirm that the multilayer Si films grown on Ag(111) have a bulk Si structure, not a stack of silicene [1]. Thanks The authors wish to acknowledge the financial support of Taiwan's National Science Council under grant NSC 102-2112-M-007-008-MY3. References [1]. Chen, H.-D.; Chien, K.-H.; Lin, C.-Y.; Chiang, T.-C.; Lin, D.-S., Few-Layer Silicon Films on the Ag(111) Surface. J. Phys. Chem. C 2016, 120, 2698-2702.

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P7-GRA_230 NOVEL GRAPHENE-TITANIA INTERFACES AS A POTENTIAL CATALYTIC MATERIAL TOWARDS CLEAN ENERGY PRODUCTION

GRA - Graphene and carbon-based nanomaterials N. Jabeen * University of Trieste, Italy - Trieste (Italy) The increase energy demand of the world stimulated an intense research to develop clean energy technologies. In this respect, a lot of efforts have been spent in the last decade to develop materials for hydrogen production. Graphene, along with transition metal oxides have received much attention as photocatalyst, electrocatalyst and interlayer materials in energy conversion devices, especially because of their stability, controllable band gap and charge carrier properties. To exploit all these properties we have grown high-quality and thermally stable graphene-titania interfaces. We adopted the strategy of growing titania clusters above the corrugated graphene layer prepared on Ir(111), at the interface and in both configurations. A detailed description of titania clusters and Ti intercalation and oxide formation have been successfully determined by following in-situ the evolution of the surface species using core-level photoemission spectroscopy with synchrotron radiation. This study allows us to understand the reaction of titanium surface with oxygen above and at the interface of graphene and demonstrate the co-existence of sub oxide moieties along with titania. We expect that the knowledge acquired in the photoemission experiments will allows us to understand the relationship between interfacial structure, chemical composition and photocatalytic activity.

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P9-GRA_349 PERIODIC ARRAY OF GRAPHENE QUANTUM DOTS EMBEDDED IN A CARBON- BORON-NITROGEN ALLOY

GRA - Graphene and carbon-based nanomaterials J. Jørgensen 1,*, L. Camilli 2, A. Stoot 2, A. Cassidy 1, R. Balog 1, J. Sadowski 3, P. Bøggild 2, L. Hornekær 1 1Aarhus University - Aarhus C (Denmark), 2Technical University of Denmark - Kongens Lyngby (Denmark), 3Brookhaven National Laboratory - Upton (United States of America) Two-dimensional (2D) materials have received enormous attention in the field of materials science and condensed matter physics in the last decade, with the ultimate goal being developing a new technology based on these materials [1]. A huge variety of promising 2D materials have been identified and the ability to combine these into complex structures is essential. For this reason the synthesis of 2D hetero-structures – i.e., structures resulting from the combination of two or more 2D materials – have been subject to an intense research effort over the last few years [2]. Here we report the first observation of spontaneous formation and self-assembly of graphene quantum dot superlattices embedded in a two-dimensional boron-carbon-nitrogen alloy. By exposing a hot Ir(111) surface to carbon and boron-nitrogen precursor molecules it is found, using scanning tunnelling microscopy (STM), that the otherwise bulk-immiscible graphene and hexagonal boron nitride (hBN) materials can form a stress induced alloy. Furthermore, pure-phase dislocations are found to co-exist with the alloy resulting in the bright triangular pattern of graphene nanoribbons seen in figure A and C. Above a critical carbon concentration, a periodic array of graphene quantum dots of highly regular size and periodicity appears, as evidenced by the bright dots in the STM images of figure B and D. These findings are consistent with well-established theories on elastic relaxations in ultrathin strained systems [3]. In addition, using low energy electron microscopy LEEM, the growth of the alloy structure is followed in- situ, figure 2A, and diffraction experiments seen in figure 2B confirm the presence of the ordered quantum dot pattern even on a macroscopic level. References [1] A.C. Ferrari et al. Nanoscale 7, (2015) 4598 [2] H. Lim et al., Chemistry of Materials 26 (2014) 4891 [3] V. Ozolins et al. Phys. Rev. Lett. 88 (2002) 096101

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P10-GRA_357 AB INITIO STUDY OF AZOMETHINE DERIVATIVE CANCER DRUG ON BORON NITRIDE AND GRAPHENE NANOFLAKES

GRA - Graphene and carbon-based nanomaterials F. Picaud 1,*, J. Bentin 1,*, G. Tijani 1, E. Delabrousse 1, E. Duverger 2 1Nanomedicine Lab - Besancon (France), 2Femto Lab - Besancon (France) Many of the pharmacological properties of conventional drugs used in chemotherapy can be improved through the use of nanocarriers1. In recent years, various types of drug/agent nanocarriers have been investigated2. More recently we studied the interactions between carbon as well as boron nitride nanotubes with different molecules, such as azomethine (C2H5N) and an anticancer agent (Pt(IV) complex) linked to an amino-derivative chain. Our theoretical results have shown that the nanocarriers do not affect the complexed platinum therapeutic agent3,4. At the light of these examples, it is thus crucial to correctly select and control the surface coating of the nanocarriers to achieve specific aims in biomedical applications. In this contribution, in order to increase the number of potential nanocarriers, we study thanks to DFT method implemented in SIESTA code, non covalent and covalent interactions of aminoderivative anticancer platinum drug with graphene and boron nitride nanoflakes. We present results on the influence of the bonding on the electronic distribution of charge and on the impact on the electronic structure, activity and conformation of the drug after its interaction with the nanoflake. Thanks Computations have been performed on the supercomputer facilities of the Mésocentre de calcul de Franche-Comté. References [1] T. M. Allen, P. R. Cullis, Science 303, 1818 (2004). [2] R. Bawa, Nanomedicine 5, 5 (2009). [3] S. Kraszewski, E. Duverger, C. Ramseyer and F. Picaud, J. Chem. Phys.139, 174704 (2013). [4] E. Duverger, T. Gharbi, E. Delabrousse, F. Picaud, Physical Chemistry Chemical Physics 16, 18425 (2014).

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P11-GRA_374 DESIGN OF GRAPHENE-BASED NEW GENERATION SUPERCAPACITORS AS AN ENERGY STORAGE DEVICE

GRA - Graphene and carbon-based nanomaterials A. Karayel 1,*, O. Gulseren 2 1Hitit University, Faculty of Arts and Sciences, Department of Physics, 19030 - Corum (Turkey), 2Bilkent University, Faculty of Science, Department of Physics, 06800 - Ankara (Turkey) In this study, supercapacitors are modeled using first principles calculations based on density functional theory (DFT). Bilayer graphene as electrode and ammonia as electrolyte are used in these graphene-based supercapacitors. Both the combination of electrode and electrolyte are important in order to improve the energy storage capacity of the device. In our calculations, plane wave pseudo-potential method and the local density approximation (LDA) for exchange-correlation potential are used. First, the adsorption of ammonia on monolayer graphene is studied. The different configurations and orientations of NH3 on monolayer graphene are investigated. The relative position of NH3 with respect to graphene can be hollow (H), top (T) and bridge (B), where NH3 is placed at the center of hexagon, on top of the carbon atom and between two carbon atoms, respectively, with orientations of NH3 being up and down with respect to the position of H atoms. Bridge case is found to be the most energetically favorable. Consequently, supercapacitor is formed from bilayer graphene system. After extensive structure optimization calculations, electronic structure is investigated from density of states (DOS) calculations. Then, the quantum capacitance is calculated based on this DOS (Figure 1). Also, the effect of the concentration of the ammonia on the capacitance is studied. Then, the doping of the electrode by substituting the carbon by nitrogen or boron is examined (Table 1). In addition, defects like vacancy is also checked for possible contribution to the charge transfer of supercapacitor device. For realistic modelling of these capacitor devices, it is necessary to include the effect of solution because of the electrolyte. The effect of the solvent environment on the electronic structure and the quantum capacitance of the graphene based supercapacitor systems has been studied using the nonlinear polarizable continuum model. Accordingly, based on these thoroughly investigation, new devices are designed enhancing their energy storage performance.

Table 1. Optimization energies (E0), adsorption energies (Eads) and binding energies (Ebind) of the systems.

System Eo(eV) d (Å) Ebind(eV)

Bare_graphene with NH3 -1473.1649 6.04 -0.258224

N_doped graphene with NH3 -1471.8451 5.99 -0.407824

B_doped graphene with NH3 -1469.4113 6.02 -0.339924

Vacancy defect with NH3 -1455.1189 5.81 -0.318624 Thanks This work is supported by TÜBİTAK Project No: 114F118

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P13-GRA_425 APPLYING GRAPHENE: A CORROSION PREVENTING COATING

GRA - Graphene and carbon-based nanomaterials S. Halkjær 1,*, J. Iversen 1, A. Cassidy 1, L. Kyhl 2, L. Hornekær 1 1Department of Physics and Astronomy, Aarhus University - Aarhus (Denmark), 2Interdisciplinary Nanoscience Center, Aarhus University - Aarhus (Denmark) Corrosion protection is a global billion dollar industry. Ni/Cr alloys of the brand Inconel are highly resistant towards oxidation and corrosion and are used in a wide range of applications including nuclear and marine operations. The high corrosion resistance of Inconel stems from a thick passivation layer formed by metal oxides. Even though this passivation layer provides some protection against e.g. acidic environments an enhanced corrosion resistance is desired. A feasible route towards enhanced corrosion resistance of a metal surface is by applying a chemically inert and impermeable coating. Ideally, such a coating should additionally be lightweight and thin. Graphene, a two-dimensional (2D) material, consisting of carbon atoms arranged in a honeycomb structure, possesses these properties. Graphene has been shown to function as the described protective coating for several metal substrates towards a range of gases, water and saltwater [1, 2, 3]. However, the production of high quality graphene anti-corrosion coatings using chemical vapour deposition (CVD) methods often requires substrate temperatures of 800ºC and above, which is not suitable for most industrial applications. Therefore, the need to develop a method for direct growth of a graphene coating using lower temperatures is crucial. This study provides a proof of concept towards succeeding in the making of an anti-corrosion graphene coating on an industrial alloy, Inconel 625, at low temperature. The route for low- temperature graphene growth is here obtained through evaporation and deposition of coronene molecules and subsequent annealing. The procedure yields a network of micrometer sized graphene-like carbon based domains constituting the anti-corrosion coating (See the Scanning Electron Microscopy (SEM) image in figure 1). The corrosion resistance of the coating has been tested through exposure of the surface to HCl. A comparison with non-coated control samples proved the coating efficient in enhancing the corrosion resistance towards the tested environment. References [1] Kyhl et al., Faraday Discussions, 2015, Vol. 180, 495. [2] Nilsson et al., ACS Nano, 2012, Vol. 6, No. 11, 10258. [3] Chen et al., ACS Nano, 2011, Vol. 5, No. 2, 1321.

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P14-GRA_286 POLYCYLCIC CARBON MOLECULES WITH ZIGZAG EDGES AS SOURCES OF DEFECTS IN GRAPHENE ON A METAL

GRA - Graphene and carbon-based nanomaterials A. Artaud *, L. Magaud, K. Ratter, V. Guisset, P. David, B. Gilles, C. Chapelier, J. Coraux Univ. Grenoble Alpes, F-38000 - Grenoble (France) Unlike the armchair edge, the zigzag edge of graphene breaks the equivalence of its two constituting carbon sub-lattices. Uncompensated magnetic moments are thus expected for such edges [1]. For the same reason, dense polycyclic molecules (PCMs) terminated by zigzag edges are predicted to host net magnetic moments. Unfortunately, their synthesis is challenging. One approach relies on the pyrolysis of hydrocarbons, catalyzed by a transition metal [2,3,4]. Here we investigate this little-explored approach, and put in evidence the formation of a series of highly symmetric zigzag edge PCMs onto Re(0001), among which phenalenyl, coronene and sumanene (see Figure). We also address the relationship between the preparation of such molecules and graphene, which both form following hydrocarbon pyrolysis. We establish that the PCMs are unexpected obstacles towards high quality graphene, due to considerable barriers hindering their incorporation in the growing graphene, and to nanometer scale defects formed as they eventually get incorporated.

References [1] J. Fernández-Rossier, and J. J. Palacios, Magnetism in graphene nanoislands. Physical Review Letters 99, 177204 (2007) [2] Y. Cui, Q. Fu, H. Zhang and X. Bao, Formation of identical-size graphene nanoclusters on Ru(0001), Chemical Communications 47, 1470-1472 (2010) [3] B. Wang, X. Ma, M. Caffio, R. Schaub, and W.X. Li, Size-selective carbon nanoclusters as precursors to the growth of epitaxial graphene, Nano Letters 11, 424-430 (2011) [4] J. Lu, P.S.E. Yeo, C.K. Gan, P. Wu and K.P. Loh, Transforming C60 molecules into graphene quantum dots, Nature Nanotechnology 6, 247-252 (2011)

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LSI - Liquid/solid and liquid/liquid interfaces

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O1-LSI _4 EVALUATION OF SURFACE HYDROPHOBICITY AT ELEVATED TEMPERATURE AND PRESSURE FOR OIL & GAS APPLICATIONS

LSI - Liquid/solid and liquid/liquid interfaces B. Yu *, J. Stevens Baker Hughes Inc. - The Woodlands (United States of America) Extracting fossil fuels out of the earth crust has never been easy as many challenges downhole need to be overcome before drilling and production become economical. Some of the typical challenges that relate to surface phenomena are how to reduce hydraulic losses, how to control the scale build-up, and also how to mitigate the sticking of rock debris to the drilling tools. Hydrophobic surfaces or coatings could offer potential solutions. Hydrophobicity is the ability of a surface to repel incoming liquids. Hydrophobicity has been widely utilized in daily life, as well as in the automobile and construction industries. Most of those applications are mainly based on the knowledge developed under ambient conditions; however, when used in downhole, additional challenges arise. Factors such as elevated temperature and wellbore pressure may potentially cause the interface behavior to change. Therefore, evaluating the surface hydrophobicity under conditions which closely simulate downhole application conditions becomes essential. This paper describes the development of a laboratory-level water contact angle testing method under those harsh conditions. We also present the testing results of water contact angle measurements on selected surfaces and coatings at up to 150 °C and 1000 bar. We show the elevated temperature and pressure is generally acting positively on the surface hydrophobicity. Combining with the superior wear resistance, those candidate coatings show good potential in tackling the aforementioned problems for downhole tools.

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O2-LSI _240 SU-8 AND EPOXY HIERARCHICAL STRUCTURES FOR ICEPHOBICITY

LSI - Liquid/solid and liquid/liquid interfaces M. Psarski *, D. Pawlak, B. Spychala, J. Grobelny, G. Celichowski Faculty of Chemistry, Department of Materials Technology and Chemistry, University of Lodz, , Pomorska 163, 90-236 - Lodz (Poland) Icing of external surfaces, exposed to atmospheric conditions, is a serious engineering challenge. External infrastructure, such as overhead power lines, ships or airplanes, is prone to serious damage and service disruption. In extreme cases, such as in aviation accidents, the outcome can be fatal. Anti-icing methods currently in use are insufficient in terms of technical and/or economical effectiveness, so passive icing prevention strategies are actively investigated. Most strategies rely on water repellency as a prerequisite for icephobicity. Extreme water repellency is provided by superhydrophobic surfaces, combining nano- and micrometric hierarchical topography with low surface free energy (SFE). Nanometric structures, however, typically suffer from limited mechanical durability. A way to overcome the problem is to build structures from durable materials, such as epoxy resins. Such a structure can be hydrophobized by chemical modification with low SFE compounds. Here, a bisphenol A/F epoxy resin and SU-8 photoresist are proposed as durable materials for icephobic structures. Surface microtopography is obtained in either SU-8, by a direct photolithographic process, or in epoxy resin, by replication of negative SU-8 photolithographic patterns. The patterns comprise different regular geometries (pillars, brick- like walls, honeycomb), characterised by a common solid area fraction. Nanometric roughness is introduced on the top of the microstructures, by means of RF air plasma etching. The effectiveness of hydrophobization of epoxy resin and SU-8, by atmospheric pressure vapor phase deposition of a series of fluoroalkyl silanes, containing 3 to 12 carbon atoms in the alkyl chain, is first investigated. Advancing and receding water contact angles increase with increasing chain length and 1H,1H,2H,2H-perfluorododecyltrichlorosilane (C12) is selected as the most efficient precursor. All the hierarchical structures investigated here exhibit superhydrophobicity upon modification with C12. Ice adhesion to superhydrophobic surfaces is investigated by means of tensile measurements of frozen water droplet adhesion strength. Superhydrophobic surfaces, either epoxy or SU-8 based, exhibit adhesion strength values within 10-90 kPa, which is a reduction by 2 orders of magnitude in comparison to respective flat surfaces, modified with C12. The replication in epoxy employed here provides a scalability potential of the procedure. Thanks This work was supported by the Polish Ministry of Science and Higher Education within Research Grant No. UMO-2012/05/B/ST8/02876

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O3-LSI _259 METALATION, DEMETALATION AND METAL CENTER EXCHANGE OF PORPHYRINS AT THE SOLID/LIQUID INTERFACE

LSI - Liquid/solid and liquid/liquid interfaces M. Franke 1,*, F. Marchini 2, N. Jux 3, H.P. Steinrück 1, O. Lytken 1, F. Williams 2 1Institute of Physical Chemistry II, FA-University Erlangen-Nürnberg - Erlangen (Germany), 2Department of Inorganic, Analytical and Physical Chemistry, University of Buenos Aires - Buenos Aires (Argentina), 3Institute of Organic Chemistry II, FA-University Erlangen-Nürnberg - Erlangen (Germany) Porphyrins are large organic molecules with potential in numerous technical applications. They exhibit a central cavity surrounded by four nitrogen atoms, capable of coordinating either two protons (free-base form) or a metal ion. In liquid medium free-base porphyrins can be metalated to form metalloporphyrins in neutral or alkaline solutions by exposure to metal ions and demetalated back to the free-base form by exposure to acidic solutions. Futhermore, it is also possible to exchange one metal ion center with another. We have transferred this liquid phase synthesis approach to the surface and studied metalation,[1] demetalation[2] and metal center exchange[2] of 5,10,15,20- tetraphenylporphyrin adsorbed on a Au(111) single-crystal surface. Exposure to a zinc acetate solution, see Figure, results in rapid metalation, as expected from the liquid phase reaction Metal center exchange is also easily achieved by exposing adsorbed zinc porphyrin to CuSO4. The formation of copper porphyrin is so favored that even a 1 ppm impurity of CuSO4 in NiSO4 results in the formation of copper porphyrin. However, unlike for the liquid phase reaction, even exposure to acid solutions with pH values as low as 0 does not result in demetalation of the adsorbed porphyrin molecules. We tentatively explain this difference by a surface-induced stabilization of the protonated intermediate in the demetalation reaction.

Figure: X-ray photoemission N 1s spectra of a Au(111) surface (a) with adsorbed free-base porphyrin (b) exposed to a solution of zinc acetate (c) and annealed to 523 K to desorb unwanted impurites (d), compared with a reference spectrum of adsorbed zinc porphyrin (bottom spectrum). Free base porphyrins are characterized by two distinct N 1s peaks, while metalated species show only one single nitrogen peak. Thanks The project was supported by the DFG through FOR 1878 (funCOS), by the DAAD and the Argentinian National Research Council (CONICET) and the National Agency for Scientific Promotion (ANPCyT) under grant PICT 2011 2062. References [1] Franke, M.; Florencia, M.; Steinrück, H.-P.; Lytken,O.; Williams, F.; J. Phys. Chem. Lett. 2015, 6, 4845- 4849 [2] Franke, M.; Florencia, M.; Jux, N.; Steinrück, H.-P.; Lytken,O.; Williams, F.; Chem. Eur. J. 2016, accepted

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I03_LSI_443 THE WATER SURFACE: COMPLEX, DYNAMIC AND WET

LSI - Liquid/solid and liquid/liquid interfaces M. Bonn * Max Planck Institute for Polymer Research Ackermannweg 10 - Mainz (Germany) Water surfaces and interfaces are ubiquitous, not just in nature (e.g. at the boundaries of cells, in rain drops, oceans, rivers and lakes) but also in many technological applications (such as electrochemistry and photocatalytic water splitting). Water is a rather unique liquid, owing to its strong intermolecular interactions: strong hydrogen bonds hold water molecules together. At the surface of water, the water hydrogen-bonded network is abruptly interrupted, conferring properties on interfacial water different from bulk water [1]. We elucidate the structure and structural dynamics of interfacial water using surface-specific vibrational spectroscopy of interfacial water molecules, with femtosecond time resolution. Specifically, we find that the interface is structurally more heterogeneous [2,3] and substantially more dynamical [4] than bulk water. We reveal the nature of the heterogeneity, and quantify the reorientational dynamics of specifically interfacial water molecules. Finally, we show that the evaporation of water – i.e. the release of individual water molecules from the bulk into the gas phase – is not a purely stochastic event. Rather, the evaporation follows one specific pathway, involving a delicately timed, concerted motion of several water molecules to ‘launch’ a single molecule from the surface [5]. References [1] Bonn, M.; Nagata, Y.; Backus, E.H.G.; Angew. Chem.-Intern. Ed. 2015, 54, 5560. [2] Hsieh, C.S.; Okuno, M.; Backus, E. H. G.; Hunger, J.; Nagata, Y.; Bonn, M.. Angew. Chem.-Intern. Ed. 2014, 31, 8146 (VIP paper). [3] van der Post, S. T.; Hsieh, C.-S.; Okuno, M.; Nagata, Y.; Bakker, H. J.; Bonn, M.; Hunger, J. Nat. Commun. 2015, 6, 8384. [4] Hsieh, C. S.; Campen, R. K.; M. Okuno; E. H. G. Backus; Y. Nagata; and M. Bonn, Proc. Nat. Acad. Sci. USA 2013, 110, 18780. [5] Nagata, Y.; Usui, K.; Bonn, M., Phys. Rev. Lett. 2015, 115, 236102.

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O4-LSI _19 DISCOVERY OF STATIC SHEAR-ELASTICITY IN LIQUIDS & MELTS

LSI - Liquid/solid and liquid/liquid interfaces L. Noirez * Laboratoire Léon Brillouin (CEA-CNRS) (France) On the basis of a Maxwell gas model (1867), it has long been suspected that liquids and melts exhibit (shear) elasticity at high solicitation frequencies (MHz or GHz) only. Recent experimental results challenge this common wisdom and bring the robust evidence that molecules are not free in the liquid but elastically correlated at the mesoscopis scale. Indeed, liquids exhibit a weak but finite static shear elasticity at low frequency, namely 0.01Hz-10Hz. Their behaviours do not differ from solids when they excited below a weak elastic threshold within sub- millimetre length-scales. The elastic property is identified on different fluids (polymer melts, molecular glass formers, Van der Waals liquids, ionic liquids, H- bond liquids, liquid water) pointing out a neglected property [1,2].The identification of static shear elasticity has profound implications in various domains related to gelation processes, glass transition and liquid transport mechanisms, active materials and requires new theoretical approaches. New effects can be predicted and are observed as the conversion of a liquid phase strongly anchored on a substrate in a strain-driven optical harmonic oscillator [3]. References [1] L. Noirez L, H. Mendil-Jakani, P. Baroni, The missing parameter in rheology: solid-like correlations in viscous liquids, polymer melts and glass formers Polymer Int. 58 962 (2009). [2] L. Noirez, P. Baroni, Identification of a low frequency elastic behavior in Liquid Water J. of Phys.: Cond. Matter 24 (2012) 372101. [3] P. Kahl, P. Baroni, L. Noirez, Bringing to Light Hidden Elasticity in the Liquid State using in-situ Pretransitional Liquid Crystal Swarms PloS One (2016),

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O5-LSI _83 XPS ENABLES VISUALIZATION OF CHARGE SCREENING IN METAL-IONIC LIQUID INTERFACES WITH TEMPORAL- AND LATERAL- RESOLUTION

LSI - Liquid/solid and liquid/liquid interfaces M. Taner Camci 1,*, P. Aydogan 1, B. Ulgut 1, C. Kocabas 2, S. Suzer 2 1Bilkent University Department of Chemistry - Ankara (Turkey), 2Bilkent University Department of Physics - Ankara (Turkey) We present an x-ray photoelectron spectroscopic (XPS) investigation of charge screening across two gold electrodes fabricated on a porous polymer surface which is impregnated with an ionic liquid (IL). The IL provides a sheet of conducting layer to the insulating polymer film, and allows monitoring charging and screening dynamics at the polymer + IL / air interface in a laterally resolved fashion across the electrodes. Time-resolved measurements are also implemented by recording F1s peak of the IL, while imposing 10 mHz square-wave- pulses (SQW) across the two electrodes in source-drain geometry. Variations in the F1s binding energy reflects directly the local electrical potential, and allow us visualize screening of the otherwise built-in local voltage drop on and across the metal electrodes. Accordingly, the device is partitioned into two oppositely polarized regions, each following polarization of one electrode through the IL medium. The presented structure and XPS measurements can impact on understanding of various electrochemical concepts. Thanks This work is partially supported by TUBITAK (The Scientific and Technological Research Council of Turkey) via the Grant No: 212M051.

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O6-LSI _101 STABILITY OF IONIC LIQUID BASED ELECTROLYTES IN LITHIUM METAL BATTERIES INVESTIGATED BY X-RAY PHOTOEMISSION AND ELECTROCHEMICAL IMPEDANCE SPECTROSCOPIES

LSI - Liquid/solid and liquid/liquid interfaces J. Morales 1,*, Y. Kerdja 2, A. Benayad 2, C. Santini 3, R. Bouchet 1 1LEPMI-INP Grenoble UMR 5279, 1130 rue de La Piscine, 38402 - Saint-Martin-D'hères (France), 2CEA, LITEN, Department of Nanomaterials, MINATEC, 17 rue des Martyrs, 38054 - Grenoble Cedex 09 (France), 3CNRS-UMR 5265, 43 Bd du 11 Novembre 1918, 69616 - Villeurbanne Cedex (France) In spite of its great theoretical capacity (3,86 Ah g-1), for more than 40 years, large- scale commercialization of lithium metal battery systems accomplishing safety requirements has not been possible. In fact, heterogeneous lithium plating during the charging process leads to dendritic growth that induces the formation of dead lithium (i.e. low faradic efficiency) and can short circuit the battery with and eventual fire risks [1]. In order to overcome this difficulty, one of the approaches is the replacement of conventional organic based electrolytes battery with special solvents known as ionic liquids (ILs) due to their thermal and electrochemical stability, flame retardant performance and high ionic conductivity [2]. The comprehension of the chemical structure and the reactivity of ILs and lithium surface is the key of interest for the development of lithium battery systems. In this work, X-ray photoelectrons spectroscopy (XPS), known as a non-destructive and powerful surface analysis tool, coupled to electrochemical impedance spectroscopy (EIS) have been used to study the side reactions between ILs (C1C6ImNTf2 and C1C6ImFSI) and a lithium electrode. Figure 1 presents the C 1s and N 1s XPS signature of C1C6ImNTf2 (a,b) and C1C6ImFSI (c,d) supported on a Viledon® separator before lithium/IL/lithium cell polarization. The interactions between cation and anion from ILs, monitored following the changes in C 1s and N 1s core peaks will be discussed depending on the electrochemical condition in lithium/IL/lithium system. The lithium surface evolution under aging in equilibrium condition as well as under polarization depending to the ILs composition, i.e. cation and anion nature, will be discussed in this work. Thanks This work is financially supported by Cienciactiva, an iniciative from Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica (CONCYTEC). References [1] Xu W, J Wang, F Ding, X Chen, EN Nasybulin, Y Zhang, and J Zhang, Energy Environ. Sci., 7, 513 (2014) [2] M. Armand, F. Endres, D. R. MacFarlane, H. Ohno and B. Scrosati, Nature Materials 8, 621 - 629 (2009)

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O7-LSI _156 SWELLING OF HYDROXYLATED HECTORITE AND SAPONITE CLAYS MONITORED BY NAP-XPS

LSI - Liquid/solid and liquid/liquid interfaces A. Boucly 1,*, F. Bournel 1, E. Dubois 2, J.J. Gallet 1, A. Koishi 3, V. Marry 2, L. Michot 2, S. Tesson 2, F. Rochet 1, F. Sirotti 4 1Sorbonne universités, UPMC Univ paris 06, UMR 7614, Laboratoire de Chimie Physique Matière et Rayonnement (LCPMR), F-75005 Paris, France - Paris (France), 2Sorbonne universités, UPMC Univ paris 06, UMR 8234, Laboratoire PHysicochimie des Elec-trolytes et Nanosystèmes InterfaciauX (PHENIX), F-75005 Paris, France - Paris (France), 3Université Joseph-Fourier Grenoble I, UMR 5275, ISTerre, F-38041 Grenoble, France - Paris (France), 4Synchrotron SOLEIL, L’orme des Merisiers, Saint Aubin, Gif sur Yvette, France - Paris (France) This study deals with the hydration of swelling clays. Those clays are made of phyllosilicate sheets separated by an interlayer space. Depending on the smectite type, those sheets can have a negative charge localized at the surface (saponite) or in the middle (hectorite) of the lamella.1 Those charges are compensated by the presence of cations in the interlayer space where water can penetrate, inducing the swelling of the clay. Understanding the role and behavior of the cation in the swelling process is vital to assess the impact of nuclear contamination in soils by predicting how radioactive elements move in confined water layers within the clays. In this regard, the study of the hydration of cesium-based smectites is of prime importance and the comparison with sodium-based smectites, highly relevant due to the much smaller size of the counter-ion. While a number of studies have already been done on swelling clay minerals, most of them have been carried out via sorption and XRD methods.2 Yet those methods do not give detailed information about the chemical environment of the counter-ions. In this regard, the use of an NAP-XPS experimental station is extremely useful as it allows to follow in situ the evolution of the chemical environment of the various clay components with increasing pressure, until liquid water appears at the sample surface. In this study we show that the core-level binding energies of the counter-ions and of the surface sheet element (Si) are affected by the penetration of water. Interestingly, we have observed very different sheet/counter-ion interactions depending on the counter-ion size which has a huge impact on their mobility and on the retention capacity of the clays. References [1] Odom I. E., Philos. Trans. R. Soc. A,311,391 (1984) [2] A) Michot, L et al., American Mineralogist., 90, 166, (2005). B) Ferrage, E. et al., J. Phys. Chem. C,114, 4526 (2010)

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O8-LSI _174 CONTRIBUTION OF LIQUID PROPERTIES TO QUANTITATIVE MEASUREMENTS USING QUARTZ CRYSTAL MICROBALANCE WITH DISSIPATION

LSI - Liquid/solid and liquid/liquid interfaces V. Mugnaini, D. Petrovykh * International Iberian Nanotechnology Laboratory - Braga (Portugal) We systematically investigated Quartz Crystal Microbalance with Dissipation (QCM-D) measurements in aqueous solutions of model strong electrolytes relevant for biointerface measurements. In particular, we examined the quantitative behavior of both frequency and dissipation responses in transitions between two different aqueous solutions. Switching between aqueous solutions differing in viscoelastic properties may be important in a variety of QCM-D measurements for biointerfaces, e.g., when the composition of the rinsing solution differs dramatically from that of the solution used during the measurement. Specifically, using more than one solution in a single measurement is known to be important for probe immobilization, for biorecognition steps, and in specialized quantitative biointerface measurements, such as measuring stabilities of DNA hybrids [1-3]. Quantitatively predicting the changes in the QCM-D responses is important, because upon switching between different solutions flowing through the QCM-D cell, these changes are often abrupt and large, e.g., relative to the contribution of a molecular layer at the liquid/solid interface. By considering the underlying viscoelastic formalism [4-5], we demonstrate in a series of systematic measurements for solutions of strong electrolytes that the QCM-D responses in different liquids can be indeed quantitatively predicted and exhibit interesting scaling behavior. Classical theory of the viscosity of electrolyte solutions provides additional insight into correlations between the results measured for different salts. References [1] D. Y. Petrovykh, H. Kimura-Suda, L. J. Whitman, M. J. Tarlov, J. Am. Chem. Soc. 125, 5219 (2003) [2] S. M. Schreiner, D. F. Shudy, A. L. Hatch, A. Opdahl, L. J. Whitman, D. Y. Petrovykh, Anal. Chem. 82, 2803 (2010) [3] S. M. Schreiner, A. L. Hatch, D. F. Shudy, D. R. Howard, C. Howell, J. Zhao, P. Koelsch, M. Zharnikov, D. Y. Petrovykh, A. Opdahl, Anal. Chem. 83, 4288 (2011) [4] K. K. Kanazawa, J. G. Gordon II, Anal. Chim. Acta, 175, 99 (1985) [5] M. Rodahl, F. Höök, A. Krozer, P. Brzezinski, B. Kasemo, Rev. Sci. Instrum. 66, 3924 (1995)

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O9-LSI _137 ELECTROCHEMISTRY OF IRON OXIDE THIN FILMS

LSI - Liquid/solid and liquid/liquid interfaces P. Seidel *, A. Ghalgaoui, M. Sterrer University of Graz, Institute of Physics - Graz (Austria) Single-crystalline oxide thin films supported by metals are a well-accepted class of model system for studying fundamental aspects of oxide surface and thin oxide layer chemistry and physics [1]. In the present contribution, we report on our efforts to expand this model approach to electrochemical studies on well-ordered oxide surfaces. Single-crystalline FeO(111) and Fe3O4(111) films were grown under ultra-high vacuum (UHV) conditions on a Pt(111) substrate and subsequently transferred into air or brought into contact with aqueous solutions [2]. We have tested the stability of the oxide layers in these environments and characterized their electrochemical properties by cyclic voltammetry. The surface morphology and potential-dependent surface structure changes were investigated in-situ by electrochemical scanning tunneling microscopy and potential-controlled sum frequency generation spectroscopy. The influences of ionic strength and pH value on the oxide-water interface were examined. Finally, two different organic compounds (Catechol and Aminophthalic acid) were deposited from solution and investigated by electrochemical and UHV methods. References [1] W. Weiss, W. Ranke, Prog. Surf. Sci. 2002, 70, 1-151. [2] H.-F. Wang, H. Ariga, R. Dowler, M. Sterrer, H.-J. Freund, J. Catal. 2012, 286, 1-5.

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O10-LSI _3 DISCLOSING THE EARLY STAGES OF ELECTROCHEMICAL INTERCALATION OF ANIONS IN GRAPHITE BY A COMBINED AFM/STM INVESTIGATION

LSI - Liquid/solid and liquid/liquid interfaces R. Yivlialin 1,*, G. Bussetti 1, A. Li Bassi 2, C.S. Casari 2, M. Passoni 2, C. Castiglioni 3, M. Tommasini 3, L. Brambilla 3, P. Biagioni 1, F. Ciccacci 1, L. Duò 1 1Dipartimento di Fisica, Politecnico di Milano - Mi (Italy), 2Dipartimento di Energia, Politecnico di Milano - Mi (Italy), 3Dipartimento di Chimica, Materiali e Ingegneria dei Materiali, Politecnico di Milano - Mi (Italy) Wide-size graphene sheets with single- or few-layer thickness and few defects are crucial for the future development of graphene applications. Different strategies can be used for graphite delamination and graphene production, but the chemical/electrochemical strategies ensure large amounts of graphene and a good quality of the products. So far, optimization of the procedural protocols was generally undertaken through a systematic investigation of the delaminated graphene flakes, while less attention has been paid to the processed graphite crystal. The current state of research in this field requires a better comprehension of the molecular mechanisms involved during the intercalation of ions within the crystal, which represents the first step towards the crystal swelling and the subsequent exfoliation of graphite. This investigation can be tackled at the nanoscale by a combination of scanning probe microscopies with specific chemical monitoring techniques. A choice is offered by electrochemical atomic force and scanning tunnelling microscopies (EC-AFM and EC-STM, respectively). However, EC-STM has been rarely exploited for a nanoscale investigation of the first intercalation stages so far, probably due to the intrinsic difficulty in piloting the STM tip during the intercalation of ions. In this work, we monitor the graphite surface changes as a function of the electrochemical potential by both EC-AFM and EC-STM coupled with cyclic voltammetry. Following this strategy, we reveal the surface modifications during the early intercalation stages in different electrolytes: surface faceting, step erosion, terrace damages, and nano-protrusions, all affecting the graphite surface and therefore the exfoliation process. The in situ analysis of the surface modification is combined with ex situ Raman analysis, aimed at the detection of chemical and/or structural modification of the graphite samples subjected to different EC treatment. In particular spectroscopic markers related to ions intercalation and/or doping and to the formation of defected areas/edges are identified and analyzed.

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P1-LSI_94 MECHANISM OF GASB (001) SURFACE PASSIVATION WITH AQUEOUS SOLUTION OF SODIUM SULFIDE

LSI - Liquid/solid and liquid/liquid interfaces I. Sedova 1,*, T. Lvova 1, M. Lebedev 1, A. Shakhmin 2, V. Baynov 3, O. Rakhimova 3, S. Ivanov 1 1Ioffe institute - St.petersburg (Russian federation), 2Peter the Great Polytechnic University - St.petersburg (Russian federation), 3State Electrotechnical University - St.petersburg (Russian federation) GaSb is very attractive material for fabrication of optoelectronic devices in the near-IR spectral region. It is also employed as a substrate for epitaxial growth of (Al,Ga,In)(As,Sb) compounds which are widely used for high-speed electronic and longer-wavelength optical devices. The key issue for fabrication of high quality devices is the preparation of a GaSb surface with controlled chemical composition and electronic properties. Recently different techniques have been developed for getting the oxide-free GaSb surface, including sulfur passivation in aqueous and nonaqueous sulfide solutions [1, 2], chemical etching with acidic solutions [3] etc. In this study we analyze chemical processes occurring at the interface of n-GaSb (001) with the 1M aqueous solution of sodium sulfide (Na2S) at room temperature. The temporal evolution of both solution pH and temperature has been measured to get insight into physical and chemical processes occurring during passivation. The GaSb (001) surface was analyzed by x-ray photoemission spectroscopy at different stages of the sulfide passivation process. It has been found that GaSb (001) surface sulfidization with the aqueous Na2S solution proceeds in two stages. At the first stage lasting for ~4 minutes, the native oxide layer is removed and the passivating sulfide layer starts to form. The pH value (~12.6) of the solution does not change at this stage. Then the composition of the passivating layer is stabilized in sulfide solution, which is accompanied by reduction of the solution pH value down to 12.45. The sulfide layer consists of gallium and antimony sulfides with a Ga/Sb atomic ratio of 0.6. In contrast to the treatment with the aqueous and alcoholic solutions of ammonium sulfide, the thickness of the passivating layer is rather small (~ some monolayers) even after the 30 min treatment, which is related to higher pH of the aqueous Na2S solution. References 1. M. Lebedev, E. Kunitsyna, W. Calvet, Th. Mayer, and W. Jaegermann, J. Phys. Chem. C 117, 15996 (2013). 2. Z.Y. Liu, T.F. Kuech, D.A. Saulys, App. Phys. Lett. 83 (13), 2587 (2003). 3. D. Seo, J. Na, S. Lee, S. Lim, J. Phys. Chem. C 119, 1358 (2015)

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P2-LSI_164 CARBON DIOXIDE STABILISATION WITHIN 1-OCTYL-3-METHYLIMIDAZOLIUM CONTAINING IONIC LIQUIDS

LSI - Liquid/solid and liquid/liquid interfaces R. Jones, J. Gibson * School of Chemistry, University of Nottingham, Nottingham NG7 2RD (United Kingdom) Ionic Liquids (ILs) are candidates for carbon capture agents, hence an understanding of the CO2 -IL interaction is required. Temperature Programmed Desorption (TPD) has been used to study the stability of carbon dioxide interacting with two ionic liquids; 1-octyl-3- methylimidazolium tetrafluoroborate ([C8C1Im][BF4]) and 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C8C1Im][Tf2N]). Experiments were performed using Low Temperature Line of Sight Mass Spectrometry (LOSMS) to ensure accurate, unambiguous TPD data. The ILs were deposited by chemical vapour deposition (≈ 1 layer per minute) onto -8 -6 a gold surface (90 K) while simultaneously adsorbing CO2 (at 2×10 - 2×10 mbar). CO2 alone does not form a monolayer on gold at ≈ 90 K, implying the activation energy for -1 desorption < 24.5 kJmol . However, when the IL and CO2 are co-adsorbed, the IL exerts a sizable stabilisation on the CO2, the extent of stabilisation depending upon the IL used. Comparison between experimental and simulated TPD profiles show that the CO2 is absorbed in a continuum of stabilised environments within the ILs. The activation energies -1 for desorption were in the range 24.5 – 43 kJmol . CO2 was stabilised most by -1 [C8C1Im][BF4], with a maximum stabilisation of ≈ 18.5 kJmol over just pure CO2 adsorption. However the [C8C1Im][Tf2N] stabilised larger quantities of CO2 but with a somewhat smaller stabilisation energy of ≈ 13.5 kJmol-1.

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P3-LSI_389 THE LIQUID METAL EMBRITTLEMENT EFFECT IN ARMCO-IRON DURING HIGH AND GIGACYCLE FATIGUE LOADING

LSI - Liquid/solid and liquid/liquid interfaces M. Bannikov *, O. Naimark ICMM UB RAS - Perm (Russian federation) The Liquid metal embrittlement effect (Rehbinder effect [1]) consists in a qualitative change of the development of multi-scale damage kinetics in a deformed sample in the presence of surfactant (in our case, liquid gallium eutectic alloy). Its influence on the fatigue life of pure iron is associated with a qualitative change of the role of the surface. The surface of the material plays a specific role in the process of irreversible deformation of solids [2-3], being a high-capacity source and sink for defects. In view of the fact that the irreversible deformation is determined by nonlocal interactions and diffusion processes, which are based on the interaction of dislocations with each other and with the vacancies, was inferred that that the surfactant can have a strong effect on the diffusion processes associated, for example, with the interaction of dislocation loops with a solid surface [4-5]. Therefore, the absence or insufficient “capacity” of the external sink for dislocations leads to a mismatch of the processes of their nucleation and movement in a macroscopic volume, which affects the development of plasticity, hardening and damage localization. Fatigue tests of pure iron were carried out with frequency of 20 Hz in high cycle fatigue regime and ultrasonic resonant machine [6] Shimadzu USF-2000 with frequency of 20 kHz in the gigacycle fatigue loading regime (the material failure occurs after realization of 109 loading cycles). The durability and strength of the material coming into contact with a surfactant are significantly reduced on the "adiabatic" surface and the region of localization of the defect density is shifted to the surface layer, which is characteristic of "embrittlement" materials being in contact with a surfactant. The Rehbinder effect radically changes the mechanism of crack initiation in gigacycle fatigue regime, which leads to the formation of cracks in the surface layer of the sample, rather than in the volume of the material, which is characteristic of this kind of fatigue failure. Thanks This work was supported by grants from RFBR № 15-08-08921, 16-41-590892 References 1.P.A. Rehbinder, E.D. Shchukin, Physics-Uspekhi108, 1 (1972). 2.E.D. Shchukin,Coll. Interf. Sci.,33,123–126 (2006). 3.Ya.I. Frenkel. Kinetic theory of liquids // Leningrad: Nauka.- 1975.-P.592 (in Russian) 4.O.B. Naimark, O.A. Plekhov, V.I. Betekhtin, A.G. Kadomtsev, M.V. Narykova // Technical Physics. – 2014. – V 59, Iss 3. – P.398-401. 5.V.V. Shevelya, B.I. Kosteckiy, // Doklady Physics, 175(6), 1270-1272, (1967). 6.C.P. Bathias, // International Journal of Fatigue. – 2006. – V.28. – P.1438-445.

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M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc.

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O1-M4E _354 DESIGN AND ELECTROCHEMICAL PROPERTIES OF NICKELATE-BASED CATHODES FOR SOLID OXIDE FUEL CELLS: ROLE OF THE INTERFACES

M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc. R. Sharma 1,*, M. Burrield 2, L. Dessemond 1, J.M. Bassat 3, E. Djurado 1,* 1Univ. Grenoble Alpes, LEPMI, F-38000 - Grenoble (France), 2Univ. Grenoble Alpes, CNRS, LMGP, F-38000 - Grenoble (France), 3ICMCB-CNRS, Univ. Bordeaux, 33608 - Pessac (France) In solid oxide fuel cells operating at intermediate temperature (~600 °C), the composition, the microstructural design and the interfaces of the cathode play an important role in 1-3 obtaining optimal performances . In this work, nickelates, such as Ln2NiO4+δ (abbreviated as LnNO; with Ln = La, Pr) were prepared by electrostatic spray deposition (ESD) and screen-printing (SP) on CGO (Ce0.9Gd0.1O2-δ) electrolyte as double-layer cathodes. The role of the electrode/electrolyte interface has been evaluated by impedance spectroscopy using (i) a dense thin (~ 100 nm) pure LnNO sub-layer and (ii) a thicker (~3 mm) porous composite CGO/LnNO sub- layer. A significant improvement in polarization resistance (Rpol) from 0.42 to 0.16 and from 0.08 to 0.04 Ω cm2 is obtained at 600 °C for LaNO and PrNO, respectively, for the electrode based on the composite sub-layer. As shown in Fig. 1, both the high frequency (HF) contribution attributed to the charge transfer at the electrode/electrolyte interface and the medium frequency (MF) contribution attributed to the various electrode processes such as adsorption and/or 2- dissociation of O2 and/or charge transfer-diffusion (O ) in the electrode, are strongly reduced when the LaNO/CGO composite sub-layer is added. To conclude, the LnNO-CGO composite sub-layer plays an important role in enhancing the electrochemical properties of these cathodes leading to the lowest Rpol available in the literature for these compositions, to the best of our knowledge.

Fig.1: Impedance diagrams at 600 °C in air of LaNO cathode with (a) a pure LaNO, thin dense sub-layer, (b) a LaNO/CGO composite, thicker and porous sub-layer. References [1] R.K. Sharma, M. Burriel, E. Djurado, J. Mater. Chem. A, 2015 (3) 23833-23843. [2] R.K. Sharma, M. Burriel, L. Dessemond, V. Martin, J.M. Bassat, E. Djurado, J. Power Sources, 2016 (316) 17-28. [3] R.K. Sharma, M. Burriel, L. Dessemond, J.M. Bassat, E. Djurado, J. Power Sources (under review).

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O2-M4E _36 INVESTIGATION OF THE SURFACE REACTIVITY OF ELECTRODE MATERIALS: AN EXPERIMENTAL AND THEORETICAL COMBINED APPROACH

M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc. D. Flahaut 1,*, A. Quesne-Turin 1, G. Vallverdu 1, L. Croguennec 2, M. Ménétrier 2, I. Baraille 1 1IPREM-UPPA - Pau (France), 2ICMCB-CNRS - Bordeaux (France)

LiCoO2 is the most widely used positive electrode material of today’s Li-ion batteries. In the last years, much research has been performed to explore alternative materials as mixed transition metal oxides LiNixMnxCo1−2xO2 (NMC). However, appreciable capacity fading is observed upon cycling to high voltages due to the instability of the passivating film formed at the surface of electrode. Thus, the performances of Li-ion batteries cannot be improved without taking into account the control of surface and interface phenomena. Within this framework, we developed an effective strategy for studying the surface reactivity of electrode materials by coupling adsorption of gaseous probes molecules (SO2/NH3), X- ray photoelectron spectroscopy and DFT calculation. The investigation is focused on the role of the transition metal nature and Al2O3 coating on the surface reactivity of LiMO2 systems.

Instead sole sulfate species is observed for LiCoO2, both sulfate and sulphite species have been identified for NMC. On the basis of XPS analysis and previous theoretical work, we propose that the acid-base adsorption mode involving the Ni2+ cation is responsible for the sulphite. After Al2O3 coating, the surface reactivity is clearly decreasing for LiCoO2 and NMC materials. Moreover, for LiCoO2, the coating modifies the surface reactivity with the identification of both sulfate and sulfite species (figure 1). This result is in line with a change in the adsorption mode from redox toward acid−base after Al/Co substitution (figure 2). In the case of NMC, the coating induces a decrease of the sulphite species content at the surface, which can be related to the cation mixing effect in the NMC.

We extend this strategy to Li2MnO3 as a model of Li-rich materials, which appears as a promising candidate for electrode materials. References Dahéron L. et al, Chem. Mater. 2008, 20, 583. Andreu N. et al., ACS Appl. Mater. Interfaces 2015, 7, 6629.

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O3-M4E _361 UNDERSTANDING ACTIVE INTERFACES IN OXYGEN ELECTRODES FOR SOLID OXIDE FUEL CELLS BY TIME DEPENDENT 3D FEM MODEL

M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc. O. Celikbilek *, D. Jauffres, E. Siebert, C.L. Martin, E. Djurado University of Grenoble Alpes - Grenoble (France) The present study concerns innovative materials to be used as energy conversion devices such as solid oxide fuel cells. In this work we present the influence of the micro/nanostructural properties of LSCF (La0.6Sr0.4Co0.2Fe0.8O3−δ) and LSCF/CGO (Ce0.9Gd0.1O2-δ) composite cathode films on their electrochemical behavior. We have recently shown that LSCF nanostructured cathodes deposited by Electrostatic Spray Deposition [1] show an order of magnitude higher oxygen surface exchange properties than those fabricated by other techniques. In the case of high oxygen transport parameters, (Do,ko), the electrochemically active layer concentrates on the first 100 nm from the electrode/electrolyte interface. Thus, tailoring the micro/nanostructure and surface properties close to the interface is of great importance. To better comprehend the intricate relationship between the amount of porosity and CGO in a composite film, a time dependent 3D finite element method (FEM) model has been developed. The model (Figure 1) reveals the effect of morphology (e.g. local heterogeneity in the pore distribution, the size of pores, etc…) conformal to 3D reconstruction of real images (FIB-SEM) inside a pillar geometry [1,2]. The influence of the porosity and the chemical composition on the electrochemical impedance spectra has been explored. Thanks This work was performed within the framework of the Centre of Excellence of Multifunctional Architectured Materials "CEMAM" n° AN-10-LABX-44-01 funded by the "Investments for the Future" Program. References Celikbilek, O., Jauffres, D., Siebert, E., Dessemond, L., Burriel, M., Martin, C.L., Djurado, E.,(2016), submitted Haffelin, A., Joos, J., Ender, M., Weber, A., Ivers-Tiffee, E. (2013). J. Electrochem. Soc. 160, F867–F876

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I17_M4E_445 MODEL STUDIES IN ENERGY-RELATED CATALYSIS AND ELECTROCATALYSIS

M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc. J. Libuda * Department Chemie und Pharmazie und Erlangen Catalysis Resource Center, Friedrich-Alexander- Universität Erlangen-Nürnberg - Erlangen (Germany) Complex interfaces are the key to new functional materials in energy conversion, energy storage, and energy-related catalysis. Most functionalities arise from the physical and chemical properties of their interfaces, i.e. from the the transport of electrons, ions, atoms, or molecules via a nanostructured phase boundary, often in a complex solid/liquid or electrochemical environment. Model strategies, which can provide insights into the chemistry and physics at such interfaces, are illustrated through examples from our current research. We prepare complex yet atomically-defined model systems under UHV conditions and explore their chemical functionality both under surface science conditions and in an electrochemically controlled environment. Specifically, the challenges are discussed that are associated with the transfer of complex model catalysts from the UHV into the electrochemical cell and back. Two specific examples of combined UHV and electrochemical studies are discussed from our recent work. First we consider model systems for proton exchange membrane fuel cell catalysts based on Pt-doped ceria films.[1] We show that Pt can be anchored to nanostructured CeO2 surfaces in ionic form with exceptionally high stability. In addition we quantify electronic metal support interactions [2] and explore other interaction mechanisms such as spillover phenomena.[3] By in-situ spectroscopy at the electrified interface, we find that the ceria support indeed stabilizes ultra-small Pt nanoparticles at the electrode under conditions of dynamically changing potential. In a second example we investigate ionic liquids as modifiers in electrocatalysis.[4] We start by studying the interaction of selected imidazolium-based ionic liquids with single-crystal-based model surfaces in UHV. Next we investigate the same systems by in-situ spectro-electrochemistry and explore the role of the ionic liquids in the electrocatalytic reaction. References [1] A. Bruix, Y. Lykhach, I. Matolínová, A. Neitzel, T. Skála, N. Tsud, M. Vorokhta, V. Stetsovych, K. Ševčíková, J. Mysliveček, K. C. Prince, S. Bruyère, V. Potin, F. Illas, V. Matolín, J. Libuda, K. M. Neyman, Angew. Chem. Int. Ed. 53, 10525 (2014) [2] Y. Lykhach, S.M. Kozlov, T. Skála, A. Tovt, V. Stetsovych, N. Tsud, F. Dvořák, V. Johánek, A. Neitzel, J. Mysliveček, S. Fabris, V. Matolín, K.M. Neyman, J. Libuda, Nature Materials 15, 284 (2016) [3] N. Vayssilov, Y. Lykhach, A. Migani, T. Staudt, G. P. Petrova, N. Tsud, T. Skála, A. Bruix, F. Illas, K. C. Prince, V. Matolín, K. Neyman, J. Libuda, Nature Materials 4, 310 (2011) [4] O. Brummel, F. Faisal, T. Bauer, K. Pohako-Esko, P. Wasserscheid, J. Libuda, Electrochimica Acta 188, 825 (2016)

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I20_M4E_446 EPITAXIAL OXIDE ENGINEERING FOR SOLAR WATER SPLITTING

M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc. H. Magnan 1,*, M. Rioult 1, M. Rioult 2, A. Barbier 1, D. Stanescu 1, S. Stanescu 1, R. Belkhou 2, F. Maccherozzi 3, E. Fonda 2 1Service de Physique de l’Etat Condensé, CEA, CNRS, Université Paris Saclay, CEA Saclay - Gif- Sur-Yvette (France), 2Synchrotron SOLEIL - Gif-Sur-Yvette (France), 3Diamond Light Source, Harwell Campus - Oxforshire (United Kingdom) The transformation of solar energy into chemical energy stored in the form of hydrogen, through photo-electrochemical water splitting is a promising method that has the important advantages of being environment friendly and free from carbon dioxide emission. Hematite (alpha-Fe2O3) has attracted much attention for application as photoanode due to its favorable optical band gap (2.2 eV) for solar light absorption, chemical stability, abundance, non-toxicity and low cost. Unfortunately, the measured performance of hematite photo- anodes remains limited because of a low absorption coefficient and a short hole diffusion length. The photo-electrochemical properties of hematite can be improved by Ti doping or by oxygen vacancies. In order to understand the physical mechanisms behind these improvements, we have studied the growth, crystal, and electronic structures of epitaxial hematite films grown by atomic oxygen assisted molecular beam epitaxy as a function of Ti doping or oxygen vacancies level [1-3]. Such single crystalline samples are suitable model system to study the effect of thickness, doping and crystallographic structure effects on the photo-electrochemical properties. Moreover, by using Extended X ray Absorption Fine Structure (EXAFS) and X-ray PhotoEmitted Electron Microscopy (X-PEEM) we have determined the role of the surface morphology [4], the crystallographic structure and the electronic structure independently. Our results demonstrate the existence of an optimal oxygen vacancies concentration and titanium doping level that induce an increase of charges diffusion length and a high photocurrent gain (>100). References [1] H. Magnan et al., Appl. Phys. Lett. 101, 133908 (2012) [2] M. Rioult et al. J. Phys Chem C 118, 3007 (2014) [3] M .Rioult et al J. Phys Chem C 120, 7482 (2016) [4] M. Rioult et al., Surface Science 641, 310 (2015).

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O4-M4E _28 REDUCTION IN OPTICAL REFLECTION AT INTERMEDIATE ADHESIVE LAYER FOR MECHANICALLY STACKED MULTI-JUNCTION SOLAR CELLS

M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc. T. Sameshima *, S. Kimura, S. Yoshidomi, T. Sugawara, M. Hasumi Tokyo University of Agriculture and Technology - Koganei (Japan) We have proposed mechanically stacked-type multi-junction solar cells using transparent epoxy adhesive layers dispersed with 20-µm-sized Indium-Tin-Oxide (ITO) conductive particles. The connecting resistivity was lower than 1 ohmcm2. In this paper, we report reduction in optical reflection loss at the adhesive layer. 130-nm-thick 0.01-ohmcm IGZO layers were formed on the top surfaces of 3-inch n-type GaAs and 4-inch p-typeSi substrates by spattering method. The top surfaces of the samples were stacked with epoxy adhesive jell dispersed with 3.8-wt%-ITO particles to make a structure of GaAs/IGZO/adhesive/IGZO/Si. Figure 1 shows experimental and calculated optical reflectivity spectra for the samples of GaAs/IGZO/adhesive/IGZO/Si (red) and GaAs/adhesive/Si (blue). A calculated reflectivity r of the top surface component of GaAs is also presented. The GaAs/IGZO/adhesive/IGZO/Si had low optical reflectivity R between 890 and 1040 nm because of the anti-reflection effect of IGZO layers. In contrast, R was high for the GaAs/adhesive/Si because of high optical reflection at the adhesive interfaces. The calculated spectra using optical interference model agreed well with experimental spectra. The effective absorption ratio Aeff was estimated by the integration of 100-R between 890 and 1040 nm normalized by the integration of 100-r. It distributed from 0.91 to 0.95 over the 3-inch sample surface. The optical reflection loss at the intermediate adhesive layer was successfully reduced between 9 and 5%. Thanks This work was supported by the New Energy and Industrial Technology Development Organization Japan (NEDO). References [1] T. Sameshima, et al., Jpn. J. Appl. Phys., 50, 052301-1-4 (2011).

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O6-M4E _26 PV CELLS BASED ON CIGS THIN FILMS: AN ORIGINAL CROSS STRATEGY APPROACH OF SURFACE AND VOLUME CHARACTERIZATIONS

M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc. A. Loubat 1,*, F. Mollica 2, C. Eypert 3, M. Bouttemy 1, D. Aureau 1, M. Frégnaux 1, J. Vigneron 1, S. Gaiaschi 4, N. Naghavi 5, M. Jubault 5, F. Donsanti 5, P. Chapon 4, D. Lincot 2, A. Etcheberry 1 1Lavoisier Institute of Versailles (ILV), UMR 8180 CNRS-UVSQ, IPVF, 45 avenue des Etats-Unis - Versailles (France), 2Institute of Research and Development on Photovoltaic Energy (IRDEP) EDF –UMR 7174 CNRS-Chimie Paristech, IPVF, 6 quai Watier - Chatou (France), 3HORIBA Jobin Yvon SAS, avenue de la Vauve, Passage Jobin Yvon, CS 45002 - Palaiseau (France), 4HORIBA Jobin Yvon, IPVF, 16 rue du Canal - Longjumeau (France), 5Institute of Research and Development on Photovoltaic Energy (IRDEP) EDF –UMR 7174 CNRS-Chimie Paristech, IPVF, 6 quai Watier - Chateau (France)

Photovoltaic cells based on CIGS (Cu(In,Ga)Se2) thin film absorbers are promising for high yield in photovoltaic conversion. It is well known that the photovoltaic cells’ performance mainly rely on the absorber properties. In this context, the fine optimization of the whole stack requires an accurate characterization of the surface and the volume of each layer and particularly of the specific interfaces. Especially for CIGS absorbers, determination of gallium gradient (GGI=Ga/[Ga+In] ratio) is a key parameter as it governs the bandgap and the front side band alignment. We have developed a strategy of cross physico-chemical characterization methods, and first practiced on the absorber. The chemical composition (major elements, impurities) is investigated from surface to depth combining EDS, ICP-OES, GD-OES and XPS [1]. This multi-technique approach associates destructive and non-destructive techniques covering different spatial and resolution scales. The surface morphology is studied by SEM and AFM imaging. Furthermore, the optical properties are determined by spectroscopic ellipsometry, performed on chemically flattened samples. Results obtained on a batch of ungraded CIGS samples (coevaporation) with GGI ratio ranging from 0.15 to 0.61 will be presented. Thicknesses and depth compositions were set constant to evaluate the sensitivity and accuracy of each technique and emphasize their complementarities. An original XPS approach, to directly access the GGI ratio, based on Ga3d-In4d region study, will be presented as a value added mean to determine the actual surface composition before buffer layer deposition. Complementary work dedicated to the determination of local scale composition using nano-Auger (spot size 12nm), allowing the investigation of grain boundaries particularities, will be also shown. Thanks This work has been carried out in the frame of the ULTRACIS-M project supported by the ANR-Progelec-2012 and IPVF Project I and J. References [1] D. Mercier, M. Bouttemy, J. Vigneron, P. Chapon, A. Etcheberry, Appl. Surf. Sci. 347, pp. 799–807, 2015.

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O7-M4E _292 TIME-RESOLVED SURFACE PHOTOVOLTAGE SPECTROSCOPY STUDY OF CHARGE DYNAMICS AT THE COLLOIDAL QUANTUM DOT/ZNO HETEROJUNCTION FOR PHOTOVOLTAICS

M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc. P. Clark 1,*, A.I. Williamson 1, R. Ahumada Lazo 1, B.F. Spencer 1, M. Silly 2, S. Fausto 2, D. Neo 3, S. Fairclough 4, A. Watt 5, W.R. Flavell 1 1University of Manchester - Manchester (United Kingdom), 2Synchrotron SOLEIL - Paris (France), 3University California Irvine - Irvine (United States of America), 4King's College London - London (United Kingdom), 5Oxford University - Oxford (United Kingdom) Colloidal quantum dots (CQDs) are promising candidates as light absorbing components in photovoltaic technology, offering tuneable energy bandgaps that can maximise absorption of the solar spectrum with the potential to overcome the Shockley-Queisser limit. [1] Once light has been absorbed it is important that the extraction of the excited carriers into a photoanode is efficient. A recent development, the depleted heterojunction colloidal quantum dot solar cell, has demonstrated efficiencies above 9%. [2] This design relies on a depletion layer at the CQD-photoanode interface to drive the charge transport and separation. We have used time-resolved laser-pump X-ray photoemission-probe spectroscopy at the TEMPO beamline, at Synchrotron SOLEIL, to study the depleted heterojunction at the CQD and ZnO (10-10) interface. Using two lasers with photon energies of 1.94 eV and 3.31 eV, we photoexcite carriers across the band gaps which induces a change in the equilibrium band bending (a surface photovoltage (SPV) shift). This is measurable with X-ray Photoelectron Spectroscopy (XPS) as a change in the binding energy of core levels. The persistent photoconductivity of ZnO limits the dark carrier lifetimes to be of the order of 10- 100s of µs, allowing us to monitor the dynamics with fast XPS. The chemical specificity of XPS allows us to monitor the charge dynamics in both the CQDs and the substrate. We have studied PbS/CdS and CdSe/CdTe core/shell CQDs chemically linked to the ZnO surface, measuring the SPV shift in both the substrate and the CQDs. We are able to demonstrate charge injection from the CQDs into ZnO under conditions where the ZnO substrate cannot be directly photoexcited. For both systems we find evidence that the depletion region at the interface extends into the QD layer. [3] References [1] M. C. Beard, J. M. Luther, and A. J. Nozik, Nat. Nanotechnol. 9, 951 (2014). [2] A. J. Labelle, S. M. Thon, S. Masala, M. M. Adachi, H. Dong, M. Farahani, A. H. Ip, A. Fratalocchi, and E. H. Sargent, Nano Lett. 15, 1101 (2015). [3] B. F. Spencer, M. A. Leontiadou, P. C. J. Clark, A. Williamson, M. G. Silly, F. Sirotti, S. M. Fairclough, D. C. J. Neo, A. A. R. Watt, and W. R. Flavell, Appl. Phys. Lett. 108, 091603 (2016).

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O8-M4E _284 NICKEL SILICIDE FORMATION FOR SILICON SOLAR CELL METALLIZATION: THERMAL AND LASER ANNEALING

M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc. H. El Belghiti 1,*, D. Aureau 2, E. Delbos 1, M. Bouttemy 2, A. Slaoui 3, A. Etcheberry 2 1KMG Ultra Pure Chemicals - Saint-Fromond (France), 2Institut Lavoisier de Versailles - Versailles (France), 3ICUBE, Université de Strasbourg - Strasbourg (France) One of the major factors limiting the efficiency of silicon solar cells is the quality of the contacts. Silver paste screen-printing is traditionally employed to elaborate the contacts, this method being cost-effective, relatively fast and easy to manage and so easily implemented in a production line. However, screen-printed metals present high resistivity and porosity. Recently, interest has grown in the photovoltaic industry to replace silver lines by nickel/copper lines respectively deposited by electroless and electrolytic processes. From this process, the electroless nickel(P) ensures a barrier role to provide the copper diffusion throughout the silicon, which would damage the solar cell efficiency. This nickel(P) layer is first annealed to obtain specifically NiSi composite, necessary to guarantee the desired contact adherence and the low contact resistance (14 µΩcm). A fine tuning of the thickness and the composition of this interlayer is required to optimize the process. This research work is focused on the comparison of two Ni(P )annealing methods to form NiSi composite: (1) thermal under Ar/5% H2 atmosphere at 400°C and (2) laser. Initially, the influence of the initial Ni(P) thickness on the diffusion depth throughout the silicon will be presented for both methods. Then, a second part will be devoted to the study of the annealing duration and the laser fluence on the diffusion depth, depending on the method considered. These studies have been made on textured silicon substrate [100] and monitored using complementary analyses techniques: XRD to confirm the formation of SiNi phase and crystallinity, SEM (imaging), EDS (bulk chemical analyses in surface and cross- section) and XPS (surface chemical information and composition profiling).

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O9-M4E _326 XPS STUDY OF PEALD OXYSULFIDE INX(S,O)Y THIN FILMS FOR PHOTOVOLTAIC APPLICATIONS: UNDERSTANDING OF PLASMA-SURFACE INTERACTION

M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc. M. Bouttemy 1,*, C. Bugot 2,*, N. Schneider 2, J. Vigneron 1, A. Etcheberry 1, D. Lincot 2, F. Donsanti 2 1Institut Lavoisier de Versailles, UMR CNRS-UVSQ 8180, IPVF - Versailles (France), 2Institut de Recherche et Développement sur l’Energie Photovoltaïque, EDF-CNRS-Chimie ParisTech – UMR 7174 - IPVF - Chatou (France) Cadmium-free buffer layers represent an important technologic challenge for future Cu(In,Ga)Se2 (CIGS) solar cells. A promising route is the oxygen insertion in indium and zinc based materials, enabling to efficiently adjust the band alignment at the CIGS/buffer interface. Using ALD process, based on self-saturated surface reactions, guarantees the growth of conformal and uniform thin films with a high control of their properties. We already demonstrated the suitability of Plasma Enhanced - ALD (PEALD) for the synthesis of indium oxysulfide films, while no growth could be observed when using classical ALD [1], the O cation balance reaching 80%. Those results evidenced a significant plasma effect on the reactivity at the surface and the need to understand the growth mechanism to adjust the O content in the films and limit impurities incorporation (precursor fragments) by controlling the gas phase composition [2]. In this study, XPS depth profiling measurements are performed to address those points focusing on the plasma assistance effect. Three specific samples were prepared on non- deoxidized Si substrates to investigate the reaction pathway and the penetration depth: Inx(S,O)y-70 nm single layer, as reference material, InxSy/Inx(S,O)y/InxSy-20 and 40 nm, where top InxSy is a capping film. Composition profiles demonstrate that thicker is the InxSy sublayer, smaller is the O incorporation during the Inx(S,O)y film deposition, confirming that growth occurs via exchange mechanisms between the plasma and the growing layer. Results obtained on similar stacks but grown on deoxidized Si substrates show an increase of the growth rate and substantial O amount at the Si/InxSy interface, evidencing an inward O diffusion and a substrate dependence of the growth mechanism.

Finally, key information are obtained to transpose the PE-ALD Inx(S,O)y buffer deposition process on CIGS absorbers. References [1] C. Bugot, N. Schneider, D. Lincot, F. Donsanti, Beilstein Journal of Nanotechnology 2013, 4, 750–757. [2] C. Bugot, N. Schneider, M. Bouttemy, A. Etcheberry, D. Lincot, F. Donsanti, Thin Solid Films 2015, 582 340–344.

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P1-M4E_13 STRUCTURAL STUDIES OF THE HYDROGENATED SILICON

M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc. F. Zeudmi Sahraoui *, A. Kebab, D.D. Sib, Y. Bouizem, D. Benlekhal, L. Chahed University of Oran Ahmed ben Bella1 - Oran (Algeria) Hydrogenated nanocrystalline silicon films have become the subject of great attention due to their remarkable properties for microelectronics and solar cells technology. The structural changes in intrinsic silicon thin films deposited by radiofrequency (rf) magnetron sputtering at room temperature (Ts = 35°C) are investigated as a function of the rf-power. The aim of this work is to get more insight into the effect of the rf-power. By varying the rf-power from 200 W to 500 W, and keeping all other parameters of the plasma constant (the total pressure is fixed at 4 Pa, the plasma gas mixture of 30% Argon and 70% H2 and the target-sample holder distance of 50 mm). The composition and the microstructure of the films were analysed by FTIR, atomic force microscopy (AFM), optical transmission measurements (OT) and spectroscopic ellipsometry. The results indicate that the films have nanocrystalline structures and the grain size decreases (5 to 2 nm) with increasing rf-power (200 to 500 W). Analysis of the surface layers reveal that the Root Mean Square (RMS) surface roughness for the samples increases (11 to 43nm) with increasing rf-power and the film thickness grows (1.4 to 3.7µm).

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P3-M4E_39 DEGRADATION OF ORGANIC PHOTOVOLTAIC THIN LAYERS BY RADIATION EXPOSURE INVESTIGATED BY PHOTOELECTRON SPECTROSCOPY

M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc. E. Darlatt 1,*, B. Muhsin 2, R. Rösch 3, F. Roth 4, M. Kolbe 1, A. Gottwald 1, W. Eberhardt 4, H. Hoppe 3, M. Richter 1 1PTB - Physikalisch-Technische Bundesanstalt - Berlin (Germany), 2Ilmenau Unversity of Technology - Ilmenau (Germany), 3Friedrich Schiller University - Jena (Germany), 4Center for Free- Electron Laser Science/DESY - Hamburg (Germany) Due to their low production costs, low-priced starting materials, and mechanical flexibility, organic photovoltaics (OPVs) represent an attractive alternative to the established solar cells with inorganic photoactive layers (e.g. Si). One disadvantage of organic components in photovoltaic devices is their comparably low stability against irradiation [1-2]. The extensive study of degradation processes, their mechanisms, and their dependence on radiant exposure and wavelength is, therefore, prerequisite for the fabrication of stable OPVs in the future. In the present contribution a study of degradation of organic thin films relevant for photovoltaic applications by the exposure of monochromatic and quantifiable synchrotron radiation in the spectral range from VUV to visible light is presented. The irradiation procedure at the insertion device beamline at PTB’s own synchrotron radiation facility - the Metrology Light Source (MLS) - is explained. The characterization of organic thin films and the investigation of ageing effects were carried out by in situ measurements of UV and X-ray photoelectron spectroscopy (UPS, XPS) before and after radiant exposure. Thanks The funding through the European Metrology Research Program (EMRP) Project ENG53- ThinErgy is gratefully acknowledged. The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union. References [1] M. JØrgensen et al. Adv. Mater. 24 (2012), 580. [2] N. Grossiord et al., Org. Electr. 13 (2012), 432.

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P4-M4E_73 LITHIUM SULFIDE-BASED THIN-FILM ELECTROLYTES FOR ALL SOLID-STATE MICROBATTERIES

M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc. P. Morin 1,*, L. Le Van-Jodin 1, A. Benayad 2, R. Bouchet 3 1CEA-LETI, MINATEC Campus, 17 rue des Martyrs - Grenoble (France), 2CEA-LITEN, Department of Nanomaterials, MINATEC, 17 rue des Martyrs - Grenoble (France), 3LEPMI-INP Grenoble UMR 5279, 1130 rue de La Piscine - St Martin D'hères (France) Thin-film microbatteries, composed of all-solid-state layers, interest a lot of researchers and companies for the last decades, in order to supply small sensors or systems in energy. To reduce the internal resistance of such systems, Li2S-based electrolytes alloys with P2S5 or GeS2 have been identified as promising solid-state electrolytes, with ionic conductivities ranging up to 10-3 S/cm [1]. Mainly studied as massive materials, this work focuses on the deposition of Li2S-based thin-film electrolytes and their properties.

Li2S-P2S5 based glassy films were deposited by radio-frequency magnetron sputtering at room temperature with variable nominal power in pure Argon plasma. Different powers and deposition times were used to control the composition and deposition rate in order to optimize the composition of the Li2S-P2S5 thin films. A Scanning Probe Microscopy (SEM) and X-Ray Photoelectron Microscopy (XPS) studies were performed to probe the change in the morphology and composition regarding the deposition conditions. XPS depth profile analyses using a focused Ar-ions beam was performed across Ti/Li2S-P2S5 based Electrolyte/Ti systems (fig. 1) to probe the chemical composition of Li2S-P2S5 deposited films. The Sulfur 2p XPS core level depth profile shows a mixed sulfur environment Li2S:P2S5 [2]. A change in the composition, from rich Li2S near the metallic interface to rich polysulfide phases, was detected across the electrolyte (fig. 2).

In this work the electronic structure of Li2S-based glassy thin-films will be discussed based on XPS core level and valence band structure in order to correlate its chemical structure to the ionic conductivity and identify the electrochemical mechanisms at the interfaces. References [1] K. Takada, Acta Mater., vol. 61, no. 3, pp. 759–770, 2013. [2] C. Zu et al, J. Phys. Chem. Lett., vol. 5, no. 22, pp. 3986–3991, 2014

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P5-M4E_88 FOREST OF STRUCTURED SILICON NANOWIRES FOR THERMOELECTRICS

M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc. D. Singhal 1,*, O. Marconot 2, P. Gentile 2, M. Zelsmann 3, D. Tainoff 4, O. Bourgeois 4, D. Buttard 5 1INAC/PHELIQS/SiNaPS-CEA Grenoble, Institut Néel,- CNRS and Université Grenoble Alps - Grenoble (France), 2INAC/PHELIQS/SiNaPS-CEA Grenoble - Grenoble (France), 3LTM-CNRS, CEA-LETI-MINATEC - Grenoble (France), 4Institut Neel, CNRS - Grenoble (France), 5INAC/PHELIQS/SiNaPS-CEA Grenoble, Université Joseph Fourier/IUT-1 - Grenoble (France) Thermoelectric modules interconvert thermal gradients for power generation through Seebeck effect. Restricted by its low efficiency, measured by a dimensionless parameter ZT (function of Seebeck coefficient, electrical and thermal conductivities), it finds niche applications. Nanomaterials allow tailoring of the interdependent parameters, which opens up new avenues to increase efficiency. Low thermal conductivity with a wide range of density of states and phonon electron scattering in nanomaterials make them ideal for thermoelectric applications1. When the dimensions of the material are comparable to the mean free path of the phonons, the thermal conductivity decreases significantly due to surface scattering mechanism. Nanowires will modulated-diameter would further decrease the thermal conductivity substantially as the corrugations would act as a trap for phonons and reduce transmitivity2. In this work, template-assisted Chemical Vapor deposition growth of dense forest (109/cm2) of diameter-modulated silicon nanowires will be done. Nanoporous alumina, used as templates, is fabricated by anodizing aluminum in acidic electrolytes. The diameter and porosity of the template depend largely on the applied voltage while anodizing. In order to fabricate porous template with modulating pore diameter, method of pulse anodisation is applied which consists of periodic potential surges. Structural engineering along the film growth direction can be achieved by deliberately designing the potential pulse sequences (Figure 1: Nanoporous alumina fabricated through pulse anodisation). The arrangement of the pores on the surface is improved by the use of nanoimprint lithography and double anodisation method. The resulting highly ordered and dense structure of modulated pore diameter is suitable as templates for growing nanowires, of which the diameter is predefined by the internal pore structure of alumina. Growth of Silicon nanowires is underway through CVD which will be followed by sensitive 3- omega measurements of the forest of nanowires to acquire the reduction in the thermal conductivity of Silicon. References 1 Boukai, A., Xu, K., Heath, J.R., Size-Dependent Transport and Thermoelectric Properties of Individual Polycrystalline Bismuth Nanowires, Advanced Materials 18, 864-869, 2006. 2 Zianni, X., & Chantrenne, P., Thermal Conductivity of Diameter-Modulated Silicon Nanowires Within a Frequency-Dependent Model for Phonon Boundary Scattering, Journal of electronic materials, 42(7), 1509- 1513, 2013.

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P6-M4E_134 TOF-SIMS AND XPS CHARACTERIZATION OF R.F. MAGNETRON SPUTTERED LI-NI- MN-CO-O THIN FILMS FOR LI-ION BATTERIES

M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc. R. Azmi *, M. Strafela, S.O. Steinmüller, H. Ehrenberg, H.J. Seifert, S. Ulrich, M. Bruns Institute for Applied Materials, Karlsruhe Institute of Technology - Eggenstein-Leopoldshafen (Germany) Recently all-solid-state Li-ion batteries attract more attention because of their thermal stability, long lifetime and especially high inherent safety. Such batteries are typically deposited onto a substrate, by successive film depositions of current collectors, cathode, electrolyte, and anode. The cathode is typically formed by R.F.-magnetron sputtering, followed by subsequent heat treatment to adjust crystalline structure for an improved electrochemical performance. A crucial point in fabricating all-solid-state batteries is the coverage and adherence between the single layers without any protuberances on electrode surfaces. However, such a heat treatment step can intensify inter-diffusion and surface protuberances as a consequence of the diffusion from substrate into the cathode thin film. Using a diffusion barrier layer can be one attempt to avoid protuberances generated by inter- diffusion [1]. The present study focusses on the surface analytical characterization of Li-Ni-Mn-Co-O (NMC) thin film cathodes fabricated by means of R.F.-magnetron sputtering and subsequent annealing. These NMC thin films were deposited on several different substrates (Stainless Steel, Au, Si, etc) to find an appropriate barrier material with sufficiently high conductivity to sustain electron transport to the cathode. As the atomic and/or ionic inter-diffusion of the layer constituents at the contact interfaces is an important issue, the in-depth distribution of the film constituents was studied by X-Ray Photoelectron Spectroscopy (XPS) and Time-of- Flight Secondary Ion Mass Spectrometry (ToF-SIMS) sputter depth profiles. Here, special care was taken to guarantee atmosphere-contact-free sample transport. The combination of complementary ToF-SIMS and XPS allows for quantitative information on the uniformity of the as prepared thin films as well as on diffusion processes during annealing. Exemplarily, an XPS sputter depth profile of NMC thin film deposited onto a gold substrate is depicted in the figure proving the Au diffusion into the NMC thin film. However, due to a strong crosstalk of Mn2p and Au4p1 and also Li1s and Au5p3 we cut the Li1s and Mn2p profile at the NMC/Au interface. Our approach to overcome this problem by calibrating ToF-SIMS data with quantitative XPS information will be presented. References [1] A. Bünting et al. / Journal of Power Sources 281 (2015) 326-333

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P7-M4E_333 FACILE RECOVERY OF SILICON NANOPARTICLES FROM WAFER SLICING WASTE AND APPLICATION TO ENERGY STORAGE MATERIALS

M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc. D. Kil *, H. Jang, H. Chang, J. Choi, H. Kim Korea Institute of Geoscience and Mineral Resources - Daejeon (Korea, republic of) A large amount of silicon nanoparticles are generated during the slicing of silicon ingots into thin wafers for the fabrication of integrated-circuit chips and solar cells. This results in a significant loss of valuable materials at about 40% of the mass of ingots. In addition, a hazardous silicon sludge waste is produced containing largely debris of silicon, and silicon carbide, which is a common cutting material on the slicing saw. Efforts in material recovery from the sludge and recycling have been largely directed towards converting silicon or silicon carbide into other chemicals. Here, we report an aerosol-assisted method to extract silicon nanoparticles from such sludge wastes and their use in lithium ion battery applications. Using an ultrasonic spray-drying method, silicon nanoparticles can be directly recovered from the mixture with high efficiency and high purity for making lithium ion battery anode. The work here demonstrated a relatively low cost approach to turn wafer slicing wastes into much higher value-added materials for energy applications, which also helps to increase the sustainability of semiconductor material and device manufacturing. Keywords: Aerosol, Silicon, Waste, Energy Materials Thanks This work was supported by the R&D Center for Valuable Recycling, funded by the Ministry of Environment(Project No. GT-11-C-01-080-0)

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P8-M4E_409 NANOPOROUS COBALT AND SILVER CATALYSTS FOR DIRECT AMMONIA- BORANE FUEL CELLS

M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc. D. Barsuk 1,*, A. Zadick 2, Y. Guo 3, N.T. Panagiotopoulos 1, K. Georgarakis 1, K. Georgarakis 4, Y. Champion 1, M. Chatenet 2, M. Chatenet 5, A.M. Jorge Jr. 1, A.M. Jorge Jr. 2, A.M. Jorge Jr. 3 1Univ. Grenoble Alpes, SIMaP / CNRS - Grenoble (France), 2Univ. Grenoble Alpes, LEPMI / CNRS - Grenoble (France), 3DEMa, Universidade Federal de Sao Carlos - Saõ Paulo (Brazil), 4WPI-AIMR, Tohoku University - Sendai (Japan), 5French University Institute (IUF) - Paris (France) Nanoporous cobalt (NPCo) and silver (NPS) electrodes for liquid fuel cell have been fabricated by selective leaching of melt-spun ribbons of Co-Cu-Si and Ag-Cu-Si ternary alloys in free-corrosion conditions. Scanning electron microscopy, x-ray diffraction and nitrogen adsorption technique (BET) were used for characterization of the prestine and final nanoporous materials. After leaching in acid solutions, a tri-dimensional open pore structure with an average surface pore size of about 160 nm for NPCo and 98 nm for NPS was formed (Figure 1). Chemical microanalysis and electron diffraction patterns showed that the ligaments are formed by Co and the eutectic Co3Si as a residual in the Co system while NPS almost entirely consists of fcc silver. Cyclic voltammetry at the NP electrodes was used to study the efficiency of ammonia-borane (AB) oxidation reaction catalyzed on nanoporous anodes. The onset potential of AB oxidation for both materials shifted to more negative potentials (-0,4 V vs. RHE for NPCo and -0,3 V vs. RHE for NPS) than observed for commercial platinum nanoparticles supported on carbon films. Lower cost, better stability and reduced redox potential of AB fuel makes these materials ideal candidates for application as anode substrate materials for liquid fuel cells [1]. Keywords: nanoporous metals, leaching, catalysts, ammonia- borane, fuel cell. References [1] Olu, P.-Y.; Deschamps, F.; Caldarella, G.; Chatenet, M.; Job, N. Investigation of Platinum and Palladium as Potential Anodic Catalysts for Direct Borohydride and Ammonia Borane Fuel Cells. J. Power Sources 2015, 297, 492–503.

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P9-M4E_219 COMBINED EXPERIMENTAL AND DFT–TDDFT STUDY OF ZINC-PORPHYRIN SENSITIZERS FOR DYE-SENSITIZED SOLAR CELLS: EFFECT OF ANCHORING GROUP NUMBER ON THE CELL PERFORMANCE

M4E - Materials for Energy: photovoltaics, solar and fuel cells, etc. S. Jungsuttiwong *, R. Tarsang * 1Center for Organic Electronic and Alternative Energy, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani 34190, Thailand - Ubon Ratchathani (Thailand) Porphyrin dyes have received great attention due to their excellent photovoltaic performance in dye-sensitized solar cells (DSSCs). In this work, a series of zinc-porphyrin sensitizers denoted as 1PEP, 2PEP and 3PEP have been synthesized by introducing various numbers of anchoring groups of 1, 2, and 3 respectively. Their photophysical, electrochemical, and photovoltaic properties were investigated. The results showed that different numbers of anchoring groups significantly affect to the performance of the cells. The 1PEP showed the highest power conversion efficiency (h) of 4.01%. Compared to 1PEP, however, the h value of 2PEP and 3PEP are lower which is due to their lower photocurrent (Jsc). To further investigate the lower h affected by increasing anchoring group numbers, theoretical calculations for the dyes and dye@TiO2 complexes were performed. The calculated results revealed that the 2PEP and 3PEP with more anchoring groups provide more effective electron withdrawing for each anchoring group, leading to suppress the electron injection processes toward to CB of TiO2 and thus reduce the Jsc. References [1] Thongkasee P, Thangthong A, Janthasing N, Sudyoadsuk T, Namuangruk S, Keawin T, et al. Carbazole-Dendrimer-Based Donor−π–Acceptor Type Organic Dyes for Dye-Sensitized Solar Cells: Effect of the Size of the Carbazole Dendritic Donor. ACS Applied Materials & Interfaces. 2014;6(11):8212-22. [2] Sudyoadsuk T, Pansay S, Morada S, Rattanawan R, Namuangruk S, Kaewin T, et al. Synthesis and Characterization of D–D–π–A-Type Organic Dyes Bearing Carbazole–Carbazole as a Donor Moiety (D–D) for Efficient Dye-Sensitized Solar Cells. European Journal of Organic Chemistry. 2013;2013(23):5051-63. [3] Khanasa T, Jantasing N, Morada S, Leesakul N, Tarsang R, Namuangruk S, et al. Synthesis and Characterization of 2D-D-π-A-Type Organic Dyes Bearing Bis(3,6-di-tert-butylcarbazol-9-ylphenyl)aniline as Donor Moiety for Dye-Sensitized Solar Cells. European Journal of Organic Chemistry. 2013;2013(13):2608-20.

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MAQ - Metal, alloy and quasicrystal surfaces

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O1-MAQ _343 FIRST SURFACE STRUCTURE DETERMINATION OF A QUASICRYSTALLINE APPROXIMANT USING COMBINED SURFACE X-RAY DIFFRACTION AND AB INITIO CALCULATIONS.

MAQ - Metal, alloy and quasicrystal surfaces E. Gaudry 1,*, C. Chatelier 1, G. Mcguirk 1, L. Serkovic 1, M.C. De Weerd 1, J. Ledieu 1, V. Fournée 1, R. Felici 2, J. Drnec 3, G. Beutier 4, M. De Boissieu 4 1Institut Jean Lamour, UMR 7198 CNRS Université de Lorraine - Nancy (France), 2ESRF, Grenoble, France and CNR-SPIN, Area della ricerca di Tor Vergata, Via del fosso del cavaliere 100, Roma, Italy - Rome (Italy), 3ESRF - Grenoble (France), 4Université Grenoble Alpes and CNRS, Simap - Grenoble (France) Because of their large crystal cells, generally described as clusters assembly, the determination of quasicrystalline approximant surface structure is a challenging task. It results from the interplay between the selection of specific atomic planes at the surface and the preservation of atomic clusters up to the surface. Moreover, surface segregation and interatomic relaxations also play a role to decrease the surface energy. In this work, we re-investigate the pseudo-10fold surface of the Al13Co4 complex intermetallic compound (Fig. 1 left) [1,2], considered as a decagonal approximant, using both surface x-ray diffraction (SXRD) and density functional theory (DFT) calculations. SXRD has the advantage compared to dynamical low-energy electron diffraction (LEED-IV) that one can generally ignore multiple scattering, which makes data analysis more straight- forward. The determination of the surface structure by SXRD was only possible due to the large experimental dataset which could be recorded at ESRF – the largest experimental dataset ever analyzed with this technique – a consequence of the high density of crystal truncation rods and of the relatively low symmetry of the system. Fits of the SXRD data allowed to discriminate among various surface models and pointed towards a bulk truncated surface at dense Al-rich puckered planes where protruding surface Co atoms are missing. Surface relaxations and exact atomic positions obtained by SXRD and complementary DFT calculations are very similar and give confidence in the analysis. In addition, the surface energy of the corresponding surface model could be estimated from DFT calculations with a rather low value of 1.09 J/m2. This in turn allowed us to estimate interfacial energy differences, consistent with a complex interface structure. This study opens new perspectives for the determination of complex surface structures, such as quasicrystalline and related intermetallic surfaces. Thanks This work was supported by the ANR CAPRICE 2011-INTB 1001-01, the European C-MAC consortium. This work was granted access to the HPC resources of IDRIS under the allocation 99642. References [1] H. Shin et al., Phys. Rev. B 84, 085411 (2011) [2] M. Krajci and J. Hafner, J. Catal. 278, 200 (2011)

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O2-MAQ _324 ORDER DISORDER PHASE TRANSITION OF A TWO-DIMENSIONAL ALLOY MADE OF IMMISCIBLE ELEMENTS

MAQ - Metal, alloy and quasicrystal surfaces Y. Girard 1,*, C. Chacon 1, J. Lagoute 1, J.B. Marie 1, R. Vincent 1, S. Rousset 1, A. Coati 2, Y. Garreau 2 1Laboratory MPQ - Paris (France), 2Synchrotron SOLEIL - L'orme Des Merisiers (France)

We have studied the FexAu1-x two-dimensional surface alloy (around x=1/3) on Ru(0001) by STM at room temperature (see figure left, black points in the bottom part of the picture are iron atoms) and grazing incidence X-ray diffraction at high temperature during annealing and freezing (see figure right). This system is exceptional because two-dimensional ordered surface alloy made of immiscible elements are very rare (a). This 2D layer is ordered at the atomic scale thanks to elasticity and magnetic interactions (b). The long-range order does not exist due to local defects (blue points on STM picture) which stabilized a mean range order inside uncorrelated domains (three colored domains). An intriguing point is the constant width of the diffracted peak intensity during the reversible transition (see bottom of the right figure). A 2-levels model (c) allows us to estimate the formation energy of this disordered two-dimensional alloy. Finally, to our knowledge, there is still no theoretical model describing that kind of phase transition (d).

Thanks We acknowledge fundings from the C'Nano IdF, the SOLEIL technical staff and the French Ministry of Research. References (a) J. Yuhara, M. Schmid and P. Varga, Phys. Rev. B 67, 195407 (2003). (b) S. Mehendale, Y. Girard,V. Repain, C. Chacon, J. Lagoute, S. Rousset, M. Marathe and S. Narasimhan, Phys. Rev. Lett. 105, 056101 (2010). (c) W. H Kirchhoff and I. W. Levin, J. Res. Nat. Bur. Stand. 92, 113 (1987). (d) J. Villain and J. G. Moreira, J. Phys.: Condens. Matter 3, 4587 (1991).

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O3-MAQ _141 HOW TO SORT REGULAR-ALLOYED, CORE-SHELL AND SKIN-HEART AUCU BIMETALLIC NANOPARTICLES FROM A DFT APPROACH?

MAQ - Metal, alloy and quasicrystal surfaces M. Iachella *, R. Ferreira De Morais, D. Loffreda Ecole Normale Supérieure de Lyon - Lyon (France) In heterogeneous catalysis, the most used catalytic system is composed of metallic particles supported on a large range of amorphous materials. In the realm of supported nanoparticules, gold nanoparticles deposited on rutile TiO2 (110) are of particular interest, being one of the model systems widely studied. Recently, the nucleation, the growth and the morphology of gold nanoparticles deposited on rutile support have been studied by various techniques. [1,2,3] To improve a catalytic system, one of the most used methods is to create a bimetallic nanoparticle (BNP), such as AuCu, for instance. The key questions are the competitive morphology, composition and relative stability of such nano-objects (relative atomic contents, structure,…). In this context, the role of atomic-scale theoretical modelling is essential to solve those problems. In this study, we propose DFT calculations for the different families of AuCu bimetallic nanoparticles in the range 0.5-2 nm in vacuum: regular-alloyed, core-shell and skin-heart structures with different morphologies and stoichiometries (regular polyhedra). This study aims to compare those different types of bimetallic nanoparticles, by examining their surface energy. This descriptor is calculated on the basis of a thermodynamic phenomenological new model for evaluating the stability of the bulk references. According to the analysis of the relative stability of a hundred considered BNPs, linear correlations have been captured by sorting specific morphologies and size against stoichiometry.[4] This theoretical study opens promising perspectives for the understanding of the growth of gold-copper BNPs on catalytic supports and their change of reactivity compared to respective monometallic ones. References [1] Wahlström, Phys. Rev. Lett., 90 (2003) 026101 [2] Shibata, Phys. Rev. Lett., 102 (2009) 136105 [3] Saint-Lager, Faraday Discuss., 162 (2013) 179–190 [4] M. Iachella, R. Ferreira de Morais, D. Loffreda, (2016), submitted

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O4-MAQ _100 CARBON SEGREGATION AND OXIDATION ON FE0.85AL0.15(110) : A STM, LEED AND XPS STUDY

MAQ - Metal, alloy and quasicrystal surfaces Z. Dai *, P. Borghetti, G. Cabailh, J. Jupille, R. Lazzari Institut des NanoSciences de Paris - Paris (France)

Fe0.85Al0.15 single crystals in the ferritic phase were used as a model system of oxidative behaviour of strongly Al-alloyed light steel. By combining Scanning Tunnelling Microscopy (STM), Low Energy Electron Diffraction (LEED) and X-ray Photoelectron Spectroscopy (XPS), it was found that carbon impurities segregate on top of the reconstructed bare surface in the form of parallel monoatomic stripes, spaced by approximately 12 nm. These stripes run along the [001] direction with a temperature dependent coverage; the dominant step edges are parallel to the stripes at lower annealing temperatures. However, such carbon segregation disappears after intensive sputtering/annealing cycles. The carbon free areas of the substrate show superstructure LEED diffraction spots which correspond to a local hexagonal arrangement as imaged by STM (periodicity of 3 nm). This observation matches a FeAl2 Al-rich surface reconstruction model [3]. These surfaces have then been oxidized in ultra-high vacuum conditions at 800°C with increasing exposure to molecular oxygen. The oxide formation competes with the carbon stripes; it grows in stripes free areas until the surface is fully oxidized. The oxide film, 0.7 nm thick as estimated by XPS, presents several rotated domains and a LEED pattern reminiscent of previous observations on NiAl surfaces. Three aluminium chemical environments have been detected and assigned to atoms in the bulk, interface and in the film. Thanks We are grateful to Stéphane Chenot and Pascal David for continuous technicien support, the author would like to think China Scholarship Council for financial support with contract N. 201406150013. Thanks for the valuable suggestions of Jacek Goniakowski. References [1] H. Graupner et al., Surface Science 322 (1995), 103-115 [2] G. Kresse et al., Science, 308:1440, 2005 [3] L. Hammeret al., Surface Science 412/413 (1998) 69–81 [4] G. Panaccione et al., Phys. Rev. B, 73:035431, 2006

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O5-MAQ _86 TRIBOLOGICAL PROPERTIES OF PLASMA SPRAYED FERROCHROMIUM-NICKEL COMPOSITE COATINGS

MAQ - Metal, alloy and quasicrystal surfaces M. Salehi *, M. Tabeshfar *, A. Monshi isafahan university of technology (Iran, islamic republic of) In this paper, the mechanical and tribological properties of plasma sprayed high carbon ferrochromium-nickel (HCFeCr-Ni) composite coatings with different amounts of Ni (10, 20 and 30wt.%) were investigated. Toward this purpose, the HCFeCr-Ni composites powders were prepared by sintering and crushing method. Scanning electron microscopy (SEM) observations exhibited a uniform distribution of Ni within the metallic matrix of composite coating. HCFeCr-10wt.%Ni revealed the weakest properties amongst all coatings because 10wt% of Ni was not sufficient enough to provide a suitable cohesion between ferrochromium particles leading to a high percentage of porosity (8.1%) and maximum weight loss of (0.035g). In contrast, HCFeCr-20wt.%Ni coating showed the optimum mechanical and wear behavior by incorporating 20wt.%Ni to HCFeCr, microhardness was increased from 763 to 950 HV, and the weight loss was decreased from 0.0061g to 0.0025g. The predominant wear mechanism for composite coatings was identified to be adhesive wear together with microcracking with different severity.

Table:Parameters of APS technique

Spray parameter Value

Primary gas flow rate (Ar) 24.5(lit/min)

Secondary gas flow rate (N) 3.8(lit/min)

Current(A) 800

Voltage (V) 3.8

Stand-off distance 9 cm References [1] C. Katsich, E. Badisch, M. Roy, G.R. Heath, F. Franek, Erosive wear of hardfaced Fe–Cr–C alloys at elevated temperature, Wear. 267 (2009) 1856-1864. [2] Y. Yuan, Zh. Li, Effects of rod carbide size, content, loading and sliding distance on the friction and wear behaviours of (Cr,Fe)7C3-reinforced α-Fe based composite coating produced via PTA welding process Surf. Coat. Technol. 248 (2014) 9–22. [3] C.M. Chang, C.M. Lin, C.C. Hsieh, J.H. Chen, W. Wu, Micro-structural characteristics of Fe–40 wt%Cr– xC hardfacing alloys with [1.0–4.0 wt%] carbon content, j. Alloys Compd.487 (2009)83-89. [4] S. Tailor, R.M. Mohanty, V.K. Sharma, and P.R. Soni, Fabrication and wear behaviour of nanostructured plasma-sprayed6061Al-SiCp composite coating, J.Therm. Spray Techn(2014)1-8.

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O6-MAQ _260 VAN DER WAALS DENSITY-FUNCTIONAL STUDY FOR LOW-INDEX METALLIC SURFACES

MAQ - Metal, alloy and quasicrystal surfaces R. Topolnicki *, R. Kucharczyk Surface Theory Group, Institute of Experimental Physics, University of Wroclaw, Poland - Wroclaw (Poland) One of the known drawbacks of GGA and hybrid functionals is that they fail to describe long- range electron correlations, essential to characterize interactions in a number of relevant systems, such as organic and layered materials or molecules adsorbed on surfaces. Hence, incorporation of van der Waals (vdW) forces to DFT becomes a method of choice for many surface-science-related problems. Several encouraging approaches have been proposed to include both dispersive and repulsive long-range interactions in the standard DFT framework [1,2], however, there is no agreement on the reliability of particular methods. Moreover, most studies are focused solely on the proper description of adsorbate–substarte interactions. In this work, the influence of vdW corrections on the main characteristics of clean surfaces ― such as surface energy, work function, structural relaxations and electronic structure of the topmost layers ― is investigated in a systematic manner for a series of (100), (110) and (111)-oriented metallic substrates. The corresponding effect on bulk parameters [3] is also addressed. We focus on transition and noble metals, but some free-electron-like metals are examined for comparison. Several commonly used vdW corrections, including DFT-D2, DFT-D3, revPBE-vdW, optB86b and DFT-TS, are employed. Results are contrasted with the corresponding GGA and LDA computations as well as available experimental data. Deviations of the calculated lattice constant, bulk modulus, work function and surface energy from the respective experimental values are exemplified in figures below. Some statistical analysis is performed in order to demonstrate performance of various considered vdW-DFT algorithms. References [1] A. Tkatchenko et al., Phys. Rev. Lett. 108 (2012) 236402. [2] K. Berland et al., Rep. Prog. Phys. 78 (2015) 066501. [3] J. Park et al., Curr. Appl. Phys. 15 (2015) 885.

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O7-MAQ _405 BI1TE1: A NEW DUAL TOPOLOGICAL INSULATOR

MAQ - Metal, alloy and quasicrystal surfaces L. Plucinski 1,*, M. Eschbach 1, M. Lanius 1, C. Niu 1, E. Mlynczak 1, E. Mlynczak 2, P. Gospodaric 1, J. Kellner 3, P. Schüffelgen 1, M. Gehlmann 1, S. Döring 1, E. Neumann 1, M. Luysberg 4, B. Holländer 1, G. Mussler 1, M. Morgenstern 3, D. Grützmacher 1, G. Bihlmayer 1, S. Blügel 1, C.M. Schneider 1 1Peter Grünberg Institute and JARA-FIT, FZ Jülich GmbH - Jülich (Germany), 2Faculty of Physics and Applied Computer Science, AGH University - Krakow (Poland), 3II. Institute of Physics B and JARA-FIT, RWTH Aachen University - Aachen (Germany), 4Peter Grünberg Institute and ER-C, FZ Jülich GmbH - Jülich (Germany) We present, a combined theoretical and experimental study on the prediction and verification of the dual topological insulating character of the stoichiometric natural superlattice phase Bi1Te1 = [Bi2]1[Bi2Te3]2 [1]. We identify Bi1Te1 by density functional theory to exhibit a non-trivial time-reversal symmetry-driven character of 2 = (0; 001) and additionally a mirror-symmetry induced mirror Chern number of M = -2, which indicates that Bi1Te1 is both a weak topological insulator (WTI) and a topological crystalline insulator (TCI). The coexistence of the two phenomena preordain distinct crystal planes to host topological surface states that are protected by the respective symmetries. From the analysis of time- reversal invariant momenta (TRIM-points) the surface perpendicular to the stacking direction, for instance, is found as the time-reversal symmetry dark surface, while hosting mirror-symmetry protected non-TRIM surface states along the direction. We confirm the stacking sequence of our MBE-grown Bi1Te1 thin films by X-ray diffraction and transmission electron microscopy (STEM), and find clear indications of the TCI and WTI character in the surface electronic spin structure by spin- and angle-resolved photoemission spectroscopy (spin-ARPES). Figure 1 shows the TCI surface state in the off-normal emission ARPES maps on natural cleavage single QL terminated surface, a dark surface concerning the WTI properties of Bi1Te1. Figure 1(e) demonstrates the Dirac crossing in the WTI surface state at off-normal emission, i.e. at a non-TRIM point of the Brillouin zone. References [1] M. Eschbach et al., arXiv:1604.08886 (2016).

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O8-MAQ _373 METHODS FOR HIGH THROUGHPUT STUDY OF ALLOY CORROSION ACROSS ALLOY COMPOSITION SPACE

MAQ - Metal, alloy and quasicrystal surfaces A. Gellman *, M. Payne, J. Miller Carnegie Mellon University - Pittsburgh (United States of America) Our understanding of alloy surface chemistry is hampered by the need to study the surfaces of alloys of many different compositions that span continuous and mutidimensional composition spaces. For example, improving our fundamental understanding of the oxidation of multicomponent alloys is crucial to their ongoing development but requires preparation and characterization of many samples of discrete and differing compositions. In this work, high-throughput methods were developed to study oxidation of AlxFeyNi1-x-y alloys in dry [1] and humid [2] air at 427 °C using composition spread alloy films as combinatorial libraries (x = 0 → 1, y = 0 → [1-x]) (Figure 1). Methods such as EDX, XPS, and Raman spectroscopy have been used to map the extents of corrosion and the phases formed across the entire ternary alloy composition space (Figure 2). The results divide the AlxFeyNi1-x-y composition space into four regions of phenomenologically distinct oxidation behaviour. Most importantly, the boundary defining the critical Al concentration, (x, y), for establishment of a passivating Al2O3 scale was determined across the entire continuous AlxFeyNi1-x-y composition space. The trajectory of this boundary is shown to be sensitive to the oxidation environment and the critical aluminum concentration is shifted to higher values by the presence of humidity. Thanks This work was financially supported at the Carnegie Mellon University by the DOE NETL through the RES Contract No. DE-FE000400. References

1. M.A. Payne, J.B. Miller, A.J. Gellman, “High-throughput characterization of AlxFeyNi1-x-y oxidation across composition space” Corrosion Science 91, (2015), 46-57 (10.1016/j.corsci.2014.10.034)

2. M.A. Payne, J.B. Miller, A.J. Gellman, “High-throughput characterization of the effects of H2O vapour on early oxidation across AlxFeyNi1-x-y composition space” Corrosion Science 106, (2016), 61–81 (10.1016/j.corsci.2016.01.026)

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P1-MAQ_85 HEAT ACTIVATED BLUR OF SURFACE OF ANTIPHASE BOUNDARIES IN THE CUZN ALLOY.

MAQ - Metal, alloy and quasicrystal surfaces A. Chaplygina 1,*, M. Starostenkov 2, P. Chaplygin 3 1assistant professor - Barnaul (Russian federation), 2professor - Barnaul (Russian federation), 3graduate student - Barnaul (Russian federation) This paper examines the effects of smearing antiphase boundaries in the alloy CuZn with superstructure B2 depending on the temperature. Computer simulations were performed using the Monte Carlo method, as in [1-3]. Interatomic interaction specified by using Morse pair potentials [4]. Mechanism of migration, applied in this investigation was diffusion of the atoms for vacancies. We used periodic boundary conditions. Were considered the influence of antiphase boundaries in <100> direction on the structural and energy characteristics of β-brass during the phase transition of the order-disorder. Were shown structural changes of the alloy near the antiphase boundaries with increasing temperature, leading to their smearing and faceting (Fig. 1). It is shown that the alloy without disturbances of superstructure more stable than alloy with antiphase boundaries in <100> direction. First disordered areas always appear near the antiphase boundaries.

Fig. 1. Pictures of the changes of the domain structure of the alloy CuZn with APB in the <100> direction in the process of disordering References 1. Starostenkov M., Chaplygina A., Romanenko V. Details of the formation of superstructures in the process of ordering in Cu-Pt alloys//Key Engineering Materials. 2014. Т. 592-593. С. 321-324. 2. Chaplygin P.A., Starostenkov M.D., Potekaev A.I., Chaplygina A.A., Kulagina V.V., Grinkevich L.S. // Structural-phase transformations of an BCC-alloy during thermal cycling// Russian Physics Journal. №4 (2015) p. 52-57 3. Starostenkov M.D., Chaplygina A.A., Chaplygin P.A., Potekaev A.I., Romanenko V.V.// Structural and energetic characteristics of the alloy CuPt with APB in the <111> direction // Fundamental Problems of modern materials. 2014. T. 11. № 4-2. S. 614-618. 4. Starostenkov M.D., Bakaldin A.V., Pivenj V.V.// Defects in alloys of L11, L10 superstructures and their influence on plastic deformation and phase transformations // Book of abstracts. Materials week’ 93 TMS, USA, Pittsburgh, PA.- October 17-21, 1993.- p.163.

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P2-MAQ_273 SPINODAL DECOMPOSITION OF CU-NI ALLOY ON NI(111)

MAQ - Metal, alloy and quasicrystal surfaces T. Fukuda 1,*, K. Umezawa 2, I. Kishida 1 1Osaka City University - Osaka (Japan), 2Osaka Prefecture University - Sakai (Japan) Cu-Ni alloy is an ubiquitous material and it is employed extensively as coinages and piping known as cupronickel. It forms a fcc structure in solid states with any fraction of constituents, i.e., an all proportional solid solution. However, the mixing energies for a Cu impurity in bulk Ni and vice versa are positive, indicating potential phase separation of constituent elements at low temperatures, known as spinodal decomposition. Of course for bulk alloys marginal diffusion at low temperatures prohibits the spinodal decomposition and no clear evidence of the phase separation was reported so far. For surface alloy enhancement of diffusion due to the lower coordination of surface atoms would promote surface diffusion even at low temperatures and the phase separation will take place. In addition, because individual Cu and Ni can be discriminated by scanning tunnelling microscopy (STM),[1] the phase separation would be unambiguously observed. Here we address the phase separation of Cu-Ni thin alloy films by depositing Cu and Ni on the Ni(111) surface and observing by STM in an UHV. Cu and Ni were co-deposited with the same rate within 10%, or the ratio of Cu to Ni being 10 and 0.1. Total Cu-Ni alloy films up to 1 ML were examined for the room temperature and 100°C substrates. A typical wide scan STM image is shown in Fig. for a total 0.4 ML Cu-Ni alloy deposited at room temperature. In Fig. an original monoatomic step is indicated by a white broken line. Below the line monolayer-thick Cu-Ni alloy film was grown. An apparent inhomogeneity in the grown region is a clear evidence of the composition fluctuation between Cu and Ni. The brighter region is a Cu-rich phase because of the higher density of surface states by the Shockley state, which is confirmed by STS spectra (not shown here). Dendritic lines across the grown region are due to Ni and surrounding the dendrites Cu-Ni composite alloy was aggregated. Similar dendrite growth is also seen on the island at the upper left corner in Fig. References [1]T. Fukuda, et. al, Phys. Rev. B 78, 195422 (2008).

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P3-MAQ_420 PRODUCTION AND SCALE-UP OF SIZE-CONTROLLED ELEMENTAL AND SELECTED BINARY NANOCLUSTERS

MAQ - Metal, alloy and quasicrystal surfaces S. Gholhaki * University of Birmingham - Birmingham (United Kingdom) In recent years many nanoparticles have demonstrated interesting properties applicable to industrial sectors such as catalysis, drug delivery and electronics. These applications demand precise characterization and thus advanced measurement to quantify and characterize the nanoparticles, as well as scale up of the production rates. Here we explore the atomic structure of metallic nanoclusters, generated using two kinds of cluster beam source, a magnetron sputtering gas aggregation source with a time-of-flight mass filter (M/ΔM = 20) [1] and the Matrix Assembly Cluster Source (MACS) which is capable of industrial scale research and development nanoparticle production [2]. Aberration-corrected Scanning Transmission Electron Microscopy (STEM) provides the atomic resolution needed to investigate the nanoclusters precisely. We report two main results: (i) It has been shown that size-selected Pt/Ti binary clusters demonstrate multiple Pt core formation when fully oxidised [3]. However, new STEM images of clusters prior to oxidation presented here show a mixed alloy of the two metals. Video imaging shows that Pt core develop upon annealing nanoclusters before oxidation. (ii) The MACS approach preserves good precise control of nanocluster but allows production rates more similar to traditional chemical (colloidal) methods. We demonstrate the deposition quality of Au cluster (1.8 nm) to generate colloidal nanoparticles as reference nanomaterials. References [1] Pratontep, S., Carroll, S. J., Xirouchaki, C., Streun, M., & Palmer, R. E. (2005). Size-selected cluster beam source based on radio frequency magnetron plasma sputtering and gas condensation. Review of Scientific Instruments, 76(4). http://doi.org/10.1063/1.1869332 [2] Palmer, R. E., Cao, L., & Yin, F. (2016). Note : Proof of principle of a new type of cluster beam source with potential for scale- up, Review of Scientific Instruments 046103, 68–71. http://doi.org/10.1063/1.4947229 [3] Blackmore, C. E., Rees, N. V., & Palmer, R. E. (2015). Modular construction of size-selected multiple- core Pt–TiO 2 nanoclusters for electro-catalysis. Phys. Chem. Chem. Phys. http://doi.org/10.1039/C5CP00285K

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P4-MAQ_423 NANOSIZE-INDUCED STRUCTURES AND DISTORTION IN SUPPORTED PT-AG NANOPARTICLES

MAQ - Metal, alloy and quasicrystal surfaces J. Pirart 1,*, P. Andreazza 1,*, C. Andreazza-Vignolle 1, C. Mottet 2, A. Lemoine 1, Y. Garreau 3, A. Coati 3 1ICMN, Université d'Orléans, CNRS - Orléans (France), 2CINaM - Marseille (France), 3Synchrotron SOLEIL - Gif-Sur-Yvette (France) The nanoalloys’ structural properties are highly complex and very interesting because of their size-dependent evolution. Indeed, due to the size reduction (surface effect and finite number of atoms), nanoalloys exhibit exotic atom arrangements and internal deformations which modify their atomic and chemical structure, as for the Pt-Ag system, widely studied due to its promising catalytic properties1. Macroscopic study of Pt-Ag alloy shows an interesting but complex phase diagram2 especially at low temperature: an ordered alloy is formed only at the AgPt equi-stoichiometry of, and a quasi-complete immiscibility for the rich-Pt side compared to a partial miscibility for a high Ag concentration. Concerning Pt-Ag nanoalloys, the size reduction can modify the ordered alloys stability, or induce segregation between Pt and Ag leading to core-shell, janus-like… structures. Three principal forces allow the nanostructure prediction (alloy, segregation…): the size and surface energy difference between the two elements and also their ability to mix in the bulk. For Pt-Ag nanoparticles, Monte Carlo simulations3, taking into account these three forces, predict a core(Pt)-shell(Ag) segregation in competition with an alloying effect depending on the composition. The aim of this study is to experimentally determine the phase nanoscale diagram and whether the deformation state of nanoparticles affect their stability. Pt-Ag nanoalloys are prepared by atomic evaporation using two separate sources operating simultaneously and deposition under UHV conditions. Then, the sample is annealed to promote their isothermal equilibrium crystallographic structure. The structure and morphology are studied ex-situ using transmission electron microscopy in HRTEM and STEM-HAADF (high angle annular dark-field) modes. For the quasi-equiatomic composition, an alloy phase L11 (alternating pure Ag and Pt (111) planes) is observed with a higher rhombohedral deformation than those expected in bulk materiel. In addition, with a simultaneous core-shell segregation in agreement with Monte Carlo simulations. Furthermore, UHV grazing incidence X-ray scattering at the SIXS beamline of the SOLEIL synchrotron has been performed in situ, in real time, to observe the structural evolution during growth of the nanoobjects4. References 1 Hwang et al, Property of Pt-Ag alloy nanoparticle catalysts in carbon monoxide oxidation, Phys. Chem. C, 118, 49, 28739-28745, 2014 2 M H. F. Sluiter et al, Ab initio calculation of the phase stability in Au-Pd and Ag-Pt alloys, Phys. Rev. B, 73, 17, 2006 3 K. Yun et al, Monte Carlo simulations of the structure of Pt-based bimetallic nanoparticles, Acta materiala 60,12, 4908-4916, 2012 4 P. Andreazza, Invited talk, ECOSS32, Grenoble 2016

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MOS - Molecules at surfaces

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O0-MOS_294 FULLERENE: A NANOSCALE SENSOR TO PROBE THE SURFACE POTENTIAL OF METALS AND ALLOYS

MOS - Molecules at surfaces S. Karthäuser *, M. Paßens *, N. Atodiresei, R. Waser Forschungszentrum Jülich - Jülich (Germany) Close-packed monolayers of fullerenes on metallic substrates are very rich systems with respect to their rotational degrees of freedom and possible interactions with different adsorption sites or next neighbours. They have attracted much attention due to their structural and electronic properties. Here, we focus on the ability of fullerenes to form self- assembled monolayers that mirror impressively the electronic properties of the respective substrate. Using low-temperature UHV-STM and LEED in combination with DFT calculations the interactions of fullerene molecules with a metallic surface [1,2], an alloy [3], and a thin oxide film are characterized in detail. The LT-STM images with orbital resolution allow a detailed assignment of the fullerene orientation with respect to the underlying substrate. Moreover, even second order interface effects, that is, interaction of fullerenes with atoms of the subsurface layer are identified (Fig. 1). Most interestingly, in the case of a Pt3Ti-single crystal alloy [3] used as substrate the influence of subsurface Ti-atoms on the self- assembly behavior of fullerenes is determined [4]. Here, third layer Ti-atoms influence the surface potential of the single crystal alloy and the interaction with fullerenes in such a way that new surface structures are built. References [1] M. Paßens, R. Waser, S. Karthäuser, „Enhanced fullerene-Au(111) coupling in (2√3 x 2√3)R30°- superstructures with cooperative intermolecular interactions“, Beilstein Journal of Nanotechnology 6, 1421- 1431 (2015). [2] M. Paßens, S. Karthäuser, “Interfacial and intermolecular interactions determining the rotational orientation of C60 adsorbed on Au(111)”, Surf. Sci. 642, 11-15 (2015). [3] M. Paßens, V. Caciuc, N. Atodiresei, M. Moors, S. Blügel, R. Waser, S. Karthäuser, „Tuning the surface electronic structure of a Pt3Ti(111) electro catalyst“, Nanoscale (2016) DOI: 10.1039/C5NR08420B. [4] M. Paßens, V. Caciuc, N. Atodiresei, M. Feuerbacher, M. Moors, S. Blügel, R. Waser, S. Karthäuser, ready for submission.

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O1-MOS _119 ELECTRIC FIELD DRIVEN CHEMICAL REACTION OF INDIVIDUAL MOLECULAR SUBUNITS BY SCANNING TUNNELING MICROSCOPY

MOS - Molecules at surfaces U. Schlickum 1,*, T. Michnowicz 1, B. Borca 1, R. Pétuya 2, R. Gutzler 1, V. Schendel 1, I. Pentegov 1, U. Kraft 1, H. Klauk 1, P. Wahl 3, A. Arnau 2, K. Kern 1 1Max-Planck-Institut für Festkörperforschung - Stuttgart (Germany), 2Donastia International Physics Centre - San Sebastian (Spain), 3University of St Andrews, School of Physics and Astronomy - St Andrews (United Kingdom) The atomic scale control and understanding of elementary steps in chemical reactions might improve significantly their efficiency. Scanning tunneling microscopy (STM) not only allows investigating but also stimulating chemical reactions of individual organic subunits for example via the tunneling current, electric field or precise mechanical interaction. Here we present a study of an STM stimulated desulfurization process of one thiophene part included in a tetracenothiophene (TCT) molecule on a Cu(111) surface. Precise control of the external stimuls via the positioning of the STM tip apex allows determining a two-step process responsible for this chemical reaction. High resolution STM images help us to correlate the first reaction step to the breaking of one sulfur bond and the second to the breaking of the second sulfur bond. The latter reaction also leads to a significant increase of the bond strength of the broken thiophene part to Cu surface atoms. These observations are supported by DFT calculations. The chemical reaction is triggered by positioning the tip apex above the thiophene part and applying a threshold voltage that depends linearly on the tip-molecule distance. This linear dependence is characteristic for an electric field driven process. In addition, conduction measurements through single TCT molecules present in the different conformations on the Cu(111) surface have been performed. Compared to the intact molecule we observed a 50% increase of conductance through the modified molecule after the chemical reaction in agreement with the finding of a much stronger bond formation between the molecule and Cu surface atoms.

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O2-MOS _415 ELECTRONIC STRUCTURE OF ALKANETHIOLS AND BDMT MONOLAYERS ON AU (1 1 1)

MOS - Molecules at surfaces P. Häberle 1,*, J. Correa-Puerta 2,*, V. Del Campo 1, R. Henríquez 1, V. Esaulov 3, H. Hamoudi 4, M. Flores 5 1Universidad Técnica Federico Santa María - Valparaíso (Chile), 2Pontificia Universidad Católica de Valparaíso - Valparaíso (Chile), 3Université-Paris Sud - Orsay (France), 4Qatar Foundation - Doha (Qatar), 5Universidad de Chile - Santiago (Chile) The unoccupied electronic structure of ordered alkanethiols molecules (CnT; n=8, 12, 16, 18) and 1,4-benzenedimethanethiol (BDMT) forming self-assembled monolayers (SAMs) on Au (111) have been explored. We have used both numerical calculations and inverse photoemission spectroscopy (IPES) to examine their electronic structure close to the Fermi level (EF). The energy edge of the lowest unoccupied system orbital (LUSO) has been identified in the IPES data for the different SAMs. The IPES spectra also provide experimental evidence for the existence of induced density of interface states (IDIS) and an antibonding Au-S state, roughly 1.4 eV above EF in all CnT molecules. Since both the IDIS and the Au-S antibonding state are located at the interface, their expression in the IPES spectra is suppressed for the longer chain molecules. This particular behaviour can be explained in terms of the mean free path limitations imposed in the sampling electrons, which have to travel through the SAM before sensing the states at the interface. The comparison between calculations and experiments provides useful information regarding the molecular origin of the different spectral features in the IPES data. The figure below shows in the right (a), a scanning electron microscopy image of a C8T-SAM on Au(111), in which different molecular supercells can be observed. In the left (b), IPES spectra collected form different SAMs on Au, displaying the characteristic onset of the LUSO states.

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O3-MOS _225 FORMIC ACID DECOMPOSITION ON THE CU(111) SURFACE: VAN DER WAALS DENSITY FUNCTIONAL STUDY

MOS - Molecules at surfaces F. Muttaqien *, S. Torii, Y. Hamamoto, H. Kizaki, K. Inagaki, Y. Morikawa Department of Precision Science and Technology, Graduate School of Engineering, Osaka University - Osaka (Japan) Adsorption and decomposition of formic acid on Cu surfaces has received considerable attention. It has been experimentally reported that the formic acid decomposes to formate species upon adsorption on Cu(100)1 and Cu(110).2 On the other hand, it was pointed out that formic acid does not dissociate at room temperature on the Cu(111) surface. At low temperature, the formic acid decomposition can be induced on Cu(111) from polymeric structures.3,4 The hydrogen bonding network in polymeric structure is responsible to stabilize the formic acid and enhance its decomposition.4 In the present work, we carried out self-consistent van der Waals density functional (vdW-DF) study of formic acid decomposition on the single crystal Cu(111) surface. We implemented vdW-DF based functionals (vdW-DF1, rev-vdW-DF2, and optB86b) to describe molecule-surface interaction and molecule-molecule interaction in the system more accurate. Our results showed that isolated single formic acid is easily desorbed rather than decomposed on the Cu(111) surface. On the other hand, the polymeric structure of formic acid is more stable on the Cu(111) surface, and easily decomposed into formate species. We also noticed that the formate product tends to form bidentate formation on the surface (Fig. 1). The formation of polymeric formic acid is necessary to enhance formic acid decomposition. References [1]. J. Stöhr, D. A. Outka, R. J. Madix, and U. Döbler, Phys. Rev. Lett. 54, 1256 (1985). [2]. B. E. Hayden, K. Prince, D.P. Woodruff, and A.M Bradshaw, Surf. Sci. 133, 589 (1983). [3]. A. E. Baber, K. Mudiyanselage, S. D. Senanayake, A. Beatriz-Vidal, K. A. Luck, E. C. H. Sykes, P. Liu, J. A. Rodriguez, and D. J. Stacchiola, Phys. Chem. Chem. Phys. 15, 12291 (2013). [4]. Y. Shiozawa, T. Koitaya, K. Mukai, S. Yoshimoto, J. Yoshinobu, J. Chem. Phys. 143, 234707 (2015).

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O4-MOS _362 DIPYRANYLIDENES (DIP) AS HOLE COLLECTORS IN PV HETEROSTRUCTURES STUDIED BY SCANNING TRANSMISSION X-RAY MICROSCOPY

MOS - Molecules at surfaces Q. Arnoux 1,*, B. Watts 2, J. Raabe 2, S. Stanescu 3, S. Swaraj 3, L. Tortech 4, F. Rochet 1 1Sorbonne Universités, UPMC Univ Paris 06, UMR 7614, Laboratoire de Chimie Physique Matière et Rayonnement (LCPMR), F-75005 - Paris (France), 2Paul Scherrer Institute, 5232 - Villigen Psi (Switzerland), 3Synchrotron SOLEIL, BP 48, Saint-Aubin, F-91192 - Gif-Sur-Yvette (France), 4Sorbonne Universités, UPMC Univ Paris 06, UMR 8232, Institut Parisien de Chimie Moléculaire (IPCM), F-75005 - Paris (France) In thin film organic solar cells (OSCs) the stacked layers must respect an appropriate energy alignment in order to allow efficient charge separation and transport to the electrodes. Numerous studies report on the advantage of using an interfacial layer (IFL) to drain and/or collect charges at the electrode interfaces. In this field we demonstrated the efficiency of a highly crystalline thin layer of a dipyranylidene derivative (DIPS) as a hole transport layer at the ITO anodic contact.[1] The efficiency of IFL and its electronic properties is strongly linked to the orientation of these conjugated flat molecules with respect to each other and with the substrate.[2] In this study we investigated the oxygenated substituted compound. After a thermal deposition under vacuum on SiN substrates the layers were characterized by atomic force microscopy and scanning transmission X-ray microscopy [3] on Pollux beamline at SLS synchrotron (Switzerland). From these measurements we firstly had access to the precise topography of the organic layer (Figure a): AFM images of a DIPO/SiN system). Secondly, we got the precise molecular orientation inside our 3D structures (Figure b): Absorption spectroscopy of a DIPO structure, successive LUMOs are indicated by the numbers). We will also present the impact of thicknesses layer on the molecular organization. Thanks The authors would like to thank the Labex MiChem for funding the PhD grant to Quentin ARNOUX and POLLUX beamline for the support. References [1] S. Berny et al. ACS Appl. Mater. Interfaces 2 (2010) 3059–3068. [2] D. Qi et al. J. Am. Chem. Soc. 129 (2007) 8084-8085 [3] C. R. McNeill et al. Nanotechnology 19 (2008) 424015

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O6-MOS _55 MOLECULES ON SURFACES: WHISPERING GALLERIES FOR ELECTRONS ?

MOS - Molecules at surfaces F. Scheurer 1,*, G. Reecht 2,*, H. Bulou 1, G. Schull 1 1IPCMS UMR 7504 CNRS-Université de Strasbourg - Strasbourg (France), 2Freie Universität Berlin, Fachbereich Physik - Berlin (Germany) Whispering galleries have been known for a long time for sound waves, but also for electromagnetic waves, from radio domain range to hard x-rays. Whispering gallery waves are peculiar waves propagating along a smooth and curved wall, allowing waves to sneak along the wall [1]. An amazing consequence is the whispering gallery effect. For sound waves for example, one can hear somebody whispering close to the wall far away at another place along the wall. This phenomenon has nothing to do with a focusing effect of the waves but it is due to the existence of particular wave modes, the so-called whispering gallery modes. These modes are not limited to classical waves but have also been discovered recently for material waves like neutrons [2]. When electrons are confined in a ribbon-shaped or spherical box, a centrifugal potential appears, giving rise to whispering gallery-like modes [3,4]. These electronic whispering gallery modes have been evidenced recently in nanoscale conjugated polymer rings grown on a surface [3] and in cavities in graphene [5]. On the basis of a very simple formalism of free electrons in a spherical box, one can show that these whispering gallery modes correspond to the so-called Super Atom Molecular Orbitals discovered in fullerenes and described by density functional theory [6]. References [1] O. Wright, Physics World, February 2012, p.31 [2] V.V. Nesvizhevsky et al. Nat. Phys. 6, 114 (2010) [3] G. Reecht et al. Phys Rev. Lett. 110, 056802 (2013) [4] G. Reecht et al. J. Phys. Cond. Matt. 28, 165001 (2016) [5] Y. Zhao al. 2015 Science 348, 672 (2015) [6] M. Feng et al. Science 320, 359 (2008)

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O7-MOS _184 SELF-ASSEMBLING AND CHEMISTRY OF FERROCENE DICARBOXYLIC ACID ON DIFFERENT METAL AND INSULATOR SUBSTRATES

MOS - Molecules at surfaces K. Kosmider *, J. Berger *, O. Stetsovych, M. Švec, P. Jelínek Czech Academy of Sciences - Prague (Czech republic) Ferrocene based molecules are extremely appealing as they provide the possibility of having built-in spin or charge functionalities. However, there are only limited studies of structural and electronic properties on surfaces so far. In this contribution, we investigated 1,1’-Ferrocenedicarboxylic acid molecules deposited on both metallic (Au(111), Ag(111), Cu(110)) and insulating (Cu3N/Cu(110)) with whole set a complementary surface science techniques including high-resolution AFM/STM combined with XPS and NEXAFS. The experimental evidence is corroborated with total energy DFT calculations and advanced AFM simulations. The only combination of the experimental and theoretical tools allows us to identify the unique arrangement and adsorption geometry of the molecules on each substrate, as well as undergoing chemical changes of the carboxylic groups on Cu-based surfaces. Where the molecules on the Au(111) and Ag(111) show only a weak interaction with the substrate and a complex self-assembling configuration. In the contrary, on the Cu(110) and Cu3N/Cu(110) the carboxylic groups are a subject to dehydrogenation forming strong chemical bond to the substrate onto the Cu atoms, keeping an upright orientation of the ferrocene cyclopentadienide rings.

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O8-MOS _385 THE (ROOT3XROOT3)R30º SURFACE STRUCTURE OF LONG ALKANETHIOLS ON THE AU(111) SURFACE

MOS - Molecules at surfaces X. Torrelles 1,*, R. Salvarezza 2, P. Carro 3, E. Cortés 4, E. Pensa 4, C. Hernández 5 1Institute of Materials Science of Barcelona (ICMAB-CSIC) - Barcelona (Spain), 2Universidad Nacional de La Plata INIFTA-CONICET - La Plata (Argentina), 3Universidad de La Laguna Departamento de Química Instituto de Materiales y Nanomateriales - La Laguna (Spain), 4mperial College London Blackett Laboratory Department of Physics - London (United Kingdom), 5UNiversity Autonomous of Barcelona - Barcelona (Spain) Self assembled monolayers (SAM) of alkanethiols and dialkanethiols on gold surfaces and interfaces are still being one of the most studied systems nowadays. Thiolate-gold surfaces are considered as archetypal model systems due to their relevance in various fields of materials science (nonoscience, surface science and inorganic chemistry), i.e., passivation of gold nanoclusters, molecule-gold junctions, molecular self-assembling on gold, etc... Understanding this interface at nano-scale level is consequently essential for a wide range of applications in different areas of bio and nanotechnology for biological and medical applications, chemical diagnostics, molecular electronics, catalysis or used for building more complex systems. Consequently, one of the greatest scientific aspirations related with the thiol-gold system has always been to know the nature of the interaction between these molecules with the surface substrate. The nature of this interaction, however, still remains elusive not only due to the multiple ways in which these molecules can be ordered on the surface, mainly depending on their chain length, but also to their phobic behaviour to high energy photons that make difficult the X-ray experiments with them. Despite this drawback, crystallography is the most suited technique to unravel the nature of this interaction through the “exact” localization of the atoms at the interface. For this reason an X-ray diffraction experiment, performed at the ID03 beamline of the ESRF, permitted to acquire a data set of enough quality to unravel the basic structural blocks linked to the interface structure between molecule and gold substrate, i.e. adatoms, vacancies, molecular orientation, gold layer relaxation and more. The experiment was designed to accomplish or give basic answers to fundamental questions concerning alkanethiol adsorption on the Au(111) surface. Thanks X. T. thanks the Spanish MICINN Ministry for economical support through MAT2015-68760- C2-2-P as well as CSIC for scientific and economical support.

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O9-MOS _268 AN ELECTRICALLY ACTUATED MOLECULAR TOGGLE SWITCH

MOS - Molecules at surfaces L. Gerhard 1,*, K. Edelmann 1, J. Homberg 1, M. Valasek 1, S. Bahoosh 2, M. Lukas 1, F. Pauly 2, M. Mayor 3, W. Wulfhekel 1 1Institut of Nanotechnologie, Karlsruhe Institute of Technology - Eggenstein-Leopoldshafen (Germany), 2Department of Physics, University of Konstanz - Konstanz (Germany), 3Department of Chemistry, University of Basel - Basel (Switzerland) Molecular electronics is considered a promising approach for future nanoelectronic devices. In order that molecular junctions can be used as electrical switches or even memory devices they need to be actuated between two distinct conductance states in a controlled and reproducible manner by external stimuli. In this respect, it is helpful to design the molecule specifically such that it binds to the substrate electrode in a well-defined geometry and to lift the functional group of the molecule from the metallic substrate. Here we show that this can be achieved with the help of a tripodal carrier platform designed to bind specifically to the Au(111) surface, and that a functional group consisting of a cantilever arm with a local dipole moment at its end is lifted from the surface [1]. Both approaching and retracting the tip of a scanning tunneling microscope (STM) (see Fig. a,b) and the electrostatic forces acting on the molecular dipole in the STM junction (see Fig. c,d) can be used to switch the conductance of the junction by more than two orders of magnitude. We are able to open and close the molecular junction by bending the flexible subunit of the firmly immobilized molecular platform. A coordinative bond between the nitrile nitrogen and the gold tip stabilizes the closed form and results in hysteretic features. Our results highlight the importance of atomic-scale control of the junction geometry in order to obtain reliable mechanical and electrical properties in future molecular devices. The very reliable control of the presented molecular toggle switch allows us to demonstrate new experimental methods that reveal the forces involved in the mechanical deformation of the molecular cantilever. References [1] Valásek, M. et al. Synthesis of Molecular Tripods Based on a Rigid 9,9’-Spirobifluorene Scaffold. J. Org. Chem. 79, 7342–7357 (2014).

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O10-MOS_462 GRAPHENE-MEDIATED ANTI-FERROMAGNETIC COUPLING BETWEEN METALPHTHALOCYANINE

MOS - Molecules at surfaces G. Avvisati 1,*, P. Mondelli 1, P. Gargiani 2, S. Lisi 1, D. Pacilè 3, M. Valvidares 2, M.G. Betti 1 1Dipartimento di Fisica, Sapienza Università di Roma - Roma (Italy), 2ALBA synchrotron light source, 08290 Cerdanyola del Vallès - Barcelona (Spain), 3Dipartimento di Fisica, Università della Calabria - Arcavacata Di Rende (Italy) Surface-supported organometallic molecular systems with defined magnetic properties are recently arousing much interest for molecular spintronics, but a fine tuning of the magnetic state and an ultimate understanding of the interaction process are fundamental to ensure their performances. Metalphthalocyanine (M-Pc) molecules are appealing building blocks as, when deposited on metal surfaces, they easily form long range ordered low-dimensional architectures, but whose magnetic properties are deeply affected by molecule-substrate interactions. Hereof, graphene (G) can be used as a buffer layer to decouple the molecules from the metal substrate and, thanks to its gentle corrugation, lead the selfassembly of the ordered MPc networks [1], with low molecule-substrate interaction [2] and enhanced inplane magnetic anisotropy [3]. The intercalation of Co layers between the G sheet has the effect to enhance (for an ultrathin Co layer) or reduce (for thicker Co films) the G corrugation, tuning also the magnetic properties (anisotropy) [4]. In this project we investigated, via X-ray Magnetic Circular Dichroism (XMCD) measurements, the Gmediated magnetic coupling between M-Pc molecules and the intercalated Co. We found that the FePc molecules strongly antiferromagnetically couple with the intercalated Co layer, but the energetics of the system depends critically on the adsorption sites and, accordingly, on the thickness of the intercalated Co. At a single Co layer (magnetization perpendicular to the surface) the FePc, adsorbed in the valleys of the corrugated G layer, present a strong coupling (see figure), while at higher Co thickness (Co magnetization parallel to the surface) the coupling is reduced. This exotic magnetic configuration may unveil a viable route to investigate magnetic frustration as a function of lattice symmetry and can be exploited to selectively inject spin currents with different spin sign, by choosing appropriate adsorption sites [5]. References [1] Mao J. et al., Journal of the American Chemical Society 131, 14136-14137 (2009) [2] Scardamaglia M. et al., The Journal of Physical Chemistry C 117, 3019-3027 (2013) [3] Lisi S. et al., The Journal of Physical Chemistry Letters 6, 1690-1695 (2015) [4] Chappert C. et al., Journal of Applied Physics 64, 5736-5741 (1988) [5] Decker R. et al., Physical Review B 87, 041403(R) (2013)

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O11-MOS _356 ATOMIC-SCALE INSIGHT INTO THE COMPLEXATION AND TAUTOMERIZATION OF GUANINE MOLECULES ON SURFACE

MOS - Molecules at surfaces C. Zhang *, L. Xie, L. Wang, W. Xu College of Materials Science and Engineering, Tongji University - Shanghai (China) DNA bases, as particularly important constituents of nucleobases, are involved in base pairing and play a crucial role in recognition of nucleobases and even the high fidelity of DNA replication. Among others, Guanine (G) has varieties of noncanonical tautomeric forms under different environments which may be responsible for base mismatch, mutagenesis, and further genetic damage; and moreover G is also involved in the formation of G- quadruplex structures in vivo via stacking of G-quartets by interaction with template cations. Thus, atomic-scale investigation into these interesting issues of G molecules on the solid surface may serve as a prototypical system to provide important insights. Here, by combining high-resolution scanning tunneling microscopy imaging and density functional theory calculations, (1) We have fabricated different G-quartet-M (M: Na/K/Ca) complexes by introducing alkali and alkaline earth salts (NaCl/KBr/CaCl2) onto Au(111) as reactants. (2) By using this strategy, we have also successfully achieved the tautomeric recognition, separation, and interconversion of G molecular networks (formed by two tautomeric forms G/9H and G/7H) with the aid of NaCl on Au(111) in ultrahigh vacuum conditions. (3) We have found the real-space evidence of the formation of one rare G tautomer on Au(111) by delicately introducing water into the UHV system and revealed the key to the formation of this rare tautomer is the “water bridge” that largely reduces the energy barriers of intramolecular proton- transfer processes. We believe that the above results may provide an alternative feasible way to bring metal elements to surfaces (in the form of salts) for constructing metal-organic systems and also serve as a prototypical system to provide important insights into tautomerization-related issues. References 1. Zhang, C.; Xie, L.; Wang, L.; Kong, H.; Tan, Q.; Xu, W. J. Am. Chem. Soc. 2015, 137, 11795-11800. 2. Zhang, C.; Xie, L.; Ding, Y.; Sun, Q.; Xu, W. ACS Nano 2016, 10, 3776-3782. 3. Zhang, C.; Wang, L.; Xie, L.; Kong, H.; Tan, Q.; Cai, L.; Sun, Q.; Xu, W. ChemPhysChem 2015, 16, 2099-2105.

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O12-MOS _334 MOLECULE-METAL INTERACTION CONTROLLED BY HYDROGEN MANIPULATION IN AN ORGANIC MOLECULE

MOS - Molecules at surfaces J. Lagoute 1,*, V.D. Pham 1, V. Repain 1, C. Chacon 1, A. Bellec 1, Y. Girard 1, S. Rousset 1, A. Smogunov 2, Y. Dappe 2 1Laboratoire Matériaux et Phénomène Quantiques (MPQ), UMR CNRS/Université Paris Diderot - Paris (France), 2SPEC, CEA, CNRS, Universite´ Paris-Saclay, CEA Saclay - Gif-Sur-Yvette (France) Controlling the conformation of molecules and their interaction with their environment is a challenge for molecular electronics. Using scanning tunneling microscopy (STM) at low temperature, it is possible to manipulate the internal hydrogen atoms of 5,10,15,20- Tetraphenyl-21H,23Hporphyrin molecules (H2TPP). As it was previously demonstrated by W. Auwärter et al. on a Ag(111) substrate, it is possible to achieve tip induced tautomerization and dehydrogenation in such molecules [1]. Here, we performed such hydrogen manipulations on H2TPP molecules adsorbed on Au(111) [2]. In addition to tip induced hydrogen removal or switching, local tunneling spectroscopy allowed to reveal the electronic states of the molecules for different conformations and hydrogenation degrees. Combining STM experiments with ab initio calculation the molecule-substrate interaction was found to be increased with dehydrogenation. More surprisingly, the switching of inner hydrogen atoms that occurs in the tautomerization process was also found to tune this interaction. The ab initio analysis allows to understand the strong difference observed in the shape of the HOMO state of the two tautomer forms (see the figure showing a conductance map that exhibits the HOMO state of 7 molecules revealing two kinds of shapes for that molecular orbital). Experimentally, we probed the electronic interaction of different hydrogenation degrees of the molecules (H2TPP, HTPP and TPP) with the surface by mapping the scattering of the Shockley surface state of Au(111) induced by the molecules. It was found that dehydrogenation increases the molecule-surface interaction. Finally, we recently performed molecular and atomic manipulation to build porphyrin-metal complex and probe their electronic properties. A modification of the local density of states (LDOS) was found to occur on such structure as compared to bare H2TPP molecules. Thanks ANR and CGI are gratefully acknowledged for their financial support of this work through Labex SEAM, ANR 11 LABX 086, ANR 11 IDEX 05 02. The calculations have been performed using HPC computation resources from GENCI-[TGCC] (Grant 2016097416). References [1] W. Auwärter et al., Nat. Nanotechnol. 7, 41−46 (2011) [2] V. D. Pham et al. J. Phys. Chem. Lett. 7, 1416 (2016)

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O13-MOS _345 KONDO EFFECT IN 2D SELF-ASSEMBLY OF CERIUM-BASED MOLECULES INVESTIGATED BY SCANNING TUNNELLING MICROSCOPY AND SPECTROSCOPY

MOS - Molecules at surfaces J. Granet 1,*, M. Sicot 1, B. Kierren 1, Y. Fagot-Revurat 1, D. Malterre 1, S. Lamare 2, F. Chérioux 2 1Institut Jean Lamour, UMR 7198, CNRS Université de Lorraine, BP 70239,54506 Vandoeuvre lès Nancy, France - Vandoeuvre Lès Nancy (France), 2Institut FEMTO-ST, Université de Franche- Comté, CNRS, 15B Avenue des Montboucons, F-25030 Besançon cedex, France - Besançon (France) Molecular spintronics is an emerging field in surface science. Indeed, magnetic molecules can be used as building blocks to create molecular and supramolecular devices such as field-effect transistors, sensors, light-emitting devices with better performances compared with all-inorganic architectures. A class of molecules is particularly interesting for this purpose, i.e. the double-decker phthalocyanine lanthanoid (LnPc2) complex. These molecules have been shown to exhibit single-molecule magnet behavior [1]. Recently, TbPc2, DyPc2, YPc2 have been successfully self-assembled on metallic surfaces [2]. Spin-states have been investigated through the study of the Kondo resonance and successfully manipulated by scanning-tunneling microscopy [2]. However, so far, studies on Ce-based counterparts are lacking [3]. In this work, we have investigated the growth and the electronic properties of (Phthalocyanato) (Porphyrinato) Cerium (IV) molecules (CePcTPP) on Cu(111) and Ag(111) by means of low-energy electron diffraction (LEED) and scanning tunnelling microscopy/ spectroscopy (STM/STS) at a temperature of 5 K. We have shown that, in the submonolayer range, CePcTPP adsorbed on Cu and Ag, self-assemble on both substrates. Lattice parameters and packing have been extracted from STM images and LEED patterns. STS spectra revealed the HOMO-LUMO energy gap and a Kondo resonance. Finally, we have shown than these Ce-based supramolecular networks are thermally robust since those features remain intact after heating up to 400 K. According to these results, the use of Ce-based double-decker complex adsorbed on metallic surfaces paves the way to molecular architectures with novel properties and these complexes could be integrated as functional units in next-generation nanospintronics devices. References [1] N. Ishikawa et al., J. Am. Chem. Soc. 125 (2003) 8694 [2] T. Komeda et al., Prog. Surf. Sci. 89 (2014) 127 and reference therein [3] D. Ecija et al., Angew. Chem. Int. Ed. 50 (2011) 3872

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O14-MOS_464 SURFACE-CONFINED POLYMERIZATION BY ULLMANN AND SCHIFF-BASE COUPLING REACTIONS

MOS - Molecules at surfaces G. Contini * Istituto di Struttura della Materia, CNR and Physics Department, University of Rome “Tor Vergata” - Roma (Italy) Graphene-like two-dimensional organic materials can be grown and confined with different strategies onto suitable surfaces depositing and activating selected molecules. In this respect, the surface-confined polymerization is a very promising bottom-up approach that allows the creation of layers with desired architectures and tunable properties changing the molecules used as precursor. In this talk I will report on our studies on surface-confined polymerization obtained in ultra- high vacuum (UHV) and at the solid-water interface by using Ullmann and Schiff-base coupling reactions, respectively. The Ullmann reaction, obtained for 1,4-dibromobenzene (C6H4Br2) on Cu(110), will be discussed by complementary spectroscopic measurements of occupied and unoccupied states (using photoelectron spectroscopy (XPS, ARUPS) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy, respectively), scanning tunneling microscopy (STM) and density functional theory (DFT). These methodologies have allowed to pinpoint a signature of the polymerization reaction and have added new information on the role played by the halogen atom in the organometallic intermediate structure. Fast-XPS measurements performed during the annealing of the surface provided real-time information about the transition. Schiff-base reaction, which involves amines and aldehydes as building blocks, has been explored at the solid-water interfaces. 4,4’- diaminostilbene dihydrochloride and terephtalaldehyde have been studied in solution and onto iodine-modified Au(111) in water, analyzed in situ by STM and ex situ by XPS, to obtain information on polymerization. A spectroscopic evidence of the surface-confined polymer formation as a function of the pH has been found, confirming the validity of the proposed Schiff-base method, so far studied mainly by local probe techniques. Insights into the catalytic effect of the substrate and the reaction steps will be shown.

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O15-MOS _224 NAPHTHALENE ADSORPTION ON GRAPHENE: VAN DER WAALS DENSITY FUNCTIONAL STUDY

MOS - Molecules at surfaces S.A. Wella 1,*, N. Kawaguchi 2, F. Muttaqien 1, Y. Hamamoto 1, K. Inagaki 1, I. Hamada 3, Y. Morikawa 1 1Department of Precision Science and Technology, Graduate School of Engineering, Osaka University - Osaka (Japan), 2Department of Applied Chemistry, Graduate School of Engineering, Osaka University - Osaka (Japan), 3International Center for Materials Nanoarchitectonics (WPI- MANA) and Global Research Center for Environment and Energy based on Nanomaterials Science (GREEN), National Institute for Materials Science, - Tsukuba (Japan) Fundamental understanding of interactions between molecules and solid surfaces is critically important in developing molecular based electronic devices. Naphthalene, a typical aromatic hydrocarbon molecule, on graphene is commonly used as a model system for studying the interface effects. Recently, in scanning tunneling microscope (STM) investigation, experimentalist observed that naphthalene is adsorbed on highly oriented pyrolytic graphite (HOPG) (2√3×2√3) R30° in tilting configuration.1 However, some theoretical studies have reported that naphthalene is stable in flat configuration. Since geometrical structure of the interface has a strong influence to the electronic properties of the interface and vice versa, it becomes essentially important to investigate the interactions precisely. In this work, we examine the adsorption of naphthalene on graphene by using van der Waals density functionals (vdW-DFs). In order to know the origin of the tilting angle, we investigate the dependence of naphthalene/graphene interactions on the naphthalene coverage and the number of graphene layers. As a result, we found that naphthalene is slightly tilted (about 6±0.5°) on graphene (2√3×2√3) R30° and tends to be parallel to the surface in lower coverage (Figure). On the other hand, the number of graphene layers gives an insignificant contribution for the tilting angle. It clarifies that the intermolecular interaction is more dominant than the molecule-substrate interaction. Besides, STM tip that produces electric field between a tip and a sample during the STM measurement does concern us. Therefore, we also check the dependence of the geometrical and electronic properties of the adsorbed system on the electric field by using an effective screening medium.2 We found that electric field is not the origin of the tilting angle. Nevertheless, by introducing the electric field, the energy position of LUMO, HOMO, and the image potential state (IPS) are shifted up with respect to the Fermi level and those are in good agreement with experimental results.3 References [1] T. Yamada, Y. Takano, M. Isobe, K. Miyakubo, T. Munakata, Chem. Phys. Lett. 546, 136–140 (2012). [2] M. Otani and O. Sugino, Phys. Rev. B 73, 115407 (2006). [3] T. Yamada, M. Isobe, M. Shibuta, H.S. Kato, T. Munakata, J. Phys. Chem. C 118, 1035–1041 (2014).

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O16-MOS _275 OPTICAL PROPERTIES OF SINGLE-MOLECULE JUNCTIONS

MOS - Molecules at surfaces H. Bulou 1,*, M. Chong 1, G. Reecht 2, A. Boeglin 1, F. Scheurer 1, F. Mathevet 3, G. Schull 1 1IPCMS/CNRS UMR7504/Strasbourg University - Strasbourg (France), 2Freie Universität Berlin - Berlin (Germany), 3IPCM/CNRS UMR8232/Pierre et Marie Curie University - Paris (France) The Metal/Molecule/Metal nanojunctions are powerful devices for investigating phenomena involved in the domain of molecular electronics. Nowadays, thanks to the scanning tunneling microscope, it is possible to assemble atoms and molecules for building molecular junctions, to measure and manipulate their electric properties at the nanometric scale[1], and to excite these devices to induce optical transitions from one state to another[2]. In addition, molecular junctions are suitable systems for theoretical investigations with ab initio methods, since both size (few thousands atoms) and characteristic timescale of optical phenomena (picoseconds) are accessible to the current high performance computing systems, allowing for a direct comparison to experiment. In this talk, I will present density functional theory (DFT) and time-dependent DFT results concerning a single-molecule light-emitting diode, composed of a thiophene- and porphyrine-based molecule grafted between two gold electrodes, a device recently developed in our laboratory [2,3]. The electric current crossing the nanodiode acts as a local source for molecular excitations (Figure 1). We will focus on the emission spectra of such a device, paying particular attention to the vibronic transitions occurring in the nanojunction. Thanks This work was performed using HPC resources from GENCI-IDRIS (Grant No. 2015097459). The Agence National de la Recherche (Project SMALL’LED No. ANR- 14-CE26-0016-01), the Labex NIE (Contract No. ANR-11-LABX-0058_NIE), and the Région Alsace and the International Center for Frontier Research in Chemistry (FRC) are acknowledged for their financial support. References [1] G. Schull, Y. J. Dappe, C. Gonzalez, H. Bulou, and R. Berndt, Nano Letters 11, 3142-3146 (2011). [2] G. Reecht, F. Scheurer, V. Speisser, Y. J. Dappe, F. Mathevet, and G. Schull, Phys. Rev. Lett. 112, 047403 (2014). [3] M. C. Chong, G. Reecht, H. Bulou, A. Boeglin, F. Scheurer, F. Mathevet, and G. Schull, Phys. Rev. Lett. 116, 036802 (2016).

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I11_MOS_102 METALATION OF PORPHYRINS INTERACTING WITH SURFACES

MOS - Molecules at surfaces A. Goldoni 1,*, G. Di Santo 1, M. Caputo 1, M. Panighel 1, L. Floreano 2, C.A. Pignedoli 3, D. Passerone 3, G. Montanari 4, S. Suran-Brunelli 1, A. Verdini 2 1ST-INSTM lab., Elettra - Sincrotrone Trieste S.C.p.A. - Trieste (Italy), 2Istituto Officina dei Materiali- CNR, Lab. TASC - Trieste (Italy), 3EMPA - Theory and atomistic simulation group - Dübendorf (Switzerland), 4Trieste University - Trieste (Italy) Self-assembled metallo-porphyrin monolayers on substrates are currently considered as templates for the ordered organization of “isolated” metallic atoms, which correspond the metallic ions at the center of the macrocycles. The fine control on the self-assembling and, possibly, on the metalation of the molecules represent a key issues in the development of these organic-substrate interfaces. One fundamental question is about the way porphyrins (metalated or not) interact with the substrates and in which way the self-assembled organic monolayer can be modified. Here we show several methods to metalate the un-metalated porphyrins on surfaces, the modification of these molecules with temperature and the interaction of porphyrins with the substrate. In particular, we illustrate an interesting way to metalate the porphyrins by picking- up substrate metal atoms on the surface and how the surface oxidation influences this process.

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O17-MOS _5 A THERMODYNAMIC MODEL FOR WAFER-BONDING

MOS - Molecules at surfaces K. Hingerl 1,*, T. Plach 2, B. Rebhan 2 1Center for Surface and Nanoanalytics, University Linz - Linz (Austria), 2EVGroup St. Florian am Inn - Schärding (Austria) Waferbonding is an increasingly important process for fabricating advanced-semiconductor structures as e.g. tandem-solar-cells, MEMS, etc. The physics of the interfacial processes is, however, not well understood and often a multitude of heuristic approaches is tested to achieve high bond-strength at low temperature. We review the findings of ref.[1,2] and present a general model based on minimization of Gibbs-free-energy(GFE). The importance of kinetic effects is highlighted. The total change of GFE is schematically presented in Fig.1, where (e.g. for Si): 1-the first transition indicates the splitting of solid material creating two additional free surfaces (e.g. in UHV), 2-the second displays the environmental effect (= thermodynamic reservoir), e.g. oxidation of the outermost Si-layers in air,

3-the third shows schematically adsorption of water on SiO2 reducing the electrostatic dipolar energy, 4-the fourth the enhancement of GFE due to the external activation of the surface or topmost layers- possible processes are: oxide removal, amorphization due to plasma, breaking bonds, H2O capturing defetcs, etc. 5-This activated state must have a life-time longer than the storage /bonding/ time,and finally 6-the reduction of GFE when the materials are brought into contact and the activated states decay and a bond is formed. We will discuss the different physical processes for each material system, but the steps above are always present..

References [1] T. Plach, K. Hingerl et al. "Mechanisms for room temperature direct wafer bonding", J. Appl. Phys. 113, 094905 (2013), [2] B. Rebhan and K. Hingerl, "Physical mechanisms of copper-copper wafer bonding", J. Appl. Phys. 118, 135301 (2015);

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O18-MOS _108 PROTON ORDER AT ICE SURFACES: CAN HELIUM SCATTERING PROVIDE QUANTITATIVE ANSWERS?

MOS - Molecules at surfaces N. Avidor *, W. Allison Cavendish Laboratory, University of Cambridge, JJ Thomson Ave, Cambridge, CB3 0HE, United Kingdom - Cambridge (United Kingdom) The extent of proton-order at surfaces of adsorbed water and ice is a challenging question for experiment [1]. Helium scattering has the potential to provide quantitative answers since the scattering is sensitive to the outermost electron density. In a classic experiment [2] the proton order was discussed on the basis of approximate scattering calculations using a hard-wall model within the eikonal approximation. Here, we explore the applicability of exact scattering calculations using realistic interaction potentials. The scattering potential is constructed from an empirical gas-phase model [3] for intact H2O, and the surface potential is generated by pairwise addition taking the molecular orientation into account. We have investigated several surface structures including some with proton order, such as the bilayer and “Fletcher's striped phase”, and others with a range of proton disordered structures. Comparisons with earlier calculations demonstrate that low-energy scattered intensities are, in all cases, poorly represented by a hard-wall potential. We show that the diffraction pattern is complicated and significantly changes with beam energy. Proton order is best inferred from selective adsorption resonances of the helium atom. We use the results to discuss the validity of the latest assumptions for the ice Ih surface [4] with respect to proton ordering. To the best of our knowledge, this is the first work to construct an interaction pair-potential for Helium with a non-linear molecule as the monomer for the scattering surface. References [1] Maier, S.; Salmeron, M. In Surface and Interface Science; Wandelt, K., Ed.;Wiley-VCH Verlag GmbH & Co. KGaA, (2016) 357. [2] Glebov, A.; Graham, A. P.; Menzel, A.; Toennies, J. P.; Senet, P. Journal of Chemical Physics (2000) 112, 11011. [3] Hodges, M. P.; Wheatley, R. J.; Harvey, A. H. Journal of Chemical Physics (2002) 116, 1397. [4] Carrasco, J.; Hodgson, A.; Michaelides, A. Nature Materials (2012) 11, 667.

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O19-MOS _290 NANOSTRUCTURATION OF DY-BASED SINGLE MOLECULE MAGNETS

MOS - Molecules at surfaces I. Cimatti 1,*, K. Bernot 2, F. Pointillart 3, E. Otero 4, P. Sainctavit 5, M. Mannini 1, R. Sessoli 1 1Università degli Studi di Firenze - Sesto Fiorentino (fi) (Italy), 2Institut National des Sciences Appliquees de Rennes - Rennes (France), 3Université de Rennes 1 - Rennes (France), 4Synchrotron Soleil - Gif-Sur-Yvette (France), 5Université Pierre et Marie Curie - Paris (France) Magnetic molecules can have different applications in the new frontiers of nanoelectronics, in particular in the field of spintronics (spin + electronics) that exploits the spin degree of freedom as an information carrier through molecules inserted in a device. One of the most interesting candidates for molecular spintronics [1] purposes are Single Molecule Magnets (SMMs). This class of magnetic molecules presents low temperature magnetic bistability of molecular origin. [2] With their intriguing combination of quantum and classical properties, they are the ideal candidates for challenging studies on molecular spintronics. Among the SMMs, the ones containing lanthanides present very interesting features, for instance a large magnetic anisotropy, one of the key properties for the bistable behaviour. In particular, LnPc2 represents one of the rare examples of SMMs that can be deposited on surfaces keeping intact its magnetic properties, therefore being the focus of many recent studies. [3] In fact, the grafting of SMMs is a key process for the exploitation of their peculiar properties in technological applications. However, SMMs are often modified by the interaction with the substrate, losing their fascinating properties. [4] Here we will present two Dy-based SMMs deposited on metallic surfaces following two different routes: wet chemistry and sublimation in High Vacuum (HV). The Self Assembled Monolayer is a simple wet chemistry approach that allows the creation of a film with a limited thickness of a monolayer. This approach requires to exploit a specific interaction promoting covalent bonding of the molecule with the substrate; therefore, the molecule must be appropriately functionalized to bind the substrate. The single-ion SMM we employed presents several sulphur-containing moieties, perfect for the binding on gold substrate. XPS characterization confirmed the grafting of the molecules on the substrate and XMCD characterization indicated that after chemisorption the molecules retain the SMMs behaviour. An alternative approach, based on HV sublimation has been adopted for the second class of molecules, dysprosium dimers. [5] The film obtained in HV was then characterized using ToF-SIMS, XPS and standard magnetometry displaying that the molecules were intact after the sublimation process and preserved its peculiar behaviour. Thanks We acknowledge financial support from ERC through the AdG ‘‘MolNanoMas’’ (267746). References [1] S. Sanvito, Chem. Soc. Rev. 40, 3336 (2011). [2] D. Gatteschi et.al. Angew. Chem. Int. Ed. Engl. 268 (2003). [3] K. Katoh, et.al. Chem. Rec. 00 (2016). [4] L. Margheriti, et al. Small 5, 1460 (2009). [5] E. Kiefl, et al. Submitted.

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O20-MOS _189 TUNING OF THE OXIDATION STATE OF METAL IONS BY USING ALTERNATIVE TETRAPYRROLE LIGANDS: SYNTHESIS OF CO(III) AND NI(III)-CORROLES ON AG(111)

MOS - Molecules at surfaces M. Schmid 1,*, M. Chen 1, M. Zugermeier 1, L. Ruppenthal 1, F. Niefind 2, J. Herritsch 1, R. Tonner 1 1Philipps-Universität Marburg - Marburg (Germany), 2Leibniz Institute of Surface Modification (IOM) - Leipzig (Germany) Metal(II)tetrapyrrole complexes are an intensively studied group of molecules with applications ranging from heterogeneous catalysis to molecular electronics. It is well established that thin films of metal-free tetrapyrroles (e.g. 2H-porphyrins and 2H- phthalocyanines) may be converted to metal(II)tetrapyrroles during a surface confined reaction by incorporating co-adsorbed metal atoms such as Co, Ni, or Fe into the central pockets of the molecules. In order to overcome the limitation to +2 oxidation states while retaining the vacant coordination sites perpendicular to the molecular plane, we substituted the well-studied porphyrin/phthalocyanine ligands by 3H-corrole ligands. These tetrapyrroles have a similar structure than their well-studied counterparts, however, in the unmetalated state their central cavities contain three instead of two hydrogen atoms (connected to N atoms) and they miss one bridging methin group between two of the four pyrrole subunits. In theory, the tighter coordination environment, in combination with the possibility of removing up to three hydrogen atoms during metalation, may favor a +3 oxidation state. However, metallo-corroles with a +2 or even +1 oxidation state are also well known, making it a non-trivial question which oxidation state is reached by direct metalation. Our experiments show that adsorbed corroles react under under-high vacuum (UHV) conditions with Co and Ni atoms, resulting in metal(III)tetrapyrroles with vacant coordination sites perpendicular to the molecular planes. Thus, our approach successfully utilized the structure of an organic ligand as a switch for the oxidation state of the metal ion. X-ray and UV Photoelectron Spectroscopy (XPS, UPS), Scanning Tunneling Microscopy (STM), and Density Functional Theory (DFT) reveal the fundamental properties of multilayers and monolayers of in-situ prepared metal(III)corroles on Ag(111) and their interaction with the substrate.

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I28_MOS_465 REVEALING ATOMIC SITE-DEPENDENT G-FACTOR WITHIN A SINGLE MAGNETIC MOLECULE VIA EXTENDED KONDO EFFECT

MOS - Molecules at surfaces S. Du 1,*, L.W. Liu 1, K. Yang 1, Y.H. Jiang 1, B.Q. Song 1, W.D. Xiao 1, S.R. Song 1, H.J. Gao 1, M. Ouyang 2, W.A. Hofer 3, A.H. Castro Neto 4 1Institute of Physics CAS - Beijing (China), 2Univ. of Maryland - College Park (United States of America), 3Newcastle Univ. - Newcastle Upon Tyne (United Kingdom), 4National Univ. of Singapore. - Singapour (Singapore) The magnetic properties of a nanostructure play a pivotal role in the design of miniaturized spintronic devices. The Kondo resonance, due to many-body spin-flip scattering between a local magnetic moment and the conduction electrons of a host metal, has been increasingly popular in the scientific community in recent years. The field-induced Kondo splitting can be used to characterize the g-factor of systems like quantum dots in transport or scanning tunneling microscopy experiments. Importantly, the effective g-factor depends not only on magnetic anisotropy but also on the local spin-orbit coupling. Here, we report a systematic investigation of the Kondo effect in a series of dehydrogenated Mn-phthalocyanine (MnPc) molecules, which are modified through detachment of hydrogen atoms by STM. We observe that the Kondo effect is extended in space beyond the central Mn ion, and onto the non- magnetic constituent atoms of the molecule. This extended Kondo effect can be explained by spin polarization induced by symmetry breaking of the molecular framework, as confirmed by density functional theory calculations. Measuring the evolution of the Kondo splitting with applied magnetic fields at different atomic sites, we find a spatial variation of the g-factor within a single molecule for the first time. The existence of atomic site-dependent g-factors can be attributed to specific molecular orbitals distributed over the entire molecule. As both, molecular orbitals and their associated g-factor are relevant for the chemical environments, our results provide a new route to explore the internal electronic and spin structure of complex molecules, hard to achieve otherwise. References Liwei Liu, et al. Phys. Rev. Lett. 114, 126601 (2015).

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O23-MOS _75 ELECTRONIC STRUCTURE AND TRANSPORT PROPERTIES OF SWITCHABLE DIARYLETHENE MOLECULE.

MOS - Molecules at surfaces G. Reecht 1,*, D. Sysoiev 2, T. Huhn 2, K.J. Franke 1 1Freie Universität Berlin - Berlin (Germany), 2Universität Konstanz - Konstanz (Germany) One important challenge for molecular electronics is the design and the use of molecules with the capacity to change their properties by switching between two or more stable conformations [1]. Diarylethenes are a class of photo-switchable molecules which present a major interest [2]. Indeed, with a simple ring-opening/closing reaction, the molecule can switch between a π-conjugated and a non-conjugated conformation, which modifies drastically its conductance properties. Here, with a low-temperature scanning tunneling microscope (STM), we studied one type of diarylethene molecule with additional pyridine groups (C5F-4Py) [3] on Au(111) surface. We show that the electric field can induce the switching of the molecule between its open and closed forms. With scanning tunneling spectroscopy measurement, electronic properties of the two conformations are investigated. They show a drastic change of the HOMO-LUMO gap and some differences in the spatial distribution of the molecular orbitals, resulting of the change of the conjugation properties between these two conformations. Finally, using the high level of control of the STM, single molecules are lifted, and conductance of the molecular junctions are recorded during the procedure. Depending of the conformation of the lifted molecule, a high difference of conductance is measured. References [1] Charge transport through molecular switches, S. J. van der Molen and P. Liljeroth, Journal of Physics: Condensed Matter, 2010 ,22, 133001 [2] Diarylethenes for memories and switches, M. Irie, Chem. Rev., 2000, 100, 1685 - 1716 [3] Synthesis and photoswitching studies of difurylperfluorocyclopentenes with extended π-systems, Sysoiev, D et al., Chem. Eur. J., 2011, 17, 6663 - 6672

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O24-MOS _302 ON-SURFACE SYNTHESIS OF LARGE ORGANIC MOLECULES AND ORGANOMETALLIC NANOSTRUCTURES

MOS - Molecules at surfaces M. Gottfried 1,*, Q.T. Fan 2, J.Y. Dai 2, M. Chen 1, M. Zugermeier 1, B.P. Klein 1, J. Kuttner 1, G. Hilt 1, J.F. Zhu 2 1Fachbereich Chemie, Philipps-Universität Marburg - Marburg (Germany), 2National Synchrotron Radiation Laboratory, University of Science and Technology of China - Hefei (China) The on-surface synthesis of organic and organometallic molecules and nanostructures is a promising approach for surface modification and functionalization [1]. Surface reactions in ultrahigh vacuum can produce compounds which are not accessible by conventional synthesis in solution or which are too large or too reactive for vapor deposition. Catalytic and template effects exerted by the substrate can help driving the reaction into the desired direction. In this contribution, specially designed bromoarene molecules on Cu surfaces are used for Ullmann-type on-surface synthesis. Temperature-dependent XPS and STM studies show that the C-Br bonds dissociate already at low temperatures and are replaced by C- Cu-C bonds, which lead to the formation of linear, cyclic or two-dimensional organometallic oligomers and polymers. The hexagonal, fully conjugated honeycombenes are prominent examples for a class of molecules for which no solution-based synthesis is available, but which are accessible by a surface reaction [2]. As room-temperature stable intermediates, the corresponding organometallic macrocycles with C-Cu-C bridges were found [3]. Surface template effects were studied in the synthesis of low-dimensional organic nanostructures on different Cu substrate surfaces, i.e., Cu(111), Cu(110) and Cu(110)-(2x1)O. The latter shows the well-known 'piano keyboard' type pattern consisting of alternating stripes of Cu- O chains and bare Cu. The width of the stripes can be controlled by the oxygen coverage. Since the Ullmann reaction proceeds exclusively on the bare Cu stripes, the pattern provides a controlled spatial confinement. Depending on the width of the Cu stripes, either 1D zigzag organometallic oligomeric chains with different lengths or organometallic macrocycles with different sizes are obtained (Figure) [4]. References [1] Q. Fan et al., Surface-catalyzed C- C covalent coupling strategies towards the synthesis of low-dimensional carbon-based nanostructures, Acc. Chem. Res. 48 (2015) 2484. [2] Q. Fan et al., Surface-assisted organic synthesis of hyperbenzene nanotroughs, Angew. Chem. Int. Ed. 52 (2013) 4668. [3] Q. Fan et al., Surface-Assisted Formation, Assembly and Dynamics of Planar Organometallic Macrocycles and Zigzag Shaped Polymer Chains with C-Cu-C Bonds, ACS Nano 8 (2014) 709. [4] Q. Fan et al., Confined Synthesis of Organometallic Chains and Macrocycles by Cu–O Surface Templating, ACS Nano 10 (2016) 3747.

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O25-MOS _246 REVERSIBLE RING-OPEN AND RING-CLOSURE REACTIONS OF SPIROPYRAN MOLECULES IN DIRECT CONTACT WITH A BI(111) SURFACE

MOS - Molecules at surfaces F. Nickel *, M. Bernien, K. Kraffert, D. Krüger, L.M. Arruda, L. Kipgen, W. Kuch Institut für Experimentalphysik, Freie Universität Berlin - Berlin (Germany) The photochromic isomerization of molecules in direct contact with solid surfaces plays an important role in the further miniaturization of electronic devices. A good candidate for this purpose is spiropyran (SP). SP can be switched from a closed form to an open form (merocyanine, MC) by UV light and reversibly back by visible light or temperature. For nitro- spiropyran, however, the backreaction was found to be quenched on surfaces [1]. The modification of the end group from nitro- to naphtho-spiropyran leads to a lower electric dipole moment in the open form, which might favor switching back to the closed form on a surface. In-situ near-edge x-ray absorption fine structure (NEXAFS) measurements at the nitrogen and oxygen K edges and accompanying theoretical DFT simulations by means of the StoBe code have been performed. A proof and quantification of the photoisomerization ability of these molecules on a Bi(111) surface is presented. Illumination by UV light leads to an efficient switching to the open MC form of the molecule. A determination of the energy barriers of the photo-excited metastable states becomes possible by temperature-dependent measurements. Visible light induces the transition back to the closed SP form in a photostationary state, thus offering full reversible control of the isomerization of the molecule in direct contact with a single crystal surface. Thanks This work is supported by the DFG through Sfb 658. References [1] Piantek et al. J. Am. Chem. Soc. 131, 12729 (2009).

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O26-MOS _353 ENHANCEMENT MECHANISM FOR SURFACE-ENHANCED RAMAN SCATTERING AT METAL NANOSTRUCTURES

MOS - Molecules at surfaces S. Kaneko *, S. Watanabe, M. Kiguchi Tokyo Institute of Technology - Tokyo (Japan) Surface-enhanced Raman scattering at metal nanostructures has been vigorously investigated for its potential application in single-molecule detection [1]. Understanding the enhancement mechanism is very important to obtain a reliable SERS spectrum. The results showed that the electromagnetic (EM) and charge transfer (CT) effects play an important role in the enhancement of Raman signals. Although the size, shape, and separation distance of the nanostructures strongly affect the intensity of the EM effect, it is difficult to precisely determine these factors owing to experimental limitations. The undetermined contribution of the EM effect hinders the understanding of the SERS enhancement mechanism. In this study, we aim to clarify the contribution of the EM effect by changing the separation distance between the lithographically fabricated nanostructures. We fabricated an array of paired square gold nanostructures by electron beam lithography and lift-off (figure 1a inset). We deposited 1,4-benzenedithiol (BDT) on the substrate by means of drop-casting. The SERS spectra of BDT at the nanostructures were observed with varying degree of separation distance: from 10 to 50 nm using a 785 nm excitation laser. Figure 1a shows the SERS spectrum of the BDT observed at the square nanostructures with a separation distance of 30 nm. Two prominent peaks were observed at 1060 cm-1 and -1 1550 cm , corresponding to the C=C stretching mode (ν1) and the ring breathing mode (ν8a) of BDT, respectively. Figure 1b shows the SERS intensity of the ν1 mode, depending on the separation distance of the nanostructures when the laser beam was polarized linearly along the long axis of the nanostructures. The SERS intensity increased when the separation between the nanostructures dropped below 20 nm. In contrast, no signal variation was observed when the laser beam was polarized linearly along the short axis of the nanostructures. Because the electromagnetic field drastically decays away from the nanostructure, the plasmon coupling was observed only at nanostructures with a small separation distance. References [1] S. Kaneko, M. Kiguchi et al., J. Am Chem. Soc. 138 (2016) 1294−1300.

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O27-MOS _161 ELECTRONIC STRUCTURE OF PTCDI ON AG/SI(111)-√3×√3 STUDIED BY STM AND ARUPS

MOS - Molecules at surfaces C. Emanuelsson *, H.M. Zhang, L.S.O. Johansson Department of Engineering and Physics, Karlstad University, SE-651 88 - Karlstad (Sweden) Organic molecules and thin films of these have attracted attention the last few decades due to their promising properties for optoelectronic applications [1]. Interesting molecules in this respect are perylene derivatives such as perylene tetracarboxylic diimide (PTCDI). Perylene derivatives normally interact through hydrogen bondings and form well-defined films on several substrates. The weakly interacting semiconducting surface Ag/Si(111)-√3×√3 is a metal-induced reconstruction that is described by the inequivalent triangle model. The surface consists of Si- and Ag trimers, where there are two different sizes of the Ag trimers [2]. PTCDI on Ag/Si(111)-√3×√3 has previously been studied for submonolayer coverage. It was shown that PTCDI forms 1D rows and 2D islands that grow from step edges and substrate defects. The main molecule/molecule interaction in these structures is the hydrogen bondings between the imide groups of the molecules. Therefore, the 2D islands were also formed by rows, but to allow for this interaction, molecules in adjacent rows are oriented differently [3]. Here we have studied the substrate/molecule and molecule/molecule interactions of PTCDI on Ag/Si(111)-√3×√3 using scanning tunneling microscopy and spectroscopy (STM/STS), and angular resolved ultraviolet photoelectron spectroscopy (ARUPS). The substrate was prepared by evaporating ~ 1 ML Ag onto a clean Si 7x7 surface followed by annealing at ~600 °C for 2 min. PTCDI was deposited while the sample was kept at room temperature. High-resolution STM images were used to study the hydrogen bonding among molecules in detail. The molecular configuration found in the thin film is explained by the interplay between the stronger interaction along the molecular rows and a weaker interaction between the rows. The non-rectangular unit cell gives rise to a higher electronic density along the shorter diagonal that is clearly visible in STM images. Both ARUPS and STS reveal that the electronic structure around the Fermi level changes considerably with coverage. At 1 and 2 ML extra states are found compared to thicker films. Interestingly this correlates with high- resolution filled-state STM images: Different numbers of molecular lobes are found at tunneling biases in consistence with the different filled-states. Orbital models for both HOMO and LUMO are presented together to show the different hydrogen bondings among molecules. References [1] R. Forrest, Chem. Rev. 97, 1793 (1997) [2] H. M. Zhang, J. B. Gustafsson and L. S. O. Johansson, Phys. Rev. B 74, 201304(R) (2006) [3] J. C. Swarbrick, et al., J. Phys. Chem. B, 109, 12167 (2005)

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O28-MOS _282 ADSORPTION OF ORGANIC MOLECULES AT INSULATING SURFACES: ROLE OF MOLECULAR FLEXIBILITY

MOS - Molecules at surfaces J. Gaberle 1,*, D.Z. Gao 1, A. Shluger 1, M. Watkins 2 1University College London - London (United Kingdom), 2University of Lincoln - Lincoln (United Kingdom) We present the results of computational modelling of adsorption and diffusion of large organic molecules on terraces and step edges on the KCl (001) surface, focussing on the effects that molecular flexibility has on their dynamic behaviour. Two functionalised organic molecules: a rigid 1,3,5-tri- (4-cyano-4,4biphenyl)-benzene (TCB) and flexible 1,4- bis(cyanophenyl)-2,5-bis(decyloxy)benzene (CDB), were studied on the KCl (001) surface using density functional theory (DFT) and classical molecular dynamics (MD) simulations. MP2 calculations within CP2K code were used to benchmark the performance of van der Waals corrected DFT-D3 calculations of adsorption energies and geometries and a classical force field was parameterised for the interaction of each of the molecules with KCl(001) using a genetic algorithm.[1] These force fields allowed us to perform long time-scale simulations to study the motion of molecules on the surface. In order to better understand adsorption of TCB and CDB molecules at elevated temperatures, potential of mean force calculations were employed. It was found that the entropy change on adsorption constitutes almost half of the adsorption free energy. Diffusion coefficients for molecular diffusion on terraces were calculated using molecular dynamics at different temperatures and the activation energies evaluated as 0.52 eV for TCB and 0.36 eV for CDB. Furthermore, adhesion to step edges was investigated along with the associated changes in entropy. While the flexible CDB molecule can readily adapt to step edges, the rigid TCB molecule is unable to and exhibits a significant entropy loss upon step adhesion. We show that the simple rigid rotor model can accurately estimate entropy loss upon step adhesion for TCB but fails for CDB. The results highlight how molecular flexibility directly influences surface dynamics, which can lead to different self-assembly growth modes. References [1] Gao, D. Z., Federici Canova, F., Watkins, M. B., & Shluger, A. L. (2015). Efficient parametrization of complex molecule-surface force fields. J. Comp. Chem., 36, 1187–1195.

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O29-MOS _33 FABRICATION OF A SURFACE-CONFINED COVALENT ORGANIC FRAMEWORK ON A REACTIVE SURFACE.

MOS - Molecules at surfaces C. Larrea *, C.J. Baddeley EaStCHEM School of Chemistry, University of St Andrews - North Haugh, St Andrews, Fife, Ky16 9st (United Kingdom) Organic modifiers can bestow valuable properties on a heterogeneous catalyst such as enantioselectivity.[1] In order to ensure optimal dispersion and stability of the modifiers on the catalyst’s surface, their anchoring by means of a porous surface-confined covalent organic framework (sCOF) is a desirable strategy. Unlike on inert surfaces, the fabrication of covalent architectures from molecular precursors on reactive surfaces is a more challenging task. This is due to the dominant molecule-surface interaction which precludes monomer diffusion and assembly.[2] We demonstrate how the compromise between the fabrication of an extended covalent architecture and preservation of surface reactivity can be attained by exploiting Au-Pd surface alloys. A sCOF is synthesized from a molecular precursor using Ullman reaction on a gold-rich Au-Pd(111) surface. Subsequent Pd-enrichement is achieved by thermal processing. As a result, a porous sCOF which exhibits accessible Pd sites, is created. Scanning tunneling microscopy provides evidence of the formation of a robust porous sCOF; whilst titration of Pd sites using CO as a probe molecule confirmed the alloying step, as determined by reflection-absorption infrared spectroscopy and temperature-programmed desorption. We anticipate that this protocol may be potentially implemented for other sCOFs and find applications in the functionalisation of Pd@Au nanoparticles. Thanks EPSRC EaStCHEM References [1] G. Kyriakou, S. K. Beaumont, R. M. Lambert, Langmuir 2011, 27, 9687-9695. [2] M. Bieri, M. T. Nguyen, O. Groning, J. M. Cai, M. Treier, K. Ait-Mansour, P. Ruffieux, C. A. Pignedoli, D. Passerone, M. Kastler, K. Mullen, R. Fasel, J Am Chem Soc 2010, 132, 16669-16676.

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O30-MOS _21 ON-SURFACE MANIPULATION OF THE ION METALATION AND EXCHANGE BETWEEN PHTHALLYCONINE AND SURFACE

MOS - Molecules at surfaces F. Song *, K.C. Shen, G.W. Ji, H.L. Sun, B. Song, H.Y. Li Shanghai Institute of Applied Physics, Chinese Academy of Sciences - Shanghai (China) Molecular self assembly has been a constant topic for decades, owning to its high tunablity of not only the physics nanostructures but also the electronic properties, for instance, one dimensional nanowires, two dimensional network, confined structure induced surface states, transition from semiconductor to superconductor and so on. Phthalocyanine, as one of the intensively investigated πelectron conjugated ring complex, has been widely used in the biological processes, gas sensing，organic thin-film transistors，photovoltaic devices and so on. Herein, self assembly of cobalt phthalocyanine (CoPc) and H2Pc(metal free phthalocyanine) on Cu(111) and Bi/Cu interfaces were explored with a combination of photoemission spectroscopy and first-principle calculations.Interestingly, the exchange of ions between phthalocyanine and substrate was discovered, while the metalation of H2Pc was demonstrated. Moreover, valance band investigation by UPS which indicated the evolution of molecular orbitals and the metal features from substrates. In the end, great consistency was demonstrated between the experimental findings and DFT calculations. Thanks Fruitful discussions with Prof. Dr. Han Huang, Prof. Dr. Wells Justin and Prof. Dr. Zheng Jiang are greatly acknowledged.This project was financially supported by National Natural Science Foundation of China under project U1232112 and 91545101, Hundred Talents Program of Chinese Academy of Sciences, SOE and Shanghai Pujiang Program. References 1. Johannes V. Barth, Giovanni Costantini & Klaus Kern. Engineering atomic and molecular nanostructures at surfaces. Nature.437; 671-679 (2005). 2. Challuri Vijay Kumar,Georgia Sfyri,Dimitrios Raptis,Elias Stathatosd and Panagiotis Lianos.Perovskite solar cell with low cost Cu-phthalocyanine as hole transporting material. Rsc Adv.5;3786–3791 (2015). 3. Gottfried, J. M., Surface chemistry of porphyrins and phthalocyanines. Surf Sci Rep. 70; 259 (2015). 4. Wang, Y., Wu, K., Kröger, J. & Berndt, R., Review Article: Structures of phthalocyanine molecules on surfaces studied by STM. AIP Adv.2; 41402 (2012).

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O31-MOS _47 PORPHYRIN CHEMICAL MODIFICATION ON TIO2(110): HYDROGENATION, SELF- METALATION, CONFORMATIONAL CHANGE

MOS - Molecules at surfaces L. Floreano 1,*, G. Lovat 2, M. Dominguez 2, M. Abadia 3, C. Rogero 3, D. Forrer 4, M. Casarin 5, A. Vittadini 4 1CNR-IOM - Trieste (Italy), 2Graduate School of Nanotechnology, University of Trieste - Trieste (Italy), 3Centro de Fisica de Materiales, CSIC-UPV - San Sebastian (Spain), 4CNR-IENI and Consorzio INSTM, Padova - Padova (Italy), 5Department of Chemical Sciences, University of Padova - Padova (Italy) The modification of metal-free porphyrins adsorbed on surfaces is a viable route to achieve chemical and structural control of molecular overlayers. The polypyrrolic macrocycle can incorporate one metal atom either by metal deposition atop the molecular overlayer [1] or by extraction from the metallic substrate.[2] Thermal treatment of the molecular overlayer after deposition can further modify the molecular conformation, eventually triggering partial dehydrogenation and new C-C bond formation of the porphyrins functional terminations.[3] By a combined Synchrotron spectroscopy (XPS, NEXAFS), STM topography and DFT simulation study, I will show that all of these on-surface chemical routes are open at the rutile TiO2(110) surface. First of all, TiO2, triggers the double hydrogenation of the macrocycle of metal- free porphyrins already at room temperature (Fig. 1.A).[4] Even in this configuration, the macrocycle can be fully dehydrogenated by metal incorporation (either by room temperature deposition or by surface extraction at higher temperature, Fig. 1.B). Depending on the molecular functionalization, further conformational changes can be achieved by surface annealing, e.g. rotation of the phenyl rings in tetra-phenyl-porphyrin (Fig. 1.C). Thanks We acknowledge support from the MIUR of Italy through PRIN project DESCARTES (no. 2010BNZ3F2), and by CINECA (ISCRA-B project E-TROPPO). References [1] G. Di Santo, C. Sfiligoj, C. Castellarin-Cudia, A. Verdini, A. Cossaro, A. Morgante, L. Floreano, and A. Goldoni, Chem. Eur. J. 18 (2012) 12619-12623. [2] R. Gonzalez-Moreno, C. Sanchez-Sanchez, M. Trelka, R. Otero, A. Cossaro, A. Verdini, L. Floreano, M. Ruiz-Bermejo, A. García-Lekue, J.A. Martín-Gago, and C. Rogero, J. Phys. Chem. C 115 (2011) 6849- 6854. [3] G. Di Santo, et al., Chem. Eur. J. 17 (2011) 14354-14359. [4] G. Lovat, D. Forrer, M. Abadia, M. Dominguez, M. Casarin, C. Rogero, A. Vittadini and L. Floreano, Phys. Chem. Chem. Phys. 17 (2015) 30119-30124.

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O32-MOS _192 REACTIVITY OF LUTETIUM BIS-PHTHALOCYANINE TOWARDS OXYGEN

MOS - Molecules at surfaces M. Farronato 1,*, D. Longo 1, N. Witkowski 2 1Université Paris 6 Pierre et Marie Curie - Paris (France), 2Université Paris 6 Pierre et Marie Curie; CNRS UMR 7588, 4 Pl Jussieu, F-75005 Paris, France - Paris (France) Lutetium bis-Phthalocyanine thin films are gaining attention as candidate for efficient gas sensing applications. Their peculiar electronic structure, and in particular the presence of a Single Occupied Molecular Orbital (SOMO) makes them ideal candidates for different gas sensing, as they are available for both oxidation and reduction. However no fundamental studies exist yet about how the bonding takes place at the molecular level. In this work we studied the low temperature reactivity towards molecular oxygen of a thick film of LuPc2 deposited on Au(111) single crystal in ultra-high vacuum (UHV). We characterized the reaction via X-Ray Photoelectron spectroscopy (XPS) and Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy. We showed a weak interaction, as oxygen desorbs as the sample is heated up to around 100K. We also showed that the reaction mostly affects the isoindole N atom, and only slightly the C atoms and the π system. We also show that the adsorption geometry is almost vertical. Also quantitavie analysis showed that more than a ML was adsorbed, showing the possibility for the oxygen to diffuse inside the layer. Thanks M.F. acknowledges the People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme FP7/ 2007-2013/ under REA Grant Agreement No. 607232 for funding Thanks to Johann Luder for the DFT calculations References M. Passard; J.P. Blanc; C. Maleysson, Thin Solid Films 271 (1995) 8-14 L. Ottaviano, L. Lozzi, S. Santucci Surface Science 431 (1999) 242 F. Sedona, M. Di Marino, D. Forrer, A. Vittadini, M. Casarin, A. Cossaro, L. Floreano, A. Verdini and M. Sambi, Nature Materials 11 (2012) 970 I. Bidermane, J. Luder, S. Boudet, T. Zhang, S. Ahmadi, C. Grazioli, M. Bouvet, J. Rusz, B. Sanyal, O. Eriksson, B. Brena, C. Puglia, and N. Witkowski, Journal of Chemical Physics 138, (2013) 234701

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O33-MOS _237 INTERACTIONS OF TRANSITION METAL PHTHALOCYANINES AT METAL SURFACES – INFLUENCE OF GRAPHENE BUFFER LAYERS AND INTERCALATION

MOS - Molecules at surfaces T. Chassé 1,*, J. Uihlein 1, H. Adler 1, M. Glaser 1, D. Balle 1, M. Polek 1, A. Chassé 2, H. Peisert 1,* 1Institute of Physical and Theoretical Chemistry, University of Tübingen - Tübingen (Germany), 2Institute of Physics, Martin Luther University Halle-Wittenberg - Halle (Germany) The interactions of molecular layers with substrates strongly influence the charge transport across these interfaces, which may become important for possible future organic electronic and spintronic devices. Here, we report on investigations using X-ray absorption and photoemission spectroscopies (XAS, PES) to elucidate interactions between transition metal phthalocyanines (TMPcs) and metal substrates. In particular, the analysis of TM L- edge spectra (core-level PES and XAS) sheds light on local changes of the interface electronic structure. Valence band and TM L-edge spectra of TMPcs recorded at interfaces on Au(100) point to weak interactions only. In contrast, the spectra of the TM central atoms of TMPcs taken on Ag(111) indicate significant interactions including local charge transfer. Similar results were obtained on Ni(111), too. [1] However, for CoPc and FePc on Ni(111) the interactions can be modified by insertion of a graphene buffer-layer.[2] MnPc evidently reacts with the Ni(111). Graphene prevents this chemical reaction, reduces the interactions, and suppresses interfacial charge transfer.[2] For CoPc on graphene/Ni(111), the charge transfer is only prevented if the graphene/Ni(111) is intercalated by gold. Therefore, the disturbance of the graphene electronic structure by the interaction with the metal substrate and the corresponding charge doping has significant impact on the electronic properties of adsorbed CoPc.[3] Additionally, the experimental results (XAS) are discussed in the framework of multiplet calculations taking into account crystal field and charge transfer effects with focus on interface effects.[4] The results demonstrate opportunities for tuning interactions and electronic properties at organic-metal interfaces. Thanks We gratefully acknowledge cooperations with R. Ovsyannikov, and M. Bauer from Helmholtz Center Berlin, with P. Nagel, M. Merz, and S. Schuppler from ANKA/KIT, Germany, as well with A.B. Preobrajenski and A.V. Generalov, MaxLab, Sweden. We are grateful for financial support from HZB, ANKA, and CALIPSO. References [1] H. Peisert, J. Uihlein, F. Petraki T. Chassé, J. Electron Spectr. Rel. Phenom. 204, 49 (2015) [2] J. Uihlein, H. Peisert, H. Adler, M. Glaser, M. Polek, R. Ovsyannikov, M. Bauer, T. Chassé, J. Phys. Chem. C 118, 28671 (2014) and J. Phys. Chem. C 118, 28671 (2014) [3] J. Uihlein, M. Polek, M. Glaser, H. Adler, R. Ovsyannikov, M. Bauer, M. Ivanovic, A. Preobrajenski, A. Generalov, T. Chasse, H. Peisert, J. Phys. Chem. C 119, 15240 (2015) [4] E. Stravitski and F.M.F. de Groot, Micron 41, 687-694 (2010)

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O34-MOS _104 DIHYDROTETRAAZAPENTACENE GROWTH ON ALUMINA: FROM THE SUBMONOLAYER TO NM THICK FILMS

MOS - Molecules at surfaces C. Becker 1,*, T. Léoni 1, A. Thomas 1, A. Ranguis 1, L. Masson 1, O. Siri 1, B. Kaufmann 2, A. Matkovic 2, M. Kratzer 2, C. Teichert 2 1Aix-Marseille Université, CNRS, CINaM - UMR 7325 - Marseille (France), 2Institute of Physics, Montanuniversitaet Leoben - Leoben (Austria) Azapentacenes have received considerable interest during the past years due to their potential application as organic semiconductors. In this context, the growth of Dihydrotetraazapentacene (DHTAP) on alumina surfaces has been studied using scanning tunneling microscopy (STM) and atomic force microscopy (AFM) in the temperature ranges from 220 K to 360 K and 280 K to 390 K, respectively. For the STM measurements, DHTAP was deposited by molecular beam epitaxy in a coverage range from 0.4 ML to 3.6 ML on an ultra-thin Al2O3 film on Ni3Al(111) [1]. For the AFM investigations, DHTAP (coverage range 0.4 nm to 1.7 nm) was deposited by hot-wall epitaxy on sapphire(0001) single crystal surfaces. The STM and the AFM measurements both show a strong dependence of the growth mode on temperature. In accordance with a model of heterogeneous nucleation, they demonstrate that higher temperatures lead to fewer but bigger islands when the flux is kept constant. The STM results clearly indicate that DHTAP does not wet the surface. It could also be shown that the emerging islands are well-ordered and that the molecules are upright standing on the surface that is with their long axis perpendicular to the surface plane (see figure 1). The AFM results revealed that terraced islands and curved needle-like structures emerge above 330 K (see figure 2). The terraced islands have step heights similar to those of the upright standing molecules observed by STM. The length and curvature of the needle-like structures show a clear dependence on the temperature, they are longer and more curved for higher temperatures. Thanks The authors gratefully acknowledge the financial support of the Austrian FWF (I 1788-N20) and the French ANR (14-CE34-0003-01). References [1] S. Degen, A. Krupski, M. Kralj, A. Langner, C. Becker, M. Sokolowski, K. Wandelt, Surf. Sci. 576, L57 – L64 (2005)

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O35-MOS _67 BROMINE-FUNCTIONALIZED PYRENE DERIVATIVES ON NOBLE METAL SURFACES: SELF-ASSEMBLY AND ON-SURFACE POLYMERIZATION

MOS - Molecules at surfaces B. Tran 1,*, T.A. Pham 1, F. Song 1, M.T. Nguyen 2, M. Kivala 3, M. Stöhr 1,* 1Zernike Institute for Advanced Materials, University of Groningen - Groningen (Netherlands), 2The Abdus Salam International Center for Theoretical Physics - Trieste (Italy), 3Department of Chemistry and Pharmacy, University of Erlangen-Nürnberg - Erlangen-Nürnberg (Germany) For around one decade, on-surface polymerization has been introduced as an alternative method to classical solution-based organic synthesis for constructing novel 1D and 2D materials. One of the intriguing materials, which can be reliably obtained through on-surface polymerization based on Ullmann coupling, is graphene nanoribbons [1]. However, the presence of the split off halogen atoms generated during the polymerization reaction may hamper the diffusion of the monomers and thus, negatively influences the formation of well- ordered polymer structures. In this work, we report on both the self-assembly and on-surface polymerization of bromine- functionalized pyrene derivatives on noble metal surfaces under UHV conditions. Furthermore, we present a hydrogen dosing treatment to reduce the influence of the split off halogen atoms on the final polymer network. The results obtained from scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS) measurements and density functional theory (DFT) calculations reveal the arrangement and bonding of the as- deposited molecular monomers as well as the polymer networks on the noble metal surfaces [2,3]. References [1] J. Cai et al. Nature 466, 470 (2010). [2] T. A. Pham, et al. Chem. Eur. J., doi:10.1002/chem.201504946 [3] B. V. Tran et al. In preparation.

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O36-MOS _218 IMPACT OF HYDROPHILIC AND HYDROPHOBIC FUNCTIONALISATION OF ULTRA- FLAT TITANIUM SURFACES ON PROTEINS ADSORPTION

MOS - Molecules at surfaces H. Fabre 1,*, A. Galtayries 2, D. Mercier 2, D. Portet 3, N. Delorme 1, J.F. Bardeau 1,* 1Université du Maine - IMMM - Le Mans (France), 2Chimie Paristech - IRCP - Paris (France), 3Surfactis - Angers (France) Health care-associated infections (HAIs) or nosocomial infections have become a serious threat for many healthcare facilities. Although many initiatives were taken to limit HAIs, raising awareness for infection associated with implanted medical devices seem to be one of the more recent strategies to achieve reduction and prevention of such infections. Indeed, medical implants offer particularly a good support for the development of microorganisms which can occur several weeks or months after implantation. Titanium-based implants are widely used in modern clinical practice, and their properties in terms of porosity, roughness and functionalization are still a subject of intensive discussions especially to insure patient safety. When biomaterials are implanted into the body, they are rapidly coated with a layer of plasma proteins. Therefore, the amount of adsorbed proteins onto the surface influences the subsequent cell adhesion behaviours. As surface wettability is one important factor determining cell adhesion behaviours, a series of surfaces with different chemical properties has been prepared in order to study the role of surface wettability on protein adhesion. Ultra-flat thin films of TiO2 (Ra < 1 nm), deposited by cathodic sputtering on Si wafer, were used as a model biomaterial for implants, and functionalised with self-assembled monolayer (SAMs). The molecules were grafted to titanium oxide by a bisphosphonic group. They were terminated by perfluorinated or hydroxyl groups resulting in hydrophobic or hydrophilic surfaces respectively. Gram-positive bacteria are the commonest cause of nosocomial infections, Staphylococcus aureus being the predominant pathogen. While the protein BSA can inhibit their adherence, fibrinogen and fibronectin generally enhance it. [1, 2] Accordingly, it appeared important to measure the quantity of those proteins that can adsorb on such modified surfaces. Spatial and temporal controls of proteins adsorbed onto the surfaces were achieved using quartz microbalance (QCM), XPS and AFM. QCM allowed monitoring and quantifying the amount of protein adsorbed on the different types of surfaces. AFM were used to control the quality of the functionalized surfaces before and after proteins were adsorbed. XPS measurements provided surface composition for each element and allowed to get an estimation of the thickness of the protein film. References 1. Herrmann, et al., The journal of infectious diseases, 1988. 158 2. Nune, et al., J Biomed Mater Res A, 2012. 100

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O37-MOS _182 SELF-ASSEMBLING OF 5-FOLD SYMMETRIC MOLECULES ON QUASICRYSTALLINE SURFACES.

MOS - Molecules at surfaces N. Kalashnyk 1,*, E. Gaudry 1, J. Ledieu 1, C. Cui 2, A.P. Tsai 3, V. Fournée 1,* 1Institut Jean Lamour, UMR 7198 CNRS – Université de Lorraine - Nancy (France), 2Department of Physics, Zhejiang Sci-Tech University - Hangzhou (China), 3IMRAM, Tohoku University - Sendai (Japan) The surface of quasicrystals and their approximants usually terminates at specific planes of the bulk structure. The selected terminations depend on several parameters like their chemical composition, their atomic density and how the surface planes intercept the bonding network underlying the 3D bulk structure. The resulting surfaces present a complex energy landscape for adsorbates which can act as a template for the growth of 2D crystals with novel structures. Here we will show new results of 5-fold symmetric molecules which are trapped at 5-fold symmetric sites of the surface, enforcing long-range order in the molecular films (Fig.1 and Fig.2). This occurs for C60 molecules on several quasicrystalline substrates [1,2] but also for bowl-shaped corannulene C20H10 molecules on the 5-fold Ag-In- Yb quasicrystalline surfaces. The growth mechanism and the film structure are investigated by STM and LEED complemented by density functional theory calculations. In the case of corannulene molecules with C5v symmetry, we will discuss their packing strategy when adsorbed on quasiperiodic 5-fold surface compared to 3-fold Pd(111) surface. The growth of quasiperiodic corannulene monolayers on the Ag-In-Yb quasicrystalline surface opens the possibility to achieve 3D-like quasiperiodic molecular films through bowl-in-bowl stacking of the molecules in subsequent deposited layers. References [1] V. Fournée et al., ACS Nano, 8 (2014) 3646. [2] J. Smerdon et al., Nano Lett., 14 (2014) 1184−1189.

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O38-MOS _172 BEYOND THE HEXAGON: NON-ALTERNANT AROMATIC MOLECULES ON METAL SURFACES

MOS - Molecules at surfaces B.P. Klein *, P. Krüger, P. Müller, M. Schöniger, M. Zugermeier, P. Rosenow, R. Tonner, M. Schmid, M. Gottfried Fachbereich Chemie, Philipps-Universität Marburg - Marburg (Germany) The interaction of conjugated organic hydrocarbons, in particular aromatic species, with metal surfaces has been a major topic in surface science during the past decade. Up to now, the focus has been almost exclusively on alternant hydrocarbons, which have a uniform charge distribution and highly delocalized frontier orbitals. In contrast, non-alternant hydrocarbons have non-uniform charge distributions, which can result in considerable in- plane dipole moments, and more localized frontier orbitals. They also violate the Coulson- Rushbrooke pairing theorem and thus have shifted valence levels compared to the isomeric alternant hydrocarbons. In this contribution, we present the first systematic studies of non- alternant aromatic hydrocarbons on the (111) surfaces of Cu and Ag. In particular, we focus on naphthalene as an alternant hydrocarbon and bicyclo[5.3.0]decapentaene as its non- alternant counterpart. On the basis of extensive NEXAFS, PES, TPD and LEED studies, we show that the non-alternant hydrocarbon interacts much stronger with metal surfaces, especially in the case of Cu(111), and that the interaction is more localized. Complementary theoretical calculations using periodic density functional theory provide detailed insight into the surface chemical bond and charge redistribution between surface and molecule. In addition, considerable in- and out-of-plane deformation of the adsorbed non-alternant species can be found, which results from the localization of the frontier orbitals.

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O39-MOS _155 ADSORPTION STUDY OF TEREPHTHALIC AND BENZOIC ACIDS ON HOPG, AU(111) AND AL-OXIDE WITH METASTABLE INDUCED ELECTRON SPECTROSCOPY (MIES)

MOS - Molecules at surfaces M. Marschewski *, H. Tas, C. Otto, W. Maus-Friedrichs, A. Schmidt, O. Höfft TU Clausthal - Clausthal-Zellerfeld (Germany) The adsorption behavior of benzoic acids on metal interfaces is of high interest for metal- substrat interactions for catalysis and the construction of metal-organic frameworks. Here we present our results on the growth of thin films of TPA and 4-R-benzoic acid (R stands for hydroxyl-, methoxy-, propoxy-, pentyloxy- and decyloxy-chains, respectively) on Highly Oriented Pyrolytic Graphite (HOPG), Au(111) and oxidized aluminum. The adsorption was studied with Metastable Induced Electron Spectroscopy (MIES) and Ultraviolet Photoelectron Spectroscopy (UPS(HeI)). MIES exhibits an extremely high surface sensitivity for detecting the electronic structure of the outermost molecular orbitals and especially for the π orbitals of organic molecules. Due to this ability we are able to make assumptions about the orientation of the molecules on the surfaces. To proof a nondestructive molecule adsorption on the surfaces, X-ray Photoelectron Spectroscopy (XPS) was performed. On HOPG and Au(111) we find hints for a flat lying orientation for the monolayer of TPA [1] and the 4-R-benzoic acids. The only exception is observed for the 4-decyloxy-benzoic acid. After a coverage of approximately 1 monolayer (ML) the spectrum is dominated by the spectral features of the alkyl chains. Therefore we assume a possible reorientation of the alkyl chains after the first monolayer. For the growth on an oxidized aluminum surface we suppose an upstanding arrangement. Thereby, the MIE/UP spectra only show the features from the COOH group of the TPA molecules. We have also performed measurements on the oxidized aluminum at low temperature. Here, a random arrangement of the TPA molecules is found, this supports the assumption of an upstanding adsorption of the TPA molecules at room temperature. While the XP-spectra show a nondestructive evaporation of the acids on all surfaces, they also show radiation damage depending on the duration of the X-ray exposure for the 4-R- benzoic acid but not for TPA. References [1] M. Marschewski, C. Otto, L. Wegewitz, O. Höfft, A. Schmidt and W. Maus-Friedrichs, Appl. Surf. Sci., 2015, 339, 9-14.

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P1-MOS_11 POST-DEPOSITION HYDROGEN TREATMENT EFFECT ON SURFACE ROUGHNESS AND HYDROPHOBICITY OF AMORPHOUS SILICON FILMS

MOS - Molecules at surfaces Y. Brahmi *, L. Filali, J.D. Sib, D. Benlekhal, Y. Bouizem, L. Chahed University of Oran1 Ahmed Ben Bella - Oran (Algeria) Amorphous silicon films were deposited by radiofrequency (rf) magnetron sputtering. Then, the films were treated by pure hydrogen gas at different pressures (1, 2 and 3 Pa) for 20 min, to investigate its effect on surface hydrophobicity (or un-wettability) and roughness. Fourier transform infrared-attenuated total reflection (FTIR-ATR) spectroscopy was used to evaluate presence of Si-H bonds at the surface. Results obtained by the atomic force microscopy (AFM) showed a sharp decrease (the non-treated film had a root mean square value of 10.94 nm, which then dropped significantly to 6.69 nm for the 3 Pa hydrogenated film) in surface roughness as a result of hydrogenation. Optical transmission results revealed that optical properties were not affected. Contact angle measurements showed an enhanced hydrophobicity by 15 degrees for the 1 Pa hydrogenated film, and then it decreased for the 2 Pa and 3 Pa hydrogenated films. This result indicates that the decrease in roughness compromised the hydrophobization process.

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P2-MOS_37 FABRICATION OF A SURFACE-CONFINED COVALENT ORGANIC FRAMEWORK ON A REACTIVE SURFACE.

MOS - Molecules at surfaces C. Larrea *, C.J. Baddeley EaStCHEM School of Chemistry, University of St Andrews - North Haugh, St Andrews, Fife, Ky16 9st (United Kingdom) Organic modifiers can bestow valuable properties on a heterogeneous catalyst such as enantioselectivity.[1] In order to ensure optimal dispersion and stability of the modifiers on the catalyst’s surface, their anchoring by means of a porous surface-confined covalent organic framework (sCOF) is a desirable strategy. Unlike on inert surfaces, the fabrication of covalent architectures from molecular precursors on reactive surfaces is a more challenging task. This is due to the dominant molecule-surface interaction which precludes monomer diffusion and assembly.[2] We demonstrate how the compromise between the fabrication of an extended covalent architecture and preservation of surface reactivity can be attained by exploiting Au-Pd surface alloys. A sCOF is synthesized from a molecular precursor using Ullman reaction on a gold-rich Au-Pd(111) surface. Subsequent Pd-enrichement is achieved by thermal processing. As a result, a porous sCOF which exhibits accessible Pd sites, is created. Scanning tunneling microscopy provides evidence of the formation of a robust porous sCOF; whilst titration of Pd sites using CO as a probe molecule confirmed the alloying step, as determined by reflection-absorption infrared spectroscopy and temperature-programmed desorption. We anticipate that this protocol may be potentially implemented for other sCOFs and find applications in the functionalisation of Pd@Au nanoparticles. Thanks EPRSC EaStCHEM References [1] G. Kyriakou, S. K. Beaumont, R. M. Lambert, Langmuir 2011, 27, 9687-9695. [2] M. Bieri, M. T. Nguyen, O. Groning, J. M. Cai, M. Treier, K. Ait-Mansour, P. Ruffieux, C. A. Pignedoli, D. Passerone, M. Kastler, K. Mullen, R. Fasel, J Am Chem Soc 2010, 132, 16669-16676.

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P3-MOS_43 TIME-INTEGRATED COPPER PHTHALOCYANINE PATTERNS ON TL(1×1)/SI(111)

MOS - Molecules at surfaces F. Rozboril *, P. Matvija, P. Kocán, P. Sobotík, I. Oštádal Faculty of Mathematics and Physics, Charles University in Prague (Czech republic) Metal phthalocyanines are organic molecules known for their thermal and chemical stability and a wide range of potential applications in optical and electronic devices. To increase the diffusion rate on the Si(111) surface, a passivation layer is needed to decouple the molecules from the highly reactive silicon. We used the thallium 1×1 overlayer1.

At coverage approaching one monolayer, fluorinated copper phthalocyanine (F16CuPc) forms a regular self-assembled structure. With lower coverage, the molecules move freely on the surface, while some molecules bind to substitutional defects in the thallium layer. We are unable to distinguish the movement of individual mobile molecules in STM images at the room temperature, but the images show us the time- integrated view of the molecular diffusion on the surface. In the case of F16CuPc, a standing wave-like pattern is observed in the vicinity of defect-bound molecules (Figure I). We utilized a simple kinetic Monte Carlo model to investigate this behavior. The F16CuPc molecule is modeled with a realistic four- fold geometry and with the central Cu atom adsorbed on top of a surface Tl atom. Only repulsive interaction of overlapping molecules is considered. By integrating the simulated residence times of a molecule in each lattice point, we obtained patterns similar to those observed in STM images (Figure II). The patterns reflect the most probable positions of diffusing molecules with the given arrangement of defects. References [1] Matvija P., Sobotík P., Ošťádal I., Kocán P., Appl. Surf. Sci. 331, 339 (2015)

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P4-MOS_50 DIPYRANYLIDENES (DIP) AS HOLE COLLECTORS IN PV HETEROSTRUCTURES: IMPACT OF CHALCOGEN SUBSTITUTIONS STUDIED BY RESONANT PHOTOELECTRON SPECTROSCOPY (RESPES)

MOS - Molecules at surfaces Q. Arnoux 1,*, A. Boucly 1, A. Cossaro 2, F. Luca 2, M. Silly 3, F. Sirotti 3, L. Tortech 4, F. Rochet 1 1Sorbonne Universités, UPMC Univ Paris 06, UMR 7614, Laboratoire de Chimie Physique Matière et Rayonnement (LCPMR), F-75005 - Paris (France), 2CNR - Istituto Officina dei Materiali, TASC Laboratory, S.S. 14, km 163.5, 34149 - Basovizza (ts) (Italy), 3Synchrotron SOLEIL, BP 48, Saint- Aubin, F-91192 - Gif-Sur-Yvette (France), 4Sorbonne Universités, UPMC Univ Paris 06, UMR 8232, Institut Parisien de Chimie Moléculaire (IPCM), F-75005 - Paris (France) In thin film organic solar cells (OSCs) the stacked layers must respect an appropriate energy alignment in order to allow efficient charge separation and transport to the electrodes. Numerous studies report on the advantage of using an interfacial layer (IFL) to drain and/or collect charges at the electrode interfaces. In this field we demonstrated the efficiency of a highly crystalline thin layer of a dipyranylidene derivative (DIPS) as a hole transport layer at the ITO anodic contact [3]. To pursue a deep insight in the electronic processes of this molecular structure, we investigated analogs in which the sulfur is substituted by the oxygen or the selenium, respectively DIPO and DIPSe. After a thermal deposition under vacuum the molecules were characterized by core levels and ResPES electron photoemission measurements [4] on ALOISA beamline in ELETTRA synchrotron and on TEMPO beamline in SOLEIL synchrotron. From these measurements we firstly had access to the precise position of the HOMO of the different DIP. Secondly, we got a complete description of the localization of the excited electron thanks to the resonant Auger (Figure: ResPES mapping at O-1s edge: positions of the two O Auger levels are indicated (black dot line); resonances are observed on the main NEXAFS transitions (white dash line)). Our study was based on the comparison between a thick organic layer and a thin one in order to gain in the charge transfer comprehension. Thanks The authors would like to thank the Labex MiChem for funding the PhD grant to Quentin ARNOUX and ALOISA and TEMPO beamlines for the support. References [1] K. A. Mazzio et al. Chem. Soc. Rev. 44 (2015) 78–90. [2] Q. Zhang et al. Nat Photon. 9 (2015) 35–41. [3] S. Berny et al. ACS Appl. Mater. Interfaces 2 (2010) 3059–3068. [4] J.-J. Gallet et al. Surface Science 601 (2007) 552–561.

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P6-MOS_110 NO ADSORPTION AND ITS MAGNETISM ON THE FEO2 TERMINATED LAFEO3 (001) SURFACE WITH AND WITHOUT OXYGEN VACANCIES: FIRST-PRINCIPLES STUDY

MOS - Molecules at surfaces H. Kizaki *, Y. Morikawa Graduate School of Engineering, Osaka Univ. - Osaka (Japan) Perovskite catalysts are attracting enormous attention since they utilized especially as automotive emissions catalysts. At low temperatures, within a short time from ignition of automotive engines, the reduction mechanism of nitrogen oxides (NOX) does not work well except in case of the Rh-doped catalyst with enhanced reactivity, so that nitric oxide (NO) adsorption is studied via DFT study. However, as far as we know, there are no discussions on its magnetism.

In this study, we evaluate adsorption energy of the NO molecule, Eads = E(slab-NO) - E(slab) - E(NO), on the FeO2 terminated LaFeO3 (001) surface with and without oxygen vacancies (VO). The plane-wave pseudo-potential density functional theory method as implemented in the Quantum-ESPRESSO package was used throughout the calculations[1]. The Perdew-Burke-Ernzerhof-Generalized Gradient Approximation (PBE- GGA) was employed for the exchange-correlation functional.

As a result, on a clean surface of the LaFeO3 slab, the system realizes G-type antiferromagnetic ordering and high-spin configurations. Also, the Eads is evaluated around -1 eV, resulting in a tendency of NO adsorption. In case of a surface slab with VO of 25 at% with respect to the surface O in 1st FeO2 layer, the value is evaluated to be -1.35 eV close to that without VO, forming a bond between nitrogen of adsorbed NO with Fe in the 1st layer with the VO. In case of a surface slab with VO of 50 at% in the 1st FeO2 layer as shown in the figure, the value is evaluated to be -2.17 eV, leading to the enhancement of adsorption energy. We find strong anti-parallel spin coupling between the adsorbed NO and the Fe. We also find that formation of donor states due to the surface VO enhances the adsorption energy of NO. Thanks This work was performed under a management of "Elements Strategy Initiative for Catalysts & Batteries (ESICB) " supported by MEXT program "Elements Strategy Initiative to Form Core Rersearch Center" (since 2012), MEXT; Ministry of Education Culture, Sports, Science and Technology, Japan. References [1] http://www.quantum-espresso.org

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P7-MOS_159 HIGH-RESOLUTION AFM/STM IMAGING AND FORCE SPECTROSCOPY OF VAN DER WALLS NANOSTRUCTURES ON METAL SURFACE

MOS - Molecules at surfaces J. Berger 1,*, O. Stetsovych 1, M. Švec 1, M. Ondrácek 1, R. Sedlák 2, S.M. Eyrilmez 2, R. Lo 2, P. Hobza 2, P. Jelínek 1 1Institute of Physics AS CR, Prague, CZ - Prague (Czech republic), 2Institute of Organic Chemistry and Biochemistry AS CR, Prague, CZ - Prague (Czech republic) Proper theoretical description of the weak vdW interaction, despite the large effort, still remains elusive and is intensely investigated. We intentionally prepared and investigated vdW nanostructures made of CO and Xe co-deposited on Ag(111) surface by a high- resolution 3D mapping and molecular manipulation with the AFM technique. We identify the atomic structure of such formations using high-resolution AFM imaging supported by the total energy DFT-vdW calculations. In addition, we use the force-distance spectroscopy data, acquired with functionalized (CO, Xe) tips to gain direct access to the vdW forces acting between the functionalized tips and artificially created vdW nanostructures made of Xe and/or CO. Such information provides a unique opportunity to benchmark the available theoretical methods employed to describe the vdW interaction. We will provide a direct comparison of various vdW methods to the experimental energy vs. distance data. References

PRL 108, 236402(2012) PRL 106 046104 (2011) PRL 92, 246401(1992) PRB 82, 081101(2010)

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P8-MOS_170 A NEW POSSIBLE TYPE OF MOLECULAR SWITCH – CUPC ON SI(100)-SN-√3×√3 STUDIED BY SCANNING TUNNELING MICROSCOPY

MOS - Molecules at surfaces K. Majer *, P. Zimmermann, F. Rozboril, P. Sobotík, I. Oštádal Charles University in Prague - Prague (Czech republic) Phthalocyanines are conjugated organic molecules which are optically active in the frequency range of visible light. Their emerging applications are namely organic semiconductor devices (FET, LED, solar cells) [1], but a number of other applications have been proposed, such as spintronics [2] or single-molecule switches [3]. We report on an adsorption configuration of CuPc molecules on Si(100)-Sn-√3×√3 surface which appears noisy („fuzzy“) in scanning tunneling microscopy (STM) image (see fig. 1). The noisy appearance is caused by fluctuations of tunneling current which are faster than the scanning speed of STM. We found that a molecule in the „fuzzy“ state is adsorbed on a pair of silicon substitution defects on the surface. The state of the imaged molecule can be changed by means of set tunneling parameters. Time series of the recorded tunneling current were analyzed. They showed rapid switching between two states. A voltage threshold was revealed for activation of the double-state fluctuations. The CuPc molecules can be manipulated by means of the STM tip. We were able to disrupt the fluctuations and effectively turn them off. A possible interaction between the molecule and the surface defects is discussed together with the role of the STM tip. Thanks This work was supported by Charles University in Prague project GAUK 189015. References [1] C. G. Claessens et al., Phthalocyanines: From Outstanding Electronic Properties to Emerging Applications, The Chemical Record 8, 75-97 (2008) [2] M. M. Warner et al., Potential for spin-based information processing in a thin-film molecular semiconductor, Nature 503(7477), 504-508 (2013) [3] P. Liljeroth et al., Current-Induced Hydrogen Tautomerization and Conductance Switching of Naphthalocyanine Molecules, Science 317, 1203 (2007)

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P9-MOS_181 ADSORPTION AND GROWTH OF SEXIPHENYL ON IN2O3(111)

MOS - Molecules at surfaces M. Wagner 1,*, L.A. Boatner 2, M. Sterrer 3, M. Schmid 1, U. Diebold 1 1Institute of Applied Physics, Vienna University of Technology, Austria - Vienna (Austria), 2Material Science and Technology Division, ORNL, USA - Oak Ridge (United States of America), 3Institute of Physics, University of Graz, Austria - Graz (Austria) Indium oxide is one of the most important transparent conductive oxides (TCOs), and commonly used as a contact material. Sexiphenyl (6P) is a rod-like molecule and twice as long as the substrate surface lattice parameter of the (111) surface of In2O3 single crystals. Here, the adsorption of 6P and the monolayer structure are investigated with low temperature STM. We show that single 6P molecules have a specific adsorption site after annealing at 200°C. In empty states STM, the single 6P appears as a zig-zag line at bias voltages below +2V. At +2V the molecule starts to appear straight, which is associated with tunneling into the LUMO state. At +2.7V the apparent shape changes again into two bright features, corresponding to the LUMO+1. No well-ordered structures are formed at sub- monolayer coverages and the molecules are spaced by a substrate lattice constant. Increasing the coverage eventually leads to a reorientation of the molecules into a densly packed monolayer structure.

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P10-MOS_190 ADSORPTION OF THIOPHENE DERIVATIVES ON GOLD AND MOLECULAR DISSOCIATION PROCESSES.

MOS - Molecules at surfaces T. Jiang 1,*, E. Vladimir 2,* 1Institut des Sciences Moléculaires d’Orsay, UMR 8214 CNRS-Université Paris Sud, Université Paris-Saclay, F-91405 Orsay, France - City (France), 2Institut des Sciences Moléculaires d’Orsay, UMR 8214 CNRS-Université Paris Sud, Université Paris-Saclay, - City (France) We report a systematic study of adsorption of thiophene derivatives on gold surfaces. Very promising results for molecular electronics have been obtained on thin films of these molecules. However some experiments indicate S-C bond scission resulting in disruption of the -electron system, which affects charge transport. We explored this dissociation aspect here by XPS, measurements of core level binding energies (CLBE’s) and also near edge adsorption fine structure (NEXAFS) for the case of monocrystalline Au(111) surfaces and Au films grown on mica for a series of polythiophenes molecules (with n units, nT, n=1-4, 6) as well as for a,w-diquater and dihexylsexithiophene (DH4T and also DH6T). We observe complex shaped peaks corresponding to the S2p level, that indicate appearance of species with different S2p components. We relate these mainly to multilayer thiophene, thiophene monolayer (163.7eV) on Au, S-C bond splitting induced thiolate sulphur corresponding to alkene chains (162 eV) and alkene chain molecules at an alternative adsorption site (161eV). In the latter case there is also the possibility of desulfurisation induced atomic S appearance. In NEXAFS dichroism performed for 3T and 6T molecules show that they are strongly inclined away from the surface normal. In NEXAFS, the thiophene ring related adsorption peak decreases with appearance of dissociative processes. Dissociation processes are observed to occur more frequently for the shorter thiophene chains and also on the gold on mica substrates. We tentatively relate this aspect to presence of a larger number of defects sites: a point that is important for molecular electronic devices using diversely prepared gold contacts. X ray induced beam damage was investigated using an intense synchrotron beam of 260eV photons, for 1T and 3T and showed appearance of a 163.3eV component for 1T and 3T and also a 162eV component for 3T.

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P11-MOS_195 REACTIVITY OF LUTETIUM BIS-PHTHALOCYANINE TOWARDS OXYGEN

MOS - Molecules at surfaces M. Farronato 1,*, D. Longo 1, N. Witkowski 2 1Université Paris 6 Pierre et Marie Curie - Paris (France), 2Université Paris 6 Pierre et Marie Curie; CNRS UMR 7588, 4 Pl Jussieu, F-75005 Paris, France - Paris (France) Lutetium bis-Phthalocyanine thin films are gaining attention as candidate for efficient gas sensing applications [1]. Their peculiar electronic structure, and in particular the presence of a Single Occupied Molecular Orbital (SOMO) makes them ideal candidates for different gas sensing, as they are available for both oxidation and reduction. However no fundamental studies exist yet about how the bonding takes place at the molecular level. In this work we studied the low temperature reactivity towards molecular oxygen of a thick film of LuPc2 deposited on Au(111) single crystal in ultra-high vacuum (UHV). We characterized the reaction via X-Ray Photoelectron spectroscopy (XPS) and Near Edge X- ray Absorption Fine Structure (NEXAFS) spectroscopy. We showed a weak interaction, as oxygen desorbs as the sample is heated up to around 100K. We also showed that the reaction mostly affects the isoindole N atom, and only slightly the C atoms and the π system. We also show that the adsorption geometry is almost vertical. Also quantitavie analysis showed that more than a ML was adsorbed, showing the possibility for the oxygen to diffuse inside the layer. Thanks M.F. acknowledges the People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme FP7/ 2007-2013/ under REA Grant Agreement No. 607232 for funding Thanks to Johann Luder for the DFT calculations References M. Passard; J.P. Blanc; C. Maleysson, Thin Solid Films 271 (1995) 8 L. Ottaviano, L. Lozzi, S. Santucci Surface Science 431 (1999) 242 F. Sedona, M. Di Marino, D. Forrer, A. Vittadini, M. Casarin, A. Cossaro, L. Floreano, A. Verdini and M. Sambi, Nature Materials 11 (2012) 970 I. Bidermane, J. Luder, S. Boudet, T. Zhang, S. Ahmadi, C. Grazioli, M. Bouvet, J. Rusz, B. Sanyal, O. Eriksson, B. Brena, C. Puglia, and N. Witkowski, Journal of Chemical Physics 138, (2013) 234701

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P12-MOS_198 DENSITY FUNCTIONAL THEORY STUDY OF BENZENE ADSORPTION ON FE SURFACES

MOS - Molecules at surfaces B. Provost 1,*, J.M. Goodman 1, M.Y. Ho 2, T. Hughes 2, S.J. Jenkins 1 1Department of Chemistry, University of Cambridge - Cambridge (United Kingdom), 2Schlumberger Gould Research - Cambridge (United Kingdom) Aromatic adsorption on metal surfaces plays a key role in many fields including heterogeneous catalysis, electrochemical devices, photovoltaics, corrosion protection and chemical sensing. As the simplest aromatic molecule, benzene has been widely studied on a variety of metal surfaces both computationally and experimentally.1-3 However, one metal surface which has received very little attention in this context is iron. Experimental UHV adsorption studies carried out on iron surfaces are complicated by the metal's reactivity and strong tendency to passivate, which result in significant difficulty obtaining a high purity metal surface. Still, iron is deserving of study as it is the major component of steel and catalyses important industrial reactions such as the Fischer-Tropsch and Haber processes. A computational study of the surface chemistry of benzene on iron will provide novel insight on this system as well as a level of detail which would not be afforded using experimental techniques. We have carried out a density functional theory (DFT) study of benzene adsorption on the three most stable surface facets of bcc iron, including flat {110}, kinked {100} and stepped {211} surfaces. All identified stable adsorption sites are presented and the most energetically favourable sites are compared across the three surfaces. To support the energetic and geometric results of our study, charge density differences, residual spin densities, density of states (DOS) and work function changes have also been calculated and analysed. Finally, we have studied the effect of van der Waals corrected DFT on binding site energetics and geometries using the Tkatchenko-Scheffler (TS) correction.4 Such corrections have been shown to provide results in better agreement with experiment for aromatic adsorption on certain metal surfaces.1 References [1] Carrasco, J., Liu, W., Michaelides, A., Tkatchenko, A. J. Chem. Phys. 2014, 140, 084704 [2] Jenkins, S. J. Proc. R. Soc. A 2009, 465, 2949-2976 [3] Netzer, F. P. Langmuir 1991, 7(11), 2544-2547 [4] Tkatchenko, A., Scheffler, M. Phys. Rev. Lett. 2009, 102(7), 073005

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P13-MOS_204 CONTROLLING KONDO EFFECT OF MAGNETIC MOLECULES ON AU(111) BY VERTICAL BINDING OF AMMONIA

MOS - Molecules at surfaces M. Chang 1,*, Y.H. Chang 2, H. Kim 1, S.H. Lee 1, Y.H. Kim 2, S.J. Kahng 1 1Korea University - Seoul (Korea, republic of), 2KAIST - Daejeon (Korea, republic of) Controlling and sensing spin states of magnetic molecules at the single molecule level is essential for spintronic molecular device applications. Here, we demonstrate that spin interactions of Co-porphyrin on Au(111) can be controlled by binding and unbinding of ammonia molecules, and be sensed using scanning tunneling microscopy and spectroscopy (STM and STS). Bare Co-porphyrin showed a clear zero-bias peak, a signature of Kondo effect in STS, whereas Co-porphyrin coordinated with ammonia molecules showed modified zero-bias peaks, with reduced full width half maximum or Kondo temperature. Our density functional theory calculation results explain it with spatial redistribution of unpaired spins in dz2 Orbitals. Our study opens up ways to tune molecular spin interactions by means of chemical coordination.

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P14-MOS_232 ETHYLENE ADSORPTION ON CU(210), REVISITED: BONDING NATURE AND COVERAGE EFFECTS

MOS - Molecules at surfaces W. Diño 1,*, S. Amino 1,*, E. Arguelles 1, M. Okada 2, H. Kasai 3 1Osaka University - Suita (Japan), 2Osaka University - Toyonaka (Japan), 3National Institute of Technology, Akashi College - Akashi (Japan) With the aid of density functional theory (DFT)-based calculations, we investigate ethylene (C2H4) adsorption on Cu(210). We found two C2H4 adsorption sites, viz., the top of the step- edge atom (S) and the long bridge between two step-edge atoms (SS) of Cu(210). The step- edge atoms on Cu(210) block the otherwise active terrace sites found on copper surfaces with wider terraces. This results in the preference for π-bonded over di-σ-bonded C2H4. Based on our vibrational frequency calculation results, we conclude that C2H4 still retains it 2 sp character upon adsorption on Cu(210). We also found two stable C2H4 adsorption orientations on the S- and SS-sites, viz., with the C2H4 C=C bond parallel (fit) and perpendicular (cross) to [001]. Furthermore, we found that the three peaks 145 K, 120 K, and 90.0 K observed in previous temperature programmed desorption (TPD) experiment [1] could be attributed to C2H4 in the S-fit, S-cross, and SS-fit configurations on Cu(210), respectively. Finally, at low coverage, C2H4 can equally exists in the S-fit and S-cross configurations. The adsorption symmetry of C2H4 at higher coverages increases the vibrational frequencies of S-cross oriented C2H4, while leaving the vibrational frequency of S-fit C2H4 virtually unchanged. These findings together with the differences of their binding energies enable us to conclude that these two ’species’ of C2H4 on Cu(210) have relatively different desorption temperatures and hence, the corresponding adsorption site assignments. More details will be presented at the conference. Thanks E.A. acknowledges financial support from the Mitsubishi UFJ Foundation and the Japan Society for the Promotion of Science. Some of the numerical calculations presented here are done using the computer facilities at the following institutes: CMC (Osaka University), KEK, NIFS and YITP. This work is supported in part by: MEXT Grant-in-Aid for Scientific Research on Innovative Areas Program (2203-22104008) and Scientific Research (A)(26248006) and (B)(15KT0062); and the Osaka University Joining and Welding Research Institute Cooperative Research Program. References [1] D. Yamazaki, M. Okada, F. C. Franco Jr., and T. Kasai, Surface Science 605 (2011) 934 – 940.

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P15-MOS_253 ELECTRICAL CONDUCTANCE AND STRUCTURE OF COPPER ATOMIC JUNCTIONS IN THE PRESENCE OF WATER MOLECULES

MOS - Molecules at surfaces Y. Li *, S. Kaneko, M. Kiguchi Department of Chemistry, Tokyo Institute of Technology - Tokyo (Japan) Single atom or molecule junctions have been extensively studied both experimentally and theoretically due to their fundamental interest and potential application in nanoelectronics [1,2]. In this study, the electrical conductance and structure of Cu atomic contacts in the presence of H2O were investigated both experimentally and theoretically [3]. The experiments were performed with mechanically controllable break junction (MCBJ) technique in an ultrahigh vacuum (UHV) at 10 K. The conductance measurements (figure 1 inset) showed the formation of H2O/Cu junctions with a fixed 2 conductance value of around 0.1 G0 (G0 = 2e /h). These structures were found to be stable and could be stretched over 0.5 nm, indicating the formation of an atomic or molecular chain. Highly stable H2O/Cu junctions could be formed in UHV at low temperature. In agreement with the experimental findings, theoretical calculations revealed that the conductance of H2O/Cu junctions decreases as the junction is stretched, with the formation of a H2O/Cu atomic chain with a conductance of ca. 0.1 G0 prior to junction rupture. References [1] G. Kirczenow, in Oxford Handbook of Nanoscience and Technology, ed. A. Narlikar and Y. Y. Fu, Oxford University Press, Oxford, 2010, vol. 1, basic aspects. [2] Y. Li, S. Kaneko, S. Fujii and M. Kiguchi, The Journal of Physical Chemistry C, 2015, 119, 19143-19148. [3] Y. Li, F. Demir, S. Kaneko, S. Fujii, T. Nishino, A. Saffarzadeh, G. Kirczenow and M. Kiguchi, Physical Chemistry Chemical Physics, 2015, 17, 32436-32442.

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P16-MOS_261 THERMOPOWER AND CURRENT-VOLTAGE CHARACTERISTICS OF 1,4- BENZENEDITHIOL-SINGLE MOLECULAR JUNCTIONS

MOS - Molecules at surfaces Y. Komoto *, S. Fujii, M. Kiguchi Tokyo Institute of Technology, Department of Chemistry - Tokyo (Japan) The understanding of charge transport property in single molecules is a fundamental issue in molecular electronics [1-3]. In most studies, electronic characterizations have been limited to DC conductance measurement at fixed bias voltage. Therefore, atomic and electronic structures of the molecular junctions is still not clear. Here, we report a combined measurement of thermopower and current-voltage (I-V) measurement of a single molecular junction of 1,4-benzenedithiol (BDT) sandwiched by Au electrodes to clarify atomic and electronic structures, and their relationship in the single molecular junction. We used a scanning tunnelling microscope (STM)-based break junction method to prepare the BDT junctions. Once the molecular junction was formed during the breaking process, the STM tip was fixed and the bias voltage was swept to measure the I-V curve. Thermopower was measured by a voltage-shift in a I-V curve under different temperature-gradient across the junction.Figure 1 shows histograms of the measured thermopower of the BDT junctions. Peak voltage shifts toward negative side as increasing the temperature-gradient. This result indicates HOMO-mediated charge transport in the BDT junctions.Figure2 shows a I-V histogram of the BDT molecular junction, in which three preferential conductance states are observed. From statistical analysis of the I-V characteristics based on the single channel model, electronic coupling strength and an energy level of a conduction orbital were obtained for the BDT junctions. By comparing the experimental results with the DFT calculation results, the observed three states are ascribed to adsorption geometries of BDT on bridge-bridge, hollow-hollow and atop-atop sites on the Au electrodes in order of the conductance. References [1]Y. Komoto et al. J. Phys. Chem. C , 2013, 117, 24277 [2]Y. Komoto et al., Beilstein J. Nanotechnol .2015, 6, 2431. [3]S. Kaneko, Y. Komoto, M. Kiguchi et al., J. Am. Chem. Soc. 2016, 138 ,1294

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P17-MOS_281 DIMERIZATION OF BENZOIC ACID ON TIO2 SURFACES - AN AB-INITIO STUDY

MOS - Molecules at surfaces G. Feldbauer *, W. Heckel *, T. Würger, S. Müller Hamburg University of Technology - Hamburg (Germany) Hierarchical structures including inorganic and organic constituents allow for excellent mechanical properties found in natural biological composites such as nacre. In order to design new materials mimicking the natural role models, at first, it is essential to understand the involved processes on each hierarchical level. Starting from the smallest relevant length scale this includes the interactions at the interface between inorganic and organic components at the atomistic level. Particularly, carboxylic acids and metal oxides have proven to be excellent choices for the organic and inorganic constituents, respectively [1]. At the hybrid organic--metal-oxide interface intermolecular forces may contribute to an improved mechanical stability. For instance, linker molecules possessing an aromatic side chain interact with each other via van-der-Waals interaction. In this regard, the adsorption of benzoic acids on TiO2 (110) rutile serves as a prototype system. A very regular 2 x 2 overlayer due to dimerization via the phenyl groups has recently been reported [2]. Here, we present a density functional theory analysis of the dimerization of benzoic acids on TiO2 surfaces. To properly describe the attractive interaction of adsorbing molecules among each other, we applied an exchange correlation functional with van-der-Waals correction. For all surface orientations, the preferred dimer formation mode (hydrogen - to - π - orbital or tilted and twisted π - to - π) as well as the amount of energy gain resulting from dimerization will be discussed. Thanks Supported by the DFG, SFB 986, project A4. References [1] Dreyer et al., Nature Mater. (2016) 10.1038/nmat4553. [2] Grinter et al., J. Phys. Chem. Lett. 5, 4265 (2014).

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P18-MOS_298 ON-SURFACE ENGINEERING OF A MAGNETIC ORGANOMETALLIC NANOWIRE

MOS - Molecules at surfaces N. Bachellier 1,*, M. Ormaza 1, R. Robles 2, P. Abufager 2, N. Lorente 3, L. Limot 1,* 1IPCMS, CNRS UMR 7504, Université de Strasbourg - Strasbourg (France), 2ICN2 - Institut Català de Nanociéncia i Nanotecnologia, Campus UAB - Barcelona (Spain), 3Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU) - Donostia-San Sebastian (Spain) The manipulation of the molecular spin state by atom doping is an attractive strategy to confer desirable magnetic properties to molecules. Here, we present the formation of novel magnetic metallocenes by following this approach. In particular, two different on-surface procedures to build isolated and layer integrated Co-ferrocene (CoFc) molecules on a metallic substrate via atomic manipulation and atom deposition are shown. The structure as well as the electronic properties of the so-formed molecule are investigated combining scanning tunneling microscopy and spectroscopy with density functional theory calculations. It is found that unlike single ferrocene a CoFc molecule possesses a magnetic moment as revealed by the Kondo effect. These results correspond to the first controlled procedure toward the development of tailored metallocene-based nanowires with a desired chemical composition, which are predicted to be promising materials for molecular spintronics [1]. References [1] Ormaza et al., Nano Lett. 16, 588 (2016)

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P19-MOS_339 NICKEL OCTA ETHYL PORPHYRIN ON AU(111): A SURFACE X RAY DIFFRACTION STUDY

MOS - Molecules at surfaces A. Resta 1,*, R. Felici 2, X. Torrelles 3, A. Calzolari 4, M. Pedio 5,* 1Synchrotron SOLEIL - Gif-Sur-Yvette (France), 2ESRF - Grenoble (France), 3ICMAB-CSIC - Barcelona (Spain), 4CNR-NANO - Modena (Italy), 5CNR-IOM TASC - Trieste (Italy) One of the main challenges of molecular electronics is the controlled growth of the molecular layers on the nanometer scale. In this context the porphyrin self assembled monolayers (SAMs) attract an intense research activity. These systems represent a challenge for surface science, due to the soft nature of the organic material, to the large number of atoms in the unit cell, and to the complex physical chemistry of the self-assembly process. This work presents a detailed study of the Nickel Octaethyl Porphyrin (NiOEP) SAMs deposited onto the Au(111) herringbone (HB) surface[1], combining Surface X Ray Diffraction (SXRD) and Low Energy Electron Diffraction (LEED). Two different ordered phases of NiOEP on Au(111) have been found: a 5x5 for low coverages with an increased HB periodicity and a 5x10 structure for coverages from 0.7 to 1ML. The (5x10) phase have been studied in details. The molecular assembly is driven by the molecule-molecule interaction. The unit cell includes two molecules per cell with the ethyl groups oriented upward, in good agreement with STM literature results [2,3]. Our analysis enlighten a compression of the intermolecular distances with the intra-molecular structure slightly deformed, with the Ni atoms shifted up approximately of 0.15Å with respect to the N ring plane. The molecular arrangement in the (5x10) structure is reflected on the orbitals energies[1] and interpreted by means of Density Functional theory.

Figures: Top and side views of the (5x10) NiOEP/Au(111) model based on SXRD analysis. References [1] A. Resta, R. Felici, M. Kumar, M. Pedio,J. Non-Cryst. Sol 356, 1951—1954 (2010). [3] L. Scudiero, D. E. Barlow, K. W. Hipps, J. Phys. Chem. B 106, 996-1003 (2002); L. G. Teugels, L. G. Avila-Bront, S. J. Sibener, J. Phys. Chem. C 115, 2826—2834 (2011). [3] M. Nakamura, R. Imai, N. Hoshi, O. Sakata, Surface Science 606, 1560–1564 (2012)

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P20-MOS_352 A FULL DFT-D STUDY OF DRUG ENCAPSULATION INSIDE NANOCAPSULES

MOS - Molecules at surfaces F. Picaud 1,*, J. Bentin 1,*, E. Duverger 2, T. Gharbi 1 1Nanomedicine Lab - Besancon (France), 2FEMTO Lab - Besancon (France) Among the strategies to deliver drugs toward cancer cells, functionalized nanoparticles are now investigated in nanomedicine1. Ideally, these nanocarriers must fulfill fundamental criteria to be efficient. They should be biocompatible, offer an efficient drug encapsulation or attachment. Then they should also transport this drug to the targeted region, and release the drug successfully. Carbon or Boron Nitride nanotubes have already shown promising effects despite their hydrophobic character, circumvented by functionalizing their surface to diminish their toxicityand avoid aggregation that could cause pulmonary toxicity and inflammation. Besides functionalized SWNT exhibits remarkable reduced in vivo toxicity into animal5. Practically, loading of small molecules such as anticancer drugs follows two main strategies: covalent and non-covalent bonding. Chemical attachment of therapeutic functional groups takes benefit of their reactivity and of their large surface area for multimodal drugs delivery. For instance, anti cancer drug such as paclitaxel, doxorubicin and platinum complexes7 demonstrated their efficiency for in vitro and in vivo treatments when transported with SWCNT. On the contrary non-covalent adsorption took advantage of the large inner space inside the nanocapsule. This latter one appears then as a carrier designed to deliver the drug in the tumor. At the light of these examples, it is thus crucial to correctly select and control the nanotemplate to achieve specific aims in biomedical applications. To demonstrate it and answer to these questions, we use full DFT-D calculations within the SIESTA code. We study first the adsorption energy of a platinum drug inside the classical C-SWNTs depending on the SWNT radius. We will see that the functionalization of the dangling bonds at the extremities of the SWNT rather modifies the energy since it allows (or blocks) the drug to be encapsulated in a stable energy well. Finally the loading of the complex system will be studied on a new class of nanostructures, the BN-SWNT with the same analyses. The non covalent bonding is clearly favored in this case due to the inert surface of the BN-SWNT. Such nanotube appears thus as an ideal nanocapsule that could vectorize the drug towards the cell since it protects it towards the external media. Thanks Computations have been performed on the supercomputer facilities of the Mésocentre de calcul de Franche-Comté. References 1 Jain, K. K. Applications of Nanobiotechnology in Clinical Diagnostics. Clinical Chemistry 53, 2002-2009, (2007). 5 Liu, Z. et al. Cancer Research 68, 6652-6660, doi:10.1158/0008-5472.can-08-1468 (2008). 7 Ali-Boucetta, H. et al. Chemical Communications, 459-461 (2008).

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P21-MOS_393 CHANGE OF ELECTRONIC STATE INDUCED BY STRUCTURAL TRANSITION OF DNTT AND PICENE MONOLAYERS

MOS - Molecules at surfaces Y. Hasegawa 1,*, Y. Yamada 1,*, T. Hosokai 2, Y. Wakayama 3, M. Sasaki 1 1University of Tsukuba (Japan), 2National Institute of Advanced Industrial Science and Technology (Japan), 3National Institute for Materials Science (Japan) Small organic compounds with strong intermolecular interaction, such as rubrene, picene and DNTT, have been attracting attention as promising material for high performance organic field effect transistor(OFET) because an enhanced overlapping of molecular orbitals and, therefore, improved carrier mobility has been expected. Indeed, they have shown excellent carrier mobility as large as that of the amorphous silicon. The clear band dispersion has also been confirmed in single crystal of them, in addition to the Hall effect. The electronic state of these materials can considered to be modified easily when the overlapping of their frontier orbitals is altered. Indeed, the electronic properties of these molecules are significantly altered when the external pressure is applied. In order to design and realize the desired electronic property of these materials, structural control of thin film is also required as in the case of inorganic systems. However, the control of the thin film structure of organic semiconductor in molecular scale is still immature because the formation of the highly ordered thin films is difficult. Indeed, it is only very recently that the well-defined layer-by-layer growth of pentacene film has been realized. In this study, therefore, we focus on DNTT and Picene which show relatively simple structure and determined the molecular arrangement of the monolayers in molecular scale by means of scanning tunneling microscopy(STM). We found that both monolayers undergo similar structural transition from loosely packing phase with flat-lying molecule to densely packing phase with single-crystalline like molecular arrangement. Upon the structural transition, the highest occupied molecular orbital(HOMO) level of these molecules split into two features as suggested from both the UPS measurement and calculations. Since this characteristic electronic feature has not been recognized so far, it is considered that the HOMO structure of the film of these materials is sensitive to the molecular arrangement.

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P22-MOS_406 ON THE PHASE BEHAVIOR OF ADSORPTION MONOLAYERS OF BINARY GAS MIXTURES: MODELING

MOS - Molecules at surfaces V.F. Fefelov 1,*, A.V. Myshlyavtsev 2, P.V. Stishenko 1, V.M. Kutanov 1 1Omsk state technical university - Omsk (Russian federation), 2Omsk state technical university & Institute of hydrocarbon processing SB RAS - Omsk (Russian federation) The adsorption of gas mixtures on solid surfaces is of considerable interest both from the point of view of practical applications: gas separation, purification, heterogeneous catalysis, etc., and from the point of view of purely academic science on surface phenomena. The main parameters in the construction of theoretical adsorption models are the interaction energy of the adsorbate-adsorbate and adsorbate-substrate. Their nature and strength will determine the phase behavior of monolayer adsorption. With the increasing performance of computers and their availability a large number works appear which devoted to quantum- mechanical calculations of the interaction energies adsorbate-adsorbate and adsorbate- substrate-specific systems. Unfortunately, usually these results do not allow receiving the information of the thermodynamics of a whole adsorption monolayer due to many factors: a huge number of particles, the dependence of the interaction energies on the coverage, the reconstruction surface, chemical reactions, heterogeneity surface, etc. For this reason, to obtain some general regularities of the thermodynamic behavior of adsorption systems simplified models are constructed and investigated [1-3]. Despite the large number of simple models of binary gas adsorption, in most of them the chemical potential of one component assumed to be constant, it simplifies the calculations and allow identifying particular regularities. At the same time, in most real adsorption systems the change of the total pressure in the gas phase lead to changes in the partial pressures of all components of the gas mixture, the chemical potentials of all components will vary for this reason, and this can lead to different phase behavior of the adsorption of a monolayer. The aim of this work – to open slightly the richness of phase behavior of adsorption monolayers of binary gas mixtures. Thanks This study was supported by the Ministry of Education and Science of the Russian Federation on a budget-funded basis for 2014–2016 (Project No. 16.2413.2014/R). References 1. F. Bulnes, A.J. Ramirez-Pastor, V.D. Pereyra, J. Mol. Catal. Chem. 2001 167, 129. 2. D.A. Matoz-Fernandez, M.V. Dávila, P.M. Pasinetti, A.J. Ramirez-Pastor, Phys. Chem. Chem. Phys. 2014 16, 24063. 3. V.F. Fefelov, P. V. Stishenko, V. M. Kutanov, A. V. Myshlyavtsev, M.D. Myshlyavtseva, Adsorption 2016 22, 4, 673-680.

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P23-MOS_158 A STRUCTURAL STUDY OF THE IONIC LIQUID 1-ETHYL-3-METHYLIMIDAZOLIUM BIS[(TRIFLUOROMETHY)SULFONYL] IMIDE ON AU(110) USING NIXSW

MOS - Molecules at surfaces R. Jones 1,*, M. Buckley 1, K. Syres 1, T.L. Lee 2, P.K. Thakur 2 1School of Chemistry, University of Nottingham, Nottingham NG7 2RD (United Kingdom), 2Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom) Ionic liquids (ILs) bonding to solid surfaces are relevant to their use as two dimensional structured liquids for carrying catalysts, the bonding of ionic adsorbates, and their use as lubricants. IL bonding to metal surfaces is primarily due to ionic interaction with the surface which is modified by cooperative van der Waals interactions between particular groups and the surface. Here we use normal incidence X-ray standing wave analysis to determine the + adsorption geometry of the 1-ethyl-3-methyl imidazolium cation, [C2C1Im] , and the - bis[(trifluoromethyl)sulfonyl]imide anion, [Tf2N] of the ionic liquid [C2C1Im][Tf2N] on Au (110). The work was carried out on beamline I09 at the Diamond Light Source, UK. A monolayer of [C2C1Im][Tf2N] on Au(110) was used and the measurements carried out using the {111} {200} and {220} Bragg reflections, using the Ccat1s and Ncat1s photoelectron peaks from the cation, and the CAn1s, NAn1s, O 1s, F 1s and S 1s photoelectron peaks from the - [Tf2N] anion. To determine the adsorption geometry, a minimisation procedure was used to determine the best fit between the set of experimentally determined coherent positions and coherent fractions, and the calculated values from a grid of all possible orientations, lateral positions and distances from the surface. This gave two possible solutions for the cation adsorption geometry (one is shown below left for the reconstructed surface), and five possible solutions for the anion adsorption geometry (one is shown below right).

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P24-MOS_242 TUNABLE ENERGY-LEVEL ALIGNMENT IN DONOR-ACCEPTOR BILAYERS ON METALS

MOS - Molecules at surfaces P. Borghetti 1,*, D.G. De Oteyza 2, E. Goiri 3, C. Rogero 4, A. Verdini 5, A. Cossaro 5, L. Floreano 5, J.E. Ortega 6 1Institut des Nanosciences de Paris - Paris (France), 2Ikerbasque, Basque Foundation for Science - Bilbao (Spain), 3Donostia International Physics Center (DIPC) - San Sebastian (Spain), 4Centro de Física de Materiales (CSIC-UPV/EHU) - San Sebastian (Spain), 5CNR-IOM, Laboratorio TASC - Trieste (Italy), 6Departamento de Física Aplicada I, Universidad del Pais Vasco - San Sebastian (Spain) The use of multi-component organic layers in optoelectronics devices represents an efficient strategy for the rational design of supramolecular structures and interfacial electronics [1]. Recently, we have shown that two-dimensional "donor:acceptor" monolayers on noble metal surfaces offer the possibility to tailor the energy level-alignment [2] as well as the charge transfer [3] at molecule/metal interface. However, understanding how the first monolayer properties are affected by growing additional layers on top is pivotal for the development of organic heterojunction devices. The present work explore the interfacial properties of donor/acceptor bilayer systems in which the contact monolayer blend is capped by a single-component layer [4]. The analysis focuses on sharp heteromolecular interfaces made of pentacene (PEN) and perfluorinated copper phthalocyanine (F16CuPc) blends, on one side, and of perfluoropentacene (PFP) and copper phthalocyanine (CuPc) blends, on the other sides. The cases of PEN/PEN:F16CuPc, F16CuPc /PEN:F16CuPc and CuPc/PFP:CuPc on Ag(111) and Au(111) are investigated by core-level and valence band photoemission which reveal that, upon capping, the electronic states of both contact and capping layers “realign” with respect to the monolayer and the multilayer references. The sign of the shift depends clearly on whether the capping layer is donor-like (PEN, CuPc) or acceptor-like (F16CuPc). As proved by NEXAFS, the shift in electronic levels of the contact layer upon capping has important consequences, since it may trigger charge transfers across the molecule/metal interface. References [1] Goiri, E.; Borghetti, P. et al. Multi-Component Organic Layers on Metal Substrates. Adv. Mater. 2016, 28, 1340-1368. [2] El-Sayed, A.; Borghetti, et al. Understanding Energy-Level Alignment in Donor-Acceptor/Metal Interfaces from Core-Level Shifts. ACS Nano 2013, 7, 6914-6920. [3] Borghetti, P.; El-Sayed, et al. Spectroscopic Fingerprints of Work-Function-Controlled Phthalocyanine Charging on Metal Surfaces. ACS Nano 2014, 12, 12786-12795. [4] Borghetti, P.; de Oteyza, D. G. et al. Molecular-Level Realignment in Donor-Acceptor Bilayer Blends on Metals. J. Phys. Chem. C, 2016, 120, 5997–6005.

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P26-MOS_458 THE DIFFUSION OF COT ON CU(111) OBSERVED IN THE ANGSTROM- PICOSECOND WINDOW

MOS - Molecules at surfaces N. Avidor 1,*, I. Calvo-Almazan 1, J.A. Lau 1, P.S.M. Townsend 1, D.J. Ward 1, W. Allison 1,*, J. Ellis 1, B.J. Hinch 2 1Cavendish Laboratory, University of Cambridge, JJ Thomson Ave, Cambridge, CB3 0HE, United Kingdom - Cambridge (United Kingdom), 2Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, USA - Piscataway (United States of America) Recent developments in scattering experiments have allowed motion on a molecular scale to be explored in the pico- to nano- second timescales, using 3He Spin Echo spectroscopy[1,2]. We have applied the method to study the mobility of 1,3,5,7- cyclooctatetraene (COT,C8H8) on Cu(111). We have measured the dynamics both at low coverage (isolated molecules) and at a medium coverage of 0.3ML, at temperatures of 200K-450K. The diffusive translational motion of COT proceeds by jump diffusion over a Bravais lattice of preferred adsorption sites, with a short residence time of 2 [ps] and a low energy barrier of ~30[meV]. In addition, we see evidence for fast diffusion which we relate to rotational motion, and intermolecular interactions between adsorbates. A weakly dispersive vibrational mode at ~1[meV] is seen over a narrow window of parallel momentum transfer. References [1] G. Alexandrowicz et. al. Progress in Surface Science, 84(11), 2009. [2] AP Jardine et. al. Journal of Physics: Condensed Matter, 19(30), 2007.

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P27-MOS_459 IN VITRO ANTIOXIDANT ACTIVITY OF ROOT FRACTIONS OF ARISTOLOCHIA BAETICA

MOS - Molecules at surfaces F.Z. Majidi * University mohamed first - Oujda (Morocco) Plants and their active agents especially polyphenols may have a principal role in the treatment of diseases that result from the defect of physiological antioxidant mechanisms The root of Aristolochia baetica is well known in Moroccan traditional medicine for alleviating pain and treating various diseases. Until now, no direct in vitro study of this natural product examined the antioxidant effect of the extract from the roots of this plant. The aim of this study was to determine in vitro antioxidant activity of the Aristolochia baetica root, using antioxidant analysis methods based on methanol as a solvent system in soxhlet extraction method. Antioxidant potential of Aristolochia baetica extract was assessed using in vitro system such as DPPH. Ascorbic acid (antioxidant) was used as a standard. The results indicate that, the roots of Aristolochia baetica contain potent natural scavengers Radical. The root extract of this plant showed excellent antioxidant properties. It may represent an interesting source of antioxidant phenolics that may favour the extension of their cultivation as new source of natural antioxidants. References Bellakhdar, J., Claisse, R., Fleurentin, J., Younos, C., 1991. Repertory of standard herbal drugs in the Moroccan pharmacopoea.Journal of Ethnopharmacology 35, pages 123–143. Boubaker K, Ounissi M, Brahmi N, Goucha R, Hedri H, Abdellah TB, et al. 2013. Acute renal failure by ingestion of Euphorbia paralias. Saudi J Kidney Dis Transpl;24:571_5. Chau W, Ross R, Li JY, Yong TY, Klebe S, Barbara JA. 2011. Nephropathy associated with use of a Chinese herbal product containing aristolochic acid. Med J Aust ; 194:367_8.

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P28-MOS_310 MOLECULAR ORIENTATION IN THIN FILMS OF SPONTANEOUSLY POLARISED MOLECULAR SOLIDS

MOS - Molecules at surfaces A. Cassidy 1,*, M. Jørgensen 1, A. Rosu-Finsen 2, J. Lasne 3, J. Jørgensen 1, A. Glavic 4, V. Lauter 5, B. Iversen 1, M. Mccoustra 2, D. Field 1 1Aarhus University - Aarhus (Denmark), 2Heriot-Watt University - Edinburgh (United Kingdom), 3Laboratoire Interuniversitaire des Systèmes Atmosphériques - Paris (France), 4Paul Scherrer Institut - Villigen (Switzerland), 5Oak Ridge National Lab - Oak Ridge (United States of America) It has recently been proposed that nanoscale molecular films can spontaneously assemble to generate internal electric fields that can exceed 108 V/m. These electric fields originate from polarisation charges in the material which arise because the films self-assemble to align molecular dipole moments. This has been called the spontelectric effect and has been observed for molecular species as diverse as nitrous oxide, methyl formate and several freons. Spontaneous dipole alignment arises largely due to interactions between the dipolar molecules and the electric field which the films self-generate. The growth of such an electrical phase of molecular solids has implications for our understanding of how intermolecular interactions dicate the structure of molecular materials used in a range of applications, for example, molecular semiconductors, sensors, and catalysis. Here we present the first in situ structural characterisation of a representative spontelectic solid, namely nitrous oxide. Films were grown under ultra-high vacuum conditions by background vapour condensation. Reflection adsorption infrared spectroscopy, temperature programmed desorption and neutron reflectivity measurements have been combined for a detailed, in vacuum investigation of the structural properties of thin films. The results demonstrate that polarised films of nitrous oxide undergo a structural phase transformation upon heating above 48 K whilst the magnitude of polarisation remains relatively unchanged. A theory based on a mean field model, which assumes that polarisation results from dipole alignment within the films, has been constructed and can be used to recreate the observed electric fields spontaneously generated in the thin films. This model also predicts the phase change observed above 48 K and this raises important questions about the types of interactions which bind species together in molecular films. References 1. D. Field, O. Plekan, A. Cassidy, R. Balog, N. C. Jones, and J. Dunger, Int. Rev. Phys. Chem., 2013, 32, 345–392. 2. O. Plekan, A. Cassidy, R. Balog, N. C. Jones, and D. Field, Phys. Chem. Chem. Phys., 2011, 13, 21035– 44. 3. O. Plekan, A. Cassidy, R. Balog, N. C. Jones, and D. Field, Phys. Chem. Chem. Phys., 2012, 14, 9972– 6. 4. A. Cassidy, O. Plekan, R. Balog, N. C. Jones, and D. Field, Phys. Chem. Chem. Phys., 2012, 15, 108– 113. 5. J. Lasne, A. Rosu-Finsen, A. Cassidy, M. R. S. McCoustra, D. Field, Phys. Chem. Chem. Phys. 2015, 17, 20971

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NAM - Novel advancement of experimental and computational methods

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O1-NAM _7 FORCE-DETECTED NUCLEAR MAGNETIC RESONANCE FOR NANOSCALE IMAGING

NAM - Novel advancement of experimental and computational methods S. Won 1,*, S.B. Saun 2, Y. Rhyim 1 1Korea Institute of Materials Science - Changwon (Korea, republic of), 2Korea Advanced Institute of Science and Technology - Daejeon (Korea, republic of) In biological system, detailed information is fundamental to understanding the mechanisms of the vast array of interactions occurring between macromolecules. It may not be an accident that X-ray CT and magnetic resonance imaging (MRI) are the two most frequently used fundamental diagnosis tools in hospitals in that regard. But, conventional MRI using pick-up coils cannot resolve objects smaller than several microns. MRFM group at the IBM Almaden Research Center demonstrated MRI to the nanoscale level by using magnetic resonance force microscopy (MRFM). MRFM has been proposed as a new technique that could improve the sensitivity and spatial resolution of magnetic resonance to the single spin level. To detect a force by magnetic resonance, MRFM uses a micro-fabricated cantilever as a mechanical oscillator and the oscillation of the cantilever is detected using a high- sensitive fiber-optic interferometer based on the optical interference. However, MRFM has not become a commercialized technology up to now. All MRFMs currently including our MRFM are home-made systems manufactured in a unique way. In this study, we present a MRFM technique which can contribute to the biotechnology with nanoscale imaging. Thanks This work was supported by the Ministry of Science, ICT and Future Planning under Grant No. PNK4810 by the Principal Project of KIMS, and by DTaQ Grant No. PND0590. References 1. S. Won et al., Sci. Rep. 3, 3189 (2013). 2. S-B. Saun, S. Won, S. Kwon, S. Lee, J. Magn. Reson. 254, 71 (2015). 3. H. J. Mamin et al., Nano Lett. 9, 3020 (2009).

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O2-NAM _25 IMAGE DECONVOLUTION OF K-SPACE PATTERNS MEASURED IN NANOESCA MICROSCOPE

NAM - Novel advancement of experimental and computational methods Y. Polyak * Institute of Physics ASCR - Prague (Czech republic) Image deconvolution was performed on Cu(111) k-space images measured with He I radiation (hν=21.2 eV) in order to sharpen k-patterns degraded by blurring and noise. Main challenges of image deconvolution are to find out true point spread function (PSF) and to obtain correct image reconstruction. PSF that describes instrumental response to point object was obtained by measuring k-space image at bottom of momentum space parabola corresponding to near-zero kinetic energy of photoelectrons. Main advantage of this approach is that PSF is universal for all samples since measured specimen itself is active element of imaging system of NanoESCA photoelectron microscope. Tikhonov regularization technique was used for k-space image restoration applying Laplacian regularization matrix and reflexive boundary conditions. Unfortunately automatically computed regularization parameter using generalized cross-validation (GCV) algorithm produced unrealistic reconstructions containing many ringing artifacts. Value of optimal regularization parameter was chosen manually which required careful inspection of deconvoluted k-space patterns [1]. Image deconvolution of Cu(111) k-space patterns was carried out using ImageJ public domain software and applying parallel spectral deconvolution routine [2]. References [1] Y. Polyak et.al., Phys. Rev. B 91, 165115(1) (2015). [2] T.J. Collins, BioTechniques 43, 25 (2007).

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O3-NAM _191 CLEAVED PROBES FOR SCANNING PROBE MICROSCOPY

NAM - Novel advancement of experimental and computational methods O. Kurnosikov *, T. Siahaan, H. Swagten, B. Koopmans Eindhoven University of Technology - Eindhoven (Netherlands) An alternative type of probes for scanning tunneling microscopy (STM) and atomic force microscopy (AFM) is proposed. Instead of using a common needle-like STM tip made from a metallic wire, we use a sharp edge of a cleaved insulating substrate which is initially covered by a thin layer of conducting material (see the figures below). The sharp tip is formed at the intersection of the two cleaved sides. The planar substrates used for the tip fabrication allow us to use various materials including the alloys and multi-layer structures. This provides a very flexible way to functionalize the STM tips, for example by implementing the magnetic, superconducting or other layers with specific properties. The same approach can be realized for AFM probes with a tuning fork as a force sensor. We demonstrated our approach by fabricating the cleaved probes from metallic (Pt, Co, and CoB), optically- transparent indium-tin oxide, as well as Cu/Pt and Co/Pt multilayer films [1] and testing them in an STM by scanning the clean Cu(001) and Cu(111) surfaces as well as the epitaxial Co clusters on Cu(111). The atomic resolution is achieved together with the reproducible imaging on the nano- and mesoscopic scales. Our approach is also applicable to the STM/AFM probes with two- or several electrical terminals. The electric current across the micro- or nanostructure near the tip end can vary the tip-sample interaction and can be used either for a switchable sensing or a sample manipulation on the nanoscale. As an example, we present a prototype of magnetically switchable or adaptive probes fabricated by combining a lithography with the cleaving procedure. References 1. T. Siahaan et al. Nanotechnology, 27, 03LT01 (2016)

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O4-NAM_474 NON-DESTRUCTIVE IMAGING OF NANOSTRUCTURES BY ANALYSIS OF THE PHOTOELECTRON PEAK SHAPE

NAM - Novel advancement of experimental and computational methods O. Renault 1, C. Zborowski 1, P. Risterucci 1, C.M. Schneider 2, C. Wiemann 2, G. Grenet 3, S. Tougaard 4,* 1Univ. Grenoble Alpes & CEA, LETI, MINATEC Campus - Grenoble (France), 2Peter Grünberg Institute (PGI-6) & JARA-FIT, Research Center - Jülich (Germany), 3Institut des Nanotechnologies de Lyon, Ecole Centrale - Ecully (France), 4Despartment of Physics, Chemistry and Pharmacy, University of Southern Denmark - Odense M (Denmark) Technological applications of nano-structured materials are steadily increasing and to create materials with optimized properties, it is of utmost importance to have non-destructive techniques to characterize elemental depth distributions at the 푛푚 scale. A widely used technique [1,2] consists in analysis of the energy distribution of inelastically scattered photoelectrons which depend strongly on the depth distribution dependent transport of the photoelectrons to the surface. A QUASES- software package [2] is available to easily perform this analysis. Nano-structures can be studied up to depths of ~ 8 inelastic mean free paths [1] which with conventional XPS is ~ 10 – 15 nm. With HAXPES, synchrotron generated photons with energy ~ 10 keV are used and the potential depths probed thus increases to ~ 100 nm. In this respect we have recently demonstrated [3] that nm thin structures buried at depths > 50 nm can be studied with this method. We have further demonstrated that annealing induced diffusion of such deeply buried layers can be followed non-destructively. With the smaller lateral size of industrial devices there is also a need for non-destructive 3D- imaging of nano-structured samples. For this, automated data analysis is mandatory due to the huge number of spectra. An algorithm well suited for that was developed ~10 years ago [1]. With conventional XPS we have previously demonstrated [1] that 3D-imaging with sub- nm depth resolution is possible with a lateral resolution of ~ 10휇푚. With synchrotron radiation it should be possible to eventually obtain 3D images with ~ 100 푛푚 lateral and 1 푛푚 depth resolution. Such work has been initiated [3]. In the talk we will discuss advancements in the use of this technique for 1D and 3D imaging of nano-structures. References [1] S. Tougaard, J. Electr. Spectr. and Rel. Phen. 178 (2010) 128 [2] See www.quases.com [3] O. Renault et al Appl Phys Lett 109 (2016) 011602

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O5-NAM _392 MOLECULAR INTERFEROMETRY – A NEW EXPERIMENTAL APPROACH FOR STUDYING GAS-SURFACE INTERACTIONS.

NAM - Novel advancement of experimental and computational methods O. Godsi *, G. Corem, Y. Alkoby, G. Alexandrowicz Schulich Faculty of Chemistry, Technion - Israel Institute of Technology (Israel) The interaction of gas phase molecules with surfaces lies at the heart of a huge range of research fields and applications, however, our understanding of these processes is still quite limited. Further developments in our understanding rely on the availability of high quality measurements of state to state molecular scattering[i]. The molecular interference technique is a new approach, based on the interference of the quantum states of a molecule within a magnetic molecular-beam apparatus. In order to individually follow the dynamics of all the quantum states of a gas phase molecule as it scatters from a solid surface, we measure the coherent oscillations between the quantum states before and after the scattering event. The experiment is performed using a modified helium spin echo apparatus[ii] and makes use of strong magnetic field gradients in order to select and detect specific quantum states[iii].

The figure bellow shows a preliminary measurement of H2 molecules scattered from a copper surface (left panel), both fast and slow frequencies can be clearly seen, frequencies which can be attributed to the interference between the different magnetic and rotational angular-momentum states. For comparison, we also show the oscillations for the case of helium-3 in a typical Helium Spin Echo experiment (right panel), where there is only one frequency corresponding to the Zeeman splitting of the nuclear spins. As a first test case we used H2 to demonstrate this approach; however the technique can be extended to various molecules, such as methane, water, ammonia and other molecules with sufficiently strong magnetic moments. References [i] Rev. Phys. Chem. 66, 399 (2015) [ii] Prog. Surf. Sci., 84, 323 (2009) [iii] Science, 331, 319 (2011)

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O6-NAM _269 DEPOSITION OF DISCRETE ORGANIC MOLECULES VIA E-BEAM EVAPORATION

NAM - Novel advancement of experimental and computational methods T. Kuehn 1,*, D. Pohlenz 1, S. Molitor 2, I. Swart 3 1FOCUS GmbH - Huenstetten (Germany), 2Scienta Omicron - Taunusstein (Germany), 3Debye Institute for Nanomaterial Science, Utrecht University - Utrecht (Netherlands) E-beam evaporators are long since known for ultra-pure sub-monolayer to monolayer thin film growth of metals in ultra high vacuum (UHV). The possibility to evaporate in-situ into a STM/AFM system, in addition, allows to view and control every step of the deposition process. The extension of e-beam evaporation to high vapor-pressure materials, in particular organic molecules, is a recent application that was successfully performed with a temperature controlled FOCUS EFM3. The macrocyclic organic compounds Copper-Phthalocyanines (CuPc) as well as 1,5,9-trioxo-13-aza triangulene (TOAT) were evaporated in-situ into a Scienta Omicron LT STM. Both organics have been deposited onto a sample cooled to 5 K for 30 seconds, CuPc onto NaCl/Cu(100) with EFM evaporation (crucible) temperature stabilized at about 215°C and TOAT onto Cu(111) at about 185°C. Both deposition processes have been investigated live in STM mode, with the final results shown in Fig. 1. Both the compounds obviously stayed un-cracked during evaporation as can be deduced from their symmetrical shape. Slight deviations between molecules that are positioned along different main axes of the (100) and (111) surface, respectively, are a result of the asymmetric STM tip. No agglomeration is visible, ultra-clean and discrete deposition of the molecules was achieved.

Figure 1: STM images of CuPc (left) and TOAT (right) at 5 K. Imaging parameters: 1 V, 5 pA.

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O7-NAM _329 TRANSMISSION SURFACE DIFFRACTION: A NEW TOOL FOR IN-SITU AND OPERANDO SURFACE SCIENCE

NAM - Novel advancement of experimental and computational methods J. Drnec 1,*, F. Reikowski 2,*, T. Wiegmann 2, J. Stettner 2, V. Honkimäki 1, F. Maroun 3, O.M. Magnussen 2 1ESRF - Grenoble (France), 2Institute of Experimental and Applied Physics, Kiel University - Kiel (Germany), 3Physique de la Matière Condensée, Ecole Polytechnique, CNRS - Palaiseau (France) A new surface diffraction method for in situ studies of buried interfaces which employs synchrotron X-ray radiation of high photon energy is presented. In contrast to the standard geometry with grazing incidence angles [1], in this technique a transmission geometry where the X-ray beam passes through the sample is used (fig. 1a). Transmission surface diffraction (TSD) is a powerful and user-friendly method that enables fast simultaneous imaging of the full in-plane structure of solid surfaces. Furthermore, it allows surface X-ray diffraction studies with micrometer spatial resolution, opening up the way to map the atomic interface structure of spatially inhomogeneous systems or to study the surface properties of small samples. The feasibility of this approach is demonstrated by TSD measurements of Co and Bi electrodeposition on Au(111) electrodes [2], performed at beamline ID 31 of the ESRF (fig. 1b). The formation of the crystal truncation rods (CTRs), changes in the Au CTRs due to epitaxial strain, and the disappearance of the rods corresponding to the (22 x √3) phase of the Au surface reconstruction can be directly observed without lengthy searches in reciprocal space. In addition, in situ microscale mapping of the deposit and substrate properties and studies during Co dissolution are discussed. References [1] J. Gustafson, M. Shipilin, C. Zhang, A. Stierle, U. Hejral, U. Ruett, O. Gutowski, P.-A. Carlsson, M. Skoglundh, E. Lundgren, Science 343, 758 (2014) [2] F. Reikowski, F. Maroun, N. Di, P. Allongue, M. Ruge, J. Stettner, O. M. Magnussen, Electrochimica Acta 197, 273 (2016)

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O8-NAM _8 ENVIROESCA - FULLY AUTOMATED XPS ANALYSIS UNDER ENVIRONMENTAL CONDITIONS

NAM - Novel advancement of experimental and computational methods A. Thissen, B. Muenzing, S. Bahr *, T. Kampen, O. Schaff, T. Stempel * SPECS Surface Nano Analysis GmbH - Berlin (Germany) Since many decades XPS (or ESCA) is the well-accepted standard method for non- destructive chemical analysis of solid surfaces. To fulfill this task existing ESCA tools combine reliable quantitative chemical analysis with comfortable sample handling concepts, integrated into fully automated compact designs. Over the last years it has been possible to develop XPS systems, that can work far beyond the standard conditions of high or ultrahigh vacuum. Near Ambient Pressure (NAP) XPS has become a fastly growing field in research inspiring many scientist to transfer the method to completely new fields of application. Thus, by crossing the pressure gap, new insights in complicated materials systems have become possible using either synchrotron radiation or laboratory X-ray monochromators as excitation sources under NAP condtions. Based on this experience SPECS Surface Nano Analysis GmbH has developed a revolutionary tool to realize the long existing dream in many analytical laboratories: reproducible chemical surface analysis under any environmental condition. EnviroESCA allows for different applications, like extremely fast solid surface analysis of degassing (but also non-degassing) samples, ESCA analysis of liquids or liquid-solid interfaces, chemical analysis of biological samples, materials and device analysis under working conditions (in situ/in operando studies of catalysts, electrochemical devices etc.). Discover the new capabilities of EnviroESCA, a fully automated tool in a new sophisticated and compact design with uncompromising ease-of- use, and explore completely new fields of applications for the established analysis method XPS.

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O9-NAM _31 RECENT ADVANCES IN LOW ENERGY ION SCATTERING FOR EXTREME SURFACE SENSITIVE ANALYSIS

NAM - Novel advancement of experimental and computational methods T. Grehl *, P. Brüner, H. Brongersma ION-TOF GmbH - Münster (Germany) Low Energy Ion Scattering (LEIS) is considered the most surface sensitive techniques for the quantitative elemental characterization of the outer atomic layer of a solid. Its unique properties make it ideally suited for the characterization of materials for which the outer surface determines their performance: Heterogeneous catalysts, solid ionic conductors for fuel cells, nanoparticles and many more. But also in the early stages of film growth, the adsorption and nucleation can be monitored in order to optimize the deposition conditions. All these applications require separating the elemental information of the outer atomic layer from that of the bulk. In LEIS, a noble gas ion beam is scattered from the surface and the energy loss in each scattering event is used to calculate the mass of the scattering partner. Due to charge exchange processes, scattering from deeper layer does not contribute to the peaks in the LEIS spectra, as the noble gas ion is neutralized efficiently when penetrating the surface. However, there is still some information from these scattering events below the surface retained in the spectrum, which can be used to extract information about the first 5- 10 nm of the sample. For the practical analysis, the use of a dedicated high sensitivity analyser is essential to prevent ion beam modification of the surface during the experiment and at the same time allow for sufficient mass resolution. In this presentation we will demonstrate the recent improvements in the instrumentation but even more so in the interpretation of LEIS data. The analysis of core-shell nanoparticles and graphene will be shown. Especially the in-depth information contained in the LEIS data has been understood and modelled to a larger extent recently. Examples for this modelling of thin films for semiconductor applications will be given.

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O10-NAM _35 TRANSPORT OF FAST ELECTRONS IN DIAMOND

NAM - Novel advancement of experimental and computational methods M. Azzolini 1,*, T. Morresi 1, S. Taioli 1, G. Garberoglio 1, L. Calliari 1, N. Pugno 2, M. Dapor 1,* 1European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT) - Trento (Italy), 2Department of Civil, Environmental and Mechanical Engineering, University of Trento - Trento (Italy) Diamond has often been described as the ultimate insulator material to enhance the performance of electronic devices, due to unrivalled thermal conductivity, wide band-gap, and very high charge carrier mobility. Diamond-based electronics can represent an alternative to silicon, as its outstanding physical properties enable devices to be smaller, cooler, faster, more powerful, and cleaner. In this work, we present the calculation of observables of paramount importance for electronic transport in diamond crystals, such as inelastic mean free path, stopping power, reflection electron energy loss spectra, and secondary electron energy spectra. In particular, we assess the accuracy of three methods at different levels of computational complexity for calculating the electron energy loss function of electron beams impinging upon diamond targets: (i) as a sum of Drude-Lorentz functions [1,2], (ii) as a sum of Mermin functions [3- 5], and (iii) by first principles calculations. Finally, we will compare our theoretical results with the available experimental data. Thanks NP is supported by the European Research Council (ERC StG Ideas 2011 BIHSNAM n. 279985, ERC PoC 2013 KNOTOUGH n. 632277, ERC PoC 2015 SILKENE n. 693670) and by the European Commission under the Graphene Flagship n. 604391 (WP Nanocomposites). MD, GG, ST acknowledge support by the European Commission under the Graphene Flagship n. 604391 (WP Energy and WP Nanocomposites). References [1] R.H. Ritchie, A. Howie, Philos. Mag. 36 (1977) 463. [2] M. Dapor, G. Garberoglio, L. Calliari, Nuclear Instruments and Methods in Physics Research B 352 (2015) 181 [3] I. Abril, R. Garcia-Molina, C.D. Denton, J.F. Perez-Perez, N.R. Arista, Phys. Rev. A 58 (1998) 357 [4] P. de Vera, I. Abril, R. Garcia-Molina, J. Appl. Phys. 109 (2011) 094901 [5] M. Dapor, Appl. Surf. Sci. (2015) http://dx.doi.org/10.1016/j.apsusc.2015.12.043

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O11-NAM _167 THIN FILM ANALYSIS USING VARIABLE PERIOD X-RAY STANDING WAVES

NAM - Novel advancement of experimental and computational methods R. Jones 1,*, J. Gibson 1, K. Syres 1, M. Buckley 1, T.L. Lee 2, P.K. Thakur 2 1School of Chemistry, University of Nottingham, Nottingham NG7 2RD (United Kingdom), 2Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom) The techniques available for determining the composition of thin films 1-50 nm thick, as a function of depth, are currently rather limited. We present here variable period X-ray standing wave analysis, VPXSW, using soft X-rays (3 keV) and photoelectron detection, which can provide chemical species identification and depth location with an accuracy of 1 nm over a thin film depth range of ≲ 30 nm. Atoms embedded within an X-ray standing wave field will absorb X-rays depending on where they are positioned within the field. By sweeping the standing wave through the atomic positions, the variation in absorption can be used to determine the location of the atoms. The VPXSW is set up by reflection from an optically flat surface with X-ray absorption monitored by photoelectron emission, which also allows chemical speciation using the photoelectron chemical shift. Using oxygen and chlorine 1s photoemission (shown below as binding energy vs X-ray angle of incidence α) we have determined the thickness (1.2 nm) and position (22.6 nm) of a marker layer composed of chloroform and water on top of an organic layer composed of ionic liquid (1- octyl-3-methylimidazolium tetrafluoroborate) at 90 K on a silicon surface. This was consistent with the thickness of the ionic liquid (22.6 nm) obtained using the B, C, N and F 1s photoelectron peaks. This work establishes the principles by which it is possible to non-destructively map the density of multiple chemical species through the entire depth of thin films of thicknesses 2 - 30 nm.

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O12-NAM _342 INELASTIC BACKGROUND ANALYSIS IN HAXPES: APPLICATION TO DEEPLY BURIED TA/AL INTERFACES IN ADVANCED POWER DEVICES

NAM - Novel advancement of experimental and computational methods C. Zborowski 1,*, O. Renault 1, E. Martinez 1, A. Torres 1, Y. Yamashita 2, G. Grenet 3, S. Tougaard 4 1Univ. Grenoble Alpes, F-38000 Grenoble France & CEA, LETI, MINATEC Campus, F-38054 - Grenoble (France), 2National Institute for Materials Science (NIMS), 1-1 Namiki, Ibaraki, 305-0044 - Tsukuba (Japan), 3Institut des Nanotechnologies de Lyon, Ecole Centrale, 69134 - Ecully (France), 4Dpt of Physics, Chemistry and Pharmacy, Univ of Southern Denmark - Odense (Denmark) Recently, the advent of Hard X-ray Photoelectron Spectroscopy (HAXPES) has enabled to study deeply buried interfaces [1]. It was shown that by combining HAXPES with inelastic background analysis [2], structures at a depth >50 nm can be studied. Here, we present a study on technologically relevant High Electron Mobility power Transistors TaAl. The study was performed on stacks of GaN-based HEMTs. These samples present two metal layers of aluminum and tantalum with different thicknesses deposited on Al0.25Ga0.75N/AlN/GaN heterostructure [Fig. 1a]. We have used the technique to nondestructively study the activation annealing. HAXPES was performed at the Spring-8 synchrotron (Japan) using 8 keV photons. The figure shows spectra measured around Al, Ga and Ta peaks for an as deposited sample [Fig. 1b]. The calculation of inelastic background was performed using two input parameters; the IMFP, calculated using the TPP-2M formula [3] and as the spectra present marked plasmons, after the elastic peaks, we used an average of individual inelastic cross-sections, which can be determined from reflection electron energy- loss spectra. The figure shows how the modelling of the inelastic background is used to determine the in-depth distributions which are found in good agreement with the TEM results. We have also successfully used this technique to study the effect of annealing on the diffusion of the elements at the interfaces. Thanks Part of this work was performed at the Nanocharacterization Platform of CEA-MINATEC. NIMS and Spring-8 is acknowledged for providing beamtime and the staff of the BL15-XU beamline for their assistance during the experiment. Cyril Guedj is acknowledged for providing TEM analysis and expertise. References [1] P. Risterucci et al., Applied Physics Letters 104, (2014). [2] S. Tougaard, Journal of Electron Spectroscopy and Related Phenomena, 178–179 (2010). [3] H. Shinotsuka et al., Surface and Interface Analysis 47, 871-888 (2015).

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O13-NAM_64 WAVE FUNCTION AND PHASE RETRIEVAL OF RHEED FROM GROWING SURFACES

NAM - Novel advancement of experimental and computational methods T. Kawamura * Institute of Industrial Science, University of Tokyo - Meguro-Ku, Tokyo (Japan) Application of phase retrieval algorithm is studied for recovering surface morphology from RHEED intensities during homo-epitaxial growth on Si(001) based on the wave function analysis [1]. In RHEED, the available range of k-points along the beam direction is limited to approximately 10% of the necessary range because of the grazing incidence and the morphology contrasts are produced mostly by the absorption effect. To increase the range of k-points, the larger glancing angle is preferable, while to enhance the absorption effect, the smaller glancing angle is preferable. An optimum glancing angle for the incident energy of 15 keV is estimated to be around 3.87˚ satisfying 008 Bragg condition. RHEED intensities are calculated using surface morphologies obtained by a kinetic Monte Carlo simulation at this condition. In spite of the limitation of the data points, surface morphologies at 0.32ML, 0.45ML, 0.58ML and 0.71ML are successfully retrieved from the intensities as shown in Fig.1, where the brighter contrast corresponds to the higher layer. Fig. 2 shows the corresponding simulated morphologies (64x945 atomic sites/layer). Although the retrieved contrasts are blurred, the characteristic features of islands are well reproduced. The retrieved contrasts are more sensitive to adatom islands than vacancy islands, which is consistent with the wave function analysis. It is noted that this phase retrieval approach is very useful for in-situ observation of surface morphology. Thanks The authour would like to thank Prof. K. Fukutani for useful discussions. References T. Kawamura and P.A. Maksym, Surf. Sci. 630 (2014) 125.

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P1-NAM_53 DEVELOPMENT OF A LOW-ENERGY ELECTRON GUN USING THE PHOTOELECTRIC EFFECT

NAM - Novel advancement of experimental and computational methods H. Sawa *, M. Anzai, T. Konishi, T. Tachibana, T. Hirayama Department of Physics, Rikkyo University - Tokyo (Japan) We have developed a low-energy electron gun using the photoelectric effect for the study of electronic excitation processes in the surfaces of solids without an energy selector [1]. The photocathode is a cylindrical single-crystal LaB6(100) assembly of 1 mm in diameter. The light source is a laser diode with a photon energy of 2.62 eV and a maximum optical output power of 120 mW. The experimental setup is shown in Figure 1. All components, except the light source, are contained in a vacuum chamber evacuated to 1x10-8 Pa. The photoelectron beam current of 40 nA was achieved at a cathode temperature of 300 K. Although the current decreases by half in about 100 hours, it can be fully recovered by the cathode heating at 1800 K for several minutes. By the calculation based on the Fermi distribution function [1], the energy width of the photoelectron and the work function of the LaB6(100) photocathode were estimated to be 0.11 eV and 2.51 eV, respectively. Using the electron gun, we observed the electron-stimulated desorption (ESD) from a solid Ne surface. Figure 2 shows the desorption yields of metastable Ne atoms with respect to the incident electron energy between 17.5 eV and 23.0 eV. Three distinct peaks were observed at 18.3 eV, 19.0 eV and 20.0 eV with FWHMs of about 0.4 eV. We suggest that these peaks is due to the desorption via Feshbach resonance state [2].

Figure 1. A schematic view of an experimental setup.

Figure 2. Electron stimulated desorption yield of metastable Ne atoms from the surface of solid Ne with respect to the incident electron energy (black points). The thickness of the solid Ne is 100 monolayers.

References [1] H. Sawa, T. Konishi, T. Tachibana and T. Hirayama, submitted. [2] M. Anzai, T. Tachibana, and T. Hirayama, to be submitted.

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P3-NAM_166 CALCULATION OF THE SCATTERING PROBABILITY AND ENERGY SPECTRA IN LEIS

NAM - Novel advancement of experimental and computational methods A. Mansour 1,*, A. Mekhtiche 2, M. Benrekia 3, K. Khalal-Kouache 4 1Université des Sciences et de la Technologie Houari Boumediene (USTHB), Faculté de Physique, Bab-Ezzouar, 16111 Algiers, Algeria - Algiers (Algeria), 2Faculté des Sciences et de la Technologie, Université Yahia Farès Médéa - Médéa (Algeria), 3Faculté des Sciences, Université de Blida 1 - Blida (Algeria), 4Université des Sciences et de la Technologie Houari Boumediene (USTHB), Faculté de Physique, Bab-Ezzouar, 16111 Algiers, Algeria - Blida (Algeria) Low Energy Ion Scattering (LEIS) is widely used for quantitative composition and structure analysis of solid surfaces [1]. A solid surface is bombarded with ions (He+) at low energy (0.5 to 10keV). A TOF-LEIS set-up is used to detect the scattered particles in a given direction. The obtained TOF spectra are then converted to energy spectra. These experimental data are very important to study the scattering potential and the energy loss of the projectile in the target. Different methods can be used to calculate energy spectra (molecular dynamics and Monte Carlo codes). Due to the large calculation times required by these simulations, an alternative was proposed [2]. This model is based on the solution of the Boltzmann equation and is valid for small scattering angles. The binary collision approximation is assumed with a random homogenous distribution of scattering centers. The ZBL (Ziegler-Biersack-Littmark) potential [3] is used to describe the projectile-target atom interaction. The probability for a projectile to be scattered at an angle α and in the solid angle with a total path length in the solid comprised between and (figure 1) is calculated. Energy spectra can be deduced from the calculated scattering probabilities [2]. In this contribution, results of the scattering of H+ and He+ ions from solid surfaces (Cu, Au) are presented. The scattering probabilities are calculated especially for low L values (which correspond to higher probabilities). Energy loss of the projectiles in the solid is taken into account. Different values of the incident and the scattering angles are considered. The obtained energy spectra are compared to those calculated with TRIM (TRansport of Ions in Matter) code [3]. References [1] H. Brongersma, M. Draxler, M. Deridder, and P. Bauer, Surf. Sci. Rep. 62 (2007) 63. [2] K. Khalal-Kouache, A.C. Chami, M. Boudjema, P. Benoit-Cattin, C. Benazeth, Y. Boudouma, Nucl. Instrum. Methods Phys. Res. B 183, 279 (2001). [3] J.F.Ziegler, J.P.Biersack, U.Littmark, The Stopping and Ranges of Ions in Solids (Pergamon Press, New York, 1985).

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P4-NAM_251 EUSPEC - MODERN TOOLS FOR SPECTROSCOPY ON ADVANCED MATERIALS: A EUROPEAN MODELING PLATFORM

NAM - Novel advancement of experimental and computational methods L. Nicolaï 1,*, H. Herper 2, D. Sébilleau 3, H. Ebert 4 1Ludwig-Maximilians-Universität, Munich, Germany/Université de Cergy-Pontoise,France/DSM- IRAMIS, Spec, Cea-Saclay, France - Munich (Germany), 2Uppsala Universitet - Uppsala (Sweden), 3CNRS National Centre Scientific Research - Rennes (France), 4Ludwig-Maximilians-Universität - Muncih (Germany) The EU-funded COST action EUSpec aims for bringing together the expertise of experts working in the science of advanced materials in order to build a coherent theory and computing platform with a new common data format to model spectroscopic experiments performed at radiation sources as well as academic and industrial research laboratories. The theoretical investigation of materials is of central importance for the progress in technology and science. Currently the focus is on materials with reduced dimensions. This includes also nano-structures or molecule based systems offering a new tunable capabilities. For a use in technical application a deep understanding of the materials on the atomic scale is essential. Non-destructive spectroscopies are a fundamental tool of analysis at the nanoscopic level, allowing to probe matter and its constituents with an atomic resolution, and to monitor their time evolution down to the femtosecond range, transforming them into unique methods to trace chemical reactions. To interpret the experimental data gained in continuously increasing resolution in space, energy, momentum, spin and time, complementary theoretical support is indispensable. This is the starting point of the EU- funded COST action EUSpec. The goal is to strengthen the communication between theoreticians and experimentalists, as new types of experiments are important benchmarks for the status of theory and often require or trigger new formal theoretical and corresponding code developments. Additionally experimentalists are not always aware of the available tools and program packages provided to them by the colleagues from theory to analyze and interpret the experimental findings. EUSpec will lead to a large- scale network in order to give a strong impetus to the spectroscopy research and to give Europe a decisive lead. It will establish a platform that goes far beyond the applicability of the actual individual computational codes in order to address the relevant questions and problems for many more materials and spectroscopies.

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P5-NAM_395 DEVELOPMENT OF A HIGH INTENSITY ELECTROSPRAY SOURCE FOR UHV DEPOSITION OF LARGE FUNCTIONAL MOLECULES FOR IN-SITU STM STUDIES

NAM - Novel advancement of experimental and computational methods L. Perdigao *, D. Warr, J. Blohm, H. Pinfold, M. Barrow, C. Alex, C. Giovanni University of Warwick - Coventry (United Kingdom) Electrospray ionisation beam deposition (ESI-BD) is quickly becoming a versatile methodology for surface deposition of large thermally labile molecules for their in-situ investigation by means of high-resolution analytical techniques [1]. ESI-BD has recently been used to demonstrate intact deposition and study of a wide range of molecules from fragile molecular magnets [2] to porphyrin nanorings [3]. In this work we present a new design for a high efficiency, high transmission ESI-BD system which will offer the ability to study complex systems with the ultimate spatial resolution of scanning tunnelling microscopy (STM). Molecules will be delivered from solution in atmospheric conditions to a sample surface located in ultra-high vacuum (UHV). This will be achieved by electrospray ionisation, followed by several ion optic elements that guide and mass-select ions through successive differential pumping chambers with high transmission. Extensive ion trajectory simulations calculations (performed using the SIMION software package) coupled to differential pumping calculations have been used to devise innovative design elements for optimising the efficiency of the instrument in soft-landing large molecular ions onto the sample surface. A new design of an ion funnel will be discussed, which is simple to manufacture, and whereby the electrodes plates have variable distance between them, with demonstrated high efficiency in guiding ions through a small aperture (conductance limit). The design of a new hexapole ion guide will also be presented that propagates through three differentially pumped chambers for lossless ion transmission. Mass selection is achieved using a commercial quadrupole mass spectrometer. Results on the progress in development of the instrument will be presented, including a demonstration of its mass selection capabilities. References [1] Rauschenbach, S. et al. Electrospray Ion Beam Deposition of Clusters and Biomolecules. Small 2, 540– 547 (2006). [2] Kahle, S. et al. The Quantum Magnetism of Individual Manganese-12-Acetate Molecular Magnets Anchored at Surfaces. Nano Lett. 12, 518-521 (2012). [3] Kondratuk, D. V. et al. Vernier-Templated Synthesis, Crystal Structure, and Supramolecular Chemistry of a 12-Porphyrin Nanoring. Chem. – Eur. J. 20, 12826–12834 (2014).

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P6-NAM_220 ADVANCED MATERIALS DESIGNED BY COMPUTATIONAL SIMULATION

NAM - Novel advancement of experimental and computational methods S. Namuangruk *, C. Rungnim Nanoscale simulation laboratory (SIM), NANOTEC, National Science and Technology Development Agency, Klong Luang, Pathum Thani 12120, Thailand - Pathumthani (Thailand) Understanding insight to the molecular level of chemical processes in nanomaterials is a key of development of nanomaterials for specific purpose. Generally, the development of nanomaterials is essential in novel technologies to address challenges related to the production, storage and efficient use of energy, as well as environmental applications. However, the design, development and commercialization of a new material can take several years. To accelerate functional material development, molecular simulation is a powerful tool that can help explore the nanomaterial at a significantly faster rate and lower cost than it can typically be done experimentally. This helps experimentalist focus only on the most promising materials. Here, deep understanding of the adsorption and reaction mechanism of toxic compounds at nanoscale are shown by molecular modelling and simulations. Through computational design and calculation, promising materials were suggested, such as catalysts for NOx decomposition as well as adsorbents for elemental mercury (Hg0) removal, before they are synthesized by experimentalist.

Figure. Understanding synergetic effect of TiO2- supported silver nanoparticle as a sorbent for Hg0 removal Thanks The authors wish to thank the National Nanotechnology Center (NANOTEC) through “the Flagship Clean Air Program” and Thailand Research Fund for financial support. Chiang Mai University, Chiang Mai is also acknowledged. References 1. Rungnim, C; Hannongbua, S; Promarak, V; Kungwan, N; Namuangruk, S. J. Hazardrous Mater. (2016) doi:10.1016/j.jhazmat.2016.02.033. 2. Rungnim, C.; Meeprasert, J.; Kunaseth, M.; Junkaew, A.; Khamdahsag, P.; Khemthong, P.; Pimpha, N.; Namuangruk, S. Chem. Eng. J, 274 (2015) 132-142. 3. Maitarad, P; Meeprasert, J.; Han, J.; Shi, L.; Limtrakul, J.; Zhang, D.; Namuangruk, S. Catal. Sci. Technol. 2016, DOI: 10.1039/C5CY02116B 4. Meeprasert, J.; Junkaew, A.; Rungnim, Meeprasert, J.; C.; Kunaseth, M.; Namuangruk, S. Appl. Surf. Sci., 364 (2016) 166–175.

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P7-NAM_422 MONTE CARLO SIMULATION OF ELECTRON TRANSPORT IN DIAMOND AND GRAPHITE

NAM - Novel advancement of experimental and computational methods T. Morresi 1,*, M. Azzolini 1,*, S. Taioli 1, G. Garberoglio 1, L. Calliari 1, N. Pugno 2, M. Dapor 1 1European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT* - FBK) - Trento (Italy), 2Laboratory of Bio-Inspired & Graphene Nanomechanics Department of Civil, Environmental and Mechanical Engineering, University of Trento - School of Engineering and Materials Science, Materials research Institute, Queen Mary University of London - Trento (Italy) The use of carbon-based materials represents the frontier in the development of novel electronic devices with unsurpassed characteristics. In particular, diamond and graphite are relatively stable allotropes of carbon that have found applications in manufacturing electronic circuits. Nevertheless, they display different electronic and optical properties originating from distinct hybridization characters. Diamond shows a typical insulating behavior, and its electrical resistance, optical transmissivity and chemical inertness are correspondingly remarkable. Graphite is a zero-gap semiconductor, can conduct electricity as well as absorbs light. Furthermore, the layered structure of graphite with loosely bound stacked planes allows electrons to move easily within the planes and, thus, can be adopted as natural platform for investigating the performance of devices built with graphene and graphene-like two-dimensional materials, allowing to shrink electronic devices. Thus, to characterize the electronic properties of graphite and diamond for their work like electronic devices such as diode, transistor, and MOSFET, this study is aimed at the computational investigation of the charge transport properties from ab-initio and Monte Carlo simulations. In particular, this work is focused on the computation of backscattered electron spectra as well as of the secondary electron emission from these two carbon materials. The Monte Carlo approach is used to simulate the stochastic nature of electronic collisions within the solids, assuming that primary electron elastic scattering can be described within the framework of the Mott theory, based on the Relativistc Partial Wave Expansion Method, while inelastic interactions can be accounted for via the energy loss function. The latter relies on the calculation of the energy-dependent dielectric function at finite electron momentum. Three different approaches have been used for calculating the dielectric function, notably: (i) Drude-Lorentz [1], (ii) Mermin [2,3] and (iii) TDDFT [4]. Finally, the results are compared with the available experimental data. Thanks NP is supported by the European Research Council (ERC StG Ideas 2011 BIHSNAM n. 279985, ERC PoC 2013 KNOTOUGH n. 632277, ERC PoC 2015 SILKENE n. 693670) and by the European Commission under the Graphene Flagship n. 604391 (WP Nanocomposites). MD, GG, ST acknowledge support by the European Commission under the Graphene Flagship n. 604391 (WP Energy and WP Nanocomposites). References [1] M. Dapor, G. Garberoglio, L. Calliari, Nuclear Instruments and Methods in Physics Research B 352 (2015) 181 [2] I. Abril, R. Garcia-Molina, C.D. Denton, J.F. Perez-Perez, N.R. Arista, Phys. Rev. A 58 (1998) 357 [3] M. Dapor, Appl. Surf. Sci. (2015) http://dx.doi.org/10.1016/j.apsusc.2015.12.043 [4] http://elk.sourceforge.net/

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P8-NAM_424 HAXPES-LAB: THE FIRST LABORATORY BASED HARD X-RAY PHOTOELECTRON SPECTROSCOPY SYSTEM USING A 9.25 KEV X-RAY SOURCE

NAM - Novel advancement of experimental and computational methods M. Patt *, S. Eriksson Scienta Omicron AB - Uppsala (Sweden) Hard x-ray photoelectron spectroscopy (HAXPES) has been a topic of growing interest during the last decade. The inelastic mean free path (IMFP) of photoelectrons for photon 0.78 energies above 1000 eV increases with the kinetic electron energy roughly as Ekin [1]. This allows a significantly higher information depth of photoelectron spectroscopy in the hard X-ray regime compared, e.g., to rather surface-sensitive laboratory-based XPS systems using Al Kalpha excitation (hv = 1468.6 eV). HAXPES therefore provides the possibility to access the chemical information from the bulk of a material, which was utilized in several recent experiments, including the measurement of buried interfaces (e.g. solar cells, resistive switches, etc.), “real” samples (without surface preparation) and in operando devices [2]. We have developed a unique lab system utilizing a monochromatized Ga-metal jet technique which provides a photon energy of hv = 9.25 keV. Thus it becomes possible to bring the bulk sensitive HAXPES technique from the synchrotron into the laboratory. The IMFP of photoelectrons excited in our system is by a factor of 4 higher than for systems equipped with Al Kalpha sources and allows probing depths above 100 Å. Over 90% of the detected photoemission signal originates from the bulk region of the material. Figure 1 shows a first proof of principal measurement in which an overview spectrum of a gold sample was recorded in the kinetic electron range between 1 and 9.25 keV, illustrating the capacity of our system. References [1] C.S. Fadley, J. Electron Spectrosc. Relat. Phenom. 178 – 179 (2010) 2-32 [2] C. Weiland et al., J. Vac. Sci. Technol. A34(3) (2016) 030801

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P9-NAM_473 INVESTIGATION OF SURFACE STRUCTURES AND DYNAMICS AT THE ID03 BEAMLINE OF THE ESRF

NAM - Novel advancement of experimental and computational methods R. Znaiguia *, M. Jankowski, T. Dufrane, H. Isern, R. Felici, F. Carlà ESRF - Grenoble (France) Surface X-ray Diffraction is an extremely versatile technique for the characterization of surfaces and interfaces. The capability of X-rays to penetrate into the matter allows investigating surface structures in a variety of environments and conditions. Even if several other techniques allow a structural determination of surfaces, Surface X-ray diffraction offers unique possibilities and its applications span from UHV to solid-liquid interfaces. The use of X-ray sources with an extremely high brilliance allows performing real time experiments giving the possibility of studying growth processes and reaction at surfaces. This can be applied to investigate systems of general interest in fields such as catalysis or electrochemistry. Aim of this contribution is to show the advancement in this field carried out at the ID03 surface diffraction beamline of the ESRF. We’ll present our electrochemical setups that can be used for the characterization of electrocatalytic materials, electrodeposition and for battery-related studies, the ID03 catalytic reactor for in-situ experiments and the UHV diffractometer.

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OXI - Oxide surfaces, interfaces and thin oxide films

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O1-OXI_256 PERSISTENT PHOTOCONDUCTIVITY IN M-PLANE ZNO AS A FUNCTION OF OXYGEN VACANCY CONCENTRATION PROBED BY LASER-PUMP SYNCHROTRON RADIATION-PROBE X-RAY PHOTOELECTRON SPECTROSCOPY

OXI - Oxide surfaces, interfaces and thin oxide films A.I. Williamson 1,*, B.F. Spencer 1, M.A. Leontiadou 1, P.C.J. Clark 1, R. Ahumada Lazo 1, M.G. Silly 2, F. Sirotti 2, A.S. Walton 3, A.G. Thomas 4, C.A. Muryn 3, W.R. Flavell 1 1School of Physics and Astronomy and the Photon Science Institute, The University of Manchester - Manchester (United Kingdom), 2Synchrotron SOLEIL - Saint-Aubin (France), 3School of Chemistry and the Photon Science Institute, The University of Manchester - Manchester (United Kingdom), 4School of Materials and the Photon Science Institute, The University of Manchester - Manchester (United Kingdom) ZnO is a transparent conducting oxide (TCO) with varied potential optoelectronic applications including next generation solar cells [1] but a more complete understanding of how oxygen vacancies and other oxygen-related defects affect the overall conductivity of the material is required to fully optimise these systems [2]. Here, we employ laser-pump, synchrotron radiation-probe x-ray photoelectron spectroscopy (XPS) to probe the charge dynamics within a few nm of the surface in a chemically resolved way [3]. Determining these dynamics requires measurement of a surface photovoltage (SPV) in the ZnO crystal, which is known to vary depending on the conductivity of the crystal [4]. Photoexcited carrier lifetimes of the order of 20 are measured, limited by the persistent photoconductivity (PPC) of the ZnO surface. This is shown to vary as the number of oxygen vacancies are dynamically reduced in the crystal by conducting the experiment in an oxygen atmosphere, with the lifetime increasing by approximately 50%. An increase in the carrier lifetime is consistent with the model for PPC determined by metastable gap states whereby the PPC is controlled by the oxygen vacancy concentration [5]. We have conducted complementary measurements using near-ambient pressure (NAP) XPS on ZnO in a range of overpressures of oxygen gas up to 10 mbar to monitor the effects of surface adsorption on O 1s and Zn 3d core level spectra. Here we observe an increase in size of the high binding energy shoulder of the O 1s peak shape that arises from the presence of surface adsorbates introduced by the high overpressures of oxygen gas. References [1] A. J. Labelle et al, Colloidal Quantum Dot Solar Cells Exploiting Hierarchical Structuring, Nano Lett. 2015, 150109104244006. [2] VP. D. C. King et al, Conductivity in transparent oxide semiconductors, J. Phys. Condens. Matter. 2011, 23, 34214 [3] B. F. Spencer et al, Time-resolved surface photovoltage measurements at n-type photovoltaic surfaces: Si(111) and ZnO(1010), Phys. Rev. B, 2013, 88, 195301_1-16 [4] A Janotti et al, Fundamentals of zinc oxide as a semiconductor, Rep. Prog. Phys. 2009, 72, 126501 [5] H. L. Mosbacker et al, Role of near-surface states in ohmic-Schottky conversion of Au contacts to ZnO, Appl. Phys. Lett., 2005, 87, 012102

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O2-OXI_186 VICINAL ZNO(10-14): SURFACE STRUCTURE AND STABILITY

OXI - Oxide surfaces, interfaces and thin oxide films E. Grånäs 1,*, H. Noei 1, A. Schaefer 2, J. Gustafson 2, A. Stierle 1 1Deutsches Elektronen Synchrotron (DESY) - Hamburg (Germany), 2Lund University - Lund (Sweden) Zinc oxide (ZnO) based catalysts are commonly used in important chemical reactions as methanol synthesis (CO + 2H2 ⇔ CH3OH), low temperature water-gas shift (CO + H2O ⇔ CO2 +H2), and methanol steam reforming (CH3OH + H2O ⇔ CO2 + 3H2O) [1]. Determination of the stable ZnO surface structure and studies of how it interacts with the gases is essential for understanding these catalytic processes. The commonly studied (0001) and (000-1) orientations of ZnO are both polar, resulting in instability of these surfaces. Stabilization of the ZnO(0001) surface has recently been suggested to occur through faceting into large areas of the charge neutral, high step-density, vicinal (10-14) surface [2]. The interaction between steps on vicinal surfaces plays a crucial role for the equilibrium structure, and very little is still known about the equilibrium structure of vicinal oxide surfaces. Hitherto there are no studies confirming the stability of the ZnO(10- 14) surface. Here we will present studies of the ZnO(10-14) surface using techniques such as low-energy electron diffraction, x-ray photoelectron spectroscopy, and scanning probe microscopy. Further, the interaction of such a vicinal surface with the gases involved in the catalytic reactions is of uttermost importance. The presence of steps may influence the interaction between the surface and the gas, as has been shown theoretically for H2O on ZnO [3]. In addition, experimental studies have shown that H2 [4] and H2O [5] exposures can cause restructuring of the surface. As a first step towards understanding the catalytic role of vicinal ZnO we will discuss initial results on the gas exposed ZnO(10-14) surface. References [1] C. Wöll, Progress in Surface Science 82, 55-120 (2007) [2] H. Zheng, M. Gruyters, E. Pehlke, R. Berndt. Phys. Rev. Lett. 111, 086101 (2013) [3] D. Raymand, A. C.T. van Duin, D. Spångberg et al. Surf. Sci. 604, 741-752 (2010) [4] E. D. Batyrev, J. C. van den Heuvel. Phys. Chem. Chem. Phys. 13, 13127-13134 (2011) [5] A. Önsten, D. Stoltz, P. Palmgren et al. J. Phys. Chem. C. 114, 11157-11161 (2010)

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I04_OXI_447 MODELLING THE SURFACES OF OXIDE MATERIALS

OXI - Oxide surfaces, interfaces and thin oxide films R. Catlow 1,*, R. Catlow 2 1Dept of Chemistry, University College London (United Kingdom), 2School of Chemistry, Cardiff University (United Kingdom) The surfaces of oxide materials pose major challenges and even materials with the simplest of ionic crystal structures may show highly complex surface structural features. In this lecture, we present recent results based on the application of a variety of computational modelling techniques to predict the first the structures of the surfaces of a range of widely studied oxide materials, including zinc oxide(1), stabilised zirconia and potassium tantalate. Our modelling studies reveal complex structures in which surface reconstruction and surface defects play a major role.

We then investigate the mechanisms of surface reactions involving C-H bond and CO2 activation(2) (3) . Our results again highlight the importance of surface defects in these key reactions. References (1) D Mora Fonz, CRA Catlow et al., J.Phys Chem C, 119, 11598, (2015) (2) C Cooper, R Oldman, CRA Catlow, Chem Comm, 51, 5856 (2015) (3) C Downing, A Sokol, CRA Catlow, Phys Chem Chem Phys, 39, 21153, (2014)

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O3-OXI_179 FE-AND CR-DOPED MGO/MO(001) FILMS: MORPHOLOGY, ELECTRONIC STRUCTURE AND DOPANT-INDUCED DIFFUSION PROCESSES

OXI - Oxide surfaces, interfaces and thin oxide films S. Benedetti 1,*, N. Nilius 2, S. Valeri 3, S. Tosoni 4, E. Albanese 4, G. Pacchioni 4 1CNR, Istituto Nanoscienze - Modena (Italy), 2Carl von Ossietzky Universität Oldenburg, Institut für Physik - Oldenburg (Germany), 3CNR, Istituto Nanoscienze and Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Universita` di Modena e Reggio Emilia - Modena (Italy), 4Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca - Milano (Italy) Doping has shown to be a versatile means to tune the properties of oxide materials for electronic, optical and chemical applications.[1] Dopants modify bonds in the host lattice and can introduce new states in the band gap, giving rise to new optical transitions and modifying the conductance behavior of the material. When dopant atoms are characterized by a different charge state with respect to the host, they can result in a charge transfer in the material or towards surface adsorbates.[2] For this reason the insertion of aliovalent dopant atoms can be used to tune the physical properties of the host oxide and enhance the reactivity of the material. Despite these benefits, the practical use of doped oxides is often limited due to strong neutralization effects of the dopants.[3] For this reason the investigation of doped oxides with high resolution and atomic control is fundamental. Charge compensation can occur in an uncontrolled way due to native defects and impurity ions or can be realized deliberately by adding co-dopants with opposite polarity, and the comprehension of these mechanisms at an atomic level is the basis to tailor the material functionality. In this study we present the evolution of the MgO properties as a function of concentration of different dopant species (Cr, Fe), when grown as a thin film on Mo(001). Our investigation clarifies by means of XPS, XPD and STM the modification of the electronic, structural and morphological properties occurring in the system.[4] In particular we demonstrate that a spontaneous diffusion of Mo ions into the MgO film occurs as a consequence of doping. We show that the effect strictly depends on the dopant species, that determines the conditions for the diffusion across MgO/Mo interface. On the basis of DFT calculations, we explain the charge-driven chemical intermixing and how the oxide reaches charge equilibrium following different pathways in the two cases. Our observations are of general importance for the comprehension of doped oxide properties, as they unravel a yet unknown charge- compensation mechanism occurring at metal-oxide interfaces. Thanks Support from the COST Action CM1104 and FIRB project RBAP115AYN is gratefully acknowledged. References [1] E. W. McFarland et al., Chem. Rev. 113, 4391 (2013) [2] F. Stavale, J. Am. Chem. Soc. 134, 11380 (2012) [3] J. Robertson et al., Phys. Rev. B 83, 075205 (2011) [4] S. Benedetti et al., J. Phys. Chem. C 119, 25469 (2015)

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O4-OXI_346 INVESTIGATIONS OF COBALT OXIDE NANOISLANDS ON AU(111), PT(111) AND AG(111) AND THEIR ACTIVE SITES FOR WATER DISSOCIATION

OXI - Oxide surfaces, interfaces and thin oxide films J. Fester 1,*, A.S. Walton 2, J.V. Lauritsen 1 1Interdisciplinary Nanoscience Center, Aarhus University - Aarhus (Denmark), 2School of Chemistry, University of Manchester - Manchester (United Kingdom) Cobalt oxides have recently attracted considerable attention due to their promising properties as earth-abundant heterogeneous catalysts for the oxygen evolution reaction (OER) in electrochemical water splitting [1], replacing scarce and expensive noble metals such as Pt and Ir. However, the fundamental working principles of cobalt oxide catalysts are not well understood. An efficient approach to study nanostructured metal oxide catalysts has previously been demonstrated on noble metal substrates, highlighting the importance of catalytically active sites at the metal/oxide interface (e.g. for the water gas shift reaction (WGS) [2] and catalytic oxidation of CO [3]). Aiming to study the detailed nanostructure and chemical properties of cobalt oxides, we use Scanning Tunneling Microscopy (STM) to compare the growth of CoOx nanoislands on three different (111) surfaces of the noble metals Au, Pt and Ag.

All three surfaces promote the growth of crystalline CoOx (x=1-2) islands under oxidative conditions, but with several interesting differences in island shape and stability originating from the choice of substrate. In particular, we analyze the edge structure of Co-O bilayers [4] and observe a remarkable effect on the relative abundances of edge types, promoting Co terminated edges on islands supported on Pt(111) as opposed to a prevailing oxygen termination on Au(111). This influence on the edge structure is, in line, highly relevant to the particles chemical properties since the active sites for water dissociation are located at the metal/oxide interface. References 1. Liao, L., et al., Efficient solar water-splitting using a nanocrystalline CoO photocatalyst. Nature nanotechnology, 2014. 9(1): p. 69-73.

2. Rodriguez, J., et al., Activity of CeOx and TiOx nanoparticles grown on Au (111) in the water-gas shift reaction. Science, 2007. 318(5857): p. 1757-1760. 3. Fu, Q., et al., Interface-confined ferrous centers for catalytic oxidation. science, 2010. 328(5982): p. 1141-1144. 4. Walton, A.S., et al., Interface Controlled Oxidation States in Layered Cobalt Oxide Nanoislands on Gold. ACS nano, 2015. 9(3): p. 2445-2453.

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O5-OXI_30 ACTIVATION ENERGIES FOR SODIUM AND POTASSIUM ION INCORPORATION INTO TEMPERATURE TREATED CVD-SIOX LAYERS

OXI - Oxide surfaces, interfaces and thin oxide films S. Gruber 1,*, S. Krivec 1, G. Pobegen 2, S. Schwab 2, H. Hutter 3 1Infineon Technologies Austria AG - Villach (Austria), 2KAI Kompetenzzentrum Automobil- u. Industrieelektronik GmbH - Villach (Austria), 3Vienna University of Technology - Vienna (Austria) Alkali ions are known to be fast diffusors in dielectric layers, driven by various electrostatic forces. This can lead to unwanted reliability malfunctions for semiconductor products. Within this study different activation energies for sodium and potassium ion insertion into various thin SiOx layers are evaluated using a triangular voltage sweep method.

A 200 nm thick LP CVD-SiOx layer is deposited onto a highly doped silicon substrate material, exhibiting a standard metallization on the backside of the wafer. Afterwards, different temperature anneals are applied to the oxide resulting in unequal oxide qualities. Acting as ion host a ~ 70 nm thick Polyvinylpyrrolidone layer, including a defined concentration of sodium or potassium precursor, is attached on top of the SiOx. Finally, a 40 nm thick Au/Pd gate electrode is deposited onto the polymeric layer. By gradual increase of the gate voltage mobile ions start entering the SiOx layer and migrating towards the Si/SiOx interface, observable by a measurable displacement current. Assessment of ion kinetics within the investigated SiOx layers can be carried out via variation of measurement temperature, showing an obvious linear correlation. Extraction of the activation energies is feasible using a modified Butler-Volmer approach, primarily used to describe charge transfer in electrochemical cells [1]. Plausible values [2-3] between 1.8 eV and 3.5 eV were observed, indicating a direct correlation to altered properties of the different SiOx layers upon temperature treatment. References [1] S. Krivec, M. Buchmayr, T. Detzel, T. Froemling, J. Fleig, H. Hutter; Anal. Bioanal. Chem. 400, pp. 649- 657, 2011. [2] E. H. Snow, A. S. Grove, B. E. Deal, C. T. Sah; J. Appl. Phys. 36, pp. 1664-73, 1965. [3] H. J. Neuhaus, D. R. Day, S. D. Senturia; J. Electron. Mater. 14, pp. 379-404, 1985.

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O6-OXI_387 THE CHEMISTRY OF COBALT OXIDE THIN FILMS STUDIED WITH HIGH RESOLUTION AND HIGH-PRESSURE CORE LEVEL SPECTROSCOPY

OXI - Oxide surfaces, interfaces and thin oxide films J. Knudsen 1,*, M.A. Arman 2,*, P. Ferstl 3, L.R. Merte 2, J. Gustafson 2, K. Schulte 4, A. Schneider 3, L. Hammer 3, E. Lundgren 2 1Division of Synchrotron Radiation Research and the MAX IV Laboratory, Lund University - Lund (Sweden), 2Division of Synchrotron Radiation Research, Lund University - Lund (Sweden), 3Lehrstuhl für Festkörperphysik, Universität Erlangen-Nürnberg - Erlangen (Germany), 4The MAX IV Laboratory, Lund University - Lund (Sweden) Cobalt oxide nanomaterials have attracted attention because of their application potential in the fields of heterogeneous catalysis [1]. On the metastable Ir(100)-(1×1) surface a large number of thin Co oxide structures have been grown and characterized in detail [2]. This wealth of Co oxide structures gives a unique tool to vary the stoichiometry, surface termination, defect concentration, and study how this affects the surface chemistry. Here we use high resolution core level spectroscopy (HRCLS) to give a detailed picture of the adsorption of CO, CO2, and H2O probe molecules onto thin films of Co3O4(111) and CoO(111) grown on the Ir(100)-(1×1) surface [3]. We find that the pristine CoO(111) film without Co surface atoms is almost fully inert with respect to CO and CO2 adsorption at 90 K, while carbonate species, adsorbed CO and CO2 are identified on the pristine Co3O4(111) having Co surface atoms. Further, we demonstrate that defective CoO(111) films rich on oxygen vacancies or sprinkled with Co add-atoms have CO and CO2 adsorption properties almost identical to the ones of the Co3O4(111) surface. Based this finding we conclude that surface Co atoms are essential for CO and CO2 adsorption and most likely also for the high catalytic activity of the Co3O4(111) film. Also for water chemistry we find a higher reactivity of the Co3O4(111) surface as we only observe physisorbed water on CoO(111), while water dissociation clearly is observed on Co3O4(111). In the last part of the talk we will demonstrate the CoO and Co3O4 films also can be grown on Ag(100) and briefly characterize the films with HRCLS and scanning tunneling microscopy (STM). Subsequently, we will discuss the catalytic properties of the Ag(100) supported Co oxide films based on recent high pressure CLS measurements. One key finding from these experiments is that transformation back and forth between CoO and Co3O4 films is observed in O2:CO mixtures in the mbar regime. In pure CO the CoO film is observed while the Co3O4 film always is observed when there is oxygen in the gas supply. References [1] X. Xie et al. Nature, 458, 746 (2009). [2] K. Heinz et al., J. Phys. Cond. Matt. 25, 173001 (2013) [3] P. Ferstl et al., Jour. Phys. Chem. C. 119, 16688 (2015)

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I26_OXI_448 REACTIONS ON TRANSITION METAL OXIDE SURFACES STUDIED BY HIGH- RESOLUTION STM

OXI - Oxide surfaces, interfaces and thin oxide films S. Wendt * Interdisciplinary Nanoscience Center (iNANO) Aarhus University - Aarhus (Denmark) In this talk, I will summarize surface science studies addressing selected prototypical model oxide systems which have been conducted at the iNANO center. In all three examples, high- resolution STM was the main technique, but combinations with temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) was often very fruitful. Although very fundamental in nature, all the presented examples are of relevance for heterogeneous catalysis and/or photo-catalysis, where atomistic insights are often lacking.

In the first part, I will present examples found on the rutile TiO2(110)–(1 × 1) surface. The identification of point defects on the terraces such as oxygen vacancies, hydroxyl groups, and near surface defects such as Ti interstitials will be discussed, and examples for reactions of water and ethanol molecules with oxygen vacancies will be presented [1]. In addition, reactions at step edges are presented [1-3]. Further, I will address the oxygen– TiO2(110) interaction [4] and the photo-reaction of ethanol on differently prepared TiO2(110) surfaces [5]. In the second part, I will present atomically resolved STM images of sub-monolayer vanadium (V) on anatase TiO2(101) [6]. Following V deposition at liquid nitrogen temperature, the surface is covered with small isolated V clusters. However, embedding of V into the near-surface region was found upon warming the sample to room temperature. The density of V clusters decreased and new features appeared on the surface, which we assign to monomeric V at regular Ti surface sites. In the third part of my talk, I will address the structure of ultrathin FeO islands grown on Pt(111), with the focus on the edges of the FeO islands. The FeO–Pt interface is important for heterogeneous catalysis because it hosts the active sites. Pristine, oxidized, and reduced FeO islands are compared, and the predominant FeO boundaries of pristine, oxidized, and reduced FeO islands are unraveled [7]. The results indicate an astonishing flexibility of the FeO islands on Pt(111). Finally, I will present time-lapsed STM images acquired on this inverse model catalyst in O2 and CO environments. These STM measurements show directly that the Fe-edges host the catalytically most active sites in the CO oxidation reaction [8]. References [1] J. Ø. Hansen et al., Phys. Rev. Lett. 107, 136102 (2011). [2] U. Martinez et al., Phys. Rev. Lett. 109, 155501 (2012). [3] H. H. Kristoffersen et al., Phys. Rev. Lett. 101, 146101 (2013). [4] E. Lira et al., Catal. Today 182, 25 (2012). [5] J. Ø. Hansen et al., Scientific Rep. 6, 21990 (2016). [6] S. Koust et al. (in manuscript). [7] H. Zeuthen et al., ACS Nano 9, 573 (2015). [8] W. Kudernatsch et al., ACS Nano 9, 7804 (2015).

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O7-OXI_153 EPITAXIAL GROWTH OF ULTRATHIN MAGNETITE FILMS ON AG(100)

OXI - Oxide surfaces, interfaces and thin oxide films M. De Santis 1,*, A.D. Lamirand 2, A. Ramos 1, S. Grenier 1, A. Bailly 1, X. Torrelles 3, V. Langlais 4 1CNRS, Institut Néel - Grenoble (France), 2Diamond Light Source - Didcot (United Kingdom), 3ICMAB-CSIC - Belleterra (Spain), 4CNRS, CEMES - Toulouse (France) We report on the epitaxial growth of iron oxide layers on Ag (100). Fcc (100) metallic surfaces have been largely employed as substrates for growing transition metal oxide (TMO) films. It was found that strain is a crucial parameter in determining the epitaxial relationships. Moreover the TMO film orientation can be tuned in systems like e.g. CoO/Ir(100) by controlling the chemistry at the interface [1]. Here we show that reactive deposition of iron in molecular oxygen at room temperature (RT), followed by annealing in UHV, results in a film with hexagonal symmetry, interpreted as (111)-oriented magnetite. Instead highly ordered epitaxial layers with P4m symmetry are grown by a three steps process. Following this method, an ultrathin Fe layer is first deposited in coherent epitaxy on the Ag substrate, and then dosed twice with O2, first at RT and next during annealing. A combined low-energy electron diffraction, scanning tunneling microscopy and surface x-ray diffraction analysis allowed us to solve their structure. It consist of stoichiometric (100)-oriented magnetite, although with a slight tetragonal distortion induced by the substrate constraints. Their high-quality, compared to similar films grown on the same surface [2], is assessed by the Kiessieg oscillations observed along their characteristic diffraction rods (see Fig. 1), which indicate atomically sharp surface and interface. This is an essential requirement for the integration of such films into spintronic based devices. Thanks We thank O. Geaymond and S. Garaudee (Institut Néel) and O. Ulrich (CEA INAC) for they invaluable technical support References [1] M. Gubo, C. Ebensperger, W. Meyer, L. Hammer, K. Heinz, F. Mittendorfer, J. Redinger, Phys. Rev. Lett. 108 (2012) 066101 [2] D. Bruns, S. R. Lindemann, K. Kuepper, T. Schemme, J. Wollschläger, Appl. Phys. Lett. 103 (2013) 052401.

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O8-OXI_131 IN SITU X-RAY STUDIES OF CRYSTALLINE TEXTURE AND STRAIN DURING THE INITIAL STAGES OF ZNO ATOMIC LAYER DEPOSITION

OXI - Oxide surfaces, interfaces and thin oxide films H. Renevier 1,*, R. Boichot 2, A. Claudel 1, E. Skopin 1, M.I. Richard 3, C. Crisci 2, L. Tian 1, A. Chaker 1, V. Cantelli 1, S. Coindeau 2, S. Lay 2, T. Ouled 3, C. Guichet 3, M.H. Chu 4, N. Aubert 4, G. Ciatto 4, E. Blanquet 2, O. Thomas 3, J.L. Deschanvres 3, D. Fong 5 1Univ. Grenoble Alpes, LMGP, F-38000 Grenoble, France & CNRS, LMGP, F-38000 Grenoble, France - Grenoble (France), 2Univ. Grenoble Alpes, LMGP, F-38000 Grenoble, France & CNRS, SIMAP, F-38000 Grenoble, France - Grenoble (France), 3Aix-Marseille Univ. , CNRS, Univ. de Toulon, IM2NP UMR 7334, 13397 Marseille Cedex 20, France - Grenoble (France), 4d Synchrotron SOLEIL - L'Orme des Merisiers, Saint Aubin, F-91192, Gif sur Yvette, France - Grenoble (France), 5Argonne National Laboratory, Bldg 241/C222, 9700 S. Cass Ave., Argonne, IL 60439, USA - Grenoble (France) Atomic layer deposition (ALD) is unmatched in its ability to produce conformal films. Metal Organic Chemical Vapor Deposition (MOCVD) is the industry standard for producing stoichiometric compounds over large areas. A key consideration in many modern devices is the atomic structure of the heterointerface, which often ultimately governs the electronic or chemical process of interest. The structure of the deposit and its interface naturally depends on the atomic mechanisms that take place during growth, which for ALD and MOCVD, have been difficult to study due to the near-atmospheric pressure, and for MOCVD, high temperature deposition conditions. In LMGP laboratory we optimize and use ZnO thin films and nanostructures (nanowires, nanoparticles) as building blocks for micro-electronics, optoelectronics and photovoltaic devices. We aim to understand the growth and doping mechanisms of ZnO nanostructures grown by chemical deposition techniques. For obtaining in situ structural and chemical information during ZnO ALD [1-3], we have built an ALD/MOCVD chamber that mounts onto the diffractometer at the beamlines SIRIUS (SOLEIL) and ID3 (ESRF). Here, we report on the chemical and structural evolutions during the initial ZnO ALD by using a complementary suite of in situ synchrotron X-ray techniques: grazing-incidence diffraction, absorption, fluorescence and small angle scattering. We compare ZnO growth behavior on three different types of substrate, Si(001) with its native oxide (a-SiO 2), c-Al2O3 and In0.47Ga0.53As, focusing our studies on the first cycles of deposition [4]. We find that the growth behavior and crystalline texture depend strongly on the choice of substrate. More generally, we aim to stress on the combination of in situ characterization techniques, i.e., synchrotron x-ray scattering and absorption, optical substrate curvature measurements and others, being a powerful approach with unique potential for obtaining real-time structural and chemical information during ALD. Thanks Acknowledgments : Financial support for this work by ANR Moon (No. ANR-11-NANO-0014) and the Nanosciences Foundation is gratefully acknowledged. The reactor has been designed and built with the guidance of Mr. Dominique de Barros. References [1] M. Tallarida et al., J. Appl. Phys. 104, 064116 (2008) [2] D.D. Fong et al., Appl. Phys. Lett. 97, 191904 (2010) [3] J.A. Klug et al., Rev. Sci. Instrum. 86, 113901 (2015) [4] R. Boichot et al., Chem. Mater. 28, 592 (2016)

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O9-OXI_79 POLARON-MEDIATED SURFACE RECONSTRUCTION IN THE REDUCED RUTILE TIO2 (110) SURFACE

OXI - Oxide surfaces, interfaces and thin oxide films M. Reticcioli 1,*, M. Setvin 2, X. Hao 2, D. Ulrike 3, C. Franchini 4 1Computational Materials Physics, University of Vienna - Vienna (Austria), 2Institute of Applied Physics, Vienna University of Technology - Vienna (Austria), 3Computational Materials Physics, Vienna University of Technology - Vienna (Austria), 4Institute of Applied Physics, University of Vienna - Vienna (Austria)

The role of polarons in TiO2 is of key importance for the understanding of the fundamental properties and functionalities of this material [1]. In this work we use density functional theory with an on-site Coulomb interaction U and molecular dynamics (MD) to study the formation and dynamics of small polarons in the reduced rutile TiO2 (110) surface (Fig. 1). We show that excess electrons donated by oxygen-vacancies (VO) form mobile small polarons that hop easily in subsurface and surface Ti-sites. Surprisingly, the polaron formation becomes more favorable by increasing the VO concentration level (5.5%, 11%, 16.6% and 22.2%) due to the progressively lower energy cost needed to distort the lattice around the polaron sites. However, at higher VO concentration and high polaron density the shortening of the average polaron-polaron distance associated with an increased polaron-polaron Coulomb repulsion weakens this trend and drives the system towards an instability, which is overtaken by means of a structural surface reconstruction of the 1x2 type (Fig. 2). This type of reconstruction is typically observed at high temperature and highly reduced conditions and a few structural models have been proposed in literature [2,3]. These conclusions are substantiated by the calculation of the surface energy phase diagram and validated by a direct comparison with STM data. Our study identifies a fundamentally novel mechanism to drive surface reconstructions and resolves a long standing issue on the fundamental origin of the 1x2 reconstruction in rutile (110). Thanks Work supported by the FWF-SFB ViCoM project (Grant No. F41) and the ERC Advanced Research Grant “OxideSurfaces”. Computing time at the Vienna Scientific Cluster is greatly acknowledged. References [1] Setvin et al., PRL 113, 086402 (2014), http://dx.doi.org/10.1103/PhysRevLett.113.086402. [2] Mochizuki et al., Phys. Chem. Chem. Phys. 18, 7085-7092 (2016), doi:10.1039/C5CP07892J [3] Wang et al., PRL 113, 266101 (2014), http://dx.doi.org/10.1103/PhysRevLett.113.266101

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O10-OXI _223 INTERACTION OF FREE-BASE TETRAPHENYL PORPHYRIN WITH MGO(001) SURFACE

OXI - Oxide surfaces, interfaces and thin oxide films O. Malcioglu *, P. Auburger, M. Bockstedte * Friedrich-Alexander-Universität Erlangen-Nürnberg - Erlangen (Germany) MgO(001) as a pristine surface is chemically rather inert. Under experimental conditions, step edges, kink-sites and other low coordinated sites are present. Such sites may chemically interact with adsorbates and hence play a role in structure formation. Recently, the metalation of H2TPP with Mg via low coordinated sites on MgO(001) has been demonstrated [1]. The mechanisms underlying this procesess, however, remain unclear. We employ ab-initio molecular dynamics simulations with and without approximate Van der Waals dispersion correction [2] to study how H2TPP may interact with MgO(001) and its common low coordinated sites. We find that H2TPP is mobile on the pristine surface since the phenyl rings stericly hinder physisorption at a specific surface site. Dispersion correction acts to reduce mobility and induce stronger macrocycle distortions. In the presence of a step or kink site, however, phenyl rings help form a rather stable complex. The molecule aligns at the step or kink such that spontaneous deprotonation of the macrocycle occurs. We present the electronic and structural properties of the adsorbate complex and investigate the photophysical fingerprint of intermediates and the metallized porphyrins using (hybrid) TDDFT, self consistent GW and BSE. Thanks The authors would like to thank resources granted from DFG Research Unit FOR 1878 funCOS - Functional Molecular Structures on Complex Oxide Surfaces References [1] J. Schneider et al., ACS Appl. Mater. Interfaces 7, 22962 (2015). [2] S. Grimme et al., J. Chem. Phys. 132, 154104 (2010).

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O11-OXI_56 EVIDENCING SHARP VERWEY TRANSITION IN A ULTRATHIN MAGNETITE LAYER BY RESONANT X RAY SCATTERING

OXI - Oxide surfaces, interfaces and thin oxide films S. Grenier 1,*, A. Bailly 1, A. Ramos 1, M. De Santis 1, Y. Joly 1, E. Lorenzo 1, A. Lamirand 1, S. Garaudée 1, S. Arnaud 2, N. Blanc 2, N. Boudet 2 1Institut Néel, CNRS - Grenoble (France), 2Institut Néel, CNRS / D2AM (ESRF) - Grenoble (France)

The physical properties of ultrathin Fe3O4 films are not as well defined as in the bulk material and can be tuned with the substrate. Bulk magnetite Fe3O4 undergoes a first order metal- insulator transition originally interpreted as a charge ordering of Fe ions (Verwey transition, near Tv=123 K). Studies on 10 nm to 200 nm films show that the Verwey transition is drastically influenced by the substrate-induced microstructure [1]. The transition temperature greatly depends on domain size and film thickness, while its broadness essentially scales with the width of the domain size distribution. In ultrathin 10 nm films on MgO substrate with only 0.3% lattice mismatch the first order metal-insulator takes place over a broad temperature range around 110 K [1].

We report here on the search of the Verwey transition in a 7 nm-thick Fe3O4 layer ( 8 unit cells) using the fingerprint of this transition on Resonant X ray Scattering spectra. Since 1999 [2], many studies using RXS have been conducted on the superstructure reflections that appear below Tv, in bulk or thick films, in order to investigate the Verwey transition, the actual nature of the Fe electronic states, and their ordering in the unit cell [3]. The film was grown by MBE on a Ag(001) substrate. The measurements were conducted on the D2AM beamline (French CRG at ESRF, Grenoble, France). Even though no superstructure reflection was observed, probably due to the limited amount of material, we found a clear evidence of a transition around 120 K on the reflectivity. The temperature and the RXS spectral shape are signatures of the Verwey transition. Thanks We thank the ESRF and the French CRG D2AM for beam and expertise support. References [1] X.H. Liu et al. Phys. Rev. B90, 125142 (2014). [2] Hagiwara et al. J. of the Phys Soc. of Japan, 68, 5, 1592-1597 (1999). [3] Y. Joly et al. Phys. Rev. B78, 134110 (2008).

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O12-OXI_187 CHARGE TRANSFER TO ORGANIC MOLECULES ON ULTRATHIN INSULATING FILMS

OXI - Oxide surfaces, interfaces and thin oxide films M. Hollerer 1,*, P. Hurdax 1, D. Lüftner 2, T. Ules 1, S. Weiß 3, P. Puschnig 2, M. Ramsey 1, M. Sterrer 1 1Surface Science Group Graz, Institute of Physics, University of Graz - Graz (Austria), 2Theory Departement, Institute of Physics, University of Graz - Graz (Austria), 3Peter Grünberg Institut, Forschungszentrum Jülich - Jülich (Germany) In recent years thin layers of insulators on metal surfaces have been proposed to be active in the promotion of charge transfer [1]. Indeed evidence has been found for charge transfer to Au clusters on metal supported MgO(001) thin films [2]. Here this phenomenon is investigated with scanning tunneling microscopy (STM, STS), angle resolved photoemission spectroscopy (ARPES) and DFT calculations, for the adsorption of device relevant organic molecules on MgO thin films. In this presentation we will focus on the results for pentacene (5A), where the MgO(001) is seen to both orient and immobilize the 5A. Both the STM molecular orbital images and photoemission tomography provide unambiguous evidence for charge transfer to the lowest unoccupied molecular orbital (LUMO) of 5A. The orbital tomography and the workfunction measurements also allow the degree of charge transfer to be quantified. The experimental findings will be compared to DFT results and the generality of the process and its relevance to the field of organic devices will be discussed. References [1] G. Pacchioni et al. (2005): Charging of Metal Atoms on Ultrathin MgO/Mo(100) Films. PRL94 (22) [2] M. Sterrer et al. (2007): Control of the Charge State of Metal Atoms on Thin MgO Films. PRL98 (9)

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O13-OXI_76 ORIGIN OF RESISTIVITY CHANGES IN CBRAMS STUDIED BY X-RAY PHOTOELECTRON SPECTROSCOPY

OXI - Oxide surfaces, interfaces and thin oxide films M. Kazar Mendes 1,*, E. Martinez 1, M. Veillerot 1, O. Renault 1, A. Marty 1, R. Gassilloud 1, M. Bernard 1, Y. Yamashita 2, N. Barrett 3 1Univ. Grenoble Alpes,CEA, LETI, MINATEC Campus, F-38054 - Grenoble (France), 2National Institute for Materials Science, 1-1 Namiki - Tsukuba, Ibaraki (Japan), 3SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 - Gif-Sur-Yvette (France) Conducting bridging resistive random access memories (CBRAMs) are one option currently investigated for the next generation of non-volatile memories. Data storage is based on switching the resistivity between high and low resistance states. Under electrical bias, a conductive path is assumed to be created by ions diffusion from the active electrode into the solid electrolyte [1]. This mechanism has to be better understood but observation of the chemical processes is a real challenge. In this work, we use X-ray photoelectron spectroscopy (XPS) to learn about electrochemical reactions involved in the switching mechanism. Two methods are compared: i) Gas Cluster Ion Beams (GCIB) [2], a new high performance sputtering technique that leads to lower structure degradation, with XPS depth profiling to evaluate chemical depth distributions and ii) non-destructive Hard X-ray PhotoElectron Spectroscopy (HAXPES) to investigate chemical bonding states below the surface. ToF-SIMS measurements are also performed to get complementary in-depth chemical information. We investigate Al2O3 based CBRAMs with MxTey alloys for the active electrode [3]. Measurements are performed on as-deposited samples and after ex-situ forming. We characterize the species diffusion in the stack, such as oxygen and tellurium migration. HAXPES provides information on the reduction of Al2O3 after resistive switching. We also discuss first results obtained after in-situ electrical forming of the memories. From these last experiments, we expect a better understanding of the role of oxygen coming from ambient air. References [1] Waser, R., Dittmann, R., Staikov, G., and Szot, K. (2009). Redox-Based Resistive Switching Memories - Nanoionic Mechanisms, Prospects, and Challenges. Advanced Materials 21, 2632–2663. [2] Yamada, I., Matsuo, J., Toyoda, N., and Kirkpatrick, A. (2001). Materials processing by gas cluster ion beams. Materials Science and Engineering: R: Reports 34, 231–295. [3] Jameson, J.R., and Kamalanathan, D. (2016). Subquantum conductive-bridge memory. Applied Physics Letters 108, 053505.

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O14-OXI_211 TOWARDS MOLECULAR ELECTRONICS: SELECTIVE DEPOSITION OF METAL OXIDES

OXI - Oxide surfaces, interfaces and thin oxide films A. Walker *, Z. Shi University of Texas at Dallas - Richardson (United States of America) Robust methods for the chemically selective deposition of semiconductors and other substances are developed and applied in the construction of complex two- and three- dimensional structures. This work has important applications in molecular and organic electronics, sensing, biotechnology and photonics. These methods are easily parallelized, afford precise nanoscale placement and are compatible with photolithography. Two examples are discussed in detail: the chemical bath deposition (CBD) and atomic layer deposition (ALD) of ZnO on functionalized self-assembled monolayers (SAMs). CBD and ALD are solution-based and gas-phase methods, respectively, for the controlled deposition of semiconductors. The formation of ZnO nanocrystals and thin films are of particular interest for a wide range of applications including photovoltaics, thin film transistors and liquid crystal displays. Using ZnO ALD1 we demonstrate the selective growth of smooth, conformal films on –OH and –COOH terminated SAMs. In contrast using ZnO CBD we demonstrate the selective growth and deposition of ZnO nanocrystals on functionalized self-assembled monolayers (SAMs).2,3 On –COOH terminated SAMs strongly adherent ZnO nanocrystals form via a mixed cluster-by-cluster and ion-by-ion reaction pathway. Initially, Zn2+ ions form complexes with the terminal carboxylate groups. The Zn2+- carboxylate complexes then act as the nucleation sites for the ion-by-ion growth of ZnO. The structure of the nanocrystallites can be varied from flowers to rods to rocketships by control of the Zn2+ and complexing agent, ethylenediamine, in solution.3 No deposition is observed on –OH and –CH3 terminated SAMs. Thus under the appropriate experimental conditions ZnO can be selectively deposited onto –COOH and -OH terminated SAMs.1,2 Further, the morphology of the deposited film can precisely altered.1-3 We illustrate this by selectively depositing ZnO on patterned –COOH/–CH3 and –OH/–CH3 terminated SAM surfaces. Thanks The authors gratefully acknowledge support from the National Science Foundation (CHE1213546). References 1. Z. Shi, A.V. Walker, “Room Temperature Atomic Layer-Like Deposition of ZnO on Functionalized Self- Assembled Monolayers,” J. Phys. Chem. C, 119 (2015) 1091–1100. 2. Z. Shi, A.V. Walker, “Chemical Bath Deposition of ZnO: Effect of Substrate Chemistry on Deposit Morphology and Adherence,” Langmuir, 31 (2015) 1421–1428 3. Z. Shi, A.V. Walker, “Nanorods, Nanorockets, and Nanoflowers: Controlling the Morphology of ZnO Using Chemical Bath Deposition,” Thin Solid Films, 606 (2016) 106-112

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O15-OXI_228 EXPLORING PD ADSORPTION, DIFFUSION, PERMEATION, AND NUCLEATION ON BILAYER SIO2/RU AS A FUNCTION OF HYDROXYLATION

OXI - Oxide surfaces, interfaces and thin oxide films S. Pomp 1,*, W.E. Kaden 2, M. Sterrer 1, H.J. Freund 3 1University of Graz - Graz (Austria), 2University of Central Florida - Orlando (United States of America), 3Fritz Haber Institute of the Max Planck Society - Berlin (Germany)

The hydroxylation-dependent permeability of bilayer SiO2 supported on Ru(0001) was investigated by XPS and TDS studies in a temperature range of 100 K to 600 K. For this, the thermal behavior of Pd evaporated at 100 K, which results in surface and sub-surface (Ru-supported) binding arrangements,was examined relative to the extent of pre- hydroxylation. Samples containing only defect-mediated hydroxyls showed no effect on Pd diffusion through the film at low temperature. If, instead, the concentration of strongly bound hydroxyl groups and associated weakly bound water molecules was enriched by an electron-assisted hydroxylation procedure, the probability for Pd diffusion through the film is decreased via a pore-blockingmechanism. Above roomtemperature, all samples showed similar behavior, reflective of particle nucleation above the film and eventual agglomeration with any metal atoms initially binding beneath the film.

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O16-OXI_300 THERMAL REDUCTION OF NB-DOPED TIO2 SINGLE CRYSTALS: SURFACE PROPERTIES AND COMPOSITION EVOLUTION

OXI - Oxide surfaces, interfaces and thin oxide films D. Wrana 1,*, C. Rodenbücher 2, B.R. Jany 1, J. Rysz 1, K. Szot 3, F. Krok 1 1Marian Smoluchowski Institute of Physics, Jagiellonian University - Krakow (Poland), 2Peter Grünberg Institute and JARA-FIT, Forschungszentrum Jülich GmbH - Jülich (Germany), 3A. Chelkowski Institute of Physics, University of Silesia - Katowice (Poland) Transition metal oxides exhibiting a variety of electronic and catalytic phenomena have become key materials for future energy and information technologies. In particular the prototype oxide TiO2 has been investigated intensively e.g. as substrate for the controlled adsorption of functional molecules [1] or for redox-based memristive applications [2]. In the talk we focus on the influence of Nb doping on surface transformations during thermoreduction of rutile TiO2(110) single crystals in UHV conditions. It is known niobium acts as a donor and enhances the conductivity of TiO2 while structural properties remain unchanged. However, Nb diffusion mechanisms are not yet well understood, especially when we deal with the surface [3]. While in undoped TiO2(110), the surface reconstruction changes from (1x1) to (1x2) upon annealing, we have found that the surface of crystals doped with 0.5 wt% Nb undergoes two phase transitions, as provided by LEED, STM and conductive-AFM measurements. The first, happening at 850oC regards change from filamentary to quasi-homogenous conductivity, connected with new, previously unknown reconstruction of “zig-zag” rows (Fig: atomic resolution images of the zig-zag rows structure o 2 of Nb:TiO2(110) after annealing to 1000 C (50 x 50 nm ): a) STM topography, b) LC-AFM current map). Second transition occurring at 950oC-1000oC causes formation of higher conducting domains. The island’s conductivity can easily be reduced by oxygen exposure, unlike the zig-zag rows areas. Due to reducing conditions while annealing, Nb diffuses from the surface, as proved by SIMS depth profiling. We will present the importance of redox processes on the very surface of oxide single crystals – reduction (annealing in UHV conditions) and oxidation (oxygen exposure) connected with ongoing phase transitions opening up the opportunity to tune the electronic properties of transition metal oxide surfaces for photocatalytic, optoelectronic or memristive purposes by dedicated control of doping and subsequent reduction steps. References [1] D. Wrana et al., J. Phys. Chem. C, 119, 17004 (2015). [2] R. Waser et al., Adv. Mater., 21 (2009) 2632. [3] A. J. Gardecka et al. J. Mater. Chem. A, 3(34) (2015): 17755–17762.

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I27_OXI_449 PEROVSKITE OXIDE SURFACES: NEW STRUCTURES AND SURPRISING INTERFACE PROPERTIES

OXI - Oxide surfaces, interfaces and thin oxide films W. Widdra * Institute of Physics, Martin-Luther-Universität Halle-Wittenberg - Halle (Germany) Oxide heterostructures are a novel materials class with a variety of applications. In the easiest cases, the bulk properties define the thin film characteristics. However, oxide interfaces and surfaces can add interesting new concepts and properties. I will discuss this here for the class of perovskite single-crystal surfaces and thin films: Barium titanate (BTO), a well-studied material in the class of ferroelectric perovskites shows surface-specific ferroelectric properties as determined by photoemission electron microscopy and in-situ piezo-force microscopy [1]. A dynamic coupling of the dipolar response with phonons leads to surface-specific phonon-polaritons dominating high- resolution electron energy loss spectra, which identify different oxide phases as well as specific film strain. In the second part, it will be demonstrated for thin films of different perovskites that the interface-driven frustration at a threefold metallic substrate can lead to long-range ordered, but aperiodic structures. The oxide thin film structure is close to an ideal two-dimensional quasicrystal with a brilliant 12-fold diffraction pattern and atomic tiling pattern of triangular, quadratic and rhombic elements [2]. The structure of these quasicrystals and of similar, but periodic approximants will be discussed. References [1] A. Höfer et al., Phys. Rev. Lett. 108, 087602(2012). [2] S. Förster et al., Nature 502, 215 (2013).

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O17-OXI_255 METAL↔INSULATOR TRANSITION EVIDENCED BY ATOMIC FORCE MICROSCOPY IN V2O3 THIN FILMS

OXI - Oxide surfaces, interfaces and thin oxide films N. Alyabyeva 1,*, J. Sakai 2, J. Wolfman 2, P. Limelette 2, H. Funakubo 3, A. Ruyter 2 1Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Univ. Paris-Sud, Université Paris-Saclay - Orsay (France), 2University of Tours, GREMAN laboratory - Tours (France), 3Tokyo Institute of Technology - Tokyo (Japan) Pressure induced hysteretic transition from strongly correlated metal to Mott insulator is expected for V2O3 compounds [1, 2]. In this study, we demonstrate such metal↔insulator transition (MIT) at submicronic level by investigating the piezoresistive properties of V2O3 thin films with scanning probe microscopy.

V2O3 thin films with thickness 82 nm were prepared by pulsed laser deposition on Al2O3 substrate (orientation: (0001) [c-plane]). Investigation of the MIT was carried out using Atomic Force Microscopy (AFM) in contact mode. Room temperature AFM scans were undertaken under ultrahigh vacuum to prevent from local anodic oxidation of V2O3. In order to get a good electrical contact during the scan, a minimum set point is required which corresponds, for a given cantilever spring constant, to a fixed force or load. The corresponding pressure exerted by tip on the film will then depends on the tip radius. To access a wide range of pressure, a set of different tips has been used, keeping the same cantilever geometry and spring constant (k~0.05 N/m) : standard commercial tips with Pt- coating, (radius~35 nm) and others tips, prepared by focused ion beam (FIB), with different radii (70 nm and 300 nm). To prepare such tips, flattened Pt caps have been locally deposited on the top of standard tips by FIB chemical vapor deposition.

With such a set of tips, we have investigated the occurrence of MIT in V2O3 thin film with pressures ranging from 0.3 to 2.2 GPa. In the case of standard tips, observation of the reversible MIT is impossible due to the film deformation induced by the high tip pressure (~2 GPa). On the contrary, FIB modified cantilevers with larger tip radii allowed good electrical contact for low tip pressure (~0.3 GPa). Reversible metal↔insulator transitions have been evidenced, allowing for the local investigation of voltage-current characteristics, spreading resistance imaging and history dependence of the current at various pressure. References [1] Limelette et al., Science 302 (2003) 89 [2] Rodolakis et al., PRB 84 (2011) 245113

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O18-OXI_200 TWO-DIMENSIONAL HOLE GAS AT FERROELECTRIC BARIUMTITANATE FILM SURFACES

OXI - Oxide surfaces, interfaces and thin oxide films S. Muff 1,*, M. Fanciulli 1, N. Pilet 2, G. Landolt 2, Z. Ristic 2, N.C. Plumb 2, M. Radovic 2, H. Dil 1 1Institut de Physique, Ecole Polytechnique Fédérale de Lausanne - Lausanne (Switzerland), 2Swiss Light Source, Paul Scherrer Institute - Villigen (Switzerland)

[1,2,3] [4,5] The transition metal oxides SrTiO3 and KTaO3 show both a very similar two dimensional electron gas (2DEG) at the surface of cleanly prepared substrates. Another compound of this class is BaTiO3 which is, unlike the two transition metal oxides mentioned above, a well known ferroelectric material. Furthermore transport measurements on clean BaTiO3 show, depending of the ferroelectric polarization direction of the bulk material, a hole like surface conductance for a polarization direction pointing out-of-plane[6].

In our experiments we studied films of BaTiO3 with a thickness of 10 unit cells and 20 unit cells on single terminated SrTiO3 and KTaO3 substrates by the help of pulsed laser deposition (PLD). Piezoresponse force microscopy (PFM) measurements on a 50 unit cells thick film show an excellent surface quality as well as ferroelectricity with a preferred polarization along the out of plane direction. By using angular resolved photoelectron spectroscopy (ARPES) we directly map the existence of metallic states at the clean surface of our films. The conducting states consist of heavy electron-like bands with a three-dimensional dispersion as well as surface confined 2D states (see figure 1). These 2D states show, in contrast to the 2D electron like states observed at the surface of the closely [1,2,3] related compounds SrTiO3 and [4,5] KTaO3 , a hole like dispersion. Thanks The presented work is financially supported by Swiss National Science Foundation (PP00P2 144742/1). References [1] - A.F. Santander-Syro et al., Nature 469, 189 (2011). [2] - N.C. Plumb et al. Phys. Rev. Lett. 113, 086801 (2014). [3] - A.F. Santander-Syro et al., Nature Mater. 13, 1085-10901 (2014) [4] - P.D.C. King et al., Phys. Rev. Lett. 108, 117602 (2012). [5] - A.F. Santander-Syro et al., Phys. Rev. B. 86, 121107(R) (2012). [6] - Y. Urakami et al., Ferroelectrics 346, 32-36 (2007) [7] – P. Zhang et al., Rev. Sci. Instrum. 82, 043712 (2011)

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O19-OXI_118 ADSORPTION OF OXYGEN ON RUTHENATE PEROVSKITE SURFACES

OXI - Oxide surfaces, interfaces and thin oxide films F. Mittendorfer 1,*, W. Mayr-Schmölzer 1, D. Halwidl 1, B. Stöger 1, D. Fobes 2, J. Peng 2, Z. Mao 2, J. Redinger 1, U. Diebold 1 1Institute of Applied Physics, TU Wien - Vienna (Austria), 2Tulane University - New Orleans (United States of America) The surface chemistry of perovskite oxides plays a central role for promising applications, such as solid oxide fuel cells. Yet an atomistic understanding of the surface chemistry of these materials is only slowly evolving. In a recent study, we could demonstrate a high chemical activity of strontium ruthenate surfaces for the adsorption of CO [1] and H2O [2]. In this presentation, I will discuss the adsorption of oxygen (O2) on the (001) surface of the Ruddlesden-Popper perovskites Sr3Ru2O7 (SRO) and Ca3Ru2O7 (CRO) on the basis of density functional theory (DFT) calculations and scanning tunneling microscopy (STM) experiments. Our result show pronounced differences between these two surfaces. In the low coverage case, the calculations predict a molecular adsorption of O2 on the SRO (001) surface with a slight tilting of the O2 molecule and an adsorption energy of Eads = -1.38 eV, and the surface is uniformly covered at higher coverages up to 1ML. In contrast to the strontium ruthenate surface, the additional tilting of the Ru octahedra at the bare CaO terminated CRO (001) surface leads to a striped pattern of wide and narrow rows, displayed as alternating bright and dark channels in the STM images (see Fig. 1). This pattern strongly influences the respective adsorption energies of the O2 molecule, as the adsorption in the bright channels (Eads = -1.34 eV) is significantly more stable (~0.3 eV) than the adsorption in the dark channels. Thus the experimental saturation coverage is already reached at an oxygen coverage of 0.5 ML, where the occupation of symmetry-equivalent sites leads to the formation of a zig-zag arrangement of the O2 molecules. Thanks This work has been supported by the Austrian Science Funds (FWF, SFB-F45), the ERC Advanced Grant "OxideSurfaces" and the Vienna Scientific Cluster (VSC). References [1] B. Stöger, M. Hieckel, F. Mittendorfer, et al., Phys. Rev. Lett 113, 116101 (2014) [2] D. Halwidl, B. Stöger, W. Mayr-Schmölzer, et al., Nature Materials 15, 450 (2016)

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O20-OXI_124 ADSORPTION OF WATER ON CALCIUM RUTHENATE

OXI - Oxide surfaces, interfaces and thin oxide films D. Halwidl 1,*, W. Mayr-Schmölzer 1, F. Mittendorfer 1, O. Feya 2, D. Fobes 3, J. Peng 3, Z. Mao 3, M. Schmid 1, J. Redinger 1, U. Diebold 1 1Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, A-1040 Vienna, Austria - Vienna (Austria), 2Department of Problems of Physics and Energetics, Moscow Institute of Physics and Technology, 9 Institutskiy Lane, Dolgoprudny City, Moscow Region, 141700, Russia - Moscow (Russian federation), 3Department of Physics and Engineering Physics, Tulane University, New Orleans, LA, USA - New Orleans (United States of America) Complex ternary perovskite oxides are increasingly used in solid oxide fuel cells and catalysis [1]. Therefore it is highly desirable to obtain a better understanding of their surface chemical properties. We use low-temperature STM, XPS and DFT to investigate the adsorption of water on Ca3Ru2O7(001). Dosing small amounts of water on the clean surface at 105 K leads to bright dots sitting on the bright lines of the substrate in the [010] direction, see Fig. 1. We propose that water dissociates and that the bright dots correspond to OH groups sitting on Ca bridge sites. The OH groups are immobile at 78 K, in contrast to the interesting dynamic behavior observed on the Sr3Ru2O7(001) surface [2]. The O1s XPS spectrum shows the growth of a shoulder at 531.0 eV binding energy, 1.8 eV above the bulk oxygen peak. We attribute the shoulder to dissociated water, in agreement with our DFT calculations. At higher doses various superstructures are formed, with long-range order that depends on the coverage, dosing temperature and annealing time. Molecular water is observed only after all surface oxygen atoms have been occupied by split off hydrogens from the dissociated water. The O1s XPS spectrum shows the molecular water at 533.1 eV, 3.9 eV above the bulk oxygen peak. Thanks This work was supported by the Austrian Science Fund (FWF project F45), the ERC Advanced Grant “OxideSurfaces” and the Vienna Scientific Cluster (VSC). References [1] M. A. Pena and J. L. G. Fierro, Chem. Rev. 101, 1981 (2001) [2] D. Halwidl, B. Stöger, W. Mayr-Schmölzer et al., Nature Mater. 15, 450 (2016)

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O21-OXI_183 PROMOTION AND INHIBITION EFFECTS OF MOLYBDENUM OXIDES ON THE REACTIVITY OF ATOMICALLY THIN RH FILMS

OXI - Oxide surfaces, interfaces and thin oxide films L. Deak 1,*, I. Szenti 2, Z. Kónya 1 1MTA-SZTE, Reaction Kinetics and Surface Chemistry Research Group - Szeged (Hungary), 2University of Szeged, Department of Applied and Enviromental Chemistry - Szeged (Hungary)

A substantial promotional effect of MoOx species at high pressures on the reactivity of rhodium [1] and even on that of the rather inert Au(111) surface has been reported [2], which initiated our UHV model study. The MoOx species was formed on Rh films (0.15-20.0 ML) supported by TiO2(110) substrate and its impact on the adsorption and decomposition of CO was investigated by AES, TDS and work function (WF) measurements. Oxidation of 0.2- 20.0 ML thick Mo deposits was performed through redox reaction with the TiO2(110) support and in O2 gas. From a 1 ML thick Rh film formed on titania pre-covered by 1.2 ML Mo, following 20 L CO adsorption, beside the desorption of molecular alfa-CO (Tp=570 K), a new recombinative CO desorption state was observed with Tp=680 K, assigned as beta-CO and related to MoOx diffused onto Rh particles. In association with the TiOx overlayer, a gamma- CO state with Tp=770-810 K was found. Pre-annealing to 630-730 K the 1 ML thick Rh film formed on Mo modified (1.2 ML) titania suppressed more strongly the molecular and associative CO desorption than on the Mo-free TiO2(110) surface, indicating that MoOx inhibited the CO adsorption and according to its low surface free energy, it migrated more easily onto rhodium than TiOx. Remarkably, on a Mo-precovered (0.2-1.2 ML) titania and on a 20 ML thick oxidized molybdenum film, the development of beta-CO needs 0.5 ML threshold Rh coverage, attributable to quantum-size effect and geometric factors governing CO adsorption. The beta-CO state with Tp=680 K was also detected on 1 ML thick Rh films covered by MoOx species produced by the oxidation of Mo overlayers in O2. Similar to the findings of high pressure studies, the reactivity towards CO was maximal at around 0.2 ML Mo coverage, whereas CO adsorption was completely eliminated at tetaMo=0.5 ML. The substantially reduced peak temperature (680 K) of recombinative CO desorption for the MoOx modified rhodium compared with that for the TiOx-covered one (770-810 K) and with that for pure molybdenum (950 K) can be related to the catalytic promotion effect of molybdenum oxide additives in the hydrogenation reaction of CO, where its dissociation is a rate-determining step. References [1] E.E. Lowenthal, L.F. Allard, M. Te, H.C. Foley, J. Mol. Catal. A-Chem., 100 (1995) p129. [2] J. A. Rodriguez, S. Ma, P. Liu, J. Hrbek, J. Evans, M. Pérez, Science, 318 (2007) p1757.

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O22-OXI_84 METHANOL OXIDATION OVER TERBIUM OXIDE THIN FILMS

OXI - Oxide surfaces, interfaces and thin oxide films A. Schaefer 1,*, W.C. Cartas 2, R. Rai 2, M. Shipilin 1, L.R. Merte 1, E. Lundgren 1, J.F. Weaver 2 1Division of Synchrotron Radiation Research, Department of Physics, Lund University - Lund (Sweden), 2Department of Chemical Engineering, University of Florida - Gainesville (United States of America) Terbium oxide belongs to the group of rare earth oxides (REOs) and as such to a very fascinating group of materials. It is one of only three oxides of the lanthanide series that can form a dioxide and exhibits a high mobility of the lattice oxygen. The most stable form under ambient conditions is a mixed valence structure with the stoichiometry Tb4O7. However, up to now ceria (CeO2) is the almost exclusively studied REO in surface science and in the context of heterogeneous catalysis. Recently, considerable progress has been made in the investigation of ceria surfaces [1] while the structural and chemical properties of the other REOs remain underexplored. We report an investigation of the decomposition of methanol (MeOH) on thin films of terbium oxide grown on a Pt(111) single crystal by reactive physical vapor deposition. Unlike ceria, terbium oxide does not readily oxidize to the dioxide when exposed to molecular oxygen and additional treatments are necessary. The as-grown Tb2O3 films were subjected to oxidation treatments using atomic oxygen to obtain a stoichiometry close to TbO2 [2]. The decomposition of methanol was studied by thermal desorption spectroscopy (TDS) and photoelectron spectroscopy based on synchrotron radiation (SR-XPS). While TDS reveals the formation of H2CO and small quantities of CO2 on the oxidized surface, mainly the desorption of methanol, most likely through recombination of H3CO- with hydrogen, is observed from the as-grown oxide surface (see figure). The XPS results reveal that CH3O groups are the predominant intermediate on both surfaces during the initial stages of MeOH decomposition. Taken together, the TPD and XPS results provide evidence that CH3O groups serve as intermediates to both MeOH and and CH2O formation on the TbOx surfaces, and that the kinetic branching favors dehydrogenation to CH2O on the fully oxidized surface. The presentation will close with a comparison of our results to other REO systems and an outlook to ongoing research efforts on different REO thin film model systems. References [1] D.R. Mullins, Surface Science Reports, 70 (2015) 42-85. [2] W. Cartas, R. Rai, A. Sathe, A. Schaefer, J.F. Weaver, J. Phys. Chem. C, 118 (2014) 20916-20926

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O23-OXI_114 SUBSTRATE DEPENDENT REACTIVITY OF FEO ULTRA-THIN FILMS

OXI - Oxide surfaces, interfaces and thin oxide films E. Lundgren 1,*, L. Merte 1, S. Blomberg 1, J. Gustafson 1, M. Shipilin 1, F. Zhang 2, J. Choi 2, J.F. Weaver 2, C. Heard 3, H. Grönbeck 3 1Lund University - Lund (Sweden), 2University of Florida - Gainsville (United States of America), 3Chalmers University - Göteborg (Sweden) Recently, monolayer-thick FeO films have gained significant attention in surface chemistry and catalysis. In particular FeO films grown on the Pt(111) surface have been studied in detail [1-4] and it has been reported, most intriguingly, that the formation of an O-Fe-O trilayer phase displays a higher activity than the Pt(111) surface itself for CO oxidation [4]. It has been suggested that, due to the loosely bound top-most oxygen atoms in the O-Fe-O layer, the reaction proceeds via an Eley-Rideal mechanism; The CO solely interacts with the top-most oxygen forming CO2. With the aim of elucidating the effects of the substrate on the reactivity of ultra-thin FeO films, we have investigated the growth of FeO on Ag(100) and Ag(111) and the reactivity of the FeO film towards NO adsorption. We present a detailed structural study FeO ultra-thin films grown on the Ag(100)/Ag(111) surfaces combining STM, LEED, XPS, NEXAFS and DFT calculations. We show that it is possible to produce a well-ordered FeO(111)-type monolayer on both surfaces by reactive deposition and annealing. The monolayer structure is expanded laterally compared to similar films on Pt surfaces, which is attributed to weaker interactions with the substrate. We also show that it is also possible to grow FeO(100) grains on Ag(100) [5] and multilayer Fe and O layers. Armed with this structural information we have studied the NO adsorption and desorption on the FeO ultra-thin films on Ag(100)/ Ag(111) using LEED, IRAS and TPD and compare the adsorption properties with those found for FeO films on Pt(111). Previous studies have shown while NO adsorb on Pt(111), only a fraction adsorb on the FeO(111)/Pt(111) [6]. In the case of the FeO(111)/Ag surfaces the situation is reversed, revealing no NO adsorption on the Ag(100)/Ag(111) at 85 K while almost a full monolayer adsorb on the FeO(111)/Ag surfaces. Thus, despite their clear structural resemblance, the FeO(111) films on Pt(111) and Ag surfaces has completely different reactivity towards NO adsorption. The reasons for these differences will be discussed in the contribution. References [1] L. Giordano et al., J. Phys. Chem. C 114, 21504 (2010). [2] H. Zeuthen et al., J. Phys. Chem. C 117, 15155 (2013). [3] L. Giordano et al., Phys. Rev. B 76, 75416 (2007). [4] J. Goniakowski, and C. Noguera, Phys. Rev. B 79, 155433 (2009). [5] L. R. Merte et al, J. Chem Phys. C 119 (2015) 2572. [6] Lei et al. ChemCatChem 3, 671 (2011).

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I19_OXI_450 REDUCIBLE OXIDES AS ULTRATHIN EPITAXIAL FILMS

OXI - Oxide surfaces, interfaces and thin oxide films P. Luches * Istituto Nanoscienze, Consiglio Nazionale delle Ricerche - Modena (Italy) Reducible oxides are materials in which the cations can easily and reversibly switch between two or more oxidation states, leading to the possibility of quickly storing, releasing and transporting oxygen ions. In spite of the wide application of reducible oxides - for example in catalysis, energy conversion and biomedicine – efforts are still required to comprehensively understand and optimize their functionality. I will present the results of our studies of cerium oxide ultrathin films epitaxially supported on a Pt(111) single crystal. The use of a model reducible oxide system allows to clarify important aspects of reducibility related to dimensionality and to the mutual interaction between the oxide and the metal [1]. I will discuss the evolution of the oxide stoichiometry, morphology and surface structure induced by reducing thermal treatments and the reversibility of the observed processes [2]. The modifications of the 4f level and of the 5d band with reduction/oxidation will also be described [3]. Our studies demonstrate a higher reducibility in films of subnanometric thickness compared to thicker films, which is ascribed to the influence of the charge transferred from the platinum substrate on the surface oxygen vacancy formation energy [3]. The structural changes occurring during reduction and their influence on the reducibility of the material will also be discussed. References [1] P. Luches, L. Giordano, V. Grillo, G. C. Gazzadi, S. Prada, M. Campanini, G. Bertoni, C. Magen, F. Pagliuca, G. Pacchioni, S. Valeri, Adv. Mater. Interfaces 2, 1500375 (2015). [2] P. Luches, F. Pagliuca, S. Valeri, Phys. Chem. Chem. Phys. 16, 18848 (2014). [3] G. Gasperi, L. Amidani, F. Benedetti, F. Boscherini, P. Glatzel, S. Valeri, P. Luches, submitted.

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O24-OXI_318 COMBINED EXPERIMENTAL AND COMPUTATIONAL STUDY OF WATER ON FE3O4 (001)

OXI - Oxide surfaces, interfaces and thin oxide films J. Hulva 1,*, J. Pavelec 1, M. Meier 2, S. Maaß 1, R. Bliem 1, M. Schmid 1, U. Diebold 1, C. Franchini 1, G.S. Parkinson 1 1Institute of Applied Physics, Vienna University of Technology - Vienna (Austria), 2Faculty of Physics and Center for Computational Materials Science, Universität Wien - Vienna (Austria) The interaction of water with metal-oxide surfaces is an important topic for a wide range of technological and environmental applications. This is particularly true for the iron oxides because of their abundance in nature and their use in chemical processes where water is involved e.g. the water-gas shift reaction [1]. Recent studies of water on iron oxide surfaces have found significant complexity, with evidence for pressure dependent adsorption, mixed- mode adsorption and coverage dependent hydrogen bonding [2-4]. Here we use a multi- technique experimental approach combined with ab-initio calculations including molecular dynamics to disentangle the coverage and temperature dependent behavior of water on the reconstructed Fe3O4(001)-(√2x√2)R45° surface [5]. Temperature programmed desorption shows that the first monolayer of water desorbs from the surface in four distinct peaks between 150 K and 250 K. Based on XPS, STM images and ab-initio calculations, we conclude that the first three peaks originate from molecular water desorbing from a coverage-dependent hydrogen-bonded network, while the last peak results from recombinative desorption from a partially dissociated water trimer species. Two additional desorption states at 340 K and 520 K are ascribed to desorption from surface defects and recombinative desorption of the surface surface hydroxyl groups, respectively. References [1] Parkinson, G.S., " Iron oxide surfaces", Surface Science Reports (2016) [2] Dementyev, P., et al. "Water Interaction with Iron Oxides." Angew.Chem. Int. Ed. 54 (2015): 13942 [3] Mulakaluri, N., et al. "Partial dissociation of water on Fe3O4 (001): Adsorbate induced charge and orbital order." Phys. Rev. Lett. 103 (2009): 176102. [4] Kendelewicz, T., et al. "X-ray photoemission and density functional theory study of the interaction of water vapor with the Fe3O4 (001) surface at near-ambient conditions." J. Phys. ChemC 117 (2013): 2719- 2733. [5] Bliem, R., et al. "Subsurface cation vacancy stabilization of the magnetite (001) surface." Science 346 (2014): 1215-1218.

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O25-OXI_305 MGO-DOPED TIO2(011) SURFACE

OXI - Oxide surfaces, interfaces and thin oxide films B. Domenichini 1,*, C. Dupont 1,*, J. Jupille 2, P. Le Fevre 3, A. Verdini 4, L. Floreano 4, S. Bourgeois 1 1ICB, CNRS-Univ. Bourgogne/Franche Comté - Dijon (France), 2INP, CNRS-UPMC - Paris (France), 3SOLEIL-CASSIOPEE - Gif Sur Yvette (France), 4CNR-IOM, Laboratorio TASC - Trieste (France) Titanium dioxide is one of the most studied n-type semiconductor. Its reducibility is generally related to oxygen vacancies and/or interstitial titanium ions. The relative contribution of oxygen vacancies and interstitials Ti is still under debate [1], despite recent works [2], showing that oxygen vacancies and interstitials Ti both contribute to the non stoichiometry with relative contributions depending on the sample history.

MgO-doped TiO2 surface is a simple way to induced oxygen vacancies in the solid according to the reaction:

·· MgO(s) --> MgTi’’ + OO + VO (i) while oxygen vacancies may involve lattice titanium ion migration associated with annihilation of oxygen vacancies according to:

·· ···· TiTi + 2 VO --> Tii (ii).

Studying MgO-doped TiO2 surface should have to be a way to analyze the equilibrium between oxygen vacancies and interstitial titanium ions. Hence, surface doping with an atomic ratio between Ti and Mg close to 1:1 was performed and the obtain system was investigated through several photoemission-based techniques such like XPS, UPS and photoelectron diffraction (PED). The first result concerns the PED patterns recorded on Ti3s and Mg2s signal which are very similar (see on pictures) and close to the one recorded on titanium signal for non doped surface. This point confirms that it is possible to infer that magnesium occupies the same sites as titanium, i.e. that magnesium is present in the TiO2 topmost layers as substitutional ions which should be associated to oxygen vacancies according to eq. (i). In this case, considering the Ti/Mg ratio, one should consider that 25% of the oxygen atoms are replaced by oxygen vacancies. If interstitial titanium atoms had replaced a noticeable part of oxygen vacancies according to eq. (ii), a new Ti environment should have appeared and the PED data should have been highly modified. Therefore, in the present case, it seems that the defects in the topmost layers remain mainly oxygen vacancies. References 1 S. Wendt, P. T. Sprunger, E. Lira, G. K. H. Madsen, Z. Li, J. Ø. Hansen, J. Mathiesen, A. Blekinge- Rasmussen, 2 L. E. Walle, A. Borg, P. Uvdal and A. Sandell, Phys. Rev. B 86 (2012) 205415

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I23_OXI_451 STRUCTURAL, ELECTRONIC AND MAGNETIC RECONSTRUCTIONS OF THE THE 2DEG FORMED AT TITANATE OXIDE INTERFACES

OXI - Oxide surfaces, interfaces and thin oxide films M. Salluzzo * CNR-SPIN - Napoli (Italy)

The quasi two-dimensional electron gas (q2DEG) created at the interface between LaAlO3 and SrTiO3 have attracted strong interest in recent years. This system shows an intriguing inversion of the Ti3d bands hierarchy at the interface respect the bulk [1], and some reports even suggested a coexistence between ferromagnetism and superconductivity [2-4].

More recently, a q2DEG have been observed also at the bare surface of SrTiO3 [5]. Spin- resolved ARPES experiments performed on in-situ prepared STO (001) surfaces have revealed that the surface state exhibits a giant Rashba-like spin-orbit characterized by a broken Kramers-degeneracy at k = 0, which implies the existence of some unknown magnetic order [6]. Here, we present Grazing Incidence x-ray diffraction and x-ray magnetic circular dichroism (XMCD) studies of the Structural, Electronic and magnetic reconstructions in the q2DEG at the SrTiO3 (001) surfaces and at the LaAlO3/SrTiO3 (001) interfaces. We find a sizable Ti-3d1 magnetic moment in both systems, however the magnetic moment is quenched in LAO/STO by annealing in oxygen implying an important role of oxygen vacancies in the magnetism of these oxide interfaces [7, 8]. At the STO surface we find that the surface TiO plane is characterized by 50% of oxygen vacancies, which justify the formation of thin FM layer due to magnetic coupling between Ti3+ spin moments. A ferromagnetic ground state is, on the other hand, stabilized even in optimally oxidized conducting interfaces by inserting 2 unit cells of delta-doping EuTiO3 between LAO and STO. We find that the EuTiO3 thin layer is ferromagnetic, instead of being antiferromagnetic as in the bulk, due to the ordering of Eu2+ spin mediated by itinerant carriers. The exchange interaction between Eu2+ and Ti3d1-electrons in both ETO and STO interfacial layers give rise to a very large ordered Ti-magnetic moment and to a spin-polarization of the Ti-3d- bands. References [1] M. Salluzzo, et al., Phys. Rev. Lett. 102, 166804 (2009). [2] L. Li, C. Richter, Nature Physics 7, 762 (2011). [3] J. A. Bert, et al., Nature Physics 7, 767 (2011). [4] J. S. Lee, et al., Nature Materials 12, 703 (2013). [5] A. F. Santander-Syro, et al., Nature 469, 189 (2010). [6] A. F. Santander-Syro, et. al., Nature Materials 13, 1085 (2014). [7] N. Pavlenko, et al., Phys. Rev. B 85, 020407(R) [8] D. Stornaiuolo, Nature Materials 15, 278–283 (2016).

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O26-OXI_60 PIEZOELECTRIC AND FERROELECTRIC PROPERTIES PZN-PT PEROVSKITE NANOPARTICLES THIN LAYER DEPOSITED ON NANOSTRUCTURED P-TYPE SILICON SUBSTRATE.

OXI - Oxide surfaces, interfaces and thin oxide films D. Diouma Kobor 1,*, R. Ndioukane 1, M. Touré 1, D. Tine 1, L. Motte 2 1LCPM University Assane Seck - Ziguinchor (Senegal), 2University Paris 13 - Paris (France) This work involves an investigation of nanostructures and microelectronic properties and domain engineering of nanoparticles thin layers of PZN-PT ferroelectric single crystals deposited on nanostructured Si substrate. The aim of this study is twofold. It will be getting around, despite their excellent ferroelectric and piezoelectric properties and the difficulty of making these single crystals as a thin layer, using single crystal nanoparticles, already synthesized by conventional methods, by spin coating with a gel based on these perovskite single crystals. Studying their ferroelectric and piezoelectric properties would be able to integrate them easily in electronic devices such as sensor or transducer. A second innovative aspect relates to their use on substrates such as silicon for inorganic - inorganic hybrid perovskites solar cells knowing that, all studies are with organic – inorganic perovskites cells. By using them as active material in a silicon nanostructures, one could increase the electrical or optical properties of silicon based solar cells. However, one of the greatest difficulties in the use of such single crystals is to achieve them in thin layers form because of their incongruent melting property. In this work, to integrate them into silicon nanostructures, we realized PZN-PT nanoparticles deposit, already synthesized by the so- called solution flow method [1]. Synchrotron Radiation Beamline was used to characterize this device. Dielectric, Piezoelectric and ferroelectric properties of such thin layers were investigated. Figure 1 shows micro Xray Fluorescence mapping of Nb nanoparticles thin layer deposited on Si substrate. Keywords: Nanostructure, perovskite, silicon, thin layer References [1] A. Benayad, et al. J. of Crystal Growth, 270 (2004) 137-144

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O27-OXI_279 BAND BENDING IN PT/PB(ZR,TI)O3 INVESTIGATED BY X-RAY PHOTOELECTRON SPECTROSCOPY

OXI - Oxide surfaces, interfaces and thin oxide films C. Bucur *, L. Abramiuc, A. Lungu, L. Tanase, C. Tache, C. Teodorescu NIMP - Bucharest (Romania) Interfaces formed by platinum on single crystal layer of Pb(Zr,Ti)O3 (PZT) produced by pulsed laser deposition are analyzed by X-ray photoelectron spectroscopy (XPS). The stoichiometry of the layer reproduces fair the one of the PZT target. XPS is an appropriate tool for investigating band bendings [1,2] in contacts formed by the ferroelectrics with metals [3,4]. In the present study, the band banding was investigated by analyzing the core level shifts as function on the metal thickness deposited in the range of 2-100 Å. One can observe that when platinum is deposited on top of the PZT layer, the core levels of the substrate are strongly attenuated, which implies that the platinum layer is continuous. The 'fresh' sample exhibit lower binding energies than the 'annealed' sample indicating that the initial contamination layer is conductive and grounds the surface of the PZT layer, obstructing the band bending due to the ferroelectric polarization. Thanks This work was supported by the Romanian UEFISCDI funding agency through Contracts No. PN-II-RU-TE-2014-4-1117 project. References [1] S. Hüfner, Photoelectron Spectroscopy: Principles and Applications, Springer, Berlin, 2003. [2] H. Sezen, S. Suzer, Thin SolidFilms 534 (2013) 1–11. [3] N.G. Apostol, L.E. Stoflea, G.A. Lungu, C. Chirila, L. Trupina, R.F. Negrea, C. Ghica,L.Pintilie, C.M.Teodorescu, Appl. Surf. Sci. 273(2013) 415–425. [4] N.G. Apostol, L.E. Stoflea, G.A. Lungu, L.C. Tanase, C. Chirila, L. Frunza, L. Pintilie,C.M. Teodorescu, Thin SolidFilms 545 (2013) 13–21.

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P1-OXI_1 OPTICAL CHARACTERIZATION OF ULTRA-THIN FILMS, SURFACES AND INTERFACES USING SPECTROSCOPIC ELLIPSOMETRY

OXI - Oxide surfaces, interfaces and thin oxide films J. Gaston *, C. Eypert HORIBA Scientific - Palaiseau (France) Spectroscopic ellipsometry is a surface sensitive, non-destructive, non-intrusive optical technique that measures the change in the polarization state of light reflected from the surface of a sample.This technique is ideal to measure surfaces, ultra-thin films and interfaces including liquid/solid and liquid/liquid interfaces. It is widely used to determine film thickness and optical constants (n, k) and provides significant advantages for nano-material characterization such as determination of film thickness with Ångstrom resolution and determination of optical constants that allow the deduction of a wide range of physical properties. This technique gives also the possibility to perform dynamic studies in real time. We will present an overview of recent ellipsometric applications highlighting the importance of the optical characterization by spectroscopic ellipsometry for ultra-thin oxide films, carbon-based nanomaterials, self-assembly at the surfaces, alloys, materials for energy and liquid/solid interfaces.

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P2-OXI_17 HEAT TREATMENT IN LIQUID WATER USED TO PASSIVATE SILICON SURFACES

OXI - Oxide surfaces, interfaces and thin oxide films T. Sameshima *, T. Nakamura, T. Motoki, M. Hasumi Tokyo University of Agriculture and Technology - Koganei (Japan) We report simple heat treatment in liquid water to form thin oxide layer for passivating crystalline silicon surface [1]. 4-inch-n-type crystalline silicon substrates were heated in pure o water at 110 C for 1 h. Photo-induced effective minority carrier lifetime Teff markedly -6 -3 increased from 3.0x10 (initial) to 3.3x10 s. Teff maintained high values longer than 1000 h. The passivation oxide layer was thin of 0.7 nm, which was successfully formed over the large area. The metal-insulator-semiconductor type diodes were formed on the top surfaces by forming Al and Au metals on the thin passivated layers. The electrical current density J had a good rectified characteristic in the dark field, as shown in Fig. 1. This resulted from the built-in- potential in the silicon caused by the difference in work-function between the Al and Au electrodes. The low J under the reverse bias indicates a low density of carrier recombination defects. J also showed a good forward-bias-diode characteristic between 0.22 and 0.36 V. Fowler-Nordheim current characteristic was also observed between 0.36 and 0.45 V. AM 1.5 light illumination at 0.1 W/cm2 to the rear surface markedly increased the J. The short circuit current density was 31 mA/cm2. The photovoltaic effect was also observed with open circuit voltage of 0.47 V. Thanks This work was partly supported by Grants-in-Aid for Scientific Research C (No. 25420282) from the Ministry of Education, Culture, Sports, Science and Technology of Japan. References [1] T. Nakamura, T. Sameshima, M. Hasumi, and T. Mizuno, Jpn. J. Appl. Phys., 54, 106503-1-7 (2015).

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P4-OXI_54 PHYSICAL AND CHEMICAL PROPERTIES OF CEOX/SRTIO3(100) FILMS

OXI - Oxide surfaces, interfaces and thin oxide films J. Schusser *, K. Veltruská, T. Duchon, M. Aulická Charles University in Prague - Prague (Czech republic) Cerium is a rare earth element which has two stable oxide configurations - CeO2 and Ce2O3. The two ceria configurations differ in the occupation of the 4f level, with Ce4+ atoms having an empty 4f level, while Ce3+ atoms have one localized 4f electron. A facile reversible transition between these two states is utilized in many important industrial redox processes. Catalytic properties of cerium oxide are closely related to the concentration and coordination of oxygen vacancies. The formation of oxygen vacancies is easier on open surfaces as compared to the closed packed (111) surface. It is noteworthy that almost all model ceria studies are dealing with the (111) surface. There are only a few studies concerning the CeO2(100) and these utilize either chemically grown ceria nanocubes [1-3] or thick films grown ex situ by pulsed laser deposition, morphology and structure of which cannot be studied by STM [4-5]. In our laboratory, we were able to prepare well defined surfaces of ceria on SrTiO3(100) by evaporation in oxygen atmosphere. We studied this system in detail to fully characterize its electronic structure, Ce3+and Ce4+ fraction and re-oxidation. We also examined the interaction with platinum, which represents the next step towards designing a ceria based catalysts with low noble metal content. Surface science methods were used in order to follow the structural and chemical characteristics of prepared films, such as XPS, ISS, LEED, XPD and UPS. Thanks The study was supported by the Charles University in Prague, project GA UK No. 448216. References [1] Pan Y., Nilius N., Stiehler Ch., Freund H-J., Goniakowski J., Noguera C., 2014, Adv. Mater Interfaces, 1400404 [2] Fan Yang, YongMan Choi, Stefano Agnoli, Ping Liu, Dario Stacchiola, Jan Hrbek, and Jose A. Rodriguez, J Phys Chem C 2011, 115, 23062–23066 [3] Y. J. Kim, Y. Gao, G. S. Herman, S. Thevuthasan, W. Jiang, D. E. McCready, and S. A. Chambers, J. Vac. Sci. Technol. A 17. 3., May/Jun 1999, 926 [4] D. R. Mullins, P. M. Albrecht, T. - L. Chen, F. C. Calaza, M. D. Biegalski, H. M. Christen, S. H. Overbury, J Phys Chem C 2012, 116, 19419−19428 [5] P. M. Albrecht, D. R. Mullins, 2013, Langmuir, 29, 4559−4567

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P5-OXI_62 BIOFUNCTIONALIZATION OF TITANIUM SURFACE WITH DMP1 PEPTIDES FOR BIOMEDICAL APPLICATIONS

OXI - Oxide surfaces, interfaces and thin oxide films P. Lisboa-Filho 1,*, L. Trino 1,*, E. Bronze-Uhle 1, A. Ramachandran 2, M. Mathew 2, A. George 3 1UNESP - São Paulo State University (Brazil), 2University of Illinois at Chicago (United States of America), 3Rush University Medical Center (United States of America) Metallic biomaterials possess the combination of properties required for load-bearing applications. However, despite the good bulk characteristics, there are still an undesirable number of implants failures. In order to overcome such concerns, improvements could be achieved by designing biomaterials where the bulk and the surface are independently tailored with regenerative capabilities. Therefore, the objective of this study is to improve the osteointegration of Ti-surfaces by adding organic and biomolecules, as dentin matrix protein peptides (DMP1). We hypothesize that the hydroxyl groups presented in TiO2 surface will interact with the functional groups of the organic molecules that will enhance the DMP1 peptide interaction, improve cell adhesion and differentiation, leading to an implant success. Titanium cp discs were polished until Ra≈150 nm then cleaned with deionized water. The samples were etched and hydroxylated in Piranha solution. TiO2 deposition was performed by spin coating technique and then annealed at 830°C. The samples were divided in five groups. The control group consists in Ti substrate coated with TiO2, and the other four TiO2 surface were functionalized with 3-mercaptopropionic acid (MPA), 3-4 aminophenyl propionic acid (APPA), 3- aminopropyltrimetoxysilane (APTMS) and polyethylene glycol (PEG). Peptide pA (ESQES) and peptide pB (QESQSEQDS) were diluted in the ratio 1:4, respectively, in order to have a concentration of 1mg/mL. White Light Interferometry (WLI) was used to determine average surface roughness. To determine the chemical states of the elements X-ray Photoelectron Spectroscopy (XPS) analysis was carried out. Cell proliferation assay was performed with human mesenchymal stem cells (HMSC-GFP). Surface measurements demonstrated that the titanium surface modified with TiO2 presented low roughness than the biofunctionalized titanium. Higher surface roughness, as the presented ones, has shown improved cell adhesion. The XPS analysis revealed an increase in the intensity of C 1s for all samples, indicating the success in the functionalization process. The Proliferation assay showed that TiO2 coated with MPA and the peptides presented best results with HMSC-GFP cells. These findings suggest that the bio-functionalization of the Ti based substrates with organic and biomolecules could possibly open the door for designing better implants and their use in regenerative medicine. Thanks We would like to thank the Brazilian agency FAPESP for grants 2014/20471- 0, 2014/01713-3 and 2014/27015-0

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P6-OXI_80 FORMATION OF SILICON NANOISLANDS AND SILICON NANOCRYSTAL ON C-SI SUBSTRATES IN SIOX FILMS DEPOSITED BY HFCVD

OXI - Oxide surfaces, interfaces and thin oxide films J. Luna Lopez *, A. Benitez Lara, G. Garcia Salgado, F.J. Flores Gracia, A.D. Hernandez De La Luz, M.A. Dominguez Jimenez IC-CIDS Benemerita Universidad Autonoma de Puebla - Puebla (Mexico) In this work, we report the preparation and characterization of silicon nanoislands and silicon nanocrystals of non-stoichiometric silicon oxide (SiOx) films deposited by high filament chemical vapor deposition (HFCVD). The SiOx films are obtained at different hydrogen flow. High resolution transmission electron microscopy revealed that a high density of Si nanoislands and silicon nanocrystals (Si-ncs) were formed on the surface of the c-Si substrate and volume of SiOx films, respectively. The hydrogen flows in some case permit to obtain Si nanoislands and Si-ncs. The nanoislands are nanocrystallites with the different crystal orientation and ones similar as the substrate. The strain at the c-Si/SiOx interface is one of the main reasons for the nucleation of the self-assembled Si nanoislands that epitaxially grow on the c-Si substrate. On the others hand, Fourier transform infrared spectroscopy reveals, so that, the film composition changes with the hydrogen flow, also the vibrational band stretching have a behavior in agreement with the thickness obtained with profilometry. FTIR spectra show vibrational bands related to the presence of hydrogen in all SiOx films. SiOx films exhibit broad photoluminiscence (PL) spectra with main peaks at 650 and 850 nm with high intensity and this is enhanced when the hydrogen flow decreases. Analysis of the HRTEM, FTIR data and PL spectra can be correlated to explain this, and results are presented. Thanks This work has been partially supported by projects CONACyT-255062 and VIEP-BUAP- LULJ-EXC-2016, PROFOCIE-2016. The authors acknowledge INAOE and IFUAP laboratory for their help in the samples measurements. Authors also want to thank University of Texas (UTSA) for the HRTEM measurements. References [1] Nesbit L A, 1985 Appl. Phys. Lett. 46, 38. [2] Li Q, Pattada B, Brueck S R J, Hersee S and Han S M, 2005 J. Appl. Phys. 98 073504.

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P7-OXI_115 CHEMICAL-STATE ANALYSIS OF TRACE-LEVEL ALKALI METALS AND ALKALINE- EARTH METALS SORBED IN LAYERED OXIDES BY TOTAL-REFLECTION X-RAY PHOTOELECTRON SPECTROSCOPY

OXI - Oxide surfaces, interfaces and thin oxide films Y. Baba 1,*, I. Shimoyama 2, N. Hirao 2 1Japan Atomic Energy Agency - Fukushima (Japan), 2Japan Atomic Energy Agency - Ibaraki (Japan) After the accident of the Fukushima Daiichi Nuclear Power Station in March 2011, various kinds of anthropogenic radionuclides such as 137Cs and 90Sr were released into the environment. Most of the radionuclides are sorbed in clay minerals among geological materials. It was reported that radioactive cesium is strongly sorbed in layered oxides (mica) in clay minerals [1]. The chemical states of cesium in layered oxides have been measured by various spectroscopic methods such as X-ray photoelectron spectroscopy (XPS) [2] and X-ray absorption fine structure (XAFS) [1] using non-radioactive cesium. However, chemical states of radionuclides may be different from those of non-radioactive elements, because the number of atoms in radioactive nuclides is extremely small. In the present study, we have investigated chemical states of trace-level alkali metals (Na, Rb, Cs) and alkaline-earth metals (Sr) adsorbed on oxides and sorbed in micaceous oxides by XPS under X-ray total- reflection (TR) condition. Owing to the background reduction in TR-XPS spectra, we could observe down to 100 pg•cm-2 for cesium and 150 pg•cm-2 for strontium, respectively, sorbed in mica. These 137 90 amounts correspond to about 200 Bq of Cs (t1/2=30.2 y), and 300 Bq of Sr (t1/2=28.8 y), so it was demonstrated that trace-level cesium and strontium corresponding to radionuclide level can be measured by TR-XPS.

The XPS spectra for alkali metals (Na, Rb, Cs) adsorbed on oxides (SiO2, Al2O3) showed that the chemical states of alkali metals are the same irrespective of the layer thickness down to 1/100 monolayer, suggesting that the alkali metals are adsorbed through weak Van- der-Waals force. For alkali metals sorbed in micaceous oxides, it was found that the core- level energy in TR-XPS for trace-level cesium shifted to lower-energy side compared with that for thicker layer. This tendency was reverse to that observed for sodium. On the basis of a charge transfer within a simple point-charge model, it is concluded that the chemical bond between alkali metals and micaceous oxide for ultra-thin layer is more polarized that for thick layer. The results show that trace-level alkali metals in micaceous oxides is more ionically bonded at the interlayer due to the negative charge of the micaceous oxide compared with thicker layer. References [1] A.J. Fullera et al., Applied Clay Science 108, 128 (2015). [2] Y. Kim et al., Geochim. Cosmochim. Acta 60, 1041 (1996).

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P8-OXI_130 CONTROL OF CRYSTAL ORDER IN RF-SPUTTERED BIFEO3/SRTIO3 HETEROJUNCTIONS BY MEANS OF X-RAY PHOTOELECTRON DIFFRACTION: DEMONSTRATION OF EPITAXIAL GROWTH FOR POLARITY-DRIVEN APPLICATIONS.

OXI - Oxide surfaces, interfaces and thin oxide films A. Giampietri *, G. Drera *, L. Sangaletti ILAMP and Dipartimento di Matematica e Fisica, Università Cattolica - Brescia (Italy)

The discovery of a two-dimensional electron gas (2DEG) at the interface between LaAlO3 and SrTiO3 has disclosed new perspectives in the research field for novel materials engineering. Apart from LaAlO3, many other perovskite materials have also been considered[1], suggesting a rather universal mechanism for the conductivity onset. In particular, the 2DEG has been also detected in amorphous samples; such finding challenges both the "intrinsic" theoretical explanation for the onset of the 2DEG and the possibilities to experimentally determine the crystalline order at nanometer-thin heterointerfaces.

Among trivalent perovskites, BiFeO3 is a promising candidate material for epitaxial ABO3/SrTiO3 heterojunctions. Recently, a conductive layer has been measured in [2] BiFeO3/SrTiO3 by means of cross sectional AFM . This conductive layer, combined with the room-temperature multiferroic behaviour of BiFeO3, could enable the production of new nanotechnology devices, in which the electrical properties could be tailored magnetically. Sputtering deposition is one of the most common techniques used for device fabrication, due to the fast, cheap and reproducible growth of films with a large practicable area. Sputtering is usually considered a rough deposition technique, which may result in low- quality thin films with inadequate homogeneity; however, with a good control of growth parameters and deposition geometry, sputtering can actually produce high-quality epitaxial films[3]. The objective of this work is to demonstrate the reliability of RF sputtering in the growth of epitaxial BiFeO3 ultrathin films on SrTiO3. Particular emphasis will be given to the use of X- ray photoelectron diffraction (XPD) as a trustworthy technique for the analysis of long-range crystal order in ultrathin epitaxial films. XPD has thus been used as a tool to probe the transition from amorphous to epitaxial thin films, while retaining chemical selectivity both on substrate and BiFeO3 layer. The similitudes between BiFeO3/SrTiO3 and LaAlO3/SrTiO3 heterostructures are further demonstrated by a photoemission analysis of valence band electronic states. References

[1] Li et al., Tailoring the two dimensional electron gas at polar ABO3/SrTiO3 interfaces for oxide electronics, Scientific Reports 5 (2015) 13314.

[2] Chen et al., Two-dimensional electron gas at the Ti-diffused BiFeO3/SrTiO3 interface., Appl. Phys. Lett. 107 (2015) 031601 [3] Koster et al., Epitaxial Growth of Complex Metal Oxides, Woodhead Publishing, 2015.

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P9-OXI_145 RAMAN SPECTROSCOPY AND CL FROM ZNO INDUCED BY FS LASER IRRADIATION

OXI - Oxide surfaces, interfaces and thin oxide films Y. Esqueda Barrón 1,*, M. Herrera Zaldivar 2, A. Esparza-García 3, S. Camacho-López 1 1Departamento de Óptica, Centro de Investigación Científica y de Educación Superior de Ensenada, Carretera Ensenada-Tijuana 3918, Zona Playitas, Ensenada, Baja California 22860, México - Ensenada (Mexico), 2Centro de Nanociencias y Nanotecnología, Universidad Autónoma de México, 22800 Ensenada, Baja California, Mexico - Ensenada (Mexico), 3Fotofísica y Películas Delgadas, Departamento de Tecnociencias, Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Autónoma de México, Apdo. Postal 70-186, México, DF 04510, México - Ensenada (Mexico) This work shows a novel optical technique to rapidly synthetize ZnO thin films [1]. This technique uses laser-induced oxidation in a Zn metallic thin film previously deposited on fused silica substrates. We used a Ti:sapphire fs laser tightly focused on the surface of a metallic thin film, the exposure of the sample is carried out in atmospheric air. A series of experiments consisting of linear scans on the film surface varying the laser irradiation parameters were carried out. The synthesized ZnO was characterized to determine its crystalline structure, morphology and luminescent features. For this purpose we used micro- Raman spectroscopy, Scanning Electronic Microscopy and Cathodoluminescence (CL). Our Raman results show that we can induce nanostructured or polycrystalline ZnO when we select the right irradiation parameters. CL spectra show that good quality ZnO thin films can be obtained by this method; the quality of the ZnO is judged by computing the ratio between the intensity of the band edge emission (UV emission 3.28 eV) and the intensity of the defects associated emission (green emission 2.5eV) [2]. SEM shows the size of the ZnO particles and its morphology. This novel technique for synthesizing metallic oxides significantly reduces the oxidation time; it also eliminates the need of an annealing process and many other chemical reactions or processes after the synthesis. The optical synthesis takes only a few seconds to induce the metallic oxide of interest, and notably we can select the adequate laser irradiation parameters to obtain specific ZnO characteristics, as a selective luminescence. The results obtained through micro-Raman spectroscopy, optical microscopy and CL measurements allow us to conclude on the one hand that nanostructured ZnO formation occurs at low laser fluences, and that the nanostructures do not show CL signal (luminescence emission); on the other hand, for high fluences we obtain polycrystalline ZnO which shows two luminescence emission peaks, a weak green one related to a low density of lattice defects and a strong band edge peak in the UV. Thanks The authors acknowledge support from AFOSR through grant FA9550-15-1-0142. References [1] M. Cano-Lara, S. Camacho-López, a. Esparza-García, and M. a. Camacho-López, “Laser-induced molybdenum oxide formation by low energy (nJ)–high repetition rate (MHz) femtosecond pulses,” Opt. Mater., vol. 33, no. 11, pp. 1648–1653, 2011. [2] L. Sucheol, L. Eunmo, E. L. Cheol, J. N. Seung, and S. K. Hee, “Cathodoluminescence from ZnO Single Nanorods,” J. Korean Phys. Soc., vol. 58, no. 41, p. 894, 2011.

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P10-OXI_151 SYNTHESIS AND CHARACTERIZATION OF TIO2 NANOTUBES ENRICHED WITH CALCIUM AND PHOSPHOROUS: A PROMISING MULTIFUNCTIONAL SURFACE FOR BIOMEDICAL APPLICATIONS

OXI - Oxide surfaces, interfaces and thin oxide films P. Lisboa-Filho 1,*, S.A. Alves 2,*, S. Patel 3, C. Sukotjo 4, M. Mathew 5, J.P. Celis 6, L. Rocha 1, T. Shokuhfar 4 1UNESP - São Paulo State University (Brazil), 2University of Minho (Portugal), 3Michigan Technological University (United States of America), 4University of Illinois at Chicago (United States of America), 5Rush University Medical Center (United States of America), 6KU Leuven (Belgium) Commercially pure titanium (cp-Ti) is the material most commonly used in dental implants. Despite its outstanding properties, a significant number of failures occur due to the lack of osseointegration and degradation of dental implant material by corrosion. Nowadays, the modification of titanium surface features such as nano-morphology/topography and chemistry, has been employed in the attempt to design titanium oxide surfaces able to overcome the current failures. The main aim of this work was the synthesis and characterization of bio-multifunctionalized TiO2 nanotubular structures with Calcium (Ca) and Phosphorous (P) able to, simultaneously, enhance the biological functions and improve the bio-electrochemical stability of titanium. Mirror polished discs of cp-Ti grade 2 (15 mm diameter and 2mm thickness) were the substrates used in this study. Ca and P-doped TiO2 nanotube surfaces were synthesized by two-step anodization process. Firstly, nanotubes were grown on polished cp-Ti samples by anodization at 60V for 30min. in an electrolyte containing ethylene glycol, 0.3wt.% ammonium fluoride and 3vol.% distilled water. Afterwards, the TiO2 nanotubes were cathodically and anodically treated in an electrolyte composed of 0.35M calcium acetate and 0.04M β-glycerophosphate. The novel surfaces were characterized by Scanning Electron Microscopy (SEM), White Light Interferometry (WLI), Energy-Dispersive X-ray Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS) and Water Contact Angle (WCA) measurements. The adhesion quality of MG63 cells was studied by SEM and fluorescence microscopy and cell proliferation was assessed by MTT assay. Furthermore, the corrosion behavior of bio-functionalized TiO2 nanotubes was investigated in artificial saliva by potentyodinamic polarization. The results showed that well-ordered TiO2 nanotubes with 74.5 13.2nm diameter, 17.2 4nm wall-thickness and 13 1.1μm length were synthesized and successfully bio-functionalized and presented highly ordered nano-morphology characterized by non-uniform diameters . XPS results suggest that after functionalization treatments, Ca-based compounds were present on TiO2 nanotubes such as Calcium Oxide (CaO) and Calcium Fluoride (CaF2), as well phosphate groups. Additionally, the results showed that bio-functionalized TiO2 nanotubes were highly hydrophilic and enhanced the adhesion and proliferation of MG63 cells compared to smooth titanium, used as control. These are novel and promising surfaces for dental implants since they influenced cell functions showing potential to improve osseointegration, and simultaneously, provided a superior corrosion performance in artificial saliva. Thanks Authors thank IBTN/US – American Branch of the Institute of Biomaterials, Tribocorrosion and Nanomedicine and IBTN/Br – Brazilian Branch of the Institute of Biomaterials, Tribocorrosion and Nanomedicine.

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P11-OXI_177 HIGH-THROUGHPUT CHARACTERISATION OF THE ENERGETICS OF ALL METAL OXIDE JUNCTIONS

OXI - Oxide surfaces, interfaces and thin oxide films K. Rietwyk *, D. Keller, H.N. Barad, A. Ginsburg, K. Majhi, Z. Yan, A. Anderson, Z. Arie Bar-Ilan University - Ramat Gan (Israel) During the 1990s a major breakthrough in thin film technologies was achieved with the application of metal oxide buffer layers between organic/polymer layers and metal electrodes. This improved the energy level alignment between the layers, resulting in a drastic enhancement in the performance of a range of devices. There has since been growing interest in active metal oxide layers, due to their high abundance, stability, and low- cost processing. Consequently, metal oxides are more frequently grown as adjacent layers in thin film devices. However, the underlying mechanisms that determine the energetics across all metal oxide interfaces have yet to be extensively investigated. To address this shortcoming we have developed an innovative depth profiling method. Exploiting the proven combinatorial metal oxide growth techniques we deposit a metal oxide layer with a thickness gradient onto a homogeneous metal oxide layer. Depth profiling is then achieved by laterally scanning the energetics across the sample using scanning Kelvin probe, air photoemission and UV-Vis optical analysis and correlating the measured properties of the layer to the thickness. From this an entire band diagram of the entire active depth of the junction can be developed. To demonstrate the power of this technique we will provide a complete band diagram of the TiO2-Co3O4 heterojunction which has recently shown promise in all oxide photovoltaics and water splitting.

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P12-OXI_250 FORMATION OF A THERMALLY STABLE BILAYER EXPLOITING THE SURFACE CORRUGATION OF RUTILE TIO2(110)

OXI - Oxide surfaces, interfaces and thin oxide films D.A. Duncan 1,*, J. Pfisterer 2, P.S. Deimel 2, R.G. Acres 3, M. Fritton 4, P. Feulner 2, J.V. Barth 2, F. Allegretti 2 1Diamond Light Source (United Kingdom), 2Techincal University of Munich (Germany), 3Elettra- Sincrotone Trieste (Italy), 4Deutsches Museum (Germany) Nucleobases offer an interesting proposition as an adsorbate: they are highly polar molecules that form strong hydrogen bonds, but yet, due to their aromaticity, are also thermally stable and easy to sublimate. Similarly the rutile (110) termination of titanium dioxide provides a fairly unique corrugation in its surface both geometrically and electronically. Therefore the adsorption of thymine, a pyrimidine based nucleobase, onto TiO2(110) provides an interesting substrate to study the interaction of organic and inorganic polarity. We present a study of just such a system utilising near-edge X-ray absorption fine structure (NEXAFS), X-ray photoelectron spectroscopy (XPS), temperature programmed XPS and temperature programmed desorption. The results of this study strongly indicate the growth of a room temperature stable bilayer, which could only be removed by annealing to 450 K. The remaining first layer was remarkably robust, surviving annealing up to 550 K. The comparison to XPS of a sub-monolayer exposure of 1-methyluracil shows that the origin of the room temperature stable bilayer is not intermolecular interactions. This discovery, alongside the deprotonation of one of the first layer’s pyrimidinic nitrogen atoms at room temperature, suggests that the thymine molecules in the first layer bind to the undercoordinated surface Ti atoms, and the second layer thymine molecules coordinate with the bridging oxygen atoms which protrude above the Ti surface plane on the (110) surface as indicated in the attached figure.

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P13-OXI_280 COMBINED NEUTRON AND X-RAY REFLECTIVITY CHARACTERIZATION OF MICROELECTRONICS SENSIBLE INTERFACES IN THE FRAMEWORK OF THE IRT NANOELEC

OXI - Oxide surfaces, interfaces and thin oxide films J. Segura-Ruiz 1,*, P. Gutfreund 1, R. Cubitt 1, A. Ponard 2, G. Imbert 2 1ILL - Grenoble (France), 2STMicroelectronics - Grenoble (France) The fabrication of integrated circuits (ICs) in the microelectronics industry frequently involves multilayer structures stacking different materials (metals, dielectrics) on a substrate, typically silicon. Delamination at a weak interface is a serious problem in manufacture not only due to the loss of the product itself, but mainly because the equipment downtime due to contamination. This is the main interesting of preventing as much as possible any risk of delamination during the ICs manufacture. In this work, we report on the combined use of neutron and X-ray reflectivity to characterize key interfaces for the microelectronics industry. We use as an example the interface between a-C and SiO2. Two different deposition conditions to grow the SiO2 layer on top of a-C were considered. One particular condition showed qualitative difference in terms of adhesion when attempting to detach layers using adhesive tape (scotch test). The goal of this study was to compare neutron reflectivity (NR) spectra of two types of interfaces between SiO2 and a-C (one delaminating with scotch test, the other one no). These measurements have been complemented with X-ray reflectivity (XRR) in order to unambiguously determine the chemical composition of the structure as a function of depth. NR has shown the existence of an intermediate layer between the a-C and the SiO2 layers that was not evidenced by XRR. This IL has been associated with the accumulation of H inside the SiO2 layer near the interface with the a-C. Complementary XRR and NR characterization allows the independent determination of the mass density and the H- concentration of each layer. The characteristics of the IL, in particular its H-concentration and thickness, seem to be correlated with higher strain and hence a greater susceptibility of cracking in the vicinity of this interface consistent with the appearance of off-specular scattering. A plot of the molecular weight as a function of the mass density for each layer graphically demonstrates the risk of delamination of each sample. The combination of NR and XRR is shown to be a powerful technique in the characterization of layers and interfaces used in the micro/nanoelectronics industry. The same approach can be extended to other interfaces commonly used in microelectronics, most of them having hydrogen involved in the fabrication process. This work was done in the framework and thanks to the French national program “programme d’Investissements d’Avenir, IRT Nanoelec” ANR-10-AIRT-05.

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P14-OXI_303 EFFECTS OF MECHANICAL STRESS ON ELECTRONIC PROPERTIES OF SINGLE III- NITRIDE NANOWIRES

OXI - Oxide surfaces, interfaces and thin oxide films L. Jaloustre 1,*, G. Manchon 2, S. Le Denmat 3, F. Dahlem 2, R. Songmuang 1 1Université Grenoble Alpes, CNRS, Institut Néel, Nanophysique et Semiconducteurs group - Grenoble (France), 2Laboratoire de Tribologie et Dynamique des Systemes, Ecole Centrale de Lyon - Ecully (France), 3CNRS, Institut Néel - Grenoble (France) Harvesting energies from the ambient of our daily lives and converting them into electricity has received an increasing interest nowadays. Since 2006, ZnO piezoelectric semiconductor nanowires (NWs) has been demonstrated as a promising building block for nanogenerator applications by scavenging the mechanical energy from very tiny vibrations in our environments [1]. In order to improve the efficiency and/or create new functionalities of such devices, the fundamental mechanism responsible for their operation must be well understood. Here, we focus our interest on III-Nitride semiconductors, which are an important material in mainstream optoelectronics, high-power electronics and sensorics. GaN has several superior features compared to ZnO, such as a much better p-type doping controllability, higher thermal stability, and larger spectral response tunability from far-IR to deep-UV range. In addition, it was claimed that the piezoelectric coefficient of GaN significantly increases in NW geometry, especially in the case of the NWs with small diameter [2]. These mentioned properties of III-Nitrides could possibly enable a much more flexibility to engineer the device characteristics, than ZnO. In this present work, the catalyst-free III-Nitride NWs synthesized by plasma-assisted molecular beam epitaxy were studied via local probing techniques. We investigated the giant-piezoelectric effect in III-Nitride NWs by performing conventional and dual-frequency resonance-tracking piezoresponse force microscopies (PFM) on GaN thin films in comparison to single GaN NWs and III-N NW heterostructures. The piezoelectric coefficients were extracted from these measurements with a careful adjustment of the measurement parameters, using PPLN as a reference sample and avoiding misleading background signal / cross-talk artefacts. After this local characterization of piezoelectric properties, the current generating function of these NWs was explored by locally applying mechanical force on the ensemble of vertical NWs via SPM scanning tip. Such an electrical- mechanical conversion feature was further studied by applying a mechanical stress on single contacted III-N NWs, including the NW heterostructures. The experimental results were qualitatively compared with finite-element simulations of mechanical-induced piezopotential and electronic bandstructure calculations. References [1] Wang, Z-L. and Song, J. Science 2006, 312, 242-246 [2] Espinosa, H.D.; Bernal, R. A. and Minary‐Jolandan, M. Advanced Materials 2012, 24, 4656-4675

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P15-OXI_314 ULTRA THIN PT-DOPED CEO2 FILMS BY DLI-CVD

OXI - Oxide surfaces, interfaces and thin oxide films B. Domenichini *, N. Zanfoni *, P. Simon, R. Chassagnon, V. Potin, L. Imhoff, S. Bourgeois ICB, CNRS-Univ. Bourgogne/Franche Comté - Dijon (France) Ceria based oxides have been widely used as catalysts or as electrolyte material for fuel cells. Moreover, interaction between noble metal such as Pt with ceria enhances its catalytic activity by improving the reducibility of the surface. Recently, DFT calculations have predicted that atomically dispersed platinum is 2+ stabilized in specific oxidation state Pt at the surface of CeO2 {100} type nanofacets [1]. Our experimental study was carried out in this context.

Pt-CeO2 ultra thin films have been synthesized by direct liquid injection CVD according to a protocol where platinum is involved in process for the last deposition steps only. Growths have been carried out on silicon substrate but also on carbon coated Cu TEM grids (see pictures) allowing direct observations of the grown layers without any prior preparation of the samples, which may damage or modify their structure and chemical state. TEM results show that the layers are composed of very well crystallized ceria particles with a homogeneous grain size (~10 nm) exhibiting nanofacets (see pictures) where the presence of cationic platinum (Pt2+) is observed through photoemission analyses. Thanks This research is supported by the European Community's Seventh Framework Program within FP-7-NMP-2012 project chipCAT under Contract No. 310191 and FP7/2007-2013 CALIPSO under grant agreement No.312284. References [1] A. Bruix, Y. Lykhach, I. Matolínová, A. Neitzel, T. Skála, N. Tsud, M. Vorokhta, V. Stetsovych, K. Ševčíková, J. Mysliveček, R. Fiala, M. Václavů, K. C. Prince, S. Bruyère, V. Potin, F. Illas, V. Matolín, J. Libuda and K. M. Neyman, Angew. Chemie - Int. Ed. 201 (2014) 1.

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P16-OXI_377 QUARTZES: STRUCTURE, WATER ABSORPTION AND SURFACE MODIFICATION

OXI - Oxide surfaces, interfaces and thin oxide films K. Allaberdiev * Ukraine State Scientific Research Institute for Plastics - Donetsk (Ukraine) Quartzes are very useful fillers of polymer composites.The structure, absorption water molecules and the surface modification of commercial fused quartzes FS-105, PK-95 and natural the quartz KQ were investigated by Fourier transform infrared spectroscopy (FTIR). In the IR- spectrum of the quartz PK-95 have been identified the absorbtion band which characterizes siloxy(SiO-) defect in structure. The content this defect in studied quartzes varies in the order: KQ<< FS-105

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P17-OXI_381 SUPPRESSION OF THE CO SPIN-STATE AND METAL-INSULATOR TRANSITIONS IN EPITAXIAL THIN FILMS OF PR0.50CA0.50COO3 ON LAALO3

OXI - Oxide surfaces, interfaces and thin oxide films X. Torrelles 1,*, J. Padilla 1, J. Herrero 2, J. Blasco 3, J. Rubio 4, B. Bozzo 1, J. Gazquez 1, J.L. Garcia 1 1Institute of Materials Science of Barcelona (ICMAB-CSIC) - Barcelone (Spain), 2ALBA Synchrotron Light Source - Barcelone (Spain), 3Instituto de Ciencia de Materiales de Aragón - Zaragoza (Spain), 4SpLine Spanish CRG Beamline at the ESRF - Grenoble (France) Pr0.50Ca0.50CoO3 has received considerable attention in bulk form due to the charge transfer from Pr to Co ions at the metal-insulator transition as well as being the first strongly correlated oxide able to offer large an ultrafast photoresponse in the insulating phase [1-5]. Thin films of PrCaCoO3 (PCCO) were deposited on (100) LaAlO3 (LAO) substrates by pulsed laser deposition technique. The film grows epitaxially on the surface with two times the substrate periodicity and with the long b-axis of the Pnma cell of the bulk PCCO perpendicular to it. Compared to the latter, the film structure is noticeably relaxed, as denoted by a reduction of the space group symmetry from Pnma (bulk) to P212121 (film). Other remarkable differences were found in comparison to the bulk material. The film is ferromagnetic below 170 K and exhibits metallic conductivity in the whole temperature range, in contrast to the non-magnetic insulating behaviour of the bulk system at low temperature. We have found that the P212121 structure of the film persists down to low temperatures, confirming the suppression of the Co spin-state and metal-insulator transitions recently described in PCCO ceramic samples. Thanks We would like to thanks the Spanish MICINN Ministry for economical support through project MAT2015-68760-C2-2-P as well as the CSIC for scientific and economical support. References [1] A. J. Barón-González, C. Frontera, J. L. García-Muñoz, J. Blasco, and C. Ritter, Phys. Rev. B 81, 054427 (2010). [2] J. Hejtmánek, E. Šantavá, K. Knížek, M. Maryško, Z. Jirák, T. Naito, H. Sasaki, and H. Fujishiro, Phys. Rev. B 82, 165107 (2010). [3] K. Knizek, J. Hetjmánek, P. Novák, and Z. Jirák, Phys. Rev. B 81, 155113 (2010). [4] J. L. García-Muñoz, C. Frontera, A. J. Barón-González, S. Valencia, J. Blasco, R. Feyerherm, E. Dudzik, R. Abrudan, and F. Radu, Phys. Rev. B 84, 045104 (2011). [5] J. Herrero-Martín, J. L. García-Muñoz, S. Valencia, C. Frontera, J. Blasco, A. J. Barón-González, G. Subías, R. Abrudan, F. Radu, E. Dudzik, and R. Feyerherm, Phys. Rev. B 84, 115131 (2011). Also Phys. Rev. B 86, 125106 (2012).

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P18-OXI_400 ULTRATHIN INTERFACIAL OXYDE LAYERS IN EPITAXIAL COO/FE MAGNETIC SYSTEMS

OXI - Oxide surfaces, interfaces and thin oxide films A. Ramos 1,*, S. Grenier 1,*, A. Bailly 1, M. De Santis 1, A. Lamirand 1, E. Mossang 1, D. Testemale 1, J.M. Tonnerre 1, M. Jamet 2, C. Vergnaud 2, M.M. Soares 3, J.C. Cezar 3, H.C.N. Tolentino 3, N. Jaouen 4 1Institut Neel - Grenoble (France), 2CEA - Grenoble (France), 3LNLS - Campinas (Brazil), 4Synchrotron Soleil - Saint Aubin (France) Magnetic coupling between thin films of an antiferromagnet (AFM) and a metal ferromagnet (FM) is extremely sensitive to the interface intermixing and interfacial roughness. When the AFM is an oxide, the ultrathin layer (2-4ML) due to the oxidation of the ferromagnetic in contact is crucial to understand the magnetic properties [3]. We investigate the structural and magnetic properties of the ultrathin FeOx layer in CoO/Fe coupled layers epitaxially grown on a Ag(001) substrate. The approach combines growth and in situ structural study and ex situ extensive investigations coupling laboratory (XRR, MOKE, AFM ) and synchrotron-based techniques (XAS, XMCD,XMLD, XRMS..). Co L edge XMLD shows that the Co spins always lie in the film plane The thin Fe oxide layer is identified as Fe3O4-like. Coupled to magneto-optic Kerr effect (MOKE) measurements, element selective absorption- based probes show that exchange coupling causes a perpendicular magnetic anisotropy in the Fe layer.. The Fe easy axis lies in-plane at room temperature but rotates out-of-plane when cooled from RT under an applied out-of-plane field. The out-of-plane magnetization then vanishes when the temperature rises back to RT. Soft XRMS measurements , at the Fe and Co L3 edges were simulated by a model with the two Fe moment orientations, and including a mixed Fe and Co oxide interface layer. It confirms s the in-plane to out-of-plane easy axis spin transition below the CoO AFM ordering temperature and identifies the spin profile perpendicularly to the film plane . References [1] T.J. Regan, H. Ohldag, C. Stamm et al. Phys. Rev. B 64, 214422 (2001). [2] R. Abrudan, J. Miguel, M. Bernien et al. Phys. Rev. B 77, 014411 (2008). [3] R. Bali, M. Soares, A.Y. Ramos, et al. Appl. Phys. Lett. 100, 132403 (2012).

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P19-OXI_407 INFRARED SPECTROSCOPY AND ELLIPSOMETRY CARACTERIATION OF SOL GEL DIOXIDE TITANIUM THIN FILMS

OXI - Oxide surfaces, interfaces and thin oxide films N.H. Arabi 1,*, A. Iratni 2, B. Capoen 3, M. Bouazaoui 3, M. Halbwax 4, J.P. Vilcot 4 1Preparatory Scool of Science and Technology of Annaba - Annaba (Algeria), 2MPE Unit of Research, UMBB University - Boumerdes (Algeria), 3PhLAM laboratory, Lille 1 University - Villeneuve D'ascq (France), 4IEMN Central Laboratory - Villeneuve D'ascq (France)

Dioxide Titanium (TiO2) is an extensively studied material [1] [2] for its biocompatibility, its high dielectric constant and high refractive index, its chemical and mechanical resistance and for its catalytic activity. Different deposition techniques are commonly used according to the layer properties desired to obtain. For optical applications, a high density and a high refractive index are necessary. Intensive knowledge of its crystal structure is necessary to understand its physic-chemical, thermal and optical properties.

In this work, we are interested in the sol gel synthesis of TiO2 thin films deposited on monocrystalline silicon by dip-coating process in order to study the influence of the thickness and the heat treatment on the crystalline densification and optical parameters of TiO2 thin films, using Fourier Transmission Infrared spectroscopy (FTIR) and Ellipsometry characterization.

Keywords: TiO2, sol gel, thin films, FTIR, XRD, monocrystalline silicon References [1] Xing wang Zhangand and Lecheng Lei. Hazardous materials, 153, 2008, 1-2. [2] R. Mechiakh et al. Optical materials, 30, 2007, 4.

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P20-OXI_457 RESISTIVE SWITCHING BEHAVIOUR OF GRAPHENE OXIDE METAL-INSULATOR- METAL HETEROSTRUCTURES FOR EMERGING NON-VOLATILE MEMORY APPLICATIONS

OXI - Oxide surfaces, interfaces and thin oxide films G. Rius * IMB-CNM-CSIC (Spain) The current digital era demands new approaches for information storage, such as devices which are more efficient, effective and versatile. In this work, the resistive switching (RS) behaviour is studied on trilayer heterostructures of metal-insulator-metal (MIM) type. Graphene oxide (GO) is proposed as the insulating material; precisely, ultrathin membranes of a few tens of nanometers. The thin films are formed by disordered overlap of monoatomic GO flakes, having grain sizes of 1-10 µms. In detail, the complete MIM structure consists of Ti-GO-Ti trilayer, where the first generation of prototype devices have been fabrication using a unique combination of conventional planar technology techniques. In addition to fabrication high yield, scale up compatibility and low cost, this technology could be applied to portable and wearable electronic devices, based on GO flexibility and transparency properties. Preliminary electrical characterization of GO-RS devices have confirmed the suitability of the designed and executed nanofabrication technology, while its versatility would allow a fundamental Ti-GO-Ti RS performance comprehension, importantly, based on statistic data. Based on that one would allow operational optimization, and extended its applicability to the whole family of new two dimensional (nano)materials. Both achievements, which are very promising for non-volatile memory devices, would also be useful in other applications such as neuromorphofic layers. Practically, the fabrication efficiency of first batches of completed MIM structures based on GO membranes is ~80%. Electrical characterization is based on reported studies [1,2], where I/V curves are executed using -5 V to 0 and 0 to 5 V sweeps. Several behaviour have been observed on tested Ti-GO-Ti devices. Mainly two kinds of categories can be observed: 1) those which present stable hysteresis behaviour for several cycles, when in spite of detection of filament formation or dielectric rupture do stay in a high resistive state (HRS) permanently; and 2) those which present dielectric rupture, reversible HRS and its degradation. References [1]S. K. Kim, J. Y. Kim, S. Y. Choi, J. Y. Lee, and H. Y. Jeong, Adv. Funct. Mater., pp. 6710–6715, 2015. [2]N. T. Ho, V. Senthilkumar, and Y. S. Kim, Solid. State. Electron., vol. 94, pp. 61–65, 2014.

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P21-OXI_460 POLARIZATION DEPENDENT PT/RU/PB(ZRX TI1-X)O3 INTERFACE CHEMISTRY AND ELECTRONIC STRUCTURE STUDIED BY OPERANDO HARD X-RAY PHOTOEMISSION SPECTROSCOPY

OXI - Oxide surfaces, interfaces and thin oxide films I. Gueye 1,*, G. Le Rhun 1, O. Renault 1, D. Ceolin 2, J.P. Rueff 2, E. Defay 3, N. Barret 4 1Univ. Grenoble-Alpes - CEA, LETI, MINATEC Campus - Grenoble (France), 2Synchrotron-SOLEIL - Gif-Sur-Yvette (France), 3Luxembourg Institute of Science and Technology (LIST) - Materials Research and Technology Department - Belvaux (Luxembourg), 4SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay - Gif-Sur-Yvette (France) Pb(Zrx Ti1-x)O3 (PZT) thin films are used worldwide for applications like ferroelectric random access memories (FeRAM), Integrated Passives Devices (IPDs) such as capacitors and MicroElectroMechanical systems (sensors, actuators, energy harvesting etc.), owing to their outstanding ferroelectric, dielectric, pyroelectric and piezoelectric properties[1]. For all these applications, the basic device architecture is a Metal/Insulator/Metal (MIM) stack. The continuous trend towards miniaturization requires scaling down the thickness [2] and increasing the role of the interface on the overall electrical response [3]. Therefore the understanding of interface properties under applied bias is highly desirable in order to characterize real device interfaces under working i.e. operando, conditions. We have used hard X-ray photoemission spectroscopy to probe the electrode/PZT interface in a Pt/Ru/PZT(220nm)/Pt/TiO2/SiO2/Si stack. A customized sample-holder allows in-situ photoemission analysis of the interface while applying bias the metal-insulator-metal capacitor. Hard X-rays probe the buried interface through the top electrode. The use of operando conditions reveals additional Pb and Zr core level components related to ZrO2 interface nanostructures [4] and some residual PbO under negative top electrode bias. They suggest a dielectric polarization response to the applied bias which can only be observed by operando analysis. Keywords: PZT, Interface, HAXPES, operando

Fig.1: (a) schematic of sample wiring for application of bias voltage to top electrode in the operando photoemission experiment. (b) Ru3p, Pb4d and Zr 3s core level spectra for +3 and -7 V top electrode bias. References [1] ] N. Izyumskaya et al., Crit. Rev. Solid State Mater. Sci. 32, 111 (2007. [2] N. Setter et al., J. Appl. Phys. 100, 051606 (2006). [3] L. Pintilie and M. Alexe, J. Appl. Phys. 98, 124103 (2005) [4] I. Gueye, O. Renault, P. Gergaud, G. Le Rhun, E. Defay, N. Barrett , Appl Surf Sci. 363 (2016) 21– 28

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POL - Polymer surfaces and interfaces

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I08_POL_452 SOLID CAPILLARITY: WHEN SURFACE PROPERTIES DOMINATE THE MECHANICS OF SOFT SOLIDS

POL - Polymer surfaces and interfaces E. Dufresne * Department of Materials, ETH Zurich (Switzerland) The classic models of solid mechanics were developed to describe the behavior of stiff materials. Our recent experiments demonstrate that the deformation of soft solids cannot be described by standard elastic models when the characteristic length-scale of deformation falls below a material-dependent size. In this limit, we see qualitative changes to the interfacial phenomena of adhesion and wetting, as well as dramatic effects on the mechanics of soft composites. We are able to capture the essential features of these phenomena with linear-elastic analytic models that incorporate solid surface tension. Intriguingly, the apparent surface tension in these phenomena is larger than the expected surface energy. I will describe current experiments targeted at illuminating this discrepancy

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O1-POL _378 CORRELATION OF FOAM FILM STABILITY TO THE INTERFACIAL COMPOSITION OF POLYELECTROLYTE/SURFACTANT MIXTURES

POL - Polymer surfaces and interfaces R. Campbell 1,*, H. Fauser 2, M. Uhlig 2, R. Von Klitzing 2 1Institut Laue-Langevin - Grenoble (France), 2Technical University - Berlin (Germany) The properties of foams are of interest for many industrial applications such as enhanced oil recovery and in personal care products, and as such they are the focus of many scientific studies [1]. A way to produce stable foam films is to mix surfactants with oppositely charged polyelectrolytes, as the synergistic co-adsorption of the components reduces the free energy of the air/water interface and promotes bubble formation. We started our work with mixtures of the flexible polyelectrolyte poly(acrylamidomethyl propanesulfonate) sodium salt (PAMPS) and tetradecyltrimethylammonium bromide (C14TAB) showing that there was not a direct correlation between the foam film stability and the surface tension [2]. Then we applied neutron reflectometry (NR) to resolve the interfacial composition at the air/water interface. We showed that a peak in the surface tension can be rationalized in terms of the changing surface composition with bulk composition, rather than bulk precipitation, and the highest foam film stability occurs when there is enhanced synergistic adsorption of both components due to charge screening when the total ionic strength of the system is greatest [3]. It was still unclear, however, the influence of the backbone rigidity of the polyelectrolyte on the resulting foam film properties. Recently we have studied a mixture of the more rigid polyelectrolyte monosulfonated poly(phenylene sulfone) (sPSO2-S220) [4] also with C14TAB. The work revealed stronger synergistic interactions at the interface in sPSO2-S220/C14TAB mixtures than in PAMPS/C14TAB mixtures, which correlates with significantly more stable foam films [5]. Interestingly in this case, highly detailed NR measurements on the high flux FIGARO reflectometer at the Institut Laue- Langevin (Grenoble, France) revealed the presence of a compact interfacial structure and a precise 1:1 interfacial composition, i.e., efficient release of counterions into the bulk, when the foam films were most stable (see figure). References [1] R. Petkova et al. Langmuir, 2012, 28, 4996 // [2] N. Kristen et al. J. Phys. Chem. B, 2009 113, 7986 // [3] H. Fauser et al. J. Phys. Chem. B, 2015, 119, 348 // [4] M. Schuster et al. Macromolecules, 2009 42, 312 // [5] M. Uhlig et al. Phys. Chem. Chem. Phys. 2016, under review.

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O2-POL _41 A SPRAYABLE PROTECTIVE COATING FOR MARBLE WITH WATER-BLOCKING AND ANTI-GRAFFITI PROPERTIES

POL - Polymer surfaces and interfaces D. Kronlund 1,*, A. Bergbreiter 1, M. Lindén 2, D. Grosso 3, J.H. Smått 1 1Åbo Akademi University - Åbo (Finland), 2Ulm University - Ulm (Germany), 3Aix-Marseille Université - Marseille (France) A simple way to apply a pore-lining, protective coating to marble stone products of any size has been developed. The protective, hydrophobic coating is realized by controlling the vesicle behavior of fluorosurfactants via tuning of the solvent polarity, which is achieved by altering the co-solvent composition of the used solutions, and spray-coating 100 ml/m2 of the solutions on marble stones. Using the optimal application conditions, an effective penetration depth of the hydrophobic properties down to at least 0.5 mm was obtained, which was confirmed through combined mechanical grinding and capillary absorption measurements, showing an increase in effective functionalization depth from µm to mm scale when decreasing solvent polarity during application. This ensures a long-term protection against water uptake and long-term stability of the coated stones. Mechanistic studies of the kinetics in the functionalization process show that solution mixtures containing ethylene glycol provide the best functionalization when a penetrating coating is preferred, due to the prolonged functionalization time as a consequence of the slow evaporation rate of ethylene glycol combined with the beneficial shift in the surfactant-vesicle equilibrium towards free surfactants and a preferential shift from large multilamellar vesicles shift into small unilamellar and bilamellar vesicles as well as free surfactants due to the polarity decrease of the solutions as the volatile components in the coated solutions evaporated. The presented coatings also display anti-graffiti properties, allowing for graffiti paint to easily be washed away with a standard pressure washer 3-4 times in a row, after which a new coating can be applied to prolong the lifetime of the surface functionality. The graffiti cleaning results also suggest that water-based solutions could be used when only an anti-graffiti functionality is preferred, as the fast evaporation of the solvent in this system result in a localized higher surfactant concentration on the stone surface, thus providing a more efficiently packed anti-graffiti layer. Thanks Coligro oy, The Magnus Ehrnrooth Foundation, the Otto A. Malm foundation, the Swedish Cultural Foundation and the K.H. Renlund Foundation are greatly acknowledged for financial support (D.K.). Furthermore, the Academy of Finland is also acknowledged for funding through the project 259310 (J.H.S.).

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O3-POL _154 IN SITU FTIR STUDY OF CO2 ADSORPTION ON POLYETHYLENE-IMINE MEMBRANES

POL - Polymer surfaces and interfaces S. Moumen 1,*, S. Moumen 2, I. Raible 2, J. Woellenstein 1 1Institute of Microsystems Engineering (IMTEK) - Freiburg (Germany), 2Robert Bosch GmbH, CR/ARY - Stuttgart (Germany) A miniature CO2 hybrid sensor approach has been developed that combines the CO2 recognition ability of polyethylene-imine (PEI) with NDIR sensing technology. PEI interacts selectively with CO2 via an acid–base reaction giving rise to IR-active bonds whose intensity indicates the amount of CO2 contributing to the adsorption. PEI sorbent layers were coated on porous Alumina membrane using covalent layer-by-layer process with glutaraldehyde crosslinking. The polymer distribution on the surface and in the pores of the membrane was observed using scanning electron microscopy (SEM). The adsorption properties of the sensing layer under different temperatures and gas partial pressures was studied by in situ transmission FTIR spectrometer equipped with a gas cell allowing control over the gas temperature and pressure. The goal is a better understanding of the sorption/desorption process including CO2 diffusion into the bulk and the impact of water vapor on the nature and the amount of the formed species to further optimize the sensing properties of the membrane, mainly regarding kinetics and sorption capacity. For this purpose, the effect of sorption temperature, CO2 gaseous concentration, relative humidity and layer thickness were investigated. In addition, in-situ gravimetrical methods were employed to quantify the amount of CO2 molecules absorbed for different amounts of the polymer. It was found that CO2 sorption includes two distinct steps: rapid sorption on exposed surface layers of PEI followed by slow diffusion inside the bulk. The diffusion resistance increases with increasing PEI film thickness which slows down the layer capture capacity for the short time scale required for the sensing. The diffusion rate increases when CO2 concentration in the gas phase increases or when the sorption temperature rises to an optimum temperature depending on the layer thickness. The sorption is notably enhanced in the presence of water vapor by changing the adsorption mechanism and the polymer behavior. The diffusion is also found to influence the desorption temperature which varies as a function of the layer thickness. Hence, to reach the sensing requirements of fast sorption/desorption and large storage capacity, the diffusion effect should be minimized by taking advantage of Al2O3 membrane porosity to increase the specific surface area of the PEI coating.

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O4-POL _369 SILVER NANOPARTICLES USING CHITOSAN AS REDUCING AND STABILIZING AGENT: A COMBINED XPS, AFM AND UV-VIS STUDY

POL - Polymer surfaces and interfaces A. Rego *, A.P. Carapeto *, A.M. Ferraria CQFM and IN, Instituto Superior Técnico, ULisboa - Lisboa (Portugal) Silver nanoparticles (NP) can be synthesized using various methods like chemical and/or photochemical reaction1, thermal decomposition2, electrochemical process3, sono- chemical and microwave assisted4 synthesis. Although these methods can successfully produce silver nanoparticles in an efficient manner they usually involve the use of toxic and hazardous chemicals which have several harmful effects on the environment and human health. In this work, a system using water as solvent, chitosan as both reducing and stabilizing agent and AgNO3 as silver precursor, is studied focussing on the role of the i) atomic ratio N/Ag; ii) chitosan concentration; iii) the chitosan average molecular weight on the NP 2-D and size distributions as well as on the silver oxidation state. Combination of XPS studies with UV-Vis spectra and AFM images allowed to establish the best ratio N/Ag for each chitosan concentration and molecular weight for obtaining just metallic NP. Figures show UV-Vis spectra for solutions with [chitosan]=7 mg/mL and varying [AgNO3] (in molarity) and the AFM image for a film spread by drop evaporation from the solution with [chitosan]=7 mg/mL and -2 [AgNO3]=3×10 M. Thanks We acknowledge the financial support from the projects UID/NAN/50024/2013 and for the fellowship SFRH/BPD/108338/2015 (FCT, Portugal). We also aknowledge NATO SFP project 984842 (CATALTEX) for the AFM (Innova, BRUKER) acquisition. References [1] Boufi, S., Vilar, M. R., Ferraria, A. M., & do Rego, A. M. B., Colloid Surface A 2013, 439, 151-158. [2] Hosseinpour-Mashkani, S. M., & Ramezani, M., Mater. Lett. 2014, 130, 259-262. [3] Khaydarov, R. A., Khaydarov, R. R., Gapurova, O., Estrin, Y., & Scheper, T., J. Nanopart. Res. 2009, 11(5), 1193-1200. [4] Pal, A., Shah, S., & Devi, S., Mater. Chem. Phys. 2009, 114(2), 530-532.

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P1-POL_15 OPERANDO PHOTOELECTRON SPECTROSCOPY AT POLYMER-CATHODE INTERFACE OF ORGANIC LIGHT-EMITTING DIODE

POL - Polymer surfaces and interfaces Y. Yamashita 1,*, J. Ikeuchi 2, H. Hamamatsu 2, T. Miyamoto 2, S. Tanaka 2, H. Yoshikawa 1 1National Institute for Materials Science - Tsukuba (Japan), 2Sumitomo Chemical Co., Ltd - Tsukuba (Japan) Recently, organic light-emitting diodes (OLEDs) have been extensively studied for realizing high efficiency, long lifetime, and a good color rendering index. The interface between the light-emitting polymer (LEP) and the electrodes plays an important role in high efficiency OLEDs. Determining the electronic states and potential distribution around the EIL/LEP interface under device operation is indispensable for understanding the electron injection mechanism and improving the device properties.1 Therefore, in the present study, the electronic structure of a polymer-cathode interface of an operating organic light-emitting diode was directly investigated using operand photoelectron spectroscopy. The potential distribution profile of the light-emitting copolymer layer as a function of the depth under the Al/Ba cathode layer in the OLED depended on the bias voltage. We found that band bending occurred in the copolymer of 9,9-dioctylfluorene and N-(4-(2-butyl)-phenyl)diphenylamine (F8-PFB) layer near the cathode at 0V bias, while a linear potential distribution formed in the F8-PFB when a bias voltage was applied to the OLED. Direct observation of the built-in potential and that band bending formed in the F8-PFB layer in the operating OLED suggested that charges moved in the F8-PFB layer before electron injection from the cathode.2 References 1Y. Yamashita et al., J. Appl. Phys. 113, 163707 (2013) 2J. Ikeuchi et al., J. Appl. Phys. 118, 085308 (2015)

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P2-POL_16 THE CHARACTERISTICS OF POLY STYRENE /MONTMORILLONITE NANOCOMPOSITES

POL - Polymer surfaces and interfaces L. Mrah *, M. Benaada Laboratory of Polymer Chemistry, Department of Chemistry, Faculty of Science, Université D'Oran, BP 1524 31000 El'Menouer Oran Algeria - Oran (Algeria) A reactive cationic surfactant cetyltrimethylammonium bromide (CTAB) was synthesized for intercalation of montmorillonite Mmt. a Maghnite type of clay. The pristine montmorillonite (Mmt) was obtained from Algerian plant with a cation exchange Organophilic Mmt was prepared by ion exchange between Na+ ions in the clay. CTAB-intercalated Mmt particles were easily dispersed and swollen in styrene monomer, PS/ Mmt-CTAB nanocomposites were synthesized via in situ polymerization, in-situ polymerization, this method is based on the swelling of the silicate layers with the liquid polymer. The polymer composites were characterized using different techniques such as X-ray diffraction (XRD), The results were showed that, the basal space of the silicate layer increased, as determined by XRD, from 12.79 to 32.603 Å. The transmission electron microscopy TEM Indicate that exfoliation of Mmt was achieved. In our current research,we continue this research and study infrared spectrophotometery (IR), differentialscanning calorimetery (DSC), and balayage electron microscope (MEB) thermal gravimetric analysis (TGA), force atomic microscopy (AFM) and tensile measurements.

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P3-POL_40 MICRODROPLET PULLOUT TEST : INTERFACIAL SHEAR STRENGTH MEASUREMENTS BETWEEN REACTIVE POLYAMIDE-6 AND CELLULOSIC OR GLASS FIBRES.

POL - Polymer surfaces and interfaces B. Revol 1,*, M. Thomassey 1, F. Ruch 1, M. Bouquey 2, M. Nardin 3 1Pôle Ingénierie des Polymères et Composites, Cetim-Cermat, 21 Rue de Chemnitz - Mulhouse (France), 2Institut Charles Sadron (ICS), UPR 22–CNRS, 23 Rue du Loess - Strasbourg (France), 3Institut de Science des Matériaux de Mulhouse (IS2M), UMR-CNRS 7361, 15 rue Jean Starcky - Mulhouse (France) Objective The fibre-matrix interface plays a significant role in the stress transfer from the matrix to the fibres in composite materials. Micromechanical characterization of the interface by microdroplet pull-out test [1] is well adapted to a polyamide-6 matrix. A common method of sample preparation is the melting of the thermoplastic resin on the fibre surface. However, considering the high viscosity polyamide-6 used in our study, this technique implies the degradation of the studied cellulosic fibres. An innovative way of production of polyamide-6 based composite is reactive injection. Our study explores a new way of sample preparation by wetting the fibres with the reactive mix. Experimental conditions are nearly the same for sample preparation of our micromechanical model and for real size composite injection. Method and results The wetting of fibres with the reactive mix leads to good results. The interfacial shear strength will be compared for both types of fibres, using the usual melting method and the wetting with the reactive mix. Glass fibres will be tested in order to compare both methods and will enable us to determine if different adhesion phenomena take place when the sample preparation method changes. Cellulosic fibre will allow us to test the influence of the cellulosic surface on the polymerisation. Presented results will include optical microscopy for the observation of microdroplets before and after the pull-out test, interfacial shear strength and calculation of contact angle using Carroll’s theory [2]. References [1] B. Miller, P. Muri, L. Rebenfeld, A Microbond Method for Determination of the Shear Strength of a Fiber/Resin Interface, Compos. Sci. Technol. 28 (1987) 17–32. [2] B.J. Carroll, The accurate measurement of contact angle, phase contact areas, drop volume, and Laplace excess pressure in drop-on-fiber systems, J. Colloid Interface Sci. 57 (1976) 488–495.

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P4-POL_59 AGEING AND DEGRADATION OF PHENOL-UREA-FORMALDEHYDE BINDER

POL - Polymer surfaces and interfaces D. Okhrimenko 1,*, A.B. Thomssen 2, M. Ceccato 1, D.B. Johansson 2, D. Lybye 2, K. Bechgaard 1, S.L.S. Stipp 1 1University of Copenhagen - Copenhagen (Denmark), 2ROCKWOOL International A/S - Hedehusene (Denmark) Phenol-urea-formaldehyde (PUF) resin is one of the most important thermosetting polymers with irregular structure. It is widely used in many industrial and construction applications as an organic coating and adhesive. For example, in production of mineral wool for insulation, PUF serves as a binder to attach mineral fibers to each other and to create the necessary mechanical integrity and shape of the final product. However, during ageing under high humidity and temperature, hydrolysis degrades PUF surfaces, decreasing product quality. A better understanding of the chemical processes caused by hydrolysis would promote development of more stable PUF binders. We investigated the composition and stability towards ageing of cured PUF powder binder in hot water (80 °C), using X-ray photoelectron spectroscopy (XPS), element and thermogravimetric (TG) analysis. We analysed the composition of species released from PUF during hydrolysis by electrospray ionization analysis (ESI) of aqueous solutions. Element and TG analysis showed that the extent of PUF curing has an important impact on its stability. XPS also revealed that poorly cured PUF contains a high fraction of methyl ether bonds, -NH-CH2-O-CH2-NH-, which are easily hydrolysed, while longer curing results mostly in more stable methyl bridges, -NH-CH2-NH-. We also observed an indication of urea -NH- CO- bond decomposition and characteristic species in ESI analysis. Improved understanding of PUF ageing provides clues for making a binder that is more robust, leading to increased quality and stability of mineral wool insulation.

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P5-POL_107 AN ALTERNATIVE STRATEGY TO ACTIVATE POLYMER SAMPLES FOR ELECTROLESS COPPER DEPOSITION

POL - Polymer surfaces and interfaces A. Atli 1,*, S. Simon 1, F.J. Cadete Santos Aires 2, E. Ehret 2, P. Lourdin 1 1Université de Lyon, ECAM Lyon - Lyon (France), 2Université de Lyon, IRCELYON (UMR 5256 CNRS/UCB Lyon 1) - Lyon (France) The deposition of metals on polymers has a special interest notably in the fabrication of electrically conductive copper tracks for electronics. Electroless deposition is a common industrial method for copper deposition on polymers and includes mainly three steps: surface preparation, surface activation and copper deposition. The first step allows to increase the copper adhesion on the polymer surface. The second step consists in creating the active sites on the polymer surface to initiate the electroless copper deposition. The last step is the copper electroless deposition in a bath. For surface activation, transition metals, and especially palladium, are applied on polymer surfaces by different processes. However these processes are very laborious and, in the case of palladium, highly expensive. In this work, we demonstrate the feasibility of a simple way of sample preparation for the activation step of polymers for electroless copper deposition. The samples are prepared by incorporation of a small amount (<1 w%) of palladium, nickel or copper acetate into the molten polymer (Liquid Crystal Polymer-LCPVectra®820i) in a blender. Since the blending temperature is kept higher than the decomposition temperature of acetates, during blending, the acetates are thermally decomposed leading to the metallic Pd, Ni or Cu used as active sites for the electroless copper deposition. The samples are characterized by optical microscopy (OM), Scanning Electron Microscopy (SEM), Fourier Transformed Infrared Spectroscopy (FTIR), Wide Angle X-ray Diffraction (WAXD) and X-Ray Photoelectron Spectroscopy (XPS). After preparing the sample surfaces, electroless copper deposition is successfully realized. The influence of the nature of acetates on the electroless deposition kinetics is investigated (Fig. 1). The deposited copper layers had a uniform thickness and are free of oxides as characterized by OM and WAXD (Fig. 2). Moreover the possibility to substitute high cost Pd for surface activation by cheaper Ni or Cu is shown.

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P6-POL_113 SEQUENCE CONTROLLED GROWTH OF CROSS-LINKED POLYMER LAYERS ON SURFACES

POL - Polymer surfaces and interfaces S. Steinmüller 1,*, A. Llevot 2, D. Moock 1, B. Ridder 2, F. Scheiba 1, H. Ehrenberg 1, S. Bräse 2, M.A.R. Meier 2, M. Bruns 1 1Karlsruhe Institute for Technology - Institute for Applied Materials - Energy Storage Systems - Eggenstein-Leopoldshafen (Germany), 2Karlsruhe Institute for Technology - Institute of Organic Chemistry - Karlsruhe (Germany) The functionalization of macroscopic surface areas to generate designed and desired surface properties is a well-known process in many industrial and technical applications. However, one of the remaining challenges is the controlled and uniform coating of structured or three-dimensional surfaces. Especially in the case of electrode surfaces, e.g. in lithium ion batteries, these coating processes are more complicated and not well established. Within the recently installed and DFG funded Cooperate Research Center 1176, Molecular Structuring of Soft Matter, at the Karlsruhe Institute for Technology (KIT), one subproject is dedicated to this special topic. The controlled creation of different polymer layers with defined physical and chemical properties orthogonally and with defined distance to the surface is investigated in the objective to synthesize an artificial solid electrolyte interface (SEI) for lithium ion batteries. Indeed, in lithium ion batteries, the SEI formed at the interface[1] between the anode (made of graphite) and the electrolyte has a large influence on the electrode stability and therefore battery lifetime. In this context, the first step of the study is to investigate the electrografting of a diazonium salt on silicon and on highly oriented pyrrolytic graphit (HOPG)[2]. The HOPG hereby is a representative material for the growth of defined artificial SEI interfaces. For an easier characterization, the silicon is used in parallel as a starting point to grow sequence defined polymer layers via thiol-ene and thiol-yne chemistry[3]. Each layer is characterized by ToF- SIMS and XPS surface analyses. The combination of these two instruments, in combination with the use of different marker molecules in each layer, enables the precise characterization and evaluation of the sequence controlled character of our synthetic approach. Thanks We would like to thank Thomas Schimmel, Stefan Walheim and Jonathan Berson for preparing samples within their glove box system and Benjamin Bitterer for the synthesis of several precursor molecules for the different polymer layers. We kindly acknowledge the SFB 1176, funded by the German Research Council (DFG), in the context of projects B2 and Z1 for funding. The K-Alpha+ instrument was financially supported by the Federal Ministry of Economics and Technology on the basis of a decision by the German Bundestag. References [1] Kang Xu, Chem. Rev. 2004, 104, 4303 [2] Allongue, P.; Delamar, M.; Desbat, B.; Fagebaume, O.; Hitmi, R.; Pinson, J.; Savéant, J.-M. J. Am. Chem. Soc. 1997, 119, 201 [3] Yun-hui Li, Dong Wang, and Jillian M. Buriak, Langmuir 2010, 26 (2), 1232–1238

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P7-POL_168 CHARACTERIZATION OF SURFACE MODIFIED MATERIALS USED FOR BIOLOGICAL APPLICATIONS

POL - Polymer surfaces and interfaces V. Trouillet 1,*, A. Beloqui 2, K.N.R. Wuest 3, G. Delaittre 2, C. Barner-Kowollik 3, M. Bruns 1 1Institute for Applied Materials (IAM) and Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology (KIT) - Eggenstein-Leopoldshafen (Germany), 2Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT) - Eggenstein-Leopoldshafen (Germany), 3Institute for Chemical Technology and Polymer Chemistry, Preparative Macromolecular Chemistry, Karlsruhe Institute of Technology (KIT) - Karlsruhe (Germany) The current work presents two different examples of reactions which allow the ligation of polymeric structures onto a diverse set of surfaces used for biological applications: “thiol- click chemistry” and “photoenol chemistry”. On the one hand we focus on the synthesis and in depth characterization of generated novel nanohybrid material, single-enzyme nanogels (SENs)[1], which possess properties similar to those of their free enzyme counterpart but, more interestingly, they exhibit increased stability against organic solvents and elevated temperatures. Inherent to any crosslinking polymerization [Fig. A], the presence of remaining reactive double bonds on the SEN surface was exploited for their straightforward immobilization onto thiol-displaying silicon wafers using one class of so-called “thiol-click chemistry”, the thio- Michael addition [Fig. B]. The surface modification steps prior to SEN grafting and the SEN immobilization itself were characterized by X-ray Photoelectron Spectroscopy (XPS). Protein patterning on the surface, and thus the successful “thiol-ene” reaction, was also confirmed by fluorescence microscopy. On the other hand the present work shows the surface functionalization of nanodiamonds[2] (NDs) with the objective of influencing their properties, such as solubility, stability and biological activity. A light- triggered strategy to attach well-defined functional polymers allows mild reaction conditions like ambient temperature and catalyst-free conditions suitable for biological applications. Photoenol groups were here covalently attached via an amidation reaction to silanized, amine functional NDs. Subsequently, maleimide end group functional poly(styrene) (PS), poly(N-isopropylacrylamide) (PNIPAM) and glycopolymers with lateral mannose units were grafted to the ND surfaces [Fig. C]. The successful photografting was confirmed by X-ray Photoelectron Spectroscopy (XPS) and thermogravimetric analysis (TGA). References [1] A. Beloqui, S. Baur, V. Trouillet, A. Welle, J. Madsen, M. Bastmeyer, G. Delaittre, Small 2016, 12, 1716– 1722 [2] K. N. R. Wuest, V. Trouillet, A. S. Goldmann, M. H. Stenzel, and C. Barner-Kowollik, Macromolecules 2016, 49, 1712−1721

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P8-POL_188 APPLICATION OF ATMOSPHERIC PRESSURE PLASMA TREATMENT TO IMPORVE THE ADHESION OF A WATERBORNE PAINT ON POLYMER SURFACES

POL - Polymer surfaces and interfaces M. Boudifa 1,*, R. Bole 1, A. Hadjadj 2, J. Marthe 1, A. Tara 2, C. Bruno 1 1Centre Régional d'Innovation et de Transfert de Technologie (CRITT-MDTS), ZHT du Moulin Leblanc - Charleville-Mézières (France), 2Laboratoire d’Ingénierie et Sciences des Matériaux (LISM EA 4695), Université de Reims, Moulin de la Housse, BP 1039, 51687 - Reims (France) Polypropylene (PP) and Polyvinylchloride (PVC) are widely used plastics with many advantages (cost effective production, low density, corrosion resistant). However, their non- polar character, leads to poor adhesion and hinders a large number of applications such as coatings, adhesives and printing inks. The bonding and finishing problems are mainly related to their low surface energy attributed to the surface chemistry. In this work PP and PVC polymers were treated by a commercially available atmospheric pressure plasma jet (APPJ) system from Axcys to improve their adhesive strength. Thanks to a six-axis robotic manipulator arm, the effects of the key plasma parameters (distance to the substrate, scanning velocity and pattern of the torch) were first studied by contact angle measurements. The most influential parameters in the plasma treatment were found to be the distance between substrate and nozzle exit and the treatment residence time. For the optimized set of parameters giving the higher surface energy, the surface properties were investigated by XPS and AFM. The modification of the surface chemistry makes the polymer surfaces highly hydrophilic. Such effect mainly depends on the ratio C-O / C=O as reported by other authors [1, 2]. The activated samples exhibit a substantially increased bonding strength for PP and PVC polymers. The improvement may be attributed to an increase of oxygen concentration, and to changes in the topology of the substrate surface due to induced thermal effects. The results were validated by applying a commercial waterborne paint on plasma treated PP and PVC. The deposited paint was first qualitatively evaluated by the cross-cut test according to the ISO 2049 standard and showed a remarkable enhancement of the adhesion especially on the PP substrates. The adhesion properties of the coating were subsequently evaluated by lap shear tests and confirmed the enhancement of the adhesive strength by a factor of 4.6 on average. Moreover, the critical load was increased along with the scratch- test. Thanks Funding of the TRAPASUR project by the ‘Direction de l’Enseignement Supérieur, de la Recherche et de l’Innovation’ of the Champagne-Ardenne Region is gratefully acknowledged References 1. M. Noeske, J. Degenhardt, S. Strudthoff, U. Lommatzsch. Int J Adhes Adhes, 24 (2004), pp. 171–177 2. J. Lai, B. Sunderland, J. Xue, S. Yan, W. Zhao, M. Folkard, B.D. Michael, Y. Wang. Appl. Surf. Sci., 252 (2006), pp. 3375–3379

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P9-POL_283 EFFECTS OF THIN AMORPHOUS HYDROGENATED CARBON (A-C:H) COATINGS ON SI (100) AND HIGH-DENSITY POLYETHYLENE

POL - Polymer surfaces and interfaces C. Fischer *, A. Catena, S. Wehner Department of Physics, University Koblenz-Landau - Koblenz (Germany) Silicon wafers (100) as hard material and high-density polyethylene (HDPE) as a soft polymeric material have been covered gradually by thin a-C:H films. Thickness dependent coating series on both materials have been performed by radio frequency plasma-enhanced chemical vapor deposition (RF-PECVD) with acetylene plasma as carbon source to study the interlayer forming behavior between the base material and the carbon deposition. Two different a-C:H coatings were realized. One has been deposited in an indirect (f-type, more flexible) and the other one in a direct (r-type, more robust) way to the plasma source. Atomic force microscopy (AFM) revealed an unexpected similar morphology for both types and materials. Average height and average area of single evolving grains are analyzed. Besides the grains, a uniformly textured protrusion at the bottom is detectable. Results showed that a smaller amount of carbon deposition for the f-type than for the r-type to obtain similar surface structures independently of the substrate is needed. The average grain area increases for all f- and r-coatings. The average grain height increases in the beginning and reaches a level with nearly constant height. The correlation of average grain heights and average grain areas displays them localized in a limited area, indicating a given regularity throughout the gradually increasing depositions. This comparative study of a-C:H coated substrates provides further insights into the interaction of hard carbon coatings on soft plastic materials.

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RTP - Real-time processes at surfaces

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O2-RTP_203 ELECTRON AND EXCITON DYNAMICS IN AMORPHOUS AND CRYSTALLINE SEXITHIOPHENE FILMS ON AU(111)

RTP - Real-time processes at surfaces W. Bronsch *, S. Baum, M. Wansleben, K. Zielke, C. Gahl, M. Weinelt Freie Universität - Berlin (Germany) Exciton formation and relaxation as well as charge transfer processes across organic/inorganic interfaces are of high relevance in molecular electronics. Sexithiophene (6T)/gold represents a model system for an organic semiconductor/metal interface. The morphology of 6T films on Au(111) can be tuned by the preparation conditions. To access differences in the electronic structure and exciton dynamics in amorphous and crystalline 6T films we performed time-resolved two-photon photoelectron spectroscopy using excitation energies within the S1 absorption band. Well ordered films show a population of the lowest excitonic state within 6T crystallites within our time resolution. We show furthermore that the excitation and relaxation pathways within the ordered films change between a coverage of 2 to 3 monolayers, which we assign to the formation of 6T crystallites ontop of a wetting layer.

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O3-RTP_277 STRUCTURE AND GROWTH MECHANISMS OF SILICENE LAYERS ON AG(111) SURFACE

RTP - Real-time processes at surfaces A. Curcella 1,*, G. Prévot 1, R. Bernard 1, Y. Borensztein 1, M. Lazzeri 2, H. Cruguel 1 1Institut des Nanosciences de Paris, CNRS UMR 7588 and UPMC, Paris, France - Paris (France), 2Institut de Minéralogie, de Physique des Matériaux, et de Cosmochimie, UMR CNRS 7590, MNHN, IRD UMR 206 and UPMC, Paris, France - Paris (France) Bidimensional (2D) materials attract an increasing interest due to their specific properties. Among them, silicene, the 2D allotrope of Si, has been predicted to possess Dirac fermions, making it an appealing candidate for microelectronics devices. Experimentally, silicene has been synthesized on MoS2, ZrB2, ZrC2, Ir, and Ag. Intensive research has been performed on Ag, due to the negligible mutual solubility of Si and Ag and the 3/4 ratio of their lattice constants. Onto Ag(111), Si monolayers with an hexagonal symmetry have been reported. Angular-resolved photoelectron spectroscopy measurements have shown features initially associated to Dirac cones, lately proven to come from Ag band structure. Further studies have revealed that the electronic structure of silicene is modified by the interaction with Ag. The growth of “multilayer silicene” has been thought to be a good way to reduce this coupling. However, the structure of such layers is still controversial. Performing grazing incidence X-ray diffraction (GIXD), scanning tunneling microscopy, Auger electron spectroscopy and surface differential reflectance spectroscopy, we have followed in real-time the growth of silicene single1,2 and multi-layers3 on Ag(111) and compared the results with DFT calculations. We show, in the first stage of growth, Si atoms insert into the substrate surface2 (Fig. 1). Up to the completion of the first layer, silicene grows on the terraces by ejecting Ag atoms which form new terraces. At one monolayer (ML) deposition the ordered domains correspond to buckled Si planes, as proven by GIXD, which results are excellently reproduced by DFT simulation (Fig. 2). In the effort of growing “multilayer silicene”, further deposition results in the formation of diamondlike Si films, covered with Ag3, displaying the Ag/Si() reconstruction. References 1G. Prévot et al., Appl. Phys. Lett. 105 (2014) 2R. Bernard et al., Phys. Rev. B 92 (2015) 3Y. Borensztein et al., Phys. Rev. B 92 (2015)

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O4-RTP_116 FORMATION OF AU-RH SURFACE ALLOY AND THE EFFECT OF AU ON THE STRUCTURE OF H-BN FILM GROWN ON RH(111) SURFACE

RTP - Real-time processes at surfaces A. Berkó 1,*, L. Óvári 1, A.P. Farkas 2, R. Gubó 3, G. Vári 3, J. Kiss 1, Z. Kónya 3 1MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group - Szeged (Hungary), 2University of Szeged, Department of Physical Chemistry and Materials Science - Szeged (Hungary), 3University of Szeged, Department of Applied and Environmental Chemistry - Szeged (Hungary) The formation of hexagonal boron nitride (h-BN) on different transition metal surfaces has attracted a great attention partially because of the very interesting substrate-dependent nanomesh formation property (1). This feature can be explained with the lattice misfit and with the bimodal bonding of N atoms of the h-BN sheet to the metal atoms underneath (2). In certain cases, the chemical properties of metal surfaces can sensitively be tuned by alloying them with a second metal without any significant modification of their step structure. In this work we study the alloying of Rh(111) by gold at high temperature and the effects of Au-Rh surface alloy on the pore-wire structure of the h-BN film. Two different preparation routes were applied: (i) deposition of Au on to a clean Rh(111) surface followed by annealing at 1100 K in UHV and pyrolysis of vaporized borazine at 1000K; (ii) h-BN formation by borazin CVD on to a clean Rh(111) surface followed by Au deposition at room temperature and thermally activated intercalation/alloying of gold underneath the h-BN film. For the investigations presented here mainly scanning tunneling microscopy (STM) was used, but also some results delivered by low energy ion scattering (LEIS), X-ray photoelectron and high resolution electron energy loss spectroscopy (XPS, HREELS) were taken into account. Concerning the bulk-immiscible Au and Rh, we have found a rather uniform build- in of Au atoms into the Rh terraces above 600-700 K, moreover, an ordered 2×1 surface- nanoalloy phase consisting of three-fold domains with an average size of 3 nm was also found. By increase of the gold content up to one monolayer of the Rh terraces led to a gradually hindered formation of the h-BN layer by a factor of approximately five. The main nanomesh characteristics of the h-BN film (pore size of 2.0 nm and periodicity of 3.2 nm) did not changed significantly up to 0.5 ML coverage of Au (3). Above this value, however, both the uniformity and the ordering of the nanomesh significantly decreased. Thanks The financial support of the OTKA projects NN-110676 and K-112531 is acknowledged. References (1) M L Ng, A B Preobrajenski, A S Vinogradov, N. Martensson, Surface Science 602(2008)1250. (2) A B Preobrajenski, M A Nesterov, M L Ng, A S Vinogradov, N Martensson, Chem Phys Letters 446(2007)119. (3) M C Patterson, B F Habenicht, R L Kurtz, L Liu, Y Xu, P T Sprunger, Phys Rev B 89(2014)205423.

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O5-RTP_24 SELF-PROPELLED MOTION OF AU-SI DROPLETS AND SI NANOWIRES GROWTH ON DIFFERENT SI SUBSTRATES

RTP - Real-time processes at surfaces S. Curiotto *, F. Leroy, F. Cheynis, P. Müller Aix-Marseille Université, CNRS, CINaM UMR 7325 - Marseille (France) Particles interacting with a substrate give origin to a variety of fascinating phenomena, from particle motion [1, 2] to nanowire formation [3]. A typical example is given by eutectic systems, where, above the eutectic temperature, the particles tend to dissolve the substrate and become liquid droplets. A deeper understanding of the physical mechanism taking place in chemically interacting systems can only be achieved with in-situ and in-real-time experiments. In the present work we have carried out these studies by Low Energy Electron Microscopy for Au-Si droplets (eutectic) on Si substrates with different crystallographic orientations. We show that the crystallographic orientation of the substrate defines the droplet shapes, motion, the formation of holes, and/or nanowires on the substrate (see the figure below). During Au deposition on Si(001), the droplets do not move but form isotropic droplets which grow and dig a hole in place. On Si(111) the droplets climb the substrate atomic steps dissolving Si and leaving a faceted wake. Elongated droplets move in the [1-10] direction on Si(110) and (113), leaving a Si nanowire in- plane with the substrate. The anisotropy of dissolution of Si in contact with Au is the main factor affecting all the observed behaviors. Thanks We acknowledge the financial support of the ANR grant LOTUS (ANR-13-BS04-0004-02) References [1] A.K. Schmid, N.C. Bartelt, R.Q. Hwang. Science 290 (2000) 1561. [2] S. Curiotto, F. Leroy, F. Cheynis, P. Müller. Surface Science 632 (2015) 1-8. [3] S. Curiotto, F. Leroy, F. Cheynis, P. Müller. Nano Letters 15 (2015) 4788-4792

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O6-RTP_467 IN SITU SYNCHROTRON X-RAY SCATTERING OF SIGE NANOWIRES: GROWTH, STRAIN AND BENDING

RTP - Real-time processes at surfaces T. Zhou 1,*, V. Cantelli 1, O. Geaymond 2, O. Ulrich 1, F. Boudaa 1, N. Blanc 2, P. Müller 3, G. Renaud 1 1Univ. Grenoble Alpes, CEA, INAC/SP2M - Grenoble (France), 2Univ. Grenoble Alpes, CNRS Institut Néel INAC/SP2M - Grenoble (France), 3Aix-Marseille University CINAM CNRS-UMR 7325 - Marseille (France) The INS (In situ - Nanostructure - Surface/interface) end station of the BM32 beamline at the European Synchrotron Radiation Facility (ESRF) has been used for years to analyze the structural properties of nanoparticles in situ, during their growth, combining Grazing Incidence X-ray Diffraction (GIXD) and Grazing Incidence Small Angle X-ray Scattering (GISAXS) [1]. An auxiliary UHV-CVD injection system has been recently added to allow investigations of the VLS and VSS growth of Si/Ge NWs [2]. Results on the growth of Si NWs on Si(111) will first be presented, to demonstrate the in situ capability of the instrument. The real time NWs length and their size distribution can be measured with X-ray techniques without removing the sample from the UHV chamber. The deposition of the metal catalysts and the injection of the precursor gases were carried out side by side, making it possible to probe the very early stage of growth. The well-known sidewall dodecagon sawtooth faceting is clearly recognizable from reciprocal space mapping of both GIXD and GISAXS. The strain relaxation in Si-Ge core-shell NWs will be presented next. The samples were kept under UHV during the entire process to avoid oxidation and contamination. The level of strain was measured in situ as a function of the overgrowth amount. The composition distribution in the heterostructure was determined using anomalous X-ray scattering, from which the evolution of the composition during growth was then deduced [3]. Results on the in situ bending of as-grown NWs will also be presented. The bending was induced, in our case, by depositing a second material on one side of the NWs and was measured solely by X-ray diffraction techniques. For the quantitative interpretation of the data, we employ the so-called Displaced Bragg Method (DBM) [4]. The strain profile along the longitudinal direction of the NWs was obtained by analyzing the position shift of the displaced Bragg peaks whereas the total stress applied on the NWs was deduced by fitting the NW curvature, retrieved from integrated intensities of the displaced Bragg peaks, with a formula based on classic beam theory. Two cases will be presented to illustrate the use and capability of DBM. We found that the bending induced by Ge deposition on Si NWs sidewall at 220°C is mainly driven by the misfit stress, which scales almost linearly with Ge film thickness. On the other hand, the bending induced by the same deposition on Si NWs sidewall at RT is driven by the surface stress, which evolves from tensile eventually to compressive in the later stage of Ge growth. Finally, the so-called Stationary Method will be presented, which allows us to follow in real time, though mostly qualitatively, the entire bending process in a time efficient manner. The NWs were seen dancing back and forth with increasing amount of deposition as revealed by live stationary measurements with a 2D detector. References [1] G. Renaud, R. Lazzari, F. Leroy Surf. Sci. Rep. (2009) 64, 255. [2] V. Cantelli, O. Geaymond, O. Ulrich, T. Zhou, N. Blanc and G. Renaud, submitted. [3] T. Zhou, O. Geaymond, G. Renaud et al., in preparation. [4] T. Zhou, O. Robach, G. Renaud et al., in preparation.

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O7-RTP_388 PROGRESS IN CHARACTERIZING SUBMONOLAYER ISLAND GROWTH: CAPTURE- ZONE DISTRIBUTIONS, GROWTH EXPONENTS, & TRANSIENT MOBILITY

RTP - Real-time processes at surfaces T. Einstein 1,*, A. Pimpinelli 2, J. Morales-Cifuentes 1, D.L. González 3 1Dept. Physics & Cond. Matter Theory Center, U. of Maryland - College Park, Md (United States of America), 2Rice Quantum Institute & MSNE Department, Rice University - Houston, Tx (United States of America), 3Departamento de Física, Universidad del Valle - Cali (Colombia) Analyzing capture-zone distributions (CZD) using the general-ized Wigner distribution (GWD) has proved a powerful way to gain insight into epitaxial growth, in particular to access the critical nucleus size i, as reviewed in [1]. The CZ of an island contains all points closer to that island than to any other, a generalization of Wigner-Seitz cells known as a Voronoi tessellation. This approach complements measurements of the growth exponent a from the scaling (with flux F) of island density N ~ Fa and of the distribution of island sizes. We summarize some extensive Monte Carlo simulations and especially experiments on various systems to which the GWD has been applied. These include atomic or organic adsorbates, sometimes with impurities, and colloidal nano-particles. In some cases, most notably parahexaphenyl (6P) on sputter-modified mica [2], the value i extracted from CZD (see figures) differs from the [larger] values of i deduced from N ~ Fa. Furthermore, while the scaling was good, the values of a differed considerably at small and large F, which was attributed to DLA and ALA dynamics [2]. To reconcile the CZD and scaling measurements, we took into account long-known transient mobility (hot precursors) [3]. We close with applications to social phenomena, notably the areas of secondary administrative units (e.g. arrondissements) and of Voronoi tessellations of subway stations [4]. Figure Caption: b) Voronoi tessellation for islands of 6P on sputtered mica; c) analysis of distribution

P(s) of s, cell areas [/average area] using GWD [2] Thanks Work at UMD supported by NSF CHE 13-05892. References [1] T.L. Einstein, A. Pimpinelli, D.L. González, J. Cryst. Growth 401 (2014) 627; TLE, AP, DLG, J.R. Morales-Cifuentes, J. Physics: Conf. Ser. J. Phys.: Conf. Series 640 (2015) 012024 [2] T. Potocar et al., Phys. Rev. B 83 (2011) 075423 & later work by A. Winkler et al., see [1]. [3] JRM-C, TLE, and AP, Phys. Rev. Lett. 113 (2014) 246101. [4] DLG, TLE, Phys. Rev. E 84 (2011) 051135; R. Sathiyanarayanan Ph.D. thesis, UMD, 2009.

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O8-RTP_122 DYNAMICS OF ATOM DETACHMENT FROM 1D SN CHAINS GROWN ON SI(100)2×1 – DETERMINATION OF ACTIVATION ENERGIES FROM STM REAL TIME OBSERVATIONS

RTP - Real-time processes at surfaces I. Oštádal *, M. Kucera *, P. Sobotík, P. Kocán Charles University, Faculty of Mathematics and Physics, Department of Surface and Plasma Science - Prague (Czech republic) Controlled growing of ordered metal nanostructures on silicon surfaces attracts attention due to variety of possible applications. Deposition of tin on the surface Si(100) 2×1 results in formation of atomic chains composed of dimers. The chain length distribution is monotonous which may indicate presence of processes supporting a relaxation to an equilibrium state1. Detailed observations by means of STM revealed attachment/detachment of Sn atoms from/to the chains after sub-monolayer deposition. Real time observations of chain length fluctuations at various temperatures in a 40 K region above the room temperature were analyzed. The obtained time series confirmed a Poisson character of the thermally activated processes and showed that the detachment rate depends on a chain termination – a single Sn atom or dimer. The mean lifetimes of chain terminations, either by a single atom or dimer, were calculated from the time series. The presence of the attachment process was taken into account for the correct analysis. Finally corresponding activation energies and frequency prefactors of the detachment processes were determined.

Figure 1. Sequence of STM images shows fluctuations of Sn chain length.

Figure 2. Set of “line scans” recorded repeatedly along a fluctuating chain2 (number of atoms in the chain is shown for time intervals). References [1] J. Javorsky, M. Setvin, I. Ostadal, P. Sobotik, and M. Kotrla, Phys. Rev. B 79, 165424 (2009). [2] P. Kocan, P. Sobotik, I. Ostadal, J. Javorsky, and M. Setvin, Surf. Sci. 601, 4506 (2007).

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O9-RTP_265 STEP BUNCHING AND MACROSTEP FORMATION IN 1D ATOMISTIC SCALE MODEL OF UNSTABLE VICINAL CRYSTAL EVAPORATION

RTP - Real-time processes at surfaces F. Krzyzewski 1,*, M. Zaluska-Kotur 1, A. Krasteva 2, H. Popova 2, V. Tonchev 2 1Polish Academy of Sciences - Warsaw (Poland), 2Bulgarian Academy of Sciences - Sofia (Bulgaria) We studied recently the irreversible vicinal crystal growth in an atomistic scale model [1,2] with fully transparent steps. Important aspect of the model, since there are no step-step repulsions in it, is the formation of macrosteps but the step bunches retain a finite width consisting of both single and macro-steps. Thus, we obtained for two alternative sources of instability, biased diffusion and (infinite) Ehrlich-Schowebel [3] barrier (SE), the scaling describing the time evolution of the quantities of interest – bunch size, bunch width and macrostep size [1,2] in the two limiting regimes – diffusion-limited (DL) and kinetics-limited (KL) growth. Here we develop further this model allowing for the possibility for particle detachment from the steps and report results for unstable vicinal crystal evaporation. In this situation the instability sources, namely biased diffusion and SE, act differently and a number of models, both on atomic scale [4] and of extended BCF-type [5] is modelling sublimated systems. For our model we show that step bunching occurs with step-up diffusional bias when the add-particle diffusion is fast (KL) and since we can change smoothly the number of diffusional steps nDS per growth-sublimation one, we are able to locate the onset of bunching with increasing nDS. We analyse shape of the bunches, Fig. 1, and compare it to the growth case. We also show results for the time scaling of the bunch and macrostep size, Fig. 2. Thanks FK acknowledges grant No. 2013/11/D/ST3/02700 from Polish NCN. References [1] A. Krasteva et al., AIP Conf. Proc.1722, (2016) 220014. [2] F. Krzyżewski et al., arXiv preprint arXiv:1601.07371 (2016). [3] R. L. Schwoebel, E. J. Shipsley J. Appl. Phys. 37, 3682 (1966) [4] M. Załuska-Kotur et al., Cryst. Growth and Des. 13 , (3) (2013) 1006. [5] S. Stoyanov, V.Tonchev, Phys. Rev B 58, (3) (1998) 1590.

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I09_RTP_453 THE INITIAL STAGES OF ZNO THIN FILM GROWTH BY ATOMIC LAYER DEPOSITION

RTP - Real-time processes at surfaces D. Fong * Materials Science Division, Argonne National Laboratory - Argonne (United States of America) Atomic layer deposition (ALD) is a technique that permits monolayer-by-monolayer synthesis, but this often not the case at the earliest stages of growth. Using in situ synchrotron X-ray techniques, we investigate the nucleation and growth of nanoscale ZnO islands, examining how the crystal structure, strain, texture, and composition, evolve as the islands merge during deposition to form continuous layers. The results naturally depend strongly on the type of substrate, which were varied from SiO2/Si to Al2O3 (001) to InGaAs (001). For the SiO2 and Al2O3 substrates, we observed the development of tensile strains during coalescence and found that the ZnO microstructure developed at this stage determines the overall structure of the resulting film. The different symmetries of the substrate surfaces led to distinct preferred orientations, with ZnO / SiO2 exhibiting self- texture with a preference for (001) surfaces and ZnO / Al2O3 exhibiting three dominant textures with in-plane rotational domains. In the latter case, the relative texture populations depend on temperature but appear to be set during the coalescence stage. For ZnO on InGaAs (001), the results depended sensitively on growth temperature. At the lowest ALD temperatures, the films remained amorphous, but at slightly higher temperatures, the films underwent amorphous-to-crystalline transitions after reaching a critical thickness. We will discuss these results with those from additional in situ stress measurements and ex situ studies to provide a general description of initial growth behavior.

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O11-RTP_125 THE STRENGTH OF NONADIABATIC EFFECTS IN THE SURFACE DIFFUSION OF HYDROGEN ON PD(111): EVIDENCE FROM SPIN-ECHO EXPERIMENTS

RTP - Real-time processes at surfaces P.S.M. Townsend *, N. Avidor, D.J. Ward, W. Allison, J. Ellis Department of Physics, University of Cambridge - Cambridge (United Kingdom) The diffusion of atomic hydrogen at transition metal surfaces is a popular playground for the application of first principles calculations and quantum simulation methods. Of the transition metals, palladium has a particularly rich interaction with hydrogen, due in part to the favourable energetics of subsurface and bulk sites over the gas phase [1]. Nevertheless, the hydrogen that remains on the surface at any given time can be studied in isolation using surface-specific techniques. The surface spin-echo technique enables a detailed microscopic analysis of the equilibrium diffusion of adsorbates on single crystal surfaces [2]. We present the first microscopic measurements of the surface diffusion of protium and deuterium at Pd(111) at elevated temperatures relevant to chemical reactions. We have also performed an analysis in terms of a jump diffusion model. The analysis yields thermodynamic information in addition to jump rates for single and multiple jumps. For both isotopes, the apparent activation energy for surface diffusion is in the ballpark of generalized gradient barrier calculations from the literature, but should be interpreted semiclassically. The two symmetrically inequivalent hollow sites both participate in the diffusion mechanism, with a free energy difference of about 45meV. Aside from accurate energetics, the correct inclusion of nonadiabatic effects represents an even tougher challenge for theoretical treatments of diffusion. Nonadiabatic processes act in conjunction with the adiabatic potential to control the jump rate and jump distribution during diffusion. We present evidence in the experimental data for a high proportion of multiple jumps, which constrains the strength of the nonadiabatic interaction. References [1] Markus Lischka, and Axel Groß. Recent Developments in Vacuum Science and Technology 37/661, 111-132 (2003) [2] Paul Rotter, Barbara A. J. Lechner, Antonia Morherr, David M. Chisnall, David J. Ward, Andrew P. Jardine, John Ellis, William Allison, Bruno Eckhardt, and Gregor Witte. Nature Materials 15, 397–400 (2016)

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O12-RTP_98 SURFACE DIFFUSION OF DIMERS AND CLUSTERS OF LARGER SIZE

RTP - Real-time processes at surfaces M. Minkowski *, M. Zaluska-Kotur Institute of Physics Polish Academy of Sciences - Warsaw (Poland) Diffusion of atoms on crystal surfaces is an important process governing growth of crystal layers as well as formation of various nanostructures. Most studies deal with diffusion of single adatoms on a surface, however, it has been observed in experiments that diffusion of dimers and clusters of larger size is also important. An example of a system with significant diffusion of dimers are metallic surfaces such as Cu and Ag. It has been shown that Cu dimers move on those surfaces as separate particles and play an important role in nucleation and consequently growth [1,2,3]. In addition to a simple translational motion dimers can rotate or change their own length. It makes their dynamics more complex than that of monomers. We calculate the diffusion coefficients for diffusion of Cu dimer on Cu(111) and Ag(111) surfaces using a variational approach [4]. Our calculations are based on the ab initio results performed for those surfaces [5,6]. Understanding dimer diffusion is an important step towards analysis of dynamics of even larger clusters. As an extention we propose a simple model of trimer diffusion on a hexagonal lattice. A trimer can in general not only change its position, orientation and length but also its shape. In our model three particles can form a triangle, a broken line or a straight line. We show consequences of their complex dynamics for surface diffusion process. References [1] K. Morgenstern, K.-F. Braun, K.-H. Rieder, Phys. Rev. Lett. 93 (2004) 056102 [2] K. Morgenstern, K.-H. Rieder, New J. Phys. 7 (2005) 139 [3] J. Repp, G. Meyer, K.-H. Rieder, P. Hyldgaard, Phys. Rev. Lett. 91 (2003) 206102 [4] M. Mińkowski, M.A. Załuska-Kotur, Surf. Sci. 642 (2015) 22-32 [5] M.-C. Marinica, C. Barreteau, M.-C. Desjonquères, D. Spanjaard, Phys. Rev. B 70 (2004) 075415 [6] S.S. Hayat, M. Alcántara Ortigoza, M.A. Choudhry, T.S. Rahman, Phys. Rev. B 82 (2010) 085405

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O13-RTP_78 DYNAMICS OF PIT FILLING IN HETEROEPITAXY VIA PHASE-FIELD SIMULATIONS

RTP - Real-time processes at surfaces M. Albani *, R. Bergamaschini, F. Montalenti L-NESS and Department of Materials Science, University of Milano-Bicocca - Milano (Italy) Islanding phenomena in semiconductor heteroepitaxy have been the object of deep investigation since decades. Patterned substrates are a viable path to control island positioning, however a fine-tuning of the growth conditions is required1. Simulations offer a great support to identify the optimal parameters. A continuum model of heteroepitaxial growth on pit-patterned substrates is presented. A Phase-Field approach2 is exploited to describe both the film free surface and the substrate interface, by means of two different order parameters (φ and c), as shown in Panel (a). A set of partial differential equations, exactly solved by a finite element method, defines the film evolution, accounting for both deposition and surface diffusion. A thermodynamic driving force is assumed for material redistribution, based on the competition between surface energy, including substrate wetting contributions, and elastic energy, originated from the misfit strain. For a flat substrate geometry, the Asaro-Tiller-Grinfeld3 instability sets in, inducing island formation and enlargement. Wetting influences further dynamics, leading to coarsening. The improvement offered by our approach is the possibility to naturally tackle an arbitrary substrate geometry, including its effects on the strain relaxation in a very accurate way. Simulations performed for pit-patterned substrates are found to capture the major role of pits in the ordered growth of islands4, as illustrated in Panel (b). A detailed analysis of the competing energy contributions, responsible for the transition between pit-filling and island growth, is carried out and the role of growth parameters and pit geometries is investigated. Results are presented for Ge/Si growth, but the approach can be easily applied to any heteorepitaxial system following the Stranski-Krastanov growth mode. A good agreement with experimental evidences1 is achieved.

References 1 M. Grydlik et al., Nanotechnology 24, 106501 (2013) 2 A. Rätz, A. Ribalta, A. Voigt, J. Comp. Phys. 214, 187 (2006) 3 R.J. Asaro and W.A. Tiller, Metall. Trans. 3, 1789 (1972); M.A. Grinfeld, Dokl. Akad. Nauk. SSSR 283, 1139 (1985) 4 M. Albani, R. Bergamaschini, F. Montalenti, submitted

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P1-RTP_171 EARLY STAGES OF GROWTH OF GROUP-14 ELEMENTS ON RU(0001): A DFT STUDY

RTP - Real-time processes at surfaces R. Topolnicki *, R. Kucharczyk Surface Theory Group, Institute of Experimental Physics, University of Wroclaw - Wroclaw (Poland) As has been recently revealed, group-14 adatoms exhibit distinct growth characteristics on Ru(0001) at submonolayer coverages, despite a similar configuration of valence electrons. More specifically, Pb and Sn atoms tend to agglomerate and form dense islands of the c(2×4) or c(2×8) symmetry, respectively, with local coverage of 1/2 ML even for much lower deposition doses [1–3]. In contrast, Ge atoms preferably self-assemble into a dilute (√21×√21) structure with adatom density of 1/7 ML [4]. To trace the observed differences in the behavior of Ge, Sn and Pb deposited on ruthenium, we employed ab-initio DFT simulations and followed the early stages of growth of all group- 14 elements on Ru(0001) in a systematic manner by examining the potential energy surfaces for adsorption of several atoms in a large surface unit cell. This way the effective lateral interactions between adatoms were recognized and their most favorable dimer and trimer configurations were identified. Interpreting them as initial building blocks of the resultant adsorbate structure enabled us to explain (and predict) the overlayer properties for various group-14 elements on Ru(0001) at low nominal coverages, in particular their tendency towards forming a dense or dilute adlayer. Figures show exemplary results for the Sn/Ru(0001) system. The only stable dimers and trimers, indicated by negative formation energies, consist of Sn adatoms located in the next- nearest-neighbor fcc and hcp sites. This leads to arrangement of Sn adatoms in characteristic ‘zigzag’ chains, forming on Ru(0001) the long- range-ordered c(2×8) structure corresponding to adatom density of 1/2 ML, in accordance with experiment [1,3]. References [1] J. Yuhara et al., Surf. Sci. 616 (2013) 131. [2] M. Jurczyszyn et al., Appl. Surf. Sci. 311 (2014) 426. [3] R. Topolnicki and R. Kucharczyk, Appl. Surf. Sci. 329 (2015) 376. [4] Y.H. Lu et al., Appl. Surf. Sci. 254 (2007) 431.

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P2-RTP_243 STRUCTURE AND GROWTH MECHANISMS OF SILICENE LAYERS ON AG(111) SURFACE

RTP - Real-time processes at surfaces A. Curcella 1,*, G. Prévot 1, R. Bernard 1, Y. Borensztein 1, M. Lazzeri 2, H. Cruguel 1 1Institut des Nanosciences de Paris, CNRS UMR 7588 and UPMC, Paris, France - Paris (France), 2Institut de Minéralogie, de Physique des Matériaux, et de Cosmochimie, UMR CNRS 7590, MNHN, IRD UMR 206 and UPMC, Paris, France - Paris (France) Bidimensional (2D) materials attract an increasing interest due to their specific properties. Among them, silicene, the 2D allotrope of Si, has been predicted to possess Dirac fermions, making it an appealing candidate for microelectronics devices. Experimentally, silicene has been synthesized on MoS2, ZrB2, ZrC2, Ir, and Ag. Intensive research has been performed on Ag, due to the negligible mutual solubility of Si and Ag and the 3/4 ratio of their lattice constants. Onto Ag(111), Si monolayers with an hexagonal symmetry have been reported. Angular-resolved photoelectron spectroscopy measurements have shown features initially associated to Dirac cones, lately proven to come from Ag band structure. Further studies have revealed that the electronic structure of silicene is modified by the interaction with Ag. The growth of “multilayer silicene” has been thought to be a good way to reduce this coupling. However, the structure of such layers is still controversial. Performing grazing incidence X-ray diffraction (GIXD), scanning tunneling microscopy, Auger electron spectroscopy and surface differential reflectance spectroscopy, we have followed in real-time the growth of silicene single1,2 and multi-layers3 on Ag(111) and compared the results with DFT calculations. We show, in the first stage of growth, Si atoms insert into the substrate surface2 (Fig. 1). Up to the completion of the first layer, silicene grows on the terraces by ejecting Ag atoms which form new terraces. At one monolayer (ML) deposition the ordered domains correspond to buckled Si planes, as proven by GIXD, which results are excellently reproduced by DFT simulation (Fig. 2). In the effort of growing “multilayer silicene”, further deposition results in the formation of diamondlike Si films, covered with Ag3, displaying the Ag/Si() reconstruction. References 1G. Prévot et al., Appl. Phys. Lett. 105 (2014) 2R. Bernard et al., Phys. Rev. B 92 (2015) 3Y. Borensztein et al., Phys. Rev. B 92 (2015)

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P3-RTP_351 CONTROLLING THE GROWTH OF BI(110) AND BI(111) FILMS ON AN INSULATING SUBSTRATE

RTP - Real-time processes at surfaces M. Jankowski 1,*, D. Kaminski 2, K.H. Vergeer 3, M. Mirolo 1, F. Carlà 1, G. Rijnders 3, T.R.J. Bollmann 3,* 1ESRF-The European Synchrotron, 71 Avenue des Martyrs - Grenoble (France), 2Department of Chemistry, University of Life Sciences in Lublin, 20-950 - Lublin (Poland), 3University of Twente, Inorganic Materials Science, MESA+ Institute for Nanotechnology, P.O. Box 217, NL-7500AE - Enschede (Netherlands) Nanostructured ultrathin bismuth films [1,2] have attracted a lot of interest as they reveal exotic functional properties that do not exist in bulk. The material properties are advantageous for the realization of e.g. spin based electronic devices, magnetoresistance effects and topological properties. Therefore nanosized Bi structures grown at different orientations have high potential for both fundamental research and technological applications. Especially growth on an atomically well defined insulating substrate, providing an infinite potential well barrier, is essential for future electronic applications as well as to get a deeper understanding of its controllability. In this study we demonstrate by Surface X-ray Diffraction (SXRD) the controlled growth of thin Bi(110) and Bi(111) films on such a substrate: atomically smooth insulating sapphire (α- Al2O3(0001)). The preparation of (110)-oriented Bi films, a rather exotic orientation, is a difficult task. At temperatures as low as 40K, we are able to slow down kinetics and thereby controlling the growth of Bi towards Bi(110), stable up to 400K. By annealing the Bi(110) films beyond, they can be transformed towards stable Bi(111) films. For films grown around RT, thin films grow in (110) orientation, followed by growth in (111) orientation. At elevated temperatures, Bi crystallizes in hexagonal (111) orientation on sapphire, having a lattice misfit of 4.6% similar as it does on a wide variety of other substrates [3-7]. References [1] E.I. Rogacheva, et al. Appl. Phys. Lett. 82, 2628 (2003). [2] Y.W. Wang, et al. Appl. Phys. Lett. 88, 143106 (2006). [3] H. Hattab, et al. Thin Solid Films 516, 8227 (2008). [4] M. Kammler, et al. Surface Science 576, 56 (2005). [5] F. Song, ACS Appl. Mater. Interfaces, 7, 8525 (2015). [6] G. Bian, et al. ACS Nano, 10, 3859 (2016). [7] M.-Y. Yao, et al. Scientific Reports 6, 21326 (2016).

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P4-RTP_394 CO/PD(111): FROM ISOLATED DIFFUSION TO THE ONSET OF STRONG INTER- ADSORBATE INTERACTION

RTP - Real-time processes at surfaces N. Avidor *, P.S.M. Townsend, A. Tamtögl, D.J. Ward, W. Alison, J. Ellis Cavendish Laboratory, University of Cambridge, JJ Thomson Ave, Cambridge, CB3 0HE, United Kingdom - Cambridge (United Kingdom) The diffusion of CO on metals has been studied for several surfaces, and has become a popular benchmark for first-principles total energy calculations. To date, experimental studies [1-4] were focused on diffusion at low coverages, but suggest a complex many-body nature to the CO intermolecular interaction. We have studied the diffusion of CO on the Pd(111) surface using the surface spin-echo technique [5], a reciprocal-space technique that places tracer and collective diffusion on the same footing. Measuring at elevated temperatures and for various equilibrium over- pressures of CO, we were able to explore isolated adsorbate motion as well as phases of higher density. We present the results and compare our work to a real-space study of diffusion and interactions [3]. References [1] G Alexandrowicz et al, J. Am. Chem. Soc. 130 (2008) 6789–94 [2] PR Kole et al, J. Phys.: Condens. Matter 24 (2012) 104016 [3] T. Mitsui et al, Phys. Rev. Lett. 94 (2005) 036101 [4] M. Mehlhorn et al, Phys. Rev. Lett. 104 (2010) 076101 [5] AP Jardine et al, Prog. Surf. Sci, 84 11–12 (2009) 323-379

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P5-RTP_285 DYNAMIC EFFECTS ON ADSORPTION OF ORGANIC MOLECULES AT INSULATING SURFACES

RTP - Real-time processes at surfaces D. Gao 1,*, J. Gaberle 1,*, F. Federici Canova 2, M. Watkins 3, A. Shluger 1, L. Nony 4, C. Loppacher 4, A. Amrous 4, F. Bocquet 4, F. Para 4, S. Lamare 5, F. Palmino 5, F. Chérioux 5 1University College London - London (United Kingdom), 2Aalto University - Espoo (Finland), 3University of Lincoln - Lincoln (United Kingdom), 4Aix-Marseille University - Marseille (France), 5Université de Franche-Comté - Besancon (France) We present the results demonstrating the importance of entropic effects for adsorption, diffusion and interaction of flexible molecules with surface steps. Previous studies have mainly emphasized the enthalpy of adsorption and the interaction between molecules.[1] Recent theoretical studies of the adsorption of individual flexible and rigid molecules on the KCl (001) surface have shown significant entropy loss during adsorption[2]. Here we used NC-AFM and modelling to study the behaviour of 1,3,5-tri-(4-cyano-4,4 biphenyl)-benzene (TCB) and 1,4-bis(cyanophenyl)-2,5-bis(decyloxy)-benzene (CDB) molecules on KCl(001). Both molecules were designed to contain the same anchoring groups and benzene ring structures, yet differ in flexibility. They were deposited on the KCl (001) surface, and imaged using NC-AFM[1]. CDB self-assembled structures were observed to grow from step edges, while TCB self-assembled structures grew as islands on the terrace and from step edges. Density functional theory (DFT) and molecular dynamics simulations were performed to explain the reasons behind this qualitative difference in growth character and how molecular flexibility can affect the diffusion of the molecules towards and along steps. Lowest energy adsorption geometries of single molecules on a clean terrace were calculated using the van der Waals corrected DFT and the results were used to parameterise a force field for interaction of each molecule with KCl(001) employing a genetic algorithm[3]. These force fields were then used to calculate diffusion coefficients and barriers for CDB and TCB on clean terraces. Potential of mean force calculations were used to calculate the adsorption free energy for both molecules. It was found that entropic contributions are significant and can match the enthalpic contribution to adsorption energy at temperatures as low as 400K, thus facilitating desorption. Furthermore molecular diffusion towards and adhesion to step edges was investigated and the associated change in entropy was calculated. The results demonstrate that the conformational flexibility of the CDB molecule allows it to interact strongly with steps and kinks, where nucleation and subsequently cluster growth occurs. TCB molecules in contrast are less able to adapt to step edges and kinks. This difference in growth modes confirms experimental NC-AFM observations of different modes of layer growth. References [1] A. Amrous, F. Bocquet, L. Nony, et al.. Adv. Mater. Interf. (2014) 1, 1400414 [2] Gaberle J., Gao D. Z., Watkins M. B., et al., J. Phys. Chem. C (2016) 120, 3913-3921. [3] Gao, D. Z., Federici Canova, F., Watkins, M. B., et al. J. Comp. Chem., (2015) 36, 1187–1195.

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P6-RTP_252 SURFACE PATTERN FORMATION IN CRYSTAL GROWTH KINETICS

RTP - Real-time processes at surfaces M. Zaluska-Kotur *, F. Krzyzewski * Institute of Physics, Polish Academy of Sciences - Warsaw (Poland) Precise layer by layer crystal growth process became important instrument used in production of nano-technological devices. On the basis of experimental experience it is clear that surface dynamics of growing crystal is one of the crucial factors that decide about stability of the process. From the other side formation of various geometric patterns during crystal growth is important phenomenon to study as an interesting example of far from equilibrium process. It remains a subject of continuous interests of many researchers. We will show how typical meandered or bunched step patterns at the surface can be studied by Kinetic Monte Carlo simulation method [1-3]. They will be compared with experimental results obtained for GaN crystal growth [4]. The main aim of the extended kMC study is to find proper model parameters – coupling constants between particles, energy barriers for each type of particle jump, such that describe the main characteristics of the studied system. The simplicity of the model and small number of control parameters allows studying systems of large particle numbers, performing long time simulations and describing the model behavior in various conditions. The study was carried out on the two-component kinetic Monte Carlo model of GaN(000-1) surface grown in nitrogen rich conditions. Diffusion of gallium adatoms over N-polar surface is slow and nitrogen adatoms are almost immobile [4]. Height and type of Schwoebel barriers decides about the character of the surface instability. Different surface morphologies are presented. Step bunches, double steps, meanders, mounds and irregular patterns emerge at the surface as a result of Schwoebel barriers at some temperature or miscut values. It is illustrated by adequate stability diagrams for surface morphologies. We will analyze time dependence of step bunching and step meandering process. In particular length of step meanders decreases as a function of miscut on the contrary to relations that can be derived out of simple arguments [5]. We will describe the responsible mechanism for such dependence. Thanks Research supported by the National Science Centre(NCN) of Poland (Grant NCN No. 2013/11/D/ST3/02700) References 1.Magdalena A. Załuska-Kotur, Filip Krzyżewski, Journal of Applied Physics 111, 114311 (2012) 138 2.Magdalena A. Załuska-Kotur, Filip Krzyżewski, Stanisław Krukowski, J. Cryst. Growth 343 (2012) 3.Filip Krzyżewski and Magdalena A. Załuska–Kotur J. Appl. Phys. 115 , 213517 (2014); 4.Magdalena A. Załuska-Kotur, Filip Krzyżewski, Stanisław Krukowski, Michał Leszczyński, Robert Czernecki , Cryst. Growth & Design 13, 1006 (2013) 5.Filip Krzyżewski and Magdalena A. Załuska–Kotur, , Surf. Sci. (2016)

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SAS - Self-assembly at surfaces

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O1-SAS _367 ARGININE AND ASPARTIC ACID ON CU(110): UNRAVELING THE DIFFERENT ADSORPTION MECHANISMS OF PEPTIDES STRUCTURAL UNITS

SAS - Self-assembly at surfaces R. Totani 1,*, C. Méthivier 1, H. Cruguel 2, C.M. Pradier 1, V. Humblot 1 1Laboratoire de Réactivité de Surface, Université Pierre et Marie Curie,UPMC Paris 6, 4 place Jussieu, 75252 Paris Cedex 05, France - Paris (France), 2Institut des NanoScience de Paris, Université Pierre et Marie Curie, UPMC Paris 6, 4 place Jussieu, 75252 Paris Cedex 05, France - Paris (France) Peptides are versatile molecules, whose properties can be conveniently tailored through genetic engineering and chemical functionalization. For this reason they are employed as building-blocks for functional materials with applications in nanotechnology, medicine and biotechnology [1]. The knowledge of amino acids (peptides subunits) adsorption processes on metallic surfaces is mandatory to implement peptides and proteins in these applications, but also to collect important information on the obtained functional materials, such as their biocompatibility and their biotoxicity, and to control the biointerfaces behavior. Surface science techniques, applied to the interfaces between amino acids and metallic surfaces, allow clarifying fundamental aspects of their interaction with the substrate [2, 3]. In this work, we examined the interaction mechanisms of arginine and aspartic acid, the two main components of the polypeptide RGD (arginine-glycine-aspartic acid), with a Cu(110) crystal. The chemical state and the anchoring points of the molecules on the surface have been investigated, respectively, with X-ray Photoelectron Spectroscopy (XPS) and Polarization Modulation Infrared Reflection Absorption Spectroscopy (PM-IRRAS), for different coverage values. Low Energy Electron Diffraction (LEED) and Scanning Tunneling Microscopy (STM) furnished complementary information about the layer structure. The molecular films have been obtained by means of an electrospray source (ES): with respect to the traditional Knudsen cells, ES allows an adsorption from an aqueous solution at room temperature, avoiding the high sublimation temperatures, which can damage and break delicate molecules like arginine. We show that completely different mechanisms characterize the arginine-Cu and aspartic acid-Cu interactions. In fact, the adsorption occurs via the NH3+ reactive group for arginine and via the COO- reactive group for aspartic acid. Besides, while aspartic acid tends to grow in islands, self-assembling in dimers with a 2D chiral network of specific geometry, arginine adopts a more disordered arrangement, with the molecules located alongside Cu(110) crystallographic axis. Thus, intermolecular interactions are predominant in aspartic acid: the molecule undergoes the double process of dimerization and self-organization. On the contrary, the molecule-substrate interaction dominates in arginine, since the layer structure is influenced by the underlying substrate. This indicates that, on Cu(110), the NH3+ reactivity in arginine is stronger than the COO- reactivity in aspartic acid, where intermolecular H-bond interactions, responsible for the extended 2D chiral array, are predominant. References [1] R. de la Rica, H. Matsui, Chem. Soc. Rev. 2010, 39 [2] C. Méthivier et al. Surface Science 2015, 632 [3] V. Humblot et al. Langmuir 2014, 30

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O2-SAS _320 THERMODYNAMIC BALANCE OF PERYLENE SELF-ASSEMBLY ON AG(110)

SAS - Self-assembly at surfaces K. Bobrov *, N. Kalashnyk, L. Guillemot * Institut des Sciences Moléculaires d’Orsay, CNRS, Université Paris-Sud 11, F-91405 Orsay. - Orsay (France) We present a room temperature STM study of perylene adsorption on Ag(110) at the monolayer coverage regime. We found that structure and symmetry of the flat perylene monolayer is determined by thermodynamic balance of the three factors: (i) the site recognition effect, (ii) the intermolecular interaction and (iii) the thermal motion of the perylene molecules. The moderate strength of the site recognition and intermolecular interactions, of the same order of magnitude as kT ~25 meV, represents a key feature of the thermodynamic balance. The thermodynamic balance bestowed to this system the unique quality to form a flexible monolayer of epitaxial as well as self-assembling character. The increasing perylene coverage induced gradual crystallization of the initially fluid monolayer (<0.1 ML) into the crystalline (2 5 3 -2)/(2 -5 3 2) monolayer (0.1053 ML). The crystalline monolayer further incorporated extra molecules modifying its structure and symmetry albeit maintaining its true commensurate character. The recognition effect of moderate strength was able to lock some of the perylene molecules into favorable adsorption sites of the (110) lattice providing a skeleton of the crystalline phases. We have found that the crystalline monolayer did not quench thermal motion of the included molecules but rather accommodated it modifying its skeleton by reselecting a new set of available adsorption sites favorable in terms of intermolecular interaction. The ability of the perylene crystalline structure to accommodate its thermal motion made possible formation of the epitaxial and self-assembled perylene monolayer free of domain boundaries in the whole coverage range.

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O3-SAS _382 THE ADSORPTION OF PROTEINS ON POLYMER BRUSHES: THE IMPACT OF NEUTRON REFLECTOMETRY

SAS - Self-assembly at surfaces G. Fragneto 1,*, E. Schneck 2,*, A. Halperin 3, J. Daillant 4 1Institut Laue-Langevin - Grenoble (France), 2Max Planck Institute of Colloids and Interfaces - Potsdam (Germany), 3Université Grenoble Alpes - Grenoble (France), 4Syncrotron Soleil - Gif-Sur- Yvette (France) In nature, biomolecules are often organized as functional thin layers in interfacial architectures, a very popular example being biological membranes. Biomolecular layers play also important roles in biotechnological applications, for instance when they are the result of adsorption processes. For the understanding of many biological or biotechnologically relevant processes, detailed structural insight into the involved biomolecular layers is required. We have used protein deuterium labelling combined to neutron reflectometry [1,2] to access layers’ global density profiles and standing-wave x-ray fluorescence [3, 4] as a complementary tool that allowed us to localize chemical elements in solid-supported lipid and protein layers with near-Ångstrom precision. Neutron reflectometry was used to provide evidence of ternary protein adsorption within polyethylene glycol (PEG) brushes [1,2]. Anti-PEG Immunoglobulin G antibodies (Abs) binding the methoxy terminated PEG chain segment specifically adsorb onto PEG brushes grafted to lipid monolayers on a solid support. The Abs adsorb at the outer edge of the brush. The thickness and density of the adsorbed Ab layer, as well as its distance from the grafting surface grow with increasing brush density. At high densities most of the protein is excluded from the brush. The results are consistent with an inverted “Y” configuration with the two FAB segments facing the brush. They suggest that increasing the grafting density favors narrowing of the angle between the FAB segments as well as overall orientation of the bound Abs perpendicular to the surface. As for the standing-wave x-ray fluorescence measurements, while earlier work mostly focused on relatively heavy elements, typically metal ions, we show that it is also possible to determine the position of the comparatively light elements S and P, which are found in the most abundant classes of biomolecules [5]. Our results suggest that simultaneous localization of S, the low P amounts in phosphorylated amino acids, and metal ligands in proteins can serve to identify unambiguously their conformation and orientation when adsorbed to surfaces. This work may constitute the basis for the label free, high resolution, element specific structural investigation of complex biomolecular layers and biological surfaces. Thanks We thank Roberto Felici, Jakub Drnec and Ernesto Scoppola for participation to the SWXF measurements. References [1] E. Schneck, et al. Langmuir 29, 14178 (2013) [2] E. Schneck, et al. Biomaterials 46 (2015) 95e104 [3] Bedzyk, et al., Science 241, 1788 (1988). [4] Schneck & Demé, Curr. Opin. Coll. Int. Sci. 20 , 244 (2015) [5] Schneck et al., submitted

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I16_SAS_454 DYNAMICS OF SOLID STATE DEWETTING BY LOW ENERGY ELECTRON MICROSCOPY

SAS - Self-assembly at surfaces F. Leroy *, F. Cheynis, S. Curiotto, M. Trautmann, P. Müller CINaM, UMR 7325 Aix-Marseille Université/CNRS - Marseille (France) In the past decade there have been many theoretical and experimental efforts to study the solid state dewetting, i.e. the spontaneous agglomeration of a thin solid film into an assembly of 3D islands [1,2]. The understanding of this phenomenon has not reached the degree of maturity achieved for liquid dewetting but there is now enough experimental data to consider the possibility of a future “dewetting engineering” [3]. The most recent advances in this field uses model systems such as single crystalline films deposited or bonded on substrates. Among numerous studies I will report on a synthesis of results obtained on the dewetting mechanisms occurring on Si(001) and Ge(001) thin films bounded on amorphous SiO2 [4] (respectively known as SOI and GOI for Silicon On Insulator and Germanium On Insulator). We have achieved a detailed analysis of the dewetting dynamics performing real time measurements by Low Energy Electron Microscopy and Grazing Incidence Small-Angle x- ray Scattering coupled with Kinetic Monte Carlo simulations. I will present how to influence the dewetting by varying the film thickness, the annealing temperature, or the state of strain in the film [5,6]. Moreover, I will show how adsorbed species at the surface can modify the energies involved in the dewetting dynamics and the mobility of the contact line film/substrate [7]. The anisotropic properties of crystalline films may also be used to initiate the dewetting from perfectly oriented edge fronts (see figure), leading to highly ordered 3D islands [8].

Fig: LEEM sequence of Si(001) dewetting on SiO2 from artificial edges etched by lithography. Field of view 25 μm. Temperature 850°C. Dewetting duration from (a) to (c) is 35 min. References [1] Trends and perspectives in solid-state wetting, C.R. Acad. Sciences 7, pp 529-635, Editor: O. Pierre Louis (2013) [2] C.V. Thompson, Annual Review of Material Research, vol. 42 399-434 (2012) [3] F. Leroy, L. Borowitz, F. Cheynis, Y. Almadori, S. Curiotto, M. Trautmann, J.-C. Barbé, P. Müller, Surf. Sci. Rep. 71(2) 391-409 (2016) [4] F. Leroy, F. Cheynis, T. Passanante, and P. Müller Phys. Rev. B 88, 035306 (2013) [5] E. Bussmann, F. Cheynis, F. Leroy, P.Müller, O. Pierre-Louis, New J. Phys. 13, 043017 (2011) [6] F. Cheynis, E. Bussmann, F. Leroy, T. Passanante, P. Müller, Phys. Rev. B 84, 245439 (2011) [7] S. Curiotto, F. Leroy, F. Cheynis, P. Müller, Appl. Phys. Lett. 104, 061603 (2014) [8] F. Leroy, F. Cheynis, T. Passanante, P. Müller, Phys. Rev. B 85, 185414 (2012)

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O4-SAS _418 A NOVEL X-RAY DIFFRACTOMETER-DEFLECTOR END-STATION AT THE ESRF ID10 BEAMLINE FOR STUDIES ON LIQUID SURFACES AND INTERFACES

SAS - Self-assembly at surfaces Chumakov *, O. Konovalov European Synchrotron Radiation Facility - Grenoble (France) A new diffractometer-deflector in a single assembly is in operation since January 2016 at the soft surfaces end-station of ID10 beamline at the European Synchrotron Radiation Facility. The main peculiarity of this instrument specifically designed for studies on soft/liquid surfaces and interfaces is that the beam steering mechanism - double crystal deflector (DCD) – based on the symmetric Bragg reflections is combined together with the surface diffractometer. The advantages of the DCD are: 1) only one motor is needed to deflect the beam in vertical plane, which speeds up the data acquisition; 2) the incident beam rotates around a fix point on the stationary liquid surface. The later together with the high stability and accuracy of the instrument is extremely important for studies on liquid-liquid interfaces which are sensitive to any mechanical agitations. The reinforced rotation circles of the diffractometer detector arm allow simultaneous usage of multiple detection schemes at the same experiment. The ID10 surface scattering multipurpose end station is dedicated to structural studies on soft condensed matter surfaces and interfaces using grazing-incidence diffraction (GID), X- ray reflectivity (XRR), grazing-incidence small-angle scattering (GISAXS) and Grazing Incidence X-Ray Fluorescence (GIXRF) techniques. Anomalous scattering at absorption edges above 1.5 keV is possible for each of these techniques. Thanks to the extended up to 4m sample-detector distance the length scales from sub-nm up to sub-µm can be explored both on free and on buried surfaces/interfaces (gas-liquid, gas-solid, liquid-liquid and liquid-solid) with the available energy range of X-ray (7-30 keV) and collimated beam with the size up to the 5 µm. Some of typical applications of the end-station (Langmuir and Gibbs layers of amphiphiles, polymers and nanoparticles; surface structure of complex fluids like colloid, gel and sol; structure and growth of 2D assemblies of molecules, macromolecules, proteins and nanoparticles) will be presented on the poster.

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O5-SAS _46 ORDERING AND DYNAMIC BEHAVIOR OF COPPER PHTHALOCYANINES ON THE THALLIUM-PASSIVATED SI(111) SURFACE

SAS - Self-assembly at surfaces P. Matvija 1,*, P. Sobotík 1, I. Oštádal 1, B. Pieczyrak 2, L. Jurczyszyn 2, P. Kocán 1 1Faculty of Mathematics and Physics, Charles University in Prague - Prague (Czech republic), 2Instytut Fizyki Doswiadczalnej, Universytet Wroclawski - Wroclaw (Poland) The silicon (111) surface passivated by one monolayer of thallium represents a unique substrate suitable for growth of self-assembled molecular mono-layers (SAMs). The passivated surface on the technologically important substrate exhibits unique electronic properties [1] and thanks to saturation of surface dangling bonds, adsorbants are mobile [2] and free to self-assemble. We use room-temperature scanning tunneling microscopy (STM) to study SAMs of copper phthalocyanines (CuPc) on the Si(111)/Tl-1x1 substrate. The low reactivity of the surface enables molecules to diffuse freely at low surface coverage and to form dense arrays at the close-to- monolayer coverage. We observe three possible domain orientations of the CuPc SAM (see the STM image superimposed by the proposed SAM model in Fig. 1). Interestingly, we discovered that the assembly of the molecules is strongly affected by the electric field of the STM tip. We show that, by applying of the short voltage pulses over the ordered CuPc arrays, we are able to switch the arrays into one of the possible domains (see Fig. 2, the arrow indicates the scanning direction and stars indicate positions of the pulses). We demonstrate the existence of the threshold voltage of the switching and determine that the probability of the switching remains constant for pulses as short as 1 ms. In order to explain the switching mechanism we use ab-initio calculations to determine the spatial and electronic structure of the stable SAMs. Based on the results, we propose a simple electrostatic model in which the switching is explained by disordering of the molecules during the pulses. Thanks This work was supported by Czech Science Foundation (contract no. 16-15802S) and by the Charles University in Prague (project GAUK No. 326515). References [1] Sakamoto et al., J. Electron Spectros. Relat. Phenomena 201, 88(2015). [2] Matvija et al., Appl. Surf. Sci. 331, 339(2015).

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O6-SAS_397 DIRECT OBSERVATION OF STRUCTURAL CHANGES IN ARTICULATING CARTILAGE ON CONFINEMENT

SAS - Self-assembly at surfaces R. Barker 1,*, L. Mears 2, W. De Vos 3, S. Prescott 4, R. Richardson 2 1University of Dundee - Dundee (United Kingdom), 2University of Bristol - Bristol (United Kingdom), 3University of Twente (Netherlands), 4University of New South Wales - Sydney (Australia) Investigations into the response of individual lipids under confinement as a model for articulating cartilage is well established using the surface force apparatus (SFA). However, although the SFA provides a very sensitive measurement of forces, it is not possible to measure the structure simultaneously while the confinement is applied. Here we utilize a new type of surface force apparatus1-4 combined with in-situ neutron reflectivity experiments for the study of zwitterionic lipid stacks as a model for articulating cartilage surfaces under uniaxial confinement. Neutron reflectivity is well established to give high resolution structural information about the buried interfaces5 and thus can offer new direct insight into the lubricating properties of model cartilage systems when confined. The presented study has shown a spacing approximately equivalent to one hydration layer of water molecules per lipid head group is maintained even at high applied uniaxial confinement pressures. Offering the first direct structural evidence to support the hydration lubrication mechanism. Further, we show that an apparent new lipid phase corresponding to the overall layer thickening is accessed under confinement, independent of the lipid tail unsaturation or starting lipid state. This suggests a repacking of the lipid tail region due to the reduced cross-sectional area per lipid when the headgroups are partially dehydrated. This also offers an insight into the high mechanical robustness of the lipid bilayers, where a closer packed lipid phase would improve their resistance to the high shear experienced in human joints while still maintaining their hydrated lubricating properties. The development of a new confinement cell allowing direct observation of the structural properties of biological systems under applied uniaxial pressure has been demonstrated to provide extensive new insight. Further, with little modification these novel approaches can be used to study a broad range of bio-tribological systems. References [1] W.M. de Vos, L.L.E Mears, R.M. Richardson, T. Cosgrove, R. Dalgliesh and S.W. Prescott. Review of Scientific Instruments, 83, 113903 (2012). [2] W.M. de Vos, L.L.E. Mears, R.M. Richardson, T. Cosgrove, R. Barker and S.W. Prescott. Macromolecules, 46 (3), 1027-1034 (2013). [3] S.B. Abbott, W.M. de Vos, L.L.E. Mears, R. Barker, R.M. Richardson and S.W. Prescott. Macromolecules, 47 (10), 3263-3273 (2014). [4] S.B. Abbott, W.M. de Vos, L.L.E. Mears, B. Cattoz, M.W.A. Skoda, R. Barker, R.M. Richardson and S.W. Prescott. Macromolecules, 48 (7), 2224-2234 (2015). [5] A. Junghans, E.B. Watkins, R.D. Barker, S. Singh, M.J. Waltman, H.L. Smith, L. Pocivavsek, J. Majewski, Biointerphases, 10, 019014 (2015).

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O7-SAS _398 FROM MOLECULAR SELF-ASSEMBLY TO METAL-ORGANIC COORDINATION: TRIMESIC ACID ON AG(111):

SAS - Self-assembly at surfaces L. Diekhöner *, M. Baviloliaei, S. Kiel, M. Gastaldo Department of Physics, Aalborg University - Aalborg (Denmark) Interactions of molecules at surfaces are important for many fields such as catalysis, molecular electronics, biocompatibility or sensor applications. Understanding the interaction between molecules and surfaces as well as the inter-molecular interactions on the surface is therefore crucial. For many purposes it is of importance to assemble molecules in long range periodic networks. This can often be achieved by using organic molecules, with the right functionality, that are allowed to self-assemble and cover the whole surface[1,2]. We have studied the self-assembly of trimesic acid (TMA) on crystalline Ag(111) by scanning tunneling microscopy under ultra-high vacuum conditions. Following the deposition of TMA at room temperature we study the interactions and long range ordering depending on coverage and a wide range of annealing temperature. TMA has previously been investigated on many different noble metal surfaces [3-7]. On Ag(111) TMA interacts via hydrogen bonds and forms an open honey comb network when deposited on the surface at 300 K, which was shown to convert to a compact and denser structure upon annealing to 420K [5,6]. We show in this study that a rich variety of structures appear upon varying annealing temperature and molecular density. The results can be explained in terms of lateral compression due to an increase in molecular density - effect of coverage - and a change in the nature of the intermolecular bonds that occur when the TMA is deprotonated upon annealing and thus enable them to interact via stronger ionic hydrogen bonds. Under the right conditions it was even possible to observe the formation of metal-organic assemblies, where Ag-atoms were incorporated in the TMA network. References [1] T. Yokoyama, et al, Nature, 413 (2001) 619 [2] J.V. Barth, G. Costantini, and K. Kern, Nature, 437 (2005) 671 [3] A. Dmitriev, et al, J. Phys. Chem. B 106, 6907 (2002). [4] Y. Ye, et al, J. Phys. Chem. C 111, 10138 (2007). [5] N. Lin, et al, Angew. Chem. Int. Ed. 44, 1488 (2005) [6] D. Payer, et al, Chem. Eur. J. 13, 3900 (2007). [7] M.S. Baviloliaei and L. Diekhöner, Phys Chem Chem Phys, 16, 11265 (2014)

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P1-SAS_258 SELF-ASSEMBLY OF CHIRAL CONFORMATIONAL SWITCHES STUDIED BY UHV‐ STM

SAS - Self-assembly at surfaces A. Nuermaimaiti 1,*, J. Cramer 2, K.L. Svane 1, Y. Ning 1, S. Jethwa 1, N.D. Kjeldsen 2, C. Bombis 1, V.F. Jensen 1, B. Hammer 1, K.V. Gothelf 2, T.R. Linderoth 1 1iNANO and Department of Physics and Astronomy, Aarhus University, Denmark - Aarhus (Denmark), 2iNANO and Department of Chemistry , Aarhus University, Denmark - Aarhus (Denmark) Molecular conformational flexibility is widely recognized to be important for molecular self- assembly, but relatively few studies have addressed this explicitly and systematically [1-3]. Here, we focus on the degrees of freedom introduced by molecular conformational flexibility in a molecular system that displays up to 16 distinct conformational states upon adsorption. The custom-synthesized class of rod-shaped molecules [4] consist of three naphthalene (or isoquinoline) units connected by ethynylene spokes and functionalized by systematically varied terminal moieties, including bulky tert-butyl, alkyl and hydrogen bonding carboxyl groups. A range of different surface structures formed by this class of molecules are characterized by UHV-STM and DFT calculations .The structures are systematically compared regarding the statistical distribution of molecular conformations obtaining insight into how conformational /chiral states are selected in molecular surface structures through molecular interactions and how chiral selection can accordingly be controlled by chemical design [5].

References 1. Weigelt, S., et al., Chiral switching by spontaneous conformational change in adsorbed organicmolecules. Nature Materials, 2006. 5(2): p. 112-117. 2. Matena, M., et al., Conformation-controlled networking of H-bonded assemblies on surfaces. Chemical Communications, 2009(24): p. 3525-3527. 3. Ning, Y., et al., Selection of conformational states in self-assembled surface structures formed from an oligo(naphthylene-ethynylene) 3-bit binary switch. Journal of Chemical Physics, 2015. 142(10). 4. Cramer, J.R., et al., Oligo(naphthylene–ethynylene) Molecular Rods. European Journal of Organic Chemistry, 2013. 2013(14): p. 2813-2822. 5. Kjeldsen, N.D., E.D. Funder, and K.V. Gothelf, Synthesis of homochiral tris-indanyl molecular rods. Organic & Biomolecular Chemistry, 2014. 12(22): p. 3679-3685.

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P2-SAS_270 RATIONALISING THE STRUCTURAL DETAILS OF COMPLEX POLYMERS USING A COMBINATION OF ELECTROSPRAY DEPOSITION AND SCANNING TUNNELLING MICROSCOPY

SAS - Self-assembly at surfaces S. Jethwa *, M. Madsen, L. Lammich, K. Gothelf, T.R. Linderoth University of Aarhus - Aarhus (Denmark) Electrospray deposition (ESD) represents an important pathway for enabling thermally fragile organic molecules synthesised ex-situ to be studied under ultra-high vacuum (UHV) conditions [1]. In particular, this has the potential to allow the structures and adsorption morphologies of complex organic polymers of key interest to polymer chemists, to be studied on surfaces using scanning probe techniques [2,3]. A crucial advantage of this approach that exploits the high-resolution capability of STM is that a better structural understanding of individual polymer strands on the monomeric scale can now be obtained, not previously possible using characterisation techniques that tend to average out the contributions from multiple polymer strands. Here, we focus on the ESD of a phenylene vinylene polymer derivative (PPV) onto a Au(111) surface using a commercially available Electrospray source (MolecularSpray [4]). The polymer has large triethylene-glycol side-chains terminated with a tert-butyl diphenylsilyl (TBDPS) protecting group. Scanning in the temperature range 95– 110K, STM reveals the large-scale adsorption topologies of the intact polymer strands. Importantly, a number of high-resolution images, an example of which is shown in Figure 1, are obtained that reveal the structure of the polymer on the monomeric scale. The conformations of the flexible triethylene-glycol side-chains and their influence on the curvature of the polymer strands on the surface are discussed, as are aspects of regioisomerism resulting from the radical polymerisation process. It is demonstrated that utilising a combination of ESD and STM will allow for a deeper insight into polymer structures at the nanoscale. References [1] Rauschenbach, S., Stadler, F. L., Lunedei, E., Malinowski, N., Koltsov, S., Costantini, G., Kern, K., Small, 2, 540, (2006). [2] Yokoyama, T., Kogure, Y., Kawasaki, M., Tanaka, S., Aoshima, K., J. Phys. Chem. C, 117, 18484, (2013). [3] Förster, S., Widdra, W., J. Chem. Phys., 141, 054713, (2014). [4] O'Shea, J.N., Taylor, J.B., Swarbrick, J.C., Magnano, G., Mayor, L.C. and Schulte, K., Nanotechnology, 18, 035707 (2007).

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P3-SAS_293 UNDERSTANDING NUCLEATION AND SELF-ASSEMBLY OF LARGE ORGANIC MOLECULES ON AN INSULATING SURFACE

SAS - Self-assembly at surfaces J. Gaberle 1,*, D.Z. Gao 1, M. Watkins 2, L. Nony 3, C. Loppacher 3, A. Amrous 3, F. Bocquet 3, F. Para 3, S. Lamare 4, F. Chérioux 4, F. Palmino 5, A. Shluger 1 1University College London - London (United Kingdom), 2University of Lincoln - Lincoln (United Kingdom), 3Aix-Marseille Université, CNRS, IM2NP UMR 7334 - Marseille (France), 4Université de Franche-Comté, CNRS, FEMTO-ST - Besancon (France), 5Université de Franche-Comté, CNRS, FEMTO-ST, ENSMM - Besancon (France) We used non-contact atomic force microscopy (NC-AFM) and theoretical simulations to study the adsorption, diffusion, film stability, de-wetting, and desorption of functional organic molecules on bulk insulating surfaces at a range of different temperatures. Our results focus on the importance of molecular mobility and flexibility in order to provide insight into the mechanisms that drive self-assembly in these systems. Two functionalised molecules, 1,3,5-tri-(4-cyano-4,4 biphenyl)-benzene (TCB) and 1,4- bis(cyanophenyl)- 2,5-bis(decyloxy)benzene (CDB), were deposited and annealed on the KCl(001) substrate at temperatures between 300K to 440K and imaged using NC-AFM. CDB self-assembled structures were observed to grow from step edges, while TCB self- assembled structures grew as islands on the terrace and from step edges. Complementary theoretical calculations using van der Waals corrected DFT-D3 were used to study the adsorption of single such molecules on the KCl (001) surface and to investigate the difference in growth mechanism. Using a genetic algorithm an empirical force field was parameterised for each molecule, which were used in conjunction with molecular dynamics (MD) to study the diffusion of individual CDB and TCB molecules on terraces and at step edges. The results demonstrate that the conformational flexibility of the CDB molecule allows it to interact strongly with steps and kinks, where nucleation and subsequently cluster growth occurs. In contrast, the rigid TCB molecule is unable to adapt to step edges and kinks with a significant entropy loss upon adhesion on step edges, leading to different monolayer growth modes. Minimum energy monolayer structures were deduced from NC- AFM data and their stability was investigated in MD simulations. Our results compare well to experimental NC-AFM observations of film stability.

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P4-SAS_321 HYBRID METAL-ORGANIC COORDINATION NETWORKS FOR CO2 AND O2 ACTIVATION AT ROOM TEMPERATURE

SAS - Self-assembly at surfaces D. Hurtado Salinas 1,*, G. Ruano 1, A. Sarasola 2, A. Arnau 3, K. Kern 4, M. Lingenfelder 1 1Max Planck-EPFL Laboratory for Molecular Nanoscience, EPFL - Lausanne (Switzerland), 2Donostia International Physics Center (DIPC), Donostia, Spain 4. Applied Physics Department I, University of the Basque Country, Bilbao - Donostia (Spain), 3Donostia International Physics Center (DIPC), Donostia, Spain 5. Condensed Matter Physics Department, University of the Basque Country, Donostia - Donostia (Spain), 4Institute of Physics, EPFL, Lausanne, Switzerland 6. Max Planck Institute for Solid State Research - Stuttgart (Germany)

Photosynthesis, the model system for energy conversion, uses CO2 as its starting reactant to convert solar energy into chemical energy, i.e. organic molecules or biomass. The first and rate-determining step of this process is the immobilization and activation of CO2, a carboxylation reaction catalyzed by the enzyme RuBisCO [1]. Metal-organic structures observed in nature can be replicated in the laboratory by self- assembly on solid surfaces [2,3]. Inspired by the active site of RuBisCO, we designed the first networks using an alkaline earth metal (Group 2): magnesium (Mg). Here we present a method for producing hybrid networks of Mg and organic molecules of terephthalic acid (TPA) and 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAPT) by direct deposition onto clean metal substrates [Cu (100) and Mg (0001)] under Ultra High Vacuum (UHV) conditions at room temperature (RT). We track their reactivity and dynamic response to CO2, O2 and H2, in situ, by Scanning tunneling microscopy (STM) and X-Ray Photoelectron Spectroscopy (XPS). Specific phase transformations and active sites are identified upon gas exposure at RT (figure 1). References [1] Newman, J.; Branden, C. I.; Jones, T. A. Acta crystallographica. Section D, Biological crystallography 49, 548 (1993). [2] M.A. Lingenfelder, H. Spillmann, A. Dmitriev, S. Stepanow, N. Lin, J.V. Barth, and K. Kern, Chem. Eur. J. 10, 1913 (2004). [3] Rico Gutzler, Sebastian Stepanow, Doris Grumelli, Magalí Lingenfelder, and Klaus Kern, Acc. Chem. Res. 48, 2132−2139 (2015).

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P5-SAS_325 SELF-ASSEMBLY OF CROSS-SHAPED FUNCTIONAL ORGANIC MOLECULES ON HETEROGENEOUS SURFACES WITH SIMPLE TOPOGRAPHIES

SAS - Self-assembly at surfaces V. Gorbunov *, S. Akimenko, A.V. Myshlyavtsev Omsk state technical university - Omsk (Russian federation) Adsorption and self-assembly of functional organic molecules on metallic and graphitic substrates are generally accepted to be the most promising approach for creation large- scale functional nanostructures. The structure and morphology of the adsorption layer are usually defined by the overall balance of various interactions involved in the whole system. In general case, especially for the energetically heterogeneous surface, substrates can strongly influence the structure of organic adsorption overlayers [1-2]. For example, in the case of vicinal surface, reconstructed metallic surface such as “herringbone” Au(111) or chemically modified surface the surface plays an active role in the self-assembly process [2]. In this contribution, we use the Monte Carlo and transfer-matrix methods to explore the combined effect of directional intermolecular interactions between cross-shaped organic molecules and topography of a heterogeneous solid surface. In the proposed lattice gas model, a cross-shaped molecule with one attractive arm adsorb on one site of a square lattice. Heterogeneous surfaces are represented by two kinds of sites, so called bivariate surfaces. We considered two variants of the bivariate surfaces: strong and weak adsorption sites form 1) the parallel or 2) perpendicular linear patches of different width. Also the effect of energy difference between adsorption on the strong and weak sites on thermodynamic properties of the adlayer is investigated. The obtained results demonstrated that different topographies of the bivariate surface can lead to the formation of self-assembled monolayers ranging from patchwise and chessboard to zig-zag and perfect linear structures. It is found that the sequence of ordered structures appearing in the adlayer, when increasing the surface concentration of the molecules, strongly depends on the energy difference between adsorption on the strong and weak sites. The insights from this study can be helpful in design of 2D supramolecular architectures consisted of cross-shaped organic molecules such as porphyrins, phtalocyanines and their functional derivatives on the heterogeneous solid surfaces. Thanks The work was supported by the Ministry of Education and Science of the Russian Federation on a budget-funded basis for 2014-2016 (project №16.2413.2014/К). References [1] L. Bartels, Nature Chemistry 2, 87 (2010). [2] R. Otero, J. M. Gallego, A. L. V. de Parga, N. Martín, and R. Miranda, Advanced Materials 23, 5148 (2011). [3] V. A. Gorbunov, S. S. Akimenko, and A. V. Myshlyavtsev, Adsorption 1 (2015) (in press).

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P6-SAS_344 RAMAN STUDY OF THE VIBRATION EIGENMODES OF THE ORDERED ADSORBATE SURFACE AU-(5X2)/SI(111)

SAS - Self-assembly at surfaces B. Halbig 1,*, M. Liebhaber 1, U. Bass 1, J. Geurts 1, E. Speiser 2, J. Räthel 2, A. Baumann 2, S. Chandola 2, N. Esser 2, S. Neufeld 3, S. Sanna 3, W.G. Schmidt 3 1Universität Würzburg, Physikalisches Institut, Exp. Physik 3 - Würzburg (Germany), 2Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V. - Berlin (Germany), 3Universität Paderborn, Department Physik - Paderborn (Germany) Submonolayer coverages of metal atoms on semiconductor surfaces can exhibit self- assembly and distinct reconstruction patterns, which induce electronic correlation effects, especially for one-dimensional chains. These effects are tightly connected with the local atomic arrangement and the corresponding vibration eigenmodes. An eligible system which aroused wide interest is Au/Si(111). For appropriate submonolayer Au coverages and substrate temperatures well-defined reconstruction patterns can be induced, e.g. the Au- (5x2) reconstruction, which consists of parallel Au-induced chains. Its vibration eigenfrequencies and mode symmetries can be studied with high spectral resolution by Raman spectroscopy. We report on polarized in-situ UHV Raman spectroscopy of the vibrational eigenmodes of Au-covered Si(111) surfaces with (5x2) reconstruction, as identified by its LEED pattern. The intensity of the surface-related Raman signals is about 4 orders of magnitude below the Si bulk phonon signal due to their extremely low scattering volume. Nevertheless, high- sensitivity CCD detection allows the identification of characteristic vibration modes, induced by the ordered Au-coverage. In the Raman spectrum they replace the surface vibration modes of the clean (7x7)-reconstructed Si(111) surface [1]. The positions of the Au-induced Raman peaks are in the range from 3 meV to 15 meV, the strongest ones at 3 meV, 6 meV, and 13 meV. These Raman peaks show mode-specific polarization properties, which are correlated with the direction of the Au-induced chains. Furthermore, we performed first- principle calculations of the Au-(5x2)/Si(111)-surface dynamics with linear response routines within Density Functional Theory as implemented in the VASP package, yielding the mode elongation patterns, eigenfrequencies, and Raman scattering efficiencies. This allows us to compare our experimental results with the calculated vibrations for two currently discussed models for the (5x2) reconstruction, an intrinsically (5x1) model by Erwin et al. [2], which achieves the (5x2) periodicity by invoking a double-periodicity arrangement of Si adatoms along the chains, and alternatively a modified model by Kwon and Kang [3], where one additional Au-atom per unit cell yields a genuine (5x2) periodicity. Thanks Deutsche Forschungsgemeinschaft, research units FOR 1162 (GE 1855/10-2) and FOR 1700. References [1] M. Liebhaber et al., Phys. Rev. B 89, 045313 (2014) [2] S.C. Erwin et al., Phys. Rev. B 80, 155409 (2009) [3] S.G. Kwon and M.H. Kang, Phys. Rev. Lett. 113, 086101 (2014)

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P7-SAS_359 LATTICE DYNAMICS AND CRYSTAL FIELD SPLITTING IN CEPT5 LAYERS ON PT(111), DETERMINED BY RAMAN SPECTROSCOPY

SAS - Self-assembly at surfaces B. Halbig 1,*, U. Bass 1, J. Geurts 1, M. Zinner 2, K. Fauth 2 1Universität Würzburg, Physikalisches Institut, Exp. Physik 3 - Würzburg (Germany), 2Universität Würzburg, Physikalisches Institut, Exp. Physik 2 - Würzburg (Germany)

Ultrathin layers of the binary intermetallic compound CePt5 with thicknesses of few unit cells have found great interest in the field of Kondo physics, originating from the interaction of the 1 localized Ce 4f electrons with the itinerant electrons [1]. Such CePt5 layers are generated on Pt(111) surfaces in UHV by deposition of elemental Ce and subsequent annealing, which results in a hexagonal crystalline CePt5 structure, consisting of alternating CePt2 and Pt atomic layers, respectively, (the latter forming a kagome lattice), terminated by a dense hexagonal Pt layer at the surface [2,3]. In this crystal structure a splitting of the Ce 4f electronic levels by the crystal electric fields of the neighboring Pt atoms is expected to enable electronic transitions, which should be observable in Raman spectroscopy. Furthermore, the CePt5-layer should give rise to Raman-active lattice vibration modes.

We report on the determination of the crystal-field-induced 4f level splitting in CePt5 layers with thicknesses down to 3.5 unit cells on Pt(111) surfaces by employing electronic Raman spectroscopy from crystal field excitations (CFE). As a reference material we used identically prepared LaPt5 layers, i.e., with the same crystal structure, but without 4f electrons. In the Raman spectra of CePt5 at T = 20 K three distinct peaks appear with Raman shifts up to about 25 meV, which are absent for LaPt5. They are identified as CFE of Ce 4f electrons, located (i) in the CePt5 layer, (ii) at the interface of the CePt5 layer to the Pt(111) substrate, and (iii) at the Pt-terminated surface of the CePt5 layer.

Besides, up to three additional sharp Raman peaks occur almost identically both for CePt5 and for LaPt5. Therefore they are identified as crystal lattice vibrations. For CePt5, they are assigned to the E2g mode of the CePt5 layer and to vibrations of the uppermost part of the CePt5 layer, which is symmetry-reduced due to a slight in-depth shift of a monolayer of Pt atoms [3]. Thanks Deutsche Forschungsgemeinschaft, research unit FOR 1162 References [1] C. Praetorius et al., Phys. Rev. B 92, 045116 (2015) [2] J. Kemmer et al., Phys. Rev. B 90, 195401 (2014) [3] C. Praetorius et al., Phys. Rev. B 92, 195427 (2015)

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P8-SAS_371 THE ADSORPTION STRUCTURE OF TCNQ ON AG(111)

SAS - Self-assembly at surfaces P.J. Blowey 1,*, L.A. Rochford 2, D.A. Duncan 3, D. Warr 2, T.L. Lee 3, G. Costantini 2, D.P. Woodruff 1 1Department of Physics, University of Warwick - Coventry (United Kingdom), 2Department of Chemistry, University of Warwick - Coventry (United Kingdom), 3Diamond Light Source - Didcot (United Kingdom) 7,7,8,8-tetracyanoquinodimethane (TCNQ), is a strong electron acceptor molecule that has attracted great interest for applications in organic electronics due to its ability to induce charge transfer processes when combined with a wide range of materials. As a result of this, the adsorption and assembly of TCNQ on metal substrates has been the subject of a substantial research effort aiming to characterise the delicate interplay between the adsorption geometry and the electronic properties of the interface, typically by combining scanning tunnelling microscopy (STM) measurements with density functional theory (DFT) calculations (e.g [1,2]). However, with the exception of one study of the tetrafluorinated TCNQ derivative (F4-TCNQ) on Cu(111)[3], there has been an absence of any experimental structural investigations that give a direct route to the molecular geometry at the interface. Here, we investigate the adsorption of TCNQ on the Ag(111) surface, using the complementary techniques of scanning tunnelling microscopy (STM) to ascertain the molecular packing and low energy electron diffraction (LEED) to obtain precise surface unit meshes and determine whether the molecular overlayer is commensurate with the substrate. We find, that by annealing the sample to varying extents, an array of different phases for TCNQ on Ag(111) can be accessed. We combine this STM and LEED study with the normal incidence X-ray standing wave (NIXSW)[4] technique to determine the height of the TCNQ molecules above the surface. The NIXSW technique offers both elemental and chemical-state sensitivity allowing for the heights of the chemically-inequivalent atoms within the molecule to be resolved separately. The C1s NIXSW yields high coherent fractions (>0.9) which indicate that the molecule sits at a single well-defined height above the surface. The corresponding coherent positions of the chemically-inequivalent carbon atoms indicate that the central TCNQ ring lies flat with the peripheral groups bending slightly down towards the substrate. In contrast to this, the N1s NIXSW gives significantly lower coherent fractions (~0.4) which imply that the N atoms are present at two or more different heights above the surface. This result is most easily reconciled with the inclusion of Ag adatoms in the surface structure to which only a fraction of the N atoms are bonded. References [1] D. Stradi et al., RSC Advances 6, 15071 (2016). [2] T.-C. Tseng et al., Nat Chem 2, 374 (2010). [3] L. Romaner et al., Physical Review Letters 99, 256801 (2007). [4] D. P. Woodruff, Reports on Progress in Physics 68, 743 (2005).

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P9-SAS_401 NANOCLUSTERS ON GRAPHENE/IR(111): INSIGHTS FROM AB-INITIO CALCULATIONS AND EXPERIMENTS

SAS - Self-assembly at surfaces M. Peressi, F. Mohamed *, N. Podda, M. Corva, Z. Feng, C. Dri, E. Vesselli University of Trieste - Trieste (Italy) Fabrication of ordered arrays of metallic nanoclusters (NCs) for catalysis applications is the goal of many efforts. The Moire' pattern of graphene/Ir(111) works as an efficient template to this purpose, in particular for the growth of Pt and Ir based NCs, as predicted by ab-initio calculations and observed for different metal loadings. The chemical and morphological behavior of metallic NCs upon interaction with small molecules of environmental importance such as carbon mono- and dioxide is investigated with atomic-level detail from ultra-high vacuum to near ambient pressure by both spectroscopy and microscopy approaches. Ab initio calculations give insights into the different nucleation behavior of Pt and Ir with respect to other metals, such as for instance Cu, and predict that even materials that do not form cluster superlattices can be grown promoting their nucleation through a seeding mechanism with another properly chosen metal. Thanks Support from the Italian Ministry of Foreign Affairs and International Cooperation (MAECI), MIUR, and the University of Trieste (Finanziamento di Ateneo per progetti di ricerca scientifica - FRA2015) is acknowledged.

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P10-SAS_413 SYNTHESIS OF HYBRID (C60)-(AU35) NANO-CLUSTERS ON GRAPHITE

SAS - Self-assembly at surfaces L. Guo *, D. Kaya, Q. Guo, R.E. Palmer University of Birmingham - Birmingham (United Kingdom) Nanoclusters are attracting much attention these days due to their physical and chemical properties and their potential applications in nanotechnology [1-3]. Recently, hybrid magic [4] number clusters, (C60)m-Aun, have been produced on the surface of Au(111) . These clusters are formed with a very high selectivity due to the superior stability of clusters for specific ratios of m/n. One of the magic number clusters is composed of 10 C60 molecules [4] and 35 Au atoms . We aim to produce such a (C60)10-Au35 cluster on a graphite(HOPG) surface at room temperature using size-selected Au35 cluster as the seed. The Au35 clusters are produced from a cluster beam source [5] and deposited on HOPG with an energy of 500 eV. This energy is high enough to pin the clusters on landing hence preventing aggregation. The sample is then transferred into a UHV-STM system where C60 molecules are deposited onto the sample at room temperature. The pinned Au clusters are expected to trap the diffusing C60 molecules to hybrid cluster such as (C60)10-Au35. In this preliminary study, we focus on the size distribution of the Au35 clusters from STM. Typically, we find 3-D structure with 2-3 Au atomic layers. Latest result in C60 dosing onto this surface will as be reported. References [1] G. Schmid, M. Baumle, M. Geerkens, I. Helm, C. Osemann, T. Sawitowski, Chem. Soc. Rev. 28, 179−185 (1999). [2] S. Palomba and R. E. Palmer, J. Appl. Phys. 104, 094316 (2008). [3] F. Yin, S. Lee, A. Abdela, S. Vajda and R.E. Palmer, J. Chem. Phys. 134, 141101 (2011). [4] Y. Xie, L. Tang, and Q. Guo, Phys. Rev. Lett. 111, 186101 (2013). [5] Z. W. Wang and R. E. Palmer. Phys. Rev. Lett. 108, 245502. (2012).

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P11-SAS_2 STRUCTURE AND ELECTRONIC PROPERTIES OF ZN-TETRA-PHENYL- PORPHYRINS SINGLE- AND MULTI-LAYERS FILMS GROWN ON FE (001) P(1X1)O

SAS - Self-assembly at surfaces G. Bussetti *, A. Calloni *, M. Celeri, G. Berti, M. Finazzi, L. Duò, F. Ciccacci Department of Physics, Politecnico di Milano - Milan (Italy) Porphyrins have attracted the interest of researchers in different fields: chemistry, physics and technology. This is due to the enormous variations of the molecule reactivity obtained by simply changing the peripheral radical groups and/or the inner metal atom. Thin porphyrin films have been grown on metals, semiconductors or organic-compatible substrates in view of possible applications in scalable organic-based devices. Unfortunately, the molecule- substrate interaction can significantly perturb the reactivity of the porphyrin and the properties of the hypothetical device. Trying to overcome this limit, thin metal-oxide (MO) layers can tangibly reduce the molecule-substrate interaction. In MO an ordered layer of oxygen atoms passivates the buried metal substrate, decoupling the deposited molecules from the metal bulk. Although MO thin films represent an extremely wide class of compounds, we will focus our attention on the well characterized Fe (001)-p(1x1)O system. From a structural point of view, oxygen atoms reside in the (001) surface hollow sites with a fourfold symmetry, slightly above the Fe surface layer, a structural configuration that could help decoupling the porphyrin from the substrate. We will show results obtained when a prototypical porphyrin molecule [namely, Zn-tetra- phenyl-(meso) porphyrin (ZnTPP)] is deposited on Fe (001) p(1x1)O. The structure and electronic properties of the samples are studied by low-energy electron diffraction (LEED) and UV-(inverse) photoemission spectroscopy (PES, IPES), respectively. The results are compared with ZnTPP films grown on Si (111) 7x7, clean Fe (001) and Au (001) to evaluate the role of the oxide layer. On Fe(001)-p(1x1)O, ZnTPP molecules form a (5x5) reconstruction when the first monolayer is completed, but PES and IPES still show the characteristic HOMO and LUMO states of the molecule. These results suggest that the ultra- thin oxygen layer significantly reduces the molecule-substrate interaction and increases the porphyrin mobility, allowing the molecules to form an ordered film.

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SCR - Surface chemical reactions and kinetics

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I01_SCR_428 INTRA-PARTICULAR MOBILITY IN SUPPORTED NANOALLOYS: FROM A METASTABLE TO AN EQUILIBRIUM STRUCTURE

SCR - Surface chemical reactions and kinetics P. Andreazza 1,*, J. Pirart 1, A. Lemoine 1, A. Lemoine 2, C. Ngandjong 1, C. Andreazza- Vignolle 1, J. Creuze 3, A. Coati 2, Y. Garreau 2, Y. Garreau 4 1Interfaces, Confinement, Matériaux et Nanostructures, ICMN, Université d’Orléans, CNRS - Orléans (France), 2Synchrotron Soleil - Gif-Sur-Yvette (France), 3SP2M, ICMMO, Université Paris- Sud, CNRS - Orsay (France), 4Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Diderot-Paris 7, CNRS - Paris (France) The original properties of nanoscale metallic supported particles result from the large fraction of surface atoms and the finite size (3D confinement) effect in terms of electronic structure, magnetic moment, optical response, thermodynamic behavior, etc . Compared to monometallic ones, the addition of one or several metals induces complex behaviors, not always well understood, which give a larger diversity in the structure and morphology of “nanoalloys” and offer an additional degree of freedom to tune their properties. Besides the composition effect, finite matter quantity effects to the nanometer scale lead to original variations of atom arrangement, favoring a segregation behavior by surface and core contraction effects that can be opposed to kinetic trapping effects induced by the growth mode 1. In our works, atom mobility and structural stability in Ag-based supported nanoalloys (Ag-Co and Ag-Pt) were studied through modeling and experimental in situ investigations of the structure and especially, the formation of core-shell, janus or alloyed configurations. Our idea was to choose two systems AgM (M= Co or Pt) having a strong tendency for phase separation and Ag surface segregation, with a total immiscibility for AgCo and a partial alloying for AgPt, and consequently to study the structural transitions at small size 2, 3. The goal is to understand the inter- and intra-particular mobility in these supported nanoalloys, through the investigation of their morphological and structural evolution from a metastable to an equilibrium atom arrangement. Preliminarily, this complex behavior requires a determination of the temperature effect and the support effect on pure particle, e.g. in the Ag case 4. Because the determination of atomic structure in nanoalloys is a complex problem, x-ray methods that probe the chemical or morphological features, are much more powerful when used together. Especially during the growth and annealing processes of these nanoalloys deposited in UHV, X-ray scattering techniques allow the determination of the structural evolution at the atomic scale (at wide angles) by GIWAXS, as well as the morphological evolution at the particle scale (at small angles) by GISAXS, providing highly complementary data, with the support of Monte Carlo simulations 5. In addition, using anomalous effect 6, segregation or alloying phenomena can be confirmed as in the case of CoAg or PtAg systems supported by high angle annular dark-field (HAADF) and high resolution electron microscopy (HRTEM) 7. References 1. P. Andreazza, V. Pierron-Bohnes, F. Tournus, C. Andreazza-Vignolle, V. Dupuis, Surf. Scien. Rep., 70,2 (2015) 2. P. Wynblatt, Comput. Mater. Sci. 15, 119 (1999) 3. M H. F. Sluiter et al, Phys. Rev. B, 73, 17 (2006) 4. A. Ngandjong, C. Mottet, J. Puibasset, J. Physical Chemistry C, 120 15, 8323 (2016) 5. P. Andreazza in « Nanoalloys: Synthesis, Structure and Properties », Ed. D.Alloyeau et al., p 69-114 (2012) Springer-Verlag, London 6. H. Khelfane, P. Andreazza, C. Andreazza-Vignolle, A.Y. Ramos, J. Penuelas, O. Lyon, Phys. Chem. Chem. Phys. (2016) submitted 7. A. Lemoine, Z. Kataya, P. Andreazza, C. Andreazza-Vignolle, Y. Garreau, A. Coati, Phys. Rev. B, to be published (2016)

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O1-SCR _245 INVESTIGATING CORE/SHELL PD/AU NANOPARTICLE STRUCTURE BY PROBING CO ADSORPTION WITH SFG

SCR - Surface chemical reactions and kinetics A. Ouvrard 1,*, A. Zakaria 1, N. Alyabyeva 1, F. Charra 2, B. Bourguignon 1 1ISMO, CNRS, Univ. Paris-Sud, Université Paris-Saclay - Orsay (France), 2CEA Saclay, IRAMIS Institut Rayonnement Matière de Saclay, SPCSI - Gif/yvette (France) Interaction of molecules with nanostructures has become a growing research topic for many applications where the reduction of size and dimensionality is a major tendency: sensors, energy, plasmonics, catalysis and molecular electronics. Binding strength, stability, enhancement of interaction with light are size dependent which influence device functionalities. Probing CO vibrations on nanoparticles (NP), provides a means to understand NP size and structural/composition effects. Surface-sensitive vibrational spectroscopy is a powerful tool to address molecular environment: i.e. molecular-substrate and molecule-molecule couplings [1]. Al2O3/Ni3Al(111) surfaces allow growing high density narrow size distributed NPs [2], particularly well adapted to study small cluster reactivity [3] and promising template for molecular electronic purposes. Sum Frequency Generation (SFG) experiments have been conducted on CO adsorbed on high-density, narrow size distributed core-shell (Pd/Au) NPs grown on ultrathin Al2O3 films on Ni3Al(111) done in UHV conditions. On bare Pd NPs, CO bind on bridge sites. CO frequency is coverage and NP size-dependant as already observed [1]. For 1 monolayer (ML) thick Au shell at 300 K, a new site is observed at higher frequency and narrower bandwidth, indicating a lower adsorption energy while bridge Pd sites have disappeared. At mbar pressure, CO adsorbs on gold as expected. On 2 ML thick Au shell, almost no CO are observed. The new site is attributed to CO linearly bonded on isolated Pd which migrated from Pd core towards Au shell surface upon CO adsorption [4-5] even at very low CO dose. Pd:Au alloy formation at the core/shell interface is limited to 1-2 ML. Upon CO+O adsorption in the mbar range, NP shell structure is even more modified. CO-NP interaction varies sensitively with shell thickness. Pd:Au alloy formation is observed but limited to few ML. Au electronic structure is strongly modified by underneath Pd core. Adsorption energies and activation barriers are probably impacted and may affect the catalytic reactivity. SFG spectroscopy of CO on core/shell NPs allows measuring shell thickness with high precision and following structural changes. Keywords: Core/Shell nanoparticle, alloys, CO, Sum Frequency Generation Thanks

We would like to thank L. Guillemot for preliminary STM images of Al2O3 supported nanoparticles. References [1] A. Ouvrard et al., to be submitted to JPCC 2016 [2] G. Hamm et al., Nanotechnology 17 (2006) 1943-1947 [3] G. Sitja et al., Nano Lett. 13 (2013) 1977 [4] L. Delannoy et al., ChemCatChem 2013, 5, 2707- 2716 [5] H.L. Abott et al., J. Phys. Chem. C 2010, 114, 17099-17104

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O2-SCR _336 PALLADIUM AND CARBON MONOXIDE OXIDATION AU30PD70(110) UPON OXYGEN AND CARBON MONOXIDE ELEVATED PRESSURE

SCR - Surface chemical reactions and kinetics M.C. Saint-Lager 1,*, M.A. Languille 2, F.J. Cadete Santos Aires 3, P. Dolle 4, E. Ehret 5, S. Garaudée 4, O. Robach 6 1Institut Néel - CNRS - Grenoble (France), 2Centre de Recherche sur la Conservation (CRC) - Lyon (France), 3Institut de Recherche sur la catalyse et l'environnement de Lyon (IRC - Lyon (France), 4Institut Neel - CNRS - Grenoble (France), 5Institut de Recherche sur la catalyse et l'environnement de Lyon (IRCEL) - Lyon (France), 6CEA-Grenoble, DSM / INAC / MEM / NRS - Grenoble (France) Since supported gold nanoparticles are known to be effective for the low temperature CO oxidation [1], numerous studies has been devoted to gold based catalyst such as AuXPd1-X alloy to improve the catalytic performance of both elements.

In this context we studied Au30Pd70(110) surface from UHV up to near ambient pressure of oxygen and CO as well as reactive condition for CO oxidation (CO + O2). We coupled in situ structural analysis by GIXRD (Grazing Incidence X-Ray Diffraction) to gas analysis by mass spectroscopy, thanks to an homemade setup [2] . This was completed by chemical analysis by AES for each of the main states of the system. The (1x1) Au rich surface in UHV, at room temperature, strongly evolves under oxygen when increasing the pressure up to 500 mbar and the temperature up to 200°C. Three main (P,T) domains can be distinguished : (1) oxygen induced (1x2) reconstruction with a Pd enrichment of the outermost surface plane (2) Pd segregation of over several atomic planes without long range order as detected by GIXRD (3) formation of a well-defined PdO(100) film at the surface. High pressure of CO also induces palladium segregation [3] therefore it appears that under (semi) realistic conditions gold tends to disappear from the Au30Pd70(110) surface. The oxygen induced PdO film is also a very interesting model to study the mechanism of the CO oxidation on pure palladium surface that remains very debated [4]. This PdO(100) film was followed under reactive conditions by adding CO pressure from 0.1 to 10 mbar to the already introduced oxygen (T from RT to 200°C). Reduction and then re-oxidation was observed for a temperature which depends on the CO pressure and the reduced phase was found to give a much lower rate for CO conversion into CO2. The behavior is quite similar to what was observed for Pd nanoparticles upon CO and oxygen exposure leading to stress the existence of a PdCX phase in these conditions [5], which could to be the main rate- limiting factor to the CO oxidation rate in semi-realistic conditions. References [1] Haruta et al, N. Chem. Lett. 1987, 2, 405 ; J. Catal. 1989, 115, 301 [2] M.C. Saint-Lager et al, Rev. Sci. Instrum., 78 (2007) 083902 [3] M.A Languille et al , Catal. Today, 260 (2016) 39 [4] Kondoh et al catal Today, 260 (2016) 14 [5] Balmes et al, Phys Chem Chem Phys, 14 (2012) 4796

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O3-SCR _238 EXPERIMENTAL AND THEORETICAL STUDIES ON OXIDATION OF CU-AU ALLOY SURFACES —EFFECT OF BULK AU CONCENTRATION—

SCR - Surface chemical reactions and kinetics W. Diño 1,*, M. Okada 2,*, K. Oka 1, K. Kojima 1, A. Yoshigoe 3, H. Kasai 4 1Osaka University - Suita (Japan), 2Osaka University - Toyonaka (Japan), 3Spring-8, Japan Atomic Energy Agency - Sayo-Gun (Japan), 4National Institute of Technology, Akashi College - Akashi (Japan) We report results of our experimental and theoretical studies on the oxidation of Cu-Au alloy surfaces using hyperthermal O2 molecular beam (HOMB). We determined, both experimentally (HOMB + SR-XPS) and theoretically (DFT-based calculations), the surface Au concentration profile of Cu-Au alloys (viz., Cu3Au, CuAu, and Au3Cu) in vacuum. We observed strong Au segregation to the top layer of the corresponding clean (111) surfaces. The degree of segregation strongly depends on the bulk Au components. The richer the Au bulk components, the richer the Au surface segregation. The Au-rich layers form a protective layer against oxidation of the Cu-Au alloys. After exposing the corresponding surfaces to HOMB, we found that surfaces with higher concentrations of Au showed lower susceptibility to oxidation, as determined by the low O sticking probability. Protection again oxidation fails for processes occuring above 300K. At 500 K, Cu segregates on the surface, breaking the protective layer, and oxidation proceeds on the surface, albeit rather slowly as there is still the subsurface. This gives further insight into how we can control the reactivity and robustness of a material, i.e., via the bulk component and the segregation profile. More details will be presented at the conference. Thanks We thank Y. Teraoka, Y. Makino, T. and K. Takeyasu for their help in the experiments. We gratefully acknowledge MEXT for a Grant-in-Aid for Scientific Research (Nos. 15KT0062, 17550011, 20350005, 22655005, 25620013, and 26248006). This work was also financially supported by The Sumitomo Foundation and The Murata Science Foundation. The synchrotron radiation experiments were performed at the BL23SU in the SPring-8 facilities with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) and Japan Atomic Energy Agency (JAEA) (Proposal No. 2015A3870, 2015B3870, 2015B3801). This work was performed under the Shared Use Program of JAEA Facilities (Proposal No. 2015A-E22, 2015B-E21) with the approval of Nanotechnology Platform project supported by the Ministry of Education, Culture, Sports, Science and Technology. Some of the numerical calculations presented here done using the the computer facilities at the following institutes: CMC (Osaka University), ISSP, KEK, NIFS, and YITP.

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O4-SCR _348 IDENTIFYING THE ADSORPTION CONFIGURATION AND THERMAL DECOMPOSITION MECHANISM OF GUAIACOL ON PT(111): AN INTEGRATED X-RAY PHOTOELECTRON SPECTROSCOPY AND DENSITY FUNCTIONAL THEORY STUDY

SCR - Surface chemical reactions and kinetics R. Denecke 1,*, A.J.R. Hensley 2,*, C. Wöckel 1, C. Gleichweit 3, K. Gotterbarm 3, C. Papp 3, H.P. Steinrück 3, Y. Wang 2, J.S. Mc Ewen 2 1Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig - Leipzig (Germany), 2The Gene Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University - Pullman (United States of America), 3Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg - Erlangen (Germany) Guaiacol adsorption on Pt(111) and its thermal decomposition were studied by a combination of density-functional theory (DFT) and in-situ high-resolution x-ray photoelectron spectroscopy (HR-XPS). This organic molecule serves as a model bio-oil compound which is of interest as a renewable source for liquid fuels [1,2]. Time-dependent isothermal adsorption on Pt(111) and temperature-programmed reactions were conducted at beamline U49/2-PGM1 at BESSY II. Calculations of total energies and C 1s and O 1s core-level binding energies of adsorbed species and intermediates were performed using the Vienna Ab-initio Simulation Package. DFT with van der Waals corrections suggests adsorptions sites whose core-level binding energies are in good agreement with experimental data for C 1s and O 1s levels. The molecule preferentially adsorbs intact in a bridge adsorption site with the molecular plane parallel to the surface at around 230 K (Figure 1a). The decomposition of guaiacol is followed experimentally by temperature-programmed XPS. Figure 2 shows the resulting C 1s evolution. The simulations consider different decomposition mechanisms by stepwise loss of hydrogen atoms or the methyl group, including ring breakage. Two stages are distinguished: in a first stage up to 350 K the methyl group is removed leading to a 1,2- benzoquinone species (Figure 1b). The second step realizes the ring opening and the release of CO up to 450 K (Figure 1c). A quantitative analysis of the data enables cross- checks between the C 1s and O 1s data from both experiment and theory and further supports the suggested dissociation route. Such a combined experimental and theoretical approach is essential for unravelling the elementary reaction mechanism of complicated reaction pathways on metal surfaces which can be used to better guide the development of highly selective catalysts.

References [1] K. Lee et al., ChemSusChem 8 (2015) 315. [2] G. H. Gu et al., ACS Catal. 6 (2016) 3047.

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O5-SCR _149 REACTION DYNAMICS OF FORMATE FORMATION AND DECOMPOSITION ON CU SINGLE CRYSTAL SURFACES

SCR - Surface chemical reactions and kinetics T. Kondo 1,*, Q. Jiamei 2, T. Ogawa 2, T. Kozarashi 2, J. Nakamura 1,* 1Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba - Tsukuba (Japan), 2Graduate School of Pure and Applied Sciences, University of Tsukuba - Tsukuba (Japan)

Thermal catalytic reduction of CO2 to formate (CO2 + 1/2H2 → HCOOa) is of an initial and essential step to methanol synthesis over Cu-based catalysts. In this work, we have studied the dynamics of formate formation and decomposition (reverse reaction) on Cu(110), Cu(111) and Cu(100) surfaces by supersonic molecular beam experiments and angle- resolved time-of-flight measurements of product CO2 emitted from the surface, respectively. For the formate formation reaction, it has been found that CO2 directly attacks with a hydrogen adatom (Ha) to form formate intermediate on Cu catalysts via an Eley-Rideal (ER)-type mechanism under thermal non-equilibrium through molecular beam experiments. We found that both the translational energy and vibrational energy of CO2 are indispensable to overcome the reaction barrier of formate formation, whereas the reaction rate is independent of the surface temperature. For the formate decomposition reaction, we have measured angular intensity distribution and translational energy of product CO2 in a steady state reaction of HCOOH and O2 on Cu(110). The angular distribution of CO2 shows a sharp collimation, cos6θ, perpendicular to the surface as shown in Fig.1a,b. The translational temperature of CO2 desorbed perpendicular to the surface is 570 K independent of the surface temperature as shown in Fig.1c. These results clearly indicate that the decomposition of formate is of thermal non-equilibrium. The detail reaction dynamics of both formation and decomposition of formate will be discussed. Thanks Financial support was provided by the Advanced Catalytic Transformation Program for Carbon Utilization (ACT-C) of the Japan Science and Technology Agency (JST)

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O6-SCR _194 XPS AND STM STUDIES OF THE EFFECT OF OXYGEN CONCENTRATION ON HCL REACTION AT CU(100) AND (111) SURFACES

SCR - Surface chemical reactions and kinetics P. Davies *, H. Altass, S. Guan Cardiff University - Cardiff (United Kingdom) Chlorine use in industry is very atom inefficient and has a negative environmental impact, 30% going to waste. As a result there is intense interest in catalytic systems that use or recover chlorine more efficiently. Copper is a common catalyst in these systems and oxygen a common co-reactant but O/Cl reactions at copper surfaces is poorly understood. We have studied HCl/O(a) at Cu(110) surfaces[1] and shown surface structures consisting of <100> orientated features identified as chlorine covered [210] facets.[2] But how does oxygen facilitate the formation of these facets. Is its role to disrupt the surface of the copper accelerating mass transport of copper to the reconstruction? Or does oxygen provide a pathway for the removal of hydrogen increasing HCl decomposition? Our aim in this paper is to explore how the transition between a submonolayer oxygen state to the beginnings of an oxide affects reactivity at Cu(100) and Cu(111) surfaces both kinetically and structurally, extending a recent study on Cu(100).[3] Reaction of HCl with Cu(100) surfaces is limited to the formation of a monolayer but this barrier is removed in the presence of oxygen leading to the facile formation of multilayer chlorides, Figure 1. A similar effect is observed on Cu(111). We show the surprising reactivity of heavily oxidised surfaces despite the lack of clean copper sites: reaction being initiated with the creation of defective channels in the oxide that subsequently give rise to the development of copper chloride islands.

Figure 1: STM images of (a) Cu(100) surface 15 -2 with σO = 1.6x10 cm after exposure to O2 at 523 K. (b) surface in (a) after reaction with HCl at 295 K. CuCl islands are evident on the steps. Thanks EPSRC: EP/I038748/1 & EP/L000202 “Catalysis Hub” Suadi Arabia for providing a studentship for HA References 1 P. R. Davies, D. Edwards and D. Richards, J. Phys. Chem., 2009, 113, 10333–10336 2 B. V. Andryushechkin, V. V. Cherkez, T. V. Pavlova, G. M. Zhidomirov and K. N. Eltsov, Surf. Sci., 2013, 608, 135–145. 3. H. Altass, A. F. Carley, P. R. Davies and R. J. Davies, Surface Science 2015 DOI:10.1016/2Fj.susc.2015.12.024

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O7-SCR_466 OPERANDO CO OXIDATION STUDY OF MGAL2O4(001)-SUPPORTED PT0.33RH0.67 NANOPARTICLES USING SURFACE X-RAY DIFFRACTION

SCR - Surface chemical reactions and kinetics U. Hejral 1,*, D. Franz 2, S. Volkov 2, S. Francoual 1, J. Strempfer 1, A. Stierle 2 1Deutsches Elektronen-Synchrotron DESY - Hamburg (Germany), 2Deutsches Elektronen- Synchrotron DESY & Fachbereich Physik Universität Hamburg - Hamburg (Germany) Pt-Rh alloy nanoparticles on oxide supports are widely employed in heterogeneous catalysis with applications ranging from chemical industry to automotive exhaust control [1]. To improve the catalyst performance it is essential to grasp the interplay between the oxides forming on the particle facets, the particle size/shape and the sample’s catalytic activity [2,3]. Moreover, it is of paramount interest to unravel the underlying mechanisms of particle sintering which is one of the main reasons for catalyst deactivation [4]. This triggers the need for atomic-scale studies of supported nanoparticles during catalytic reactions under realistic pressure and temperature conditions.

Here we present our results on epitaxial MgAl2O4(001)-supported Pt0.33Rh0.67 nanoparticles “at work” during carbon monoxide oxidation obtained in a dedicated in-situ catalysis chamber [5] and by combining surface x-ray diffraction and in-situ mass spectrometry at beamline P09 at the PETRA III storage ring at DESY (E= 11.2 keV). Our time-resolved gas-switching experiments allowed for monitoring with unprecedented structural resolution at the atomic scale the formation of different surface oxides on the particle facets, and for relating the oxides’ emergence to the sample’s catalytic activity. The combination of high-resolution reciprocal space mapping (see Fig. 1) and Bragg peak scanning along high symmetry directions facilitated to unravel quantitatively the activity-induced particle shape and size changes, and yielded along with x-ray reflectivity measurements insights into the dramatic mass transport on the sample surface during particle sintering.

Fig. 1: High resolution reciprocal space map measured under reaction conditions containing signals from (111)- and (100)-facets of the Pt0.33Rh0.67 particles. References [1] G. Ertl, et al., Handbook of Heterogeneous Catalysis (Wiley-VCH, Weinheim, Germany, 2008). [2] P. Nolte, A. Stierle, N. Y. Jin-Phillipp, N. Kasper, T.U. Schulli, H. Dosch, Science 321, 1654 (2008). [3] U. Hejral, A. Vlad, P. Nolte, A. Stierle, Journal of Physical Chemistry C 117, 19955 (2013). [4] U. Hejral, P. Müller, O. Balmes, D. Pontoni, A. Stierle, Nature Comm. 7, 10964 (2016). [5] R. van Rijn et al. , Rev. Sci. Instr. 81, 014101 (2010).

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O8-SCR _317 ANISE ON PT(111): ADSORPTION AND REACTIVITY

SCR - Surface chemical reactions and kinetics C. Ouldhamou 1,*, R. Reocreu 2, C. Michel 2, P. Sautet 2, J.B. Giorgi 1,* 1University of Ottawa - Ottawa (Canada), 2Ecole normale supérieur de Lyon - Lyon (France) The transformation of biomass into useful chemical compounds with applications in a large range of industries represents the future of a clean and sustainable world. In this study, some fundamental questions regarding the conversion of lignin (primary wood component) into valuable compounds are addressed. We are investigating the reactivity of anisole with Pt metal surfaces in order to compare the facility of the C-H vs. C-O vs. C-C bond cleavage. In the present work, we have chosen a single of Pt(111) to determine the reaction pathways (Figure1). The adsorption and decomposition of Anisole on clean Pt(111) was studied as a function of temperature and exposure by means of X-ray photoelectron spectroscopy (XPS),Temperature programmed desorption (TPD) and DFT calculations (optPBE functional). Anisole was absorbed on the surface below 120K. TPD and XP spectra revealed that an amount of anisole molecularly desorbs at 260K (83 KJ/mole) for multilayer exposure and DFT is about 61 KJ/mole. For the saturated monolayer part of the anisole molecularly desorbs between 360-400K but it mainly decomposes to produce Benzene, CO and H2. At this point, anisole desorption energy (DFT: 166 kJ/mol) is much higher than the first dehydrogenation barrier (DFT: 108 kJ/mol) suggesting that hydrogen should be produced when anisole decomposition starts. Results will be further discussed broadening our fundamental understanding of catalytic reactions of lignin models on metal surfaces.

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O9-SCR_470 ATOMIC-SCALE STUDY OF THE ZIEGLER-NATTA CATALYST

SCR - Surface chemical reactions and kinetics V. D'anna *, P. Sautet Laboratory of Chemistry, University of Lyon, CNRS and Ecole Normale Supérieure of Lyon - Lyon (France) The reaction of polymerization of olefin is industrially performed through a catalytic reaction based on the Ziegler-Natta catalyst. Since the first discovery of Ziegler and Natta, the catalyst has undergone different modifications in order to improve the velocity, the yield and the stereoselectivity of the polymerization reaction[1]. Nowadays, the industrially used catalyst consists of a precatalyst composed by a surface of MgCl2 on which the precursor of the active center, TiCl4, is anchored, in presence of a Lewis base. The precatalyst is activated by alkylaluminium[2]. Despite the copious research efforts devoted to the improvement of the activity of the catalyst, its structure at molecular scale and the role of its components are not yet completely understood. An atomic scale understanding of the Ziegler-Natta catalyst is indeed of key importance for the design of more active and selective catalyst. Our work is focused on the computational study of the Ziegler-Natta catalyst from a molecular point of view. The study is performed at the Density Functional Theory (DFT), in the Generalized Gradient Approximation (GGA) using PBE functional and planewave basis set, as implemented in the VASP package. The model system chosen is a (110) MgCl2 surface, on top of which a TiCl4 unit is adsorbed. The calculated data are closely related to experiments, and, in order to compare the computed results with the experimental data available, NMR spectra are calculated on the obtained minima. This work can be divided in two parts. The first part is devoted to the structural characterization of the precatalyst MgCl2/TiCl4/Lewis base, with ethanol as Lewis base. The principal aim of this part is the understanding of the interaction of EtOH with the surface and in particular with the precursor of the active center. The energy variation in EtOH high coverage condition is also taken into account. Several structures are taken into account in order to obtain a wide and realistic view of the precatalyst.

The second part is inherent the activation process, obtained from the interaction with AlEt3. In this case our attention is more focused on the reaction paths bringing to the catalyst. References [1] L. Lyod, Handbook of Industrial Catalysts, Springer, 2011, ch. 8 [2] E. Albizzati, U. Giannini, G. Collina, L. Noristi and L. Resconi, Catalysis and polymerizations, in Popypropylene Handbook, ed. E. P.J. Moore, Hanser-Gardner Publications. Cincinnati, OH, 1996, ch. 2 [3] G. Kresse and J. Hafner, Phys. Rev. B, 47 (1993) 558

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O10-SCR _173 SIMULTANEOUS AFM/STM STUDY OF CHIRALITY AND ON-SURFACE CHEMISTRY OF DIBENZO[7]HELICENE DEPOSITED ON AG(111)

SCR - Surface chemical reactions and kinetics O. Stetsovych 1,*, M. Švec 1, J. Vacek 2, J. Vacek Chocholoušová 2, I. Stara 2, A. Jancarík 2, J. Rybácek 2, P. Jelínek 1, I. Stary 2 1Nanosurf Lab Institute of Physics of the AS CR - Prague (Czech republic), 2Institute of Organic Chemistry & Biochemistry of AS AR - Prague (Czech republic) High-resolution AFM images of single molecules brought completely new perspectives in investigation of chemical processes on surfaces. Here we investigated on-surface chemistry of Dibenzo[7]helicene deposited on Ag(111). Annealing above 100C has induced a [4+2] Diels-Alder cycloaddition reaction, which has initiated complex chemical processes on the surface. We have been able to identify an intermediate step and two final products by means of simultaneous AFM/STM measurements with Xe-tip. The intermediate products form complex chiral structures (dimers, trimers and tetramers). To understand the origin of a chiral orientation, we investigated both the racemic mixture and pure (+)-(P) enantiomer of helicene molecules deposited on the Ag(111) surface. We have found that the chiral orientation of the individual molecules as well as their complexes is driven both by chirality of helicene molecules initially deposited on the surface and annealing conditions. We have demonstrated for the first time a chemical control over the final enantiofacial adsorption of non-chiral molecules on the non-chiral metal surface that has resulted in a global mirror- symmetry breaking.

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O11-SCR _226 PHTHALIC ACID ON MGO(100) AS A MODEL FOR THE ANCHORING OF CARBOXYLIC ACID FUNCTIONALIZED LARGE ORGANIC MOLECULES

SCR - Surface chemical reactions and kinetics O. Lytken *, Q. Tariq, M. Franke, D. Wechsler, L. Zhang, H.P. Steinrück Universität Erlangen-Nürnberg - Erlangen (Germany) The anchoring of large functional organic molecules, such as porphyrins, to oxide surfaces is important in many areas of research. Using high-resolution synchrotron radiation X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure (NEXAFS) and temperature-programmed desorption (TPD), we report on the adsorption of phthalic acid on MgO(100) as a model for the anchoring of carboxylic acid functionalized, large organic molecules. Already below 150 K we find a competition between anhydride and carboxylate formation, and it is not until the surface has been completely covered, and thereby passivated, by carboxylate that we see the growth of intact phthalic acid multilayers. As the surface is heated, phthalic anhydride desorbs at 250 K and phthalic acid at 325 K, leaving a densely- packed carboxylate layer on the surface. NEXAFS confirms the upright standing nature of the carboxylate layer, which is stable up to 600 K for the densely-packed layer. At lower coverages the carboxylate layer is less stable and decomposition occurs already below 500 K.

Figure: O 1s and C 1s X-ray photoemission spectra of 4 ML phthalic acid adsorbed on MgO(100) at 100 K and annealed to the indicated temperatures. Thanks This project is supported by the DFG through FOR 1878 (funCOS).

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O12-SCR _221 MECHANISTIC STUDY OF NO REDUCTION BY CR-PHTHALOCYANINE MONOLAYER INVESTIGATED BY DFT CALCULATIONS

SCR - Surface chemical reactions and kinetics S. Namuangruk 1,*, N. Kungwan 2, J. Meeprasert 1 1National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency - Pathumthani (Thailand), 2Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai - Chiang Mai (Thailand)

The reaction mechanism of nitric oxide (NO) reduction to nitrous oxide (N2O) and N2 catalyzed by Cr-phthalocyanine sheet (CrPc) was investigated by periodic density functional theory (DFT). The results showed that direct NO dissociation on the catalyst is inhibited by large energy barrier owing to the difficulty on the direct cleavage of the strong NO bond. The dimer manner in which the two NO come to play is more preferred via the three competitive mechanistic pathways consisting of two Langmuir- Hinshelwood (LH1 and LH2) and one Eley-Rideal (ER). N2O is produced from LH1 and ER with the activation barriers (Ea) of 0.35 and 1.17 eV, respectively, while N2 is a product from LH2 with the Ea of 0.57 eV. All the three pathways are highly exothermic process. Based on the energetic aspect, LH1 is the kinetically and exothermically most favorable pathway (Ea of the rate- determining step is 0.35 eV). Therefore, we predict that NO can be easily reduced by CrPc at mild condition. In environmental implication, CrPc would be a promising catalyst for abatement of NO at low temperature. Thanks The authors wish to thank the National Nanotechnology Center (NANOTEC) through “the Flagship Clean Air Program” for financial support. References 1. Maitarad, P; Meeprasert, J.; Han, J.; Shi, L.; Limtrakul, J.; Zhang, D.; Namuangruk, S. Catal. Sci. Technol. 2016, DOI: 10.1039/C5CY02116B 2. Meeprasert, J; Junkaew, A; Kungwan, N; Jansang, B; Namuangruk, S. RSC Advances 6 (2016), 20500- 20506

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O13-SCR _239 ENERGY RELEASE AND SURFACE CHEMISTRY OF THE MOLECULAR SOLAR ENERGY STORAGE SYSTEM NORBORNADIENE / QUADRICYCLANE

SCR - Surface chemical reactions and kinetics U. Bauer 1,*, C. Papp 1,*, T. Döpper 2, S. Mohr 1, M. Schwarz 1, F. Späth 1, F. Düll 1, P. Bachmann 1, J. Bachmann 3, A. Hirsch 4, A. Görling 2, J. Libuda 1, H.P. Steinrück 1 1Physical Chemistry, FAU Erlangen-Nürnberg - Erlangen (Germany), 2Theoretical Chemistry, FAU Erlangen-Nürnberg - Erlangen (Germany), 3Inorganic Chemistry, FAU Erlangen-Nürnberg - Erlangen (Germany), 4Organic Chemistry, FAU Erlangen-Nürnberg - Erlangen (Germany)

Fossil fuel-based energy technologies lack a long-term perspective. The further development of existing renewable energy concepts is needed, regarding energy distribution and storage. One possible scenario is the storage and conversion of solar energy by chemical means in the form of strained organic molecules, e.g., the Norbornadiene (NBD) / Quadricyclane (QC) pair: by absorption of light NBD is transformed to the energy rich QC; this can be catalytically transformed back to NBD and thereby release the stored energy. We investigated the adsorption of the strained multi-cyclic hydrocarbon QC and its strain- released counterpart NBD as well as the conversion of QC to NBD and their decomposition over different catalytically active metal surfaces, in particular Ni(111) and Pt(111). We address this model system with multiple techniques to gain a full understanding of the reaction details. Ultraviolet photoelectron spectroscopy provides characteristic spectra for NBD and QC. By applying heating ramps to the samples, we can observe the thermally- triggered conversion of QC to NBD, except for the Pt(111) surface, where the reaction from QC to NBD is taking place already below 120 K. High-resolution X-ray photoelectron spectra of the adsorption at 120 K and during the heating ramps reflect the different interaction strength between molecules and surface and reveal a fundamentally changed decomposition behavior of NBD at higher temperatures for the different surfaces. Additionally, we will use infrared reflection absorption spectroscopy and DFT calculations to further study the energy release and gain insights to the adsorption mechanisms. Thanks We thank the Cluster of Excellence ‘Engineering of Advanced Materials’ and the Helmholtz- Zentrum Berlin for the allocation of synchrotron beamtime.

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O14-SCR _206 CHEMICAL BATH DEPOSITION OF MOLYBDENUM DISULFIDE ULTRA-THIN FILMS

SCR - Surface chemical reactions and kinetics J. Orbeck 1,*, A. Walker 2,* 1University of Texas at Dallas, Department of Chemistry and Biochemistry - Richardson (United States of America), 2University of Texas at Dallas, Department of Chemistry and Biochemistry, Department of Materials Science and Engineering - Richardson (United States of America) Transition metal dichalcogenide (TMD) materials are currently widely sought after for their application in semiconductor and nanoelectronic devices. The band gap energies of these materials range from semiconducting to insulating based on the selection of transition metal and chalcogenide.1 Molybdenum disulfide is a TMD which has applications in nanoelectronic devices due to its tunable bandgap ranging from 1-2 eV. By using templated substrates such as highly oriented pyrolytic graphite (HOPG) and sapphire we have successfully deposited large area ultra-thin molybdenum disulfide films using chemical bath deposition (CBD), a liquid based technique. The CBD method is an ion exchange reaction between a metallic cation and chalcogenide anion under ambient conditions in aqueous solutions. The simplicity of this technique lends itself to be easily adapted to deposit other TMDs of interest such as molybdenum diselenide or tungsten disulfide. By systematically studying reaction conditions and characterizing synthesized materials using XPS, SEM, AFM, Raman, and TOF SIMS a better understanding of the material and CBD technique is found. References 1. McDonnell, S.; Addou, R.; Buie, C.; et. al., ACS Nano 2014, 8 (3), 2880-2888.

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O15-SCR _99 INTERACTION OF IONIC LIQUIDS WITH LITHIUM METAL FILMS STUDIED WITH PHOTOELECTRON SPECTROSCOPY

SCR - Surface chemical reactions and kinetics O. Höfft *, M. Olschewski *, F. Endres Institut für Elektrochemie, Technische Universität Clausthal - Clausthal-Zellerfeld (Germany) As ionic liquids (ILs) exhibit good ion conductivities, high temperature stability and large electrochemical windows together with a good solubility for lithium salts, they are of potential interest as electrolyte for non flammable Li based batteries, like e.g. lithium/air batteries. To enable good cycle stabilities the interaction of electrolyte and lithium on electrode surfaces has to be investigated carefully. This can be achieved by disassembling of previously cycled cells and analysis of the electrode surface structure. Recently X-ray Photoelectron (XP) and infrared spectroscopy has been applied to analyze the solid electrolyte interface of a Ge electrode after lithiation/delithiation in the ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide containing (Py1,4]TFSI) 0.5 M lithium bis(trifluoromethylsulfonyl)imide [1] A variety of decomposition products of the ionic liquid prove that an interaction of cations and anions with lithium should have happened. Due to the low vapor pressure this interaction can be investigated on a fundamental level by preparing thin molecular films of Ionic Liquids in a Physical Vapor Deposition process under ultra-high vacuum conditions on lithium adsorbed on a copper surface. XP spectroscopy applied to the freshly prepared sample exhibit an interaction of the ionic liquid with lithium even at open circuit potential [2]. Thereby, the IL 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([OMIm]TFSI) adsorbed on Li/Cu [2] shows a rather different reaction mechanism compared to the study of [Py1,4]TFSI adsorbed on Li/Cu by Buchner et al. [3]. Thus the interaction of [Py1,4]TFSI, [OMIm]TFSI and 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide ([Py1,4]FSI) with lithium is analyzed in a comparative study with photoelectron spectroscopy showing reaction products of the ionic liquid and lithium, which give an insight into the individual role of cations and anions in addition. References [1] A. Lahiri, N. Borisenko, A. Borodin, M. Olschewski, F. Endres, Phys. Chem. Chem. Phys. 18 (2016) 5630-5637 [2] M. Olschewski, R. Gustus, M. Marschewski, O. Höfft, F. Endres, Phys. Chem. Chem. Phys. 16 (2014) 25969-25977 [3] Buchner F., Bozorgchenani, M., Uhl, B., Farkhondeh, H., Bansmann, J., Behm R., J. Phys. Chem. C, 2015, 119 (29), 16649–16659.

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O16-SCR _150 FIRST-PRINCIPLES SIMULATIONS OF PLATINUM-ASSISTED WATER ETCHING OF SIC

SCR - Surface chemical reactions and kinetics P. Bui *, A. Isohashi, K. Inagaki, H. Kizaki, Y. Sano, K. Yamauchi, Y. Morikawa Department of Precision Science and Technology, Graduate School of Engineering, Osaka University - Osaka (Japan) Owing to its excellent physical properties, silicon carbide (SiC) is a promising semiconductor material for electronic applications demanding high-temperature and high-power conditions. Such applications require high-quality and crystally undamaged SiC surfaces. To fulfill the growing demands and requirements of high-accuracy surface processing and low cost fabrication, chemical planarization using a catalyst pad in aqueous solutions, which we term catalyst-referred etching (CARE), has been proposed. This technique was successfully applied to the planarization of SiC wafers using hydrofluoric acid (HF) as the etchant. The obtained surface was atomically smooth with a single bilayer step-and-terrace structure over the entire wafer. Recently, Isohashi et al. [1,2] reported that CARE performed using Pt and water as the etchant, called water-CARE, could planarize a SiC wafer to a flat surface with a rough-mean- square roughness lower than 0.1 nm. To understand the mechanism, we performed first- principles molecular dynamics calculations using the Simulation Tool for Atom Technology (STATE) program package, which has been successfully applied for investigations on metals, semiconductors, and organic materials. The calculations were based on the DFT within a GGA of PBE. The barrier height was evaluated by means of the climbing image nudged elastic band method. A step-and-terrace 3C–SiC (111) surface of four bilayers and Pt (111) surface layers were used as the calculations model as shown in Fig. 1. The model entails periodically repeated unit cells. The mechanism is considered a dissociative adsorption of water/HF molecules to the Si–C bonds at the topmost Si surface [2,3]. The results show that the barrier height of the Si–C back bond breaking with Pt as the catalyst is 0.8 eV for HF CARE and 0.75 eV for water-CARE, which are smaller than the values obtained without the Pt catalyst. The gross activation barrier strongly correlates with the stability of the metastable state and is reduced by the formation of Pt–O chemical bonds, leading to an enhancement of the etching reaction. References 1. A. Isohashi et al., Mater. Sci. Forum 778–780, 722–725 (2014) 2. A. Isohashi et al., to be submitted 3. P. V. Bui et al., Appl. Phys. Lett. 107, 201601 (2015).

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I21_SCR_455 SURFACE PROPERTIES OF ELEMENTAL 2D MATERIALS IN AMBIANT CONDITIONS

SCR - Surface chemical reactions and kinetics R. Martel * Département de chimie, Université de Montréal (Canada) Over the past two decades, elemental nanomaterials, such carbon nanotube, graphene and more recently exfoliated black phosphorus (bP), have been studied for their intriguing low- dimensional semiconducting properties. These works have been largely motivated by the advancement of flexible electronics, but also because of intriguing optical effects induced by 1D and 2D confinement. Here we will first review our work on the surface properties of these nanomaterials and highlight the impact of electronic confinement on their surface chemistry. The common feature that emerges is the presence of ubiquitous charge transfer reactions in air between nanostructures and the water/oxygen redox couple. The reaction was found to induce strong environmental effects, such as p-doping of graphene [1], suppression of electron conduction in carbon nanotubes [2], leak current in Si nanowire field- emitters [3] and photo-induced oxidation of exfoliated black phosphorus layers [4]. A general reaction scheme based on Marcus-Gerischer theory is used to discuss this surface chemistry and to help develop stable interfaces with those materials. To better highlight this chemistry, we will discuss in more detail the case of bP degradation in air [4]. We took advantage of a procedure carried out in a glove box to acquire the optical and electrical properties of the layers in their pristine states. Mono-, bi- and multilayered bP samples were extensively studied using Raman (See Figure). The degradation of the layers was probed in ambient conditions using TEM-EELS, LEEM, AFM and in-situ Raman spectroscopy. The experiments reveal that a combination of oxygen, light and moisture provides the essential ingredients leading to the oxidation of the layers. They also highlight a surprising thickness dependent kinetics of this photo- oxidation reaction, which behavior is consistent with the electron transfer model (redox reaction) influenced by quantum confinement.

Figure: Raman spectra of bP layers. Highlighted (inset) is 2 the splitting of the A g mode for the bilayer, which displays an enhanced Raman intensity. References [1] C. M. Aguirre, et al., Adv. Mat.. 21, 3087-3091 (2009). [2] P. L. Lévesque et al., Nano Letters, 11, 132-135 (2011) [3] M. Choueib, et al., ACS Nano, 6, 7463-7471 (2012) [4] A. Favron et al., Nature Materials, 14, 826-832 (2015)

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P2-SCR_112 ADSORPTION AND REACTIONS OF BIFUNCTIONAL 2-CHLOROPROPANOIC ACID ON CU(100) AND O/CU(100)

SCR - Surface chemical reactions and kinetics J. Lin *, Z.X. Yang Department of Chemistry, National Cheng Kung University (Taiwan, republic of china) Surface chemistry of organic acids on transition metal surfaces, with or without surface modifiers, is of interest to a wide range of applications, such as corrosion inhibition and heterogeneous catalysis [1]. Chemisorbed bifunctional molecules are valuable, potential candidates for surface functionalization [2]. On Cu(100), only a small portion of the adsorbed CH3CHClCOOH molecules undergoes O–H or C–Cl bond scission at 120 K. After the complete O–H bond scission for the adsorbed molecules at 250 K, two intermediates of CH3CH2COO(a) and CH3CHClCOO(a) are generated on the surface. The CH3CHClCOO(a) decreases continuously due to C–Cl bond scission in the temperature range of 250 K~400 K, being transformed into CH3CH2COO(a). At a temperature higher than 400 K, the CH3CH2COO(a) starts to decompose to form H2, H2C=CH2, CO, CO2, which are desorbed between 400 K and 500 K. Other reaction products of HCl and CH3CH=C=O are generated above 710 K. The presence of preadsorbed oxygen promotes O–H bond cleavage of CH3CHClCOOH at 120 K, but suppressing the C–Cl bond dissociation. About a half of the CH3CHClCOOH molecules undergoes O–H scission at 120 K, forming CH3CHClCOO(a), and only a trace amount of the molecules undergoes C–Cl breakage even at 250 K. Upon heating to 380 K, two intermediates of CH3CH2COO(a) and η2-CH3CHCOO(a) are generated, at the sacrifice of CH3CHClCOO(a). On the oxygen- precovered Cu(100), the thermal decomposition products of the chloropropanoic acid are similar to those from the clean surface. Keywords: chloropropanoic acid, Cu(100), XPS, RAIRS, TPR/D Thanks The Ministry of Science and Technology, Republic of China References 1.J.L. Davis, M.A. Barteau, J. Molec. Catal. 77 (1992) 109-124. 2.B.-S. Yeo, Z.-H. Chen, W.-S. Sim, Langmuir 19 (2003) 2787-2794.

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P3-SCR_207 GA ON SIO2 AS CATALYST FOR NANOWIRE GROWTH: INVESTIGATION BY X-RAY PHOTOELECTRON SPECTROSCOPY

SCR - Surface chemical reactions and kinetics L. Fouquat *, X. Guan, J. Penuelas, G. Grenet Institut des Nanotechnologies de Lyon - Lyon (France) GaAs (NWs) are presently intensively studied because of their potentialities for microelectronics, photonics and energy harvesting. GaAs NWs must be grown using Ga as catalyst (auto-catalyzed growth) in order to avoid Au, which endangers optoelectronic performances. Typically, this auto-catalyzed growth is performed directly on Si substrates without any removal of the native oxide [1-2] or on a SiO2 layer previously deposited on GaAs wafers [3]. This oxide layer is thought to favor droplet formation with enhanced chemical potential compared to the SiO2 layer. However, despite this strong interest for the Ga/SiO2/Si system, the mechanism of the droplet formation and the nature of the chemical interaction between the metal and the substrate is not yet fully understood. The Ga-Si system is rather different from the Au-Si one. First, unlike gold, gallium is liquid at low temperature (about 30 °C). Second, the eutectic Ga1-xSix contains a very small amount of silicon: only 5.10-8 % vs 18.5 % in Au1-xSix eutectic. Third, Ga can be easily oxidized and most Ga oxides are stable: for example, thermal and ozone Ga oxides cannot be removed below 582 ± 1 °C and 638 ± 1°C, respectively. However, it has been shown that the removal of native oxides from GaAs wafers can be obtained at lower temperature by converting stable Ga2O3 to volatile Ga2O by exposure to Ga metallic flux. Using atomic force microscopy and x-ray photoelectron spectroscopy we have studied the effect of the growth temperature (from 50 °C to 700 °C) on the formation of the Ga droplets. Our results show that the size and density of Ga droplet can be controlled by the deposition temperature. This initial configuration of the Ga droplets is of special interest as it determines NWs dimensions and repartition. The evolution of the Si2p, O1s, Ga3d and As3d core levels as a function of the growth temperature allows for displaying interfacial Ga oxides in association with a dewetting phenomenon. Finally, the mechanism of formation of pinholes catalyzed by droplet in the SiO2 film is discussed. References [1] C. Colombo, D. Spirkoska, M. Frimmer, G. Abstreiter and A. Fontcuberta i Morral, Phys. Rev. B 77, 155326 (2008) [2] F. Jabeen, V. Grillo, S. Rubini and F. Martelli Nanotechnology 19, 275711 (2008). [3] A. Fontcuberta i Morral, C. Colombo, G. Abstreiter J. Arbiol, and R. Morante, Appl. Phys. Lett. 92, 063112 (2008)

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P4-SCR_299 THE HYDRATED ELECTRON AT THE ICE SURFACE: INSIGHT INTO DISSOCIATIVE ELECTRON ATTACHMENT TO ADSORBATES

SCR - Surface chemical reactions and kinetics M. Bockstedte, P. Auburger * Theoretische Festkörperphysik, Universität Erlangen-Nürnberg - Germany (Germany) On ice, the solvated electron facilitates electron-induced reactions of adsorbates via dissociative electron attachment (DEA) that for instance take place in atmospheric chemistry. The simultaneous interaction of the electron with the molecule and the ice surface enhances the cross section as compared with the gas phase [1]. The current understanding of the physical mechanisms at work is rather incomplete, in particular a picture on the molecular scale is missing. In this work we address this probleme within the framework of density functional theory, hybrid DFT, and many body perturbation theory. Prototypical surface electron traps, such as orientational disorder [2], surface vacancies [3], and vacancy clusters are used as a model system. Halogenated hydro carbons favor adsorption sites that are strong electron traps. In the gas phase, their antibonding molecular orbitals are scattering states with negative electron affinity. By the interaction with the trap states the affinity is considerably increased. For molecules adsorbed at strong electron traps the antibonding resonances are located close to the ice conduction band mininum. With a shift as large as 2.0-4eV (cf. the Figure below for X=Cl and Br), the effect is strongest for the antibonding state that is responsible for the dissociation of the halogen. Our results show clear trends across the halogen series F, Cl, and Br.

Thanks Funding by the Deutsche Forschungsgemeinschaft (BO1851/3 ) is greatfully acknowledged. Calculations were performed at the supercomputers at the Neuman Institute of Computing, Research Centre Jülich and the hpc-cluster of the RRZE, FAU Erlangen-Nürnberg. References [1] Q.-B. Lu and L. Sanche, Phys. Rev. Lett. 87, 078501 (2001). [2] U. Bovensiepen, C. Gahl , J. St•ahler, M. Bockstedte, M. Meyer, F. Baletto, S. Scandolo, X.-Y. Zhu, A. Rubio, and M. Wolf, J. Phys. Chem. C 113, 979 (2009). [3] A. Hermann, P. Schwerdtfeger, and W. G. Schmidt, J. Phys.: condens. matter 20, 225003 (2008).

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P5-SCR_304 NACE(WO4)2 MICROSTRUCTURES WITH HIERARCHICAL MORPHOLOGIES: EDTA- ASSISTED HYDROTHERMAL SYNTHESIS , GROWTH MECHANISMS, ELECTRICAL AND PHOTOCATALYTIC PROPERTIES.

SCR - Surface chemical reactions and kinetics N. Dirany *, J.R. Gavarri, M. Arab University of Toulon – Institute of Materials Microelectronics and Nanosciences of Provence IM2NP, UMR CNRS 7334, BP 20132, 83130 La Garde Cedex, France - Toulon (France) Since their discovery, the double rare earth tungstates with a scheelite structure have attracted a great attention due to their unique optical1 and chemical properties2. They have a high chemical stability1 and interesting potential technological applications. Paradoxically, few data are available on the chemistry of these compounds. Recently, we synthesized a novel hierarchical tetragonal structure of NaCe(WO4)2 via hydrothermal method in the EDTA-mediated process. Different architectures as hierarchical spindles, microflowers and microspheres self-assembled from different building blocks were elaborated. The obtained microstructures were characterized using X-ray diffraction (XRD) combined to Rietveld refinement, scanning electron microscopy (SEM), diffuse reflectance spectra (DRS) and Raman spectroscopy respectively. The results show that the amount of EDTA introduced and the pH of the reaction system modulate the morphology and affect the growth mechanism of the different shapes. The formation mechanisms for different architectures were studied according to a time experiments duration. A scheelite crystallization structure phase is obtained post synthesis, after thermal treatment from 500°C. The electrical conductivity of different microstructures compacted pellets systems was determined from electrical impedance spectrometry, under air, until 800°C. Finally, photocatalytic and adsorption performance of different morphologies was investigated by monitoring the degradation of Rhodamine B under visible light irradiation within different time intervals at room temperature. The photodecomposition reactivity was discussed as a function of morphology of various hierarchical structures. Thanks We gratefully acknowledge the Regional Council of Provence-Alpes-Côte d?Azur, General Council of Var, and the agglomeration community of Toulon Provence Mediterranean for their financial supports in the framework of "M2D2" project. References 1. Liu, X.; Hou, W.; Yang, X.; Liang, J. CrystEngComm, 2014,1268-1276. 2. Tian, Y.; Chen, B.; Tian, B.; Yu, N.; Sun, J.; Li, X.; Zhang, J.; Cheng, L.; Zhong, H.; Meng, Q. Journal of colloid and interface science, 2013, 393, 44-52.

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SMC - Semiconductor surfaces

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P1-SMC_14 COMBINATION SYSTEM: ADSORPTION/PHOTO-ELECTRODIALYSIS FOR LEAD REMOVAL USING BENTONITE-MEMEBRANE-SR2FE2O5

SMC - Semiconductor surfaces O. Arous *, D. Hamane *, F. Kaouah, H. Kerdjoudj, M. Trari, Z. Bendjama USTHB University (Algeria) A combination system combining adsorption/photo electrochemistry/dialysis is investigated for the first time for the Pb2+ removal. The Pb2+ adsorption on the Algerian bentonite is studied in batch mode. The initial Pb2+ concentration, adsorption dosage, pH and temperature are optimized. The maximum removal is observed at pH 6 for a concentration of 100 mg.L-1 at 25 °C. The adsorption is fast with ~ 90% occurring within 40 min of contact time. The process is spontaneous and endothermic. The Langmuir model is successfully applied to fit the experimental data. Adsorption is a pre-treatment prior the reduction of Pb2+ by photo-electrodialysis.The remaining concentration is lowered by photo-electrodialysis below the threshold required by the water standards. The ion exchange membrane, configured as a horizontal electrode, is an essential part of the process. The membrane is polymerized from cellulose triacetate modified by poly-ethyleneimine and plasticized by 2- nitrophenyl pentyle ether. It is characterized by FTIR and thermal analysis TGA. After crossing the membrane, Pb2+ is reduced owing to its redox potential, suitably positioned with respect to CuCrO2-CB (Fig.1). Indeed, the electrons coming from illuminated Sr2Fe2O5-electrode move via the external circuit where they reduce Pb2+ to its elemental metal state. The photo-electrodialysis indicates that the combined system p- CuCrO2/membrane/n-Sr2Fe2O5 enhances considerably the electrons transfer and the diffusion flux of Pb2+. 35% of Pb2+ are photo-electrochemically reduced under artificial light. The rate conversion increases up to 86% under solar light.

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P2-SMC_29 SURFACE MORPHOLOGY OF THIN FILMS BASED ON GE-SI-SN MATERIALS AT DIFFERENT GROWTH CONDITIONS

SMC - Semiconductor surfaces V. Timofeev *, A. Nikiforov, A. Tuktamyshev, V. Mashanov, S. Teys The Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences (ISP SB RAS) - Novosibirsk (Russian federation) Compounds based on Ge-Si-Sn materials have attracted a particular attention due to the possibility of the Ge-Si-Sn application in the photonics, nanoelectronics and photovoltaics [1]. In addition to the changes in the electronic and optical properties, the presence of Sn on the surface increases the surface diffusion of adatoms [2] and also influences on the appearance of a series of superstructures which aren’t observed in the GeSi system. Thin GeSiSn films in the wide range of compositions and thicknesses were obtained by molecular-beam epitaxy. The analysis of spatio-temporal distributions of the intensity of reflection high-energy electron diffraction (RHEED) patterns allows to identify the superstructure and beginning of the nanoisland formation. The mismatch of GeSiSn and Si lattices was varied up to 5%. Figure 1 shows the kinetic diagram of the GeSiSn growth under 2% mismatch. As a result the Sn segregation on the surface the series of superstructures was observed during growth of the Si film on the GeSiSn layer. The decrease of the growth temperature of Si layer contributes the inhibition of the Sn segregation and reduction of the Si film roughness covering the GeSiSn layer. Regularities of the formation of multilayer structures with quantum wells containing pseudomorphic GeSiSn layers have been investigated. Hence the synthesis of superlattices, structures with quantum wells or quantum dots and creation devices based on them can be carried out. References [1] B. Vincent et al. MicroElect. Eng., 88, 342 (2011). [2] A.E. Dolbak et al. Cent. Europ. Journal of Physics, 6, 634 (2008).

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P3-SMC_69 ULTRASONIC TREATMENT INFLUENCE ON THE SI-SIO2 SYSTEM DEFECTS STRUCTURE

SMC - Semiconductor surfaces D. Kropman *, D. Laas, D. Priimets Tallinn University - Tallinn (Estonia) The effect of ultrasonic treatment (UST) on the defect structure of the Si–SiO2 system by ESR spectroscopy and secondary ions mass-spectroscopy (SIMS) is presented. The non- monotonous dependence of the defect densities on the US wave intensity has been observed. The influence of the UST frequency on the ESR signal intensity of the defect centres depended on the defects type and structure and may be caused by vibrational energy dissipation which are a functions of defect’s centers type. The influence of the UST on the Si–SiO2 interface properties depends on the oxide thickness and crystallographic orientation.The density of point defects and absorbed impurities at the Si–SiO2 interface can be reduced and its electrical parameters improved by an appropriate choice of the UST and oxidation conditions.

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P4-SMC_96 CRITICAL METAL THICKNESS FOR THE SCHOTTKY BARRIER FORMATION: SYNCHROTRON RADIATION PHOTOEMISSION STUDY OF AG ON P-GAAS(001)-2X4

SMC - Semiconductor surfaces C. Cheng 1,*, W.S. Chen 1, G.J. Wei 1, Y.T. Cheng 1, C.H. Wei 2, K.Y. Lin 3, Y.H. Lin 3, T.W. Pi 2, J. Kwo 4, M. Hong 4 1Department of Electrophysics, National Chiayi University - Chiayi (Taiwan, republic of china), 2National Synchrotron Radiation Research Center - Hsinchu (Taiwan, republic of china), 3Graduate Institute of Applied Physics and Department of Physics, National Taiwan University - Taipei (Taiwan, republic of china), 4Department of Physics, National Tsing Hua University - Hsinchu (Taiwan, republic of china) The Schottky barrier heights (SBHs) are a vitally important property of metal-semiconductor (M-S) interfaces as they govern the carrier’s transit across the junctions. The ability to control/tune the magnitude of the SBH of the MS interfaces, thus lowering the ohmic contacts, is critical for the advanced electronic and photonic devices. A correct method for SBH determination has been an issue for decades, and most importantly, it is a prerequisite to answer if metal and III-V semiconductors interfaces are Fermi-level pinned by high gap state densities.[1] Synchrotron-radiation photoelectron spectroscopy (SRPES) is one of the best tool for understanding the interfacial properties at the M-S interface because it can not only measure the evolution of the interfacial electronic structures but also directly determine the values of the SBH. Here, the interfacial electronic structure of Ag in-situ deposited on a pristine p-GaAs(001)-2x4 surface has been studied using SRPES. The freshly prepared GaAs reconstructed surface was grown by molecular beam epitaxy, and transferred for the SRPES study with its pristine surface being intact under ultra-high vacuum of 10-10 Torr. The tunability of photon energies in the SRPES allows the data collection in reflecting most information for a thin metallic layer formation, which meets the need of current nano-scale electronic devices. As a result, initially, the Ag adatoms exhibit an atomic character, and transfer negative charges to the As-As dimers of the GaAs(001)-2x4 surface. The metallic behavior of the Ag overlayer emerges at thickness of 2.5 Å. The SBH of Ag/GaAs could not be properly determined until thickness of 5 Å, where the value is 0.39 eV. At this thickness, the ultimate change in band bending is achieved, and the GaAs stoichiometric ratio is preserved at the value of the clean surface. Beyond 5 Å, the elemental segregation of GaAs occurs and As diffuses into the Ag overlayer to form As-Ag bonds. Thanks This project is sponsored by the Ministry of Science and Technology, Taiwan, R.O.C. under grant numbers MOST 104-2112-M-415- 006, 104-2622-8-002-003, 102-2112-M-002-022- MY3, 102-2112-M-007-010-MY3, and 102-2112-M-213-002- MY3. References [1] R. T. Tung, Appl. Phys. Rev. 1, 011304 (2014)

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P5-SMC_70 ULTRASOUND INFLUENCE ON THE SI-SIO2 SYSTEM DEFECTS STRUCTURE

SMC - Semiconductor surfaces J. Priimets *, T. Laas, D. Kropman * Tallinn University - Tallinn (Estonia) The effect of ultrasonic treatment (UST) on the defect structure of the Si–SiO2 system by ESR spectroscopy and secondary ions mass-spectroscopy (SIMS) is presented. The non- monotonous dependence of the defect densities on the US wave intensity has been observed. The influence of the UST frequency on the ESR signal intensity of the defect centres depended on the defects type and structure and may be caused by vibrational energy dissipation which are a functions of defect’s centers type. The influence of the UST on the Si–SiO2 interface properties depends on the oxide thickness and crystallographic orientation.The density of point defects and absorbed impurities at the Si–SiO2 interface can be reduced and its electrical parameters improved by an appropriate choice of the UST and oxidation conditions. References [1] A. Zdebsky, D. Kropman, M. Sheinkman, J. Techn. Phys. 59 (1989), 131. [2] D. Kropman, T. Kärner, Phys. Stat. Sol. (a) 136 (1993), 125. [3] S. Ostapenko, L. Jastrzebski, J. Lagowski, R.K. Smeltzer, Appl. Phys. Lett. 68 (1996), 2873. [4] D.L. Griskom, J. Non-Crystall. Sol. 40 (1980), 211. [5] D.L. Griskom, M. Stapelbrock, E.J. Frieble, J. Chem. Phys. 78 (1983), 1638. [6] Y. Nishi, Jpn. J. Appl. Phys. 10 (1971), 52. [7] P.J. Caplan, E.H. Poindexter, B.E. Deal, R.R. Razouk, J. Appl. Phys. 50 (1979), 5847. [8] D. Kropman, A. Sügis, M. Vinnal, Phys. Stat. Sol. (a) 44 (1977), K1. [9] D. Kropman, S. Dolgov, T. Kärner, Appl. Phys. A 62 (1996) 469. [10] A. Stesmans, J. Braet, Surf. Sci. 172 (1986), 398. [11] S. Mueller, M. Sprenger, E.G. Sieverts, C.A.J. Ammerlaan, Solid State Commun. 25 (1978), 987. [12] D. Shaw (Ed.), Atomic Diffusion in Semiconductors, Plenum Press, London, New York, 1973. [13] J.C. Bourgoin, Phys. Lett. 106A (1984), 140. [14] A. Borghesi, B. Pivac, A. Sasell, A. Stella, J. Appl. Phys. 77 (1995), 4169.

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P6-SMC_71 ULTRASOUND INFLUENCE ON THE SI-SIO2 SYSTEM DEFECTS STRUCTURE

SMC - Semiconductor surfaces D. Kropman *, T. Laas, J. Priimets Tallinn University - Tallinn (Estonia) The effect of ultrasonic treatment (UST) on the defect structure of the Si–SiO2 system by means of electron spin resonance (ESR), selective etching, MOS capacitance technique and secondary ions mass-spectroscopy (SIMS) is presented.[1,2]. The non-monotonous dependence of the defect densities on the US wave intensity has been observed. The influence of the UST frequency on the ESR signal intensity of the defect centres depended on the defects type and may be caused by vibration energy dissipation, which are a function of defect centres type. The influence of the UST on the Si–SiO2 interface properties depends on the oxide thickness and crystallographic orientation. The density of point defects and absorbed impurities at the Si–SiO2 interface can be reduced and its electrical parameters improved by an appropriate choice of the UST and oxidation condition.UST is widly used in medicine, not only for diagnostic,but for cancer treatment too. UST influence on inorganic and organic materials have common properties. These allow to suggest that UST may be used in biotechnology for materials properties modification. References [1] D.Kropman,V.Poll,L.Tambek,T.Karner,U.Abru.Ultrasonics 36(1998)1021 [2] D.Kropman,S.Dolgov.Physica Stat.Solidi(c)9(2012)2173-2176.

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P7-SMC_160 CONTINUUM MODELING OF CYCLIC GROWTH IN SIGE/SI(001) HETEROEPITAXIAL SYSTEMS

SMC - Semiconductor surfaces F. Rovaris *, R. Bergamaschini, F. Montalenti University of Milano-Bicocca, L-NESS and Department of Materials Science - Milano (Italy) Integration of Ge (or SiGe alloys) on Si is appealing in order to exploit the superior optical and electronic performances of Ge maintaining the well-developed Si technology. This goal requires controlling the misfit strain arising from the lattice mismatch. Both elastic and plastic relaxation are possible and their interplay during the growth process is not yet fully understood. A continuum growth model based on surface diffusion following gradients in the chemical potential is presented. The balance between elastic and surface energy, including substrate- wetting contribution provides a description of island growth following the well-known Asaro, Tiller and Grinfeld instability [1]. The typical Stranski-Krastanov growth modality, characterized by coherent islands on a wetting layer, eventually undergoing long-time Ostwald ripening is reproduced. Here we extend this approach by including plastic relaxation via misfit dislocations. An energetic criterion is implemented to test the condition for dislocation injection during the evolution. Once the dislocation is introduced, its strain field, calculated exactly by finite element method, is added to the misfit strain in the further evolution, as shown in Fig.(1). This procedure is iterated, possibly leading to insertion of several dislocations. As we shall show, dislocations alter the morphology of the growing islands, leading to an initial flattening of their shape as shown in Fig.(2). An interesting oscillating behaviour in islands height-to-base ratio is recognized as consequence of successive dislocations injection [2]. Such “cyclic growth” was experimentally observed more than 20 years ago [3], but not yet reproduced by a simulation tackling the temporal evolution of the system. References [1] R.J. Asaro et al. Metall. Trans. 3, 1789 (1972); M.A. Grinfeld. Dokl. Akad. Nauk. SSSR 283, 1139 (1985) [2] F. Rovaris, R. Bergamaschini and F. Montalenti. (to be submitted) [3] F.K. LeGoues et al. Phys. Rev. Lett. 73, 300 (1994)

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P8-SMC_278 PHOTODEGRADATION OF METHYLENE BLUE ON THE BASIS OF SOLID COPPER BASED ON SOLID ZINC OXIDE

SMC - Semiconductor surfaces A. Belhadi 1,*, A. Boudjemaa 2,*, M. Trari 3 1Laboratory of Chemistry of Natural Gas, Faculty of Chemistry (USTHB) - Algiers (Algeria), 2Laboratory of Chemistry of Natural Gas, Faculty of Chemistry (USTHB) & Centre de Recherche Scientifique et Technique en Analyses Physico-Chimiques, Tipaza - Algiers (Algeria), 3Laboratory of Storage and Valorisation of Renewable Energies, Faculty of Chemistry (USTHB), BP 32, 16111 Algiers, Algeria - Algiers (Algeria) One of the most hazardous substances discharged with wastewater are dyes, especially industrial dyes which are used in many industrial sectors such as textile dyes, paper, leather, food and the cosmetic industries [1]. In fact, synthetic dyes play a major part in our life as they are found in the various products ranging from clothes, leather accessories to furniture. Most of these dyes are toxic and dangerous for the environment and their removal from wastewater is a major environmental challenge [2]. Many methods have been suggested to handle the dye removal from water. The elimination of methylene blue (MB), a cationic Xanthines dye is examined used photo-catalysis process. The degradation was carried out under visible light irradiation and used the heterojuction x% CuO/ZnO (x =5, 10) as photo- catalyst. The materials were prepared by impregnation method and characterized by several techniques as XRD, FTIR, RD…etc. The catalyst was tested for the degradation of MB under visible light irradiation. BM solution with an initial concentration of 10 ppm was degraded after irradiation with visible light for 240 minutes. The photo-catalyst 10 % CuO/ZnO exhibited a better ability to photo-degradation (fig.1) compared to 5% CuO/ZnO under the same conditions as ZnO is active in the degradation of BM. So we can say that the catalyst efficiency increases with increasing the concentration of CuO. Note that ZnO alone does not degrade the BM he shows a very low photocatalytic activity [3]. The diagram energetic was drowning to improve the photo-catalytic activity of the heterojunction CuO/ZnO under irradiat References [1] H. Ben Mansour, D. Corroler, D. Barillier, K. Ghedira, L. Chekir, R. Mosrati, Evaluation of genotoxicity and pro-oxidant effect of the azo dyes: Acids yellow 17, violet 7 and orange 52, and of their degradation products by Pseudomonas putida mt-2, Food Chem. Toxicology, 45 (2007) 1670 - 1677. [2] S. R. Couto, Dye removal by immobilised fungi, Biotech. Advances, 27 (2009) 227 - 235 [3] H. Bai, Z. Liu, and D. D. Sun, “Hierarchical ZnO/Cu “cornlike” materials with high photodegradation and antibacterial capability under visible light,” Physical Chemistry Chemical Physics, vol. 13, no. 13, (2011),pp. 6205–6210,

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SMG - Surface magnetism

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O1-SMG _129 ELECTRIC FIELD EFFECTS ON MAGNETIC PROPERTIES OF ULTRATHIN FILMS: WHY NOT USING THE ELECTROCHEMICAL CONTACT?

SMG - Surface magnetism P. Allongue 1,*, N. Di 1, R. Novak 1, A. Lamirand 1, F. Maroun 1, J.P. Adam 2, L. Herrera 2, D. Ravelosona 2 1Physique de la Matière Condensée, CNRS, Ecole Polytechnique - Plaiseau (France), 2Institut d’Electronique Fondamentale, Bâtiment 220, Université Paris-Sudnique - Orsay (France) Electric field effects (EFE) on magnetic properties of ultrathin ferromagnets (FM) are currently widely investigated because this would allow addressing one device component at a time and would also reduce device power consumption. While most of works are dealing with a FM in contact with a dielectric to apply the electric field, we are contacting the FM with an electrolyte without any intermediate oxide layer. This unconventional contact offers appealing opportunities because its peculiar structure (Fig.1, left) not only allows applying very large electric fields (1V/nm) at the surface of the FM layer but also provides unique flexibility to investigate EFE as a function of surface chemistry (adsorption of small molecules, oxide etc.) [1-3]. The in situ magneto optical Kerr Effect (MOKE) measurements that will be discussed at the conference, will demonstrate that the amplitude and sign of EFE-induced relative change of the magnetic anisotropy energy (MAE) of epitaxial Co/Au(111) layers is depending on the surface chemistry and may be as large as 70% per volt whereas effects are much smaller at the FM/dielectric contacts. The variations of the coercive field HC of magnetization curves in Fig. 1 (right) are an illustration of the strong EFE on the MAE for a 2.2 ML Co/Au(111) film. In addition, our recent in situ MOKE microscopy observations demonstrate that these MAE changes have a strong impact on magnetic domain wall velocity in Co/Pd(111) ultrathin films. References [1] N. Tournerie, A. P. Engelhardt, F. Maroun, and P. Allongue, Influence of the surface chemistry on the electric-field control of the magnetization of ultrathin films, Phys. Rev. B 86 (10), 104434 (2012). [2] N. Tournerie, A. Engelhardt, F. Maroun, and P. Allongue, Probing the electrochemical interface with in situ magnetic characterizations: A case study of Co/Au(111) layers, Surf. Sci. 631 (0), 88 (2015). [3] N. Di, J. Kubal, Z. Zeng, J. Greeley, F. Maroun, and P. Allongue, Influence of controlled surface oxidation on the magnetic anisotropy of Co ultrathin films, Applied Physics Letters 106 (12), 122405 (2015).

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O2-SMG _133 HIGH TEMPERATURE FERROMAGNETISM IN A MONOLAYER-THICK GDAG2 SURFACE ALLOY

SMG - Surface magnetism M. Ilin 1,*, M. Ormaza 2,*, L. Fernandez 3, A. Magana 1, B. Xu 4, M.J. Verstraete 4, M. Gastaldo 5, M.A. Valbuena 5, P. Gargiani 6, A. Ayuela 1, L. Vitali 7, M. Blanco-Rey 1, F.M. Schiller 1, J.E. Ortega 8 1Centro de Fisica de Materiales CSIC-UPV/EHU - Donostia (Spain), 2IPCMS, CNRS UMR 7504, Universite de Strasbourg - Strasbourg (France), 3Fachbereich Physik und Zentrum fur Materialwissenschaften, Philipps-Universitat - Marburg (Germany), 4Universite de Liege, Institut de Physique - Liege (Belgium), 5ICN-2 - Bellaterra (Spain), 6ALBA Synchrotron Light Source - Cerdanyola Del Valles (Spain), 7Ikerbasque, Centro de Fisica de Materiales CSIC-UPV/EHU - Donostia (Spain), 8Departamento de Fisica de Materiales, Universidad del Pais Vasco UPV/EHU - Donostia (Spain) Most research in surface magnetism is currently aimed at understanding the effect of the reduced dimensionality on magnetic anisotropy and exchange interactions [1]. The progress achieved in the characterization of multi-element metallic monolayers for heterogeneous catalysis through surface sensitive techniques [2] has triggered research on surface intermetallic compounds, which were among the most investigated materials in bulk magnetism in the past [3]. In this work we studied surface alloys of Gd with noble metals grown on the close-packed (111) surfaces of the Ag and Au single crystals. Although, Ag and Au are prone to build up volume phases, a single GdAu2 and GdAg2 monolayer can be achieved by optimizing the growth conditions, in a similar way as done in the Pt-Ni system [4]. The peculiar magnetic properties of rare-earth- based intermetallic compounds steam from the indirect exchange interactions mediated by conduction electrons [3]. Gd surface alloys studied in this work show an exemplary behavior. Our synchrotron XMCD and in-situ MOKE measurements reveal an unexpectedly large Curie temperature of the GdAg2 surface alloy of 85 ± 6 K ([5], fig b), which is almost four times the Curie temperature of the isomorphic GdAu2 [6]. Our ARPES data together with DFT calculations allowed to identify the Ag(Au)-Gd hybrid s, p − d band responsible for the indirect exchange interaction, proving that the larger filling and surface localization of this band in GdAg2 are the reasons of the drastic increase of the magnetic ordering temperature. References [1] C. A. F. Vaz, J. A. C. Bland, G. Lauhoff, Rep. Prog. Phys. 71 (2008) 056501 [2] J. G. Chen, C. A. Menning, M. B. Zellner, Surface Science Reports 63 (2008), 201 [3] K. H. J. Buschow, Reports on Progress in Physics 42 (1979), 1373 [4] P. Gambardella, K. Kern Surface Science 475 (2001), L229 [5] M. Ormaza et. al, “High temperature ferromagnetism in a monolayer-thick GdAg2 crystal”, to appear in Nanoletters [6] A. Cavallin, L. Fernandez, M. Ilyn, A. Magana, M. Ormaza, M. Matena, L. Vitali, J. E. Ortega, C. Grazioli, P. Ohresser, S. Rusponi, H. Brune, F. Schiller, Phys. Rev. B 90 (2014), 235419

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O3-SMG _222 INFLUENCE OF ATOMIC-SCALE DISORDER ON FERROMAGNETISM OF MONATOMIC-LAYER IRON NITRIDE

SMG - Surface magnetism Y. Takahashi 1,*, T. Miyamachi 1, V. Antonov 2, Y. Takagi 3, M. Uozumi 3, T. Yokoyama 3, A. Ernst 2, F. Komori 1 1ISSP, Univ. of Tokyo - Chiba (Japan), 2MPI - Halle (Germany), 3IMS, NINS - Nagoya (Japan) A structural disorder of constituents usually degrades intrinsic magnetic properties of a ferromagnet; e.g., the imperfection of a lattice ordering, just in an atomic scale, can lead to the deterioration of a sample magnetization. The relation between such a microscopic disorder and macroscopic magnetism is most highlighted in a monatomic-layer limit, because microscopic structural and electronic information studied by scanning tunneling microscopy/spectroscopy (STM/STS) can be unambiguously linked with the magnetism measured by a macroscopic technique. This is in contrast to the cases of bulk/thick films, where conventional characterization techniques provide only spatially-averaged information on the structural and electronic properties. In the present study, the relationship between the structure and magnetism was studied in monatomic-layer Fe2N on Cu(001). We have fabricated and characterized fully covered Fe2N using STM/STS [1], and investigated the magnetic properties by using x-ray magnetic circular dichroism (XMCD). Magnetic moment values estimated from XMCD depend on sample annealing temperatures: the sample annealed at high temperatures had large magnetic moments comparable to those expected from first-principles calculations, while an insufficient annealing made it much smaller. Atomically-resolved microscopic observation by STM revealed that, at low annealing temperatures, the surface lattice was not completely ordered and contained atomic point defects. Furthermore, STS spectra measured atop and around those point defects indicated that the surface electronic states were modified more widely than the defect size [2]. This possibly decreases the magnetic moments over a large area, and explains the smaller magnetic moments previously reported for the monatomic- layer Fe2N/Cu(001) [3]. Thanks This work was partly supported by the JSPS Grant-in-Aid for Young Scientists (B), Grant No. 26790004, for Scientific Research (B), Grant No. 26287061, and the Hoso Bunka Foundation. Y.T. was supported by the Grant-in-Aid for JSPS Fellows and the Program for Leading Graduate Schools (MERIT). A.E. acknowledges funding by the German Research Foundation (DFG Grants No. ER 340/4-1). References [1] Y. Takahashi et al., Phys. Rev. Lett. 116, 056802 (2016). [2] Y. Takahashi et al., submitted. [3] Y. Takagi et al., Phys. Rev. B 81, 035422 (2010).

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O4-SMG _143 MAGNETIC BEHAVIOR OF NANOPATTERNED COBALT ULTRATHIN FILMS GROWN ON SI/AG(110)

SMG - Surface magnetism L. Masson 1,*, L. Michez 1, T. Léoni 1, A. Ranguis 1, R. Bernard 2, Y. Borensztein 2, G. Prévot 2 1Aix Marseille Université, CNRS, CINaM UMR 7325 - Marseille (France), 2INSP, Université Paris 6, UMR CNRS 7588 - Paris (France) In the last thirty years, magnetic nanostructures have aroused considerable interest and numerous studies have been devoted to fundamental investigations of the magnetism at the nanoscale. In this context, nanopatterned templates can beneficially be used to grow high density assemblies of tailored nanostructures, which opens up the possibility to investigate their properties using either local or macroscopic integration probes. In this work, we use the Si ultrathin film grown on Ag(110) as a template for the formation of 1D nanopatterned Co ultrathin films. First, self-organized Si nanoribbons are formed upon Si submonolayer condensation on Ag(110). By following in situ the Si growth with STM and GIXD at room temperature and 460 K, we show that the nanoribbon growth induces an unexpected missing row reconstruction of the Ag layer underneath the Si nanoribbons.1 Upon Si deposition at 460 K, a highly perfect 1D array (pitch ~ 2 nm) composed of the Si nanoribbons is formed. In a second step, the Si template is used to guide the kinetically controlled growth at 220K of Co dimer nanolines on top of the Si nanoribbons (see Figure 1). Interestingly, the Co nanoline growth proceeds in a nearly layer-by-layer growth, reproducing the 1D pattern of the Si template up to five monolayers. Magnetic characterization of the Co ultrathin layers using XMCD at 4K has revealed a weak magnetic response of the first atomic Co layer while the second Co layer exhibits an enhanced magnetization, strongly suggesting a ferromagnetic ordering, with a surprising in-plane easy axis of magnetization, perpendicular to the Co nanolines (see Figure 2).2 Thanks Support from the ID3-ESRF and the DEIMOS-SOLEIL beamline staffs is greatly acknowledged. References 1. R. Bernard et al., Phys. Rev. B 88, 121411(R) (2013) 2. L. Michez et al., Beilstein J. Nanotechnol. 6, 777 (2015)

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O5-SMG _176 FERROMAGNETIC NANOSTRUCTURES PRODUCED ON METASTABLE FCC FE FILM ON H/SI(100) AND DIAMOND BY FOCUSED ION BEAM

SMG - Surface magnetism P. Varga 1,*, J. Gloss 1,*, V. Krizakova 2, L. Flajsman 2, M. Horky 2, M. Urbanek 2 1Institute of Applied Physics, Vienna University of Technology - Vienna (Austria), 2Central European Institute of Technology, Brno University of Technology - Brno (Czech republic) It has been show before by LEED and also STM that Fe films grown on Cu(100) have an fcc structure[1,2,3] and it was known also that such a film is nonmagnetic at room temperature[3]. We could show by high resolution STM and also by LEED that in such a film bcc structured needles are formed by ion bombardment [4]. It could also be unambiguous confirmed by SMOKE [4] that this crystallographic transition is related also to a transition from paramagnetic to ferromagnetic structure. We also demonstrated fabrication of micro- and nanoscale magnetic patterns by ion. For this purpose, we have grown such metastable face-centered cubic (fcc) Fe layers with a thickness of 22ML and 40ML by stabilizing the metastable fcc Fe by increased CO pressure [5] and for the 40ML thick layer by co- evaporation of Ni (about 20%)[6][7] respectively. On these “metastable” fcc films various magnetic patterns from nm up to mm size were produced by ion beam lithography [8] and focused ion beam (FIB) respectively [9]. Recently we managed to grow such metastable fcc Fe films also on Cu thin films which were grown on hydrogen stabilized Si(100) substrates as well directly on diamond (100) surfaces. This systems will be the starting points for us to produce thin film magnonic structures which represent a new class of metamaterials with periodically modulated magnetic properties. Thanks Supported by the Austrian Science Foundation (FWF) Project I 1937 -N20 and the Czech science foundation (GACR) Project 15-34632L References (1) A.Biedermann, M.Schmid, P.Varga, Phys. Rev. Lett.86 (2001) 464-467 (2) A.Biedermann, R.Tscheließnig, M.Schmid and P.Varga, Phys. Rev. Lett. 87 (2001) 086103 (3) J.Thomassen, F.May, B.Feldmann, M.Wuttig and H.Ibach, Phys.Rev.Lett 69 (1992) 3831 (4) W. Rupp, A. Biedermann, B. Kamenik, R. Ritter, Ch. Klein, E. Platzgummer, M. Schmid, P. Varga, Appl. Phys.Lett. 93 (2008) 063102 (5) A.Kirilyuk, J. Giergiel, J.Shen, J.Kirschner, Phys.Rev.B 52, R116772 (1995) (6) S. Shah Zaman, H. Oßmer, J. Jonner, Z. Novotný, A. Buchsbaum, M. Schmid, P. Varga, Phys. Rev. B 82 (2010) 235401 (7) S. Shah Zaman, P. Dvorak, R. Ritter, A. Buchsbaum, D. Stickler, H.P. Oepen, M. Schmid, P. Varga. J. Appl. Phys. 110 (2011) 024309 (8) W. Rupp, A. Biedermann, B. Kamenik, R. Ritter, Ch. Klein, E. Platzgummer, M. Schmid, P. Varga, Appl. Phys. Lett. 93 (2008) 063102 (9) J. Gloss, S. Shah Zaman, J. Jonner, Z. Novotny, M. Schmid, P. Varga, M. Urbánek, Appl. Phys. Lett. 103 (2013) 262405

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O6-SMG _241 KONDO EFFECT OF A CO ATOM EXCHANGED COUPLED TO A FERROMAGNETIC TIP

SMG - Surface magnetism L. Limot 1,*, D.J. Choi 1, S. Guissart 2, N. Bachellier 1, M. Ormaza 1, O. Bengone 1, P. Simon 2 1IPCMS, CNRS UMR 7504, Université de Strasbourg - Strasbourg (France), 2Laboratoire de Physique des Solides, CNRS UMR 8502, Université Paris-Sud 11 - Orsay (France) The observation of the Kondo resonance in single-magnetic impurities (atoms, molecules, quantum dots) has renewed experimental and theoretical interest in this correlated quantum state. Interestingly, the local magnetic environment of the impurity can alter the ideal line shape of the Kondo resonance. Through a line shape analysis it is then possible to sense magnetic phenomena in the impurity environment, which include magnetic interactions of the Kondo impurity to surrounding impurities, magnetic anisotropy and even spin-polarized tunneling electrons [1]. When a Kondo impurity is hybridized with a ferromagnetic electrode, the unbalance between spin-up and spin-down states in the electrode should cause the resonance to split into two asymmetric peaks [2]. Experimental observations of this kind remain however limited and have produced contradictory results [2, 3]. Additional control, as well as an improved description of the ferromagnetic environment, is therefore desirable for drawing a comprehensive picture. Here, we use a low-temperature scanning tunneling microscope (STM) to study a spin-1/2 Kondo impurity, Co/Cu(100) [4], exchanged coupled to a bulk nickel tip. We show that the ferromagnetic tip promotes a reproducible asymmetric spin-split Kondo line shape, which is well reproduced by a spin-1/2 Anderson model. The findings are corroborated by density functional theory (DFT) calculations, which also provide quantitative values for the Ni-Co exchange coupling. This is shown to be significantly smaller than the antiferromagnetic sp-d coupling ensuring the Kondo physics. References [1] von Bergmann et al., Phys. Rev. Lett. 114, 076601 (2015). [2] Pasupathy et al., Science 306, 86 (2004). [3] Calvo et al., Nature 458, 1150 (2009). [4] Baruselli et al., Phys. Rev. B 92, 045119 (2015).

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O7-SMG _57 STRONG FERROMAGNETISM AT THE SILICON SURFACE OF ANTIFERROMAGNETS CAUSED BY BURIED MAGNETIC MOMENTS

SMG - Surface magnetism D. Vyalikh 1,*, A. Generalov 2, K. Kliemt 3, C. Geibel 4, K. Kummer 5, M. Otrokov 6, E. Chulkov 6, C. Krellner 3 1Institute of Solid State Physics, Dresden University of Technology, Zellescher Weg 16, D-01062 Dresden, Germany - Dresden (Germany), 2MAX-Laboratory, Lund University, Box 118, 22100 Lund, Sweden - Lund (Sweden), 3Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt, Max-von-Laue Straße 1, 60438 Frankfurt am Main, Germany - Frankfurt Am Main (Germany), 4Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, 01187 Dresden, Germany - Dresden (Germany), 5European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble, France - Grenoble (France), 6Donostia International Physics Center (DIPC), Departamento de Fisica de Materiales and CFM-MPC UPV/EHU, 20080 San Sebastian, Spain - San Sebastian (Spain) Spin-polarized two-dimensional electron states (2DESs) at surfaces and interfaces of magnetically active materials attract immense interest because of the idea of exploiting fermion spins rather than charge in next generation electronics. The antiferromagnets GdRh2Si2 and EuRh2Si2, where ferromagnetic rare-earth layers are well separated from each other by non-magnetic Si-Rh-Si buffers, turns out to be an intriguing model systems for studying 2DESs in the presence of magnetic order. When terminated with a silicon surface, the first layer of the ordered 4f moments is hidden by a Si-Rh-Si trilayer, and simultaneously serves as a source of strong itinerant ferromagnetism at the silicon surface. Applying angle-resolved photoelectron spectroscopy, we show that the silicon surface of antiferromagnets GdRh2Si2 and EuRh2Si2 bears two distinct 2DESs, one being a Shockley surface state, and the other a Dirac surface resonance. We found that the respective 2DES’s are subject to strong exchange interaction with the ordered 4f-moments lying underneath the surface Si-Rh-Si trilayer. In GdRh2Si2 (TN ~ 107 K), the spin degeneracy of the Shockley state breaks down below ~90 K, and the splitting of the resulting subbands saturates upon cooling at values as high as ~185 meV. The spin splitting of the Dirac state becomes clearly visible around ~60 K, reaching a maximum of ~70 meV. An abrupt increase of the surface magnetization at around the same temperature suggests that the Dirac state contributes significantly to the magnetic properties at the Si surface of GdRh2Si2. In EuRh2Si2, the splitting sets in below ~ 41 K and saturates to ~ 150 meV upon cooling. Interestingly, this temperature is substantially higher than the ordering temperature of the Eu 4f moments (TN~ 24.5 K) in the bulk. The similarities and differences of ferromagnetic properties of silicon surface in Eu- and Gd- based systems will be presented and discussed. The unique temperature-dependent ferromagnetic properties of the Si-terminated surface in GdRh2Si2 and EuRh2Si2 could be exploited when combined with functional adlayers deposited on top for which novel phenomena related to magnetism can be anticipated. Thanks This work was supported by the German Research Foundation (DFG) (grants VY64/1-3, GE602/2-1, GRK1621 and SFB1143) as well as by Research Grant 15.61.202.2015 of Saint Petersburg State University. References 1. M. Güttler et. al., Scientific Reports 6 24254 (2016). 2. A. Chikina et al., Nature Comm. 5 3171 (2014). 3. M. Höppner et al., Nature Comm. 4 1646 (2013).

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O8-SMG _201 MAGNETIC ANISOTROPY IN SHIBA BOUND STATES ACROSS A QUANTUM PHASE TRANSITION

SMG - Surface magnetism B. Heinrich 1,*, N. Hatter 1, M. Ruby 1, J.I. Pascual 2, K.J. Franke 1 1Freie Universität Berlin - Berlin (Germany), 2CIC nanoGUNE and Ikerbasque, Basque Foundation for Science - San Sebastián (Spain) The exchange coupling between magnetic adsorbates and a superconducting substrate leads to Yu-Shiba-Rusinov states [1-3] inside the superconducting energy gap and a Kondo resonance outside the gap. The exchange coupling strength determines whether the quantum many-body ground state is a Kondo singlet or a singlet of the paired superconducting quasiparticles. Here, we use scanning tunnelling spectroscopy to identify the different quantum ground states of manganese phthalocyanine on Pb(111) [4]. We observe Shiba states, which are split into triplets by magnetocrystalline anisotropy (see figure). Their characteristic spectral weight yields an unambiguous proof of the nature of the quantum ground state. Our results provide experimental insights into the phase diagram of a magnetic impurity on a superconducting host and shine light on the effects induced by magnetic anisotropy on many-body interactions. This might also be of importance in 1D magnetic chains in contact with a superconductor, which are candidates to host Majorana bound states at the chain ends [5]. References [1] L. Yu, Acta Phys. Sin. 21,75 (1965). [2] H. Shiba, Prog. Theor. Phys. 40, 435 (1968). [3] A. I. Rusinov, Zh. Eksp. Teor. Fiz. 56, 2047 (1969). [4] N. Hatter et al., Nat. Commun. 6, 8988 (2015). [5] S. Nadj-Perge et al., Science 346, 602 (2014).

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O9-SMG _89 SPIN-HYBRIDIZATION BETWEEN MOLECULE AND METAL AT ROOM TEMPERATURE THROUGH INTERLAYER EXCHANGE COUPLING

SMG - Surface magnetism M. Studniarek 1,*, M. Gruber 2,*, F. Ibrahim 2, S. Boukari 2, L. Joly 2, V. Da Costa 2, M. Peter 3, J. Arabski 2, P. Ohresser 4, W. Wulfhekel 3, F. Scheurer 2, E. Beaurepaire 2, M. Alouani 2, W. Weber 2, M. Bowen 2 1Institut de Physique et Chimie des Materiaux de Strasbourg, Universite de Strasbourg, CNRS UMR 7504, Strasbourg, France / Synchrotron SOLEIL, Gif-sur-Yvette, France - Strasbourg (France), 2Institut de Physique et Chimie des Materiaux de Strasbourg, Universite de Strasbourg, CNRS UMR 7504, Strasbourg, France - Strasbourg (France), 3Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe, Germany - Karlsruhe (Germany), 4Synchrotron SOLEIL, Gif-sur-Yvette, France - Gif-Sur-Yvette (France) The organic spinterface describes the spin-polarized properties that develop, due to spin- dependent hybridization and charge transfer, at the interface between a ferromagnetic (FM) metal and the molecules of an organic semiconductor [1]. The organic spinterfaces were also indirectly observed by the strong coupling that may exist between paramagnetic molecules and the FM substrate [2]. However, the study of spinterfaces was so far limited to sublimable molecules deposited in ultra-high vacuum conditions in order to prevent the oxidation of the FM substrate. Alternatively, the strong interaction of the molecules with the FM layer may alter molecular properties, such as spin-crossover [3]. While intercalating a graphene layer [4] is one solution that introduces strong constraints on the FM selection, we investigated the possibility to use interlayer exchange coupling as the mediator of the molecule/FM magnetic coupling. Using X-ray magnetic circular dichroism (XMCD), we studied the magnetic coupling between manganese phthalocyanine (MnPc) molecules and a Cu(001)/Co FM substrate separated by a wedge-shaped Cu spacer (Fig. 1 a). The XMCD data show that the Mn ion within MnPc molecules can be magnetically coupled to the Co substrate at room temperature when separated by up to 4 ML of Cu. The XMCD intensity evolves in an oscillatory manner with increasing Cu thickness (Fig. 1 d), in agreement with ab initio calculations. By decreasing the temperature, we could observe stronger oscillations in the magnetic coupling and this over a much larger Cu thickness range (up to 12 ML). The phase and the periods of the oscillatory coupling is found to be the same than that of the prototypical Cu(001)/Co/Cu/Co system. Finally, we theoretically considered the spintronic performance of a Co/Cu(3ML)/MnPc stack. The calculations reveal a spin-polarization of the density of states in the vicinity of the Fermi level that reaches +74% suggesting thus promising spintronic performance [5]. References [1] Djeghloul et al., Scientific Reports 3, 1272 (2013) [2] Javaid et al., Physical Review Letters 105, 077201 (2010) [3] Miyamachi et al., Nature Communications 3, 938 (2012) [4] Hermanns et al., Advanced Materials 25, 3473 (2013) [5] Gruber et al., Nano Letters 15, 12 (2015)

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O10-SMG _247 PORTABILITY OF A MOLECULAR QUANTUM SPIN

SMG - Surface magnetism N. Bachellier 1,*, M. Ormaza 1, M. Faraggi 2, B. Verlhac 1, P. Abufager 3, M. Vérot 4, T. Le Bahers 4, P. Ohresser 5, L. Joly 1, M. Romeo 1, F. Scheurer 1, M.L. Bocquet 2, N. Lorente 6, L. Limot 1,* 1IPCMS, CNRS UMR 7504, Université de Strasbourg - Strasbourg (France), 2Ecole Normale Supérieure, Département de Chimie, ENS-CNRS-UMPC UMR 8640 - Paris (France), 3Instituto de Física de Rosario, CONICET, universidad Nacional de Rosario - Rosariorg (Argentina), 4Université de Lyon, Université Claude Bernard Lyon 1, CNRS, ENS Lyon - Lyon (France), 5Synchrotron SOLEIL, L'Orme des Merisiers - Gif-Sur-Yvette (France), 6Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU) - Donostia-San Sebastian (Spain) A considerable effort is being devoted at exploring new spin functionalities through specifically designed magnetic molecules. The excited spin states of these molecules are moreover potentially appealing for quantum computing and data storage technology. Despite this exciting prospect, the design of hybrid metal-molecule devices is hampered by the interaction of the molecular spin with the electrons of the metal. Decoupling layers [1,2,3] as well as superconductors [4] have been successfully used to preserve the molecular spin, but introduce important constraints in the choice of the molecular environment. Here, we combine scanning tunneling microscopy (STM), spin-flip spectroscopy (IETS), x-ray magnetic circular dichroism (XMCD) and density functional theory (DFT) calculations to study the spin-dependent properties of a simple magnetic double-decker molecule, nickelocene [Ni(C5H5)2], on metal surfaces. The particular feature of this molecule is its portability, meaning that it can be placed in different metallic environments without losing the quantum nature of its spin. Taking advantage of this property, we show that the functionalization of a STM tip with a nickelocene molecule can be used to produce double- spin flip events resulting in a large enhancement of the IETS signal. References [1] Hirjibehedin et al., Science 317, 1199 (2007) [2] Tsukahara et al., Phys. Rev. Lett. 102, 167203 (2009) [3] Rau et al., Science 344, 988 (2014) [4] Heinrich et al., Nat. Phys. 9, 765 (2013)

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P1-SMG_45 MAGNETO-OPTICAL STUDY OF CYLINDRICALLY SHAPED MAGNETS. SURFACE DOMAIN STRUCTURE AND MAGNETIZATION REVERSAL.

SMG - Surface magnetism A. Chizhik 1,*, A. Stupakiewicz 2, A. Zhukov 1, J. Gonzalez 1 1Universidad del Pais Vasco - San Sebastian (Spain), 2University of Bialystok - Bialystok (Poland) Cylindrically shaped magnetic microwires are very popular objects for technical application and basic investigations. As a response on the discovering of the giant magneto-impedance effect (GMI) we have created a new line of the magnetic study – magneto-optics of cylindrical shaped magnets [1]. During last years we have studied systematically the wire series of glass-covered microwires of different compositions and geometry. The main method which we use is the magneto-optical Kerr effect (MOKE) (see figure. The left figure – longitudinal MOKE; the right figure – polar MOKE). We combine MOKE microscopy and MOKE magnetometry in longitudinal and polar configurations. We have found great variety of surface domain structures. Now we know main parameters which permit us to control surface structure: circular and axial magnetic fields, high frequency electric current, external stress, temperature, etc. Magnetic glass covered microwire is the basic elements in the detectors which use the GMI effect. Taking into account that GMI effect is the high frequency effect, the detailed knowledge of surface domain structure obtains a special meaning. Now controlling the surface domain structure we could optimize the main parameters of GMI based magnetic sensors. From other side magnetic microwires are very promising objects for the basic study. It is sufficient to say that the existence of well-known Giant Barkhausen Jump was demonstrated in cylindrical microwires using MOKE.

References A. Chizhik, J. Gonzalez, “Magnetic Microwires: A Magneto-Optical Study,” Pan Stanford Publishing Pte. Ltd., Singapore, 2014

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P3-SMG_416 ANTIFERROMAGNETIC LONG RANGE SPIN ORDERING IN FE AND NIFE2 DOPED BATIO3 MULTIFERROIC LAYERS

SMG - Surface magnetism P. Ohresser 1,*, A. Barbier 2,*, T. Aghavnian 2, V. Badjeck 2, C. Mocuta 1, D. Stanescu 2, H. Magnan 2, C.L. Rountree 2, R. Belkhou 1, N. Jedrecy 3 1Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, F-91192 Gif-sur-Yvette Cedex, France (France), 2DSM/IRAMIS/SPEC, CNRS URA 2464, CEA Saclay, F-91191 Gif-sur-Yvette, France (France), 3Sorbonne Universités, UPMC Paris 06, UMR 7588, INSP, 4 Place Jussieu, F-75005 Paris, France (France) Doping ferroelectric compounds to produce novel multiferroic materials is a seductive approach. We report on the Fe doping and on the comparative NiFe2 co-doping of fully oxidized BaTiO3 layers (~ 20 nm) elaborated by atomic oxygen plasma assisted molecular beam epitaxy. The films were thoroughly characterized by synchrotron radiation X-Ray diffraction and X-Ray absorption spectroscopy. For purely Fe doped layers, the native tetragonal perovskite structure evolves rapidly towards cubic-like up to 5% doping level above which the crystalline order disappears. On the contrary, low co-doping levels (~5%) fairly improve the thin film crystalline structure and surface smoothness; high levels (~27%) lead to more crystallographically disordered films, although the tetragonal structure is preserved. Magnetic dichroic measurements reveal that metal clustering does not occur and allowed determining the ion valences. Ferromagnetic long range ordering can be excluded with great sensitivity in all samples as deduced from X-Ray magnetic absorption circular dichroic measurements. On the contrary, our linear dichroic X-Ray absorption results support antiferromagnetic long range ordering while piezo-force microscopy give evidence of a robust ferroelectric long range ordering showing that the films are excellent candidates for magnetic exchange coupled multiferroic applications.

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SMI - Soft Matter at Interfaces

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O1-SMI_469 SOLVENT EXTRACTION: STRUCTURE OF THE LIQUID–LIQUID INTERFACE CONTAINING A DIAMIDE LIGAND

SMI - Soft Matter at Interfaces E. Scoppola 1,*, E.B. Watkins 2, R. Campbell 3, O. Konovalov 4, L. Girard 1, J.F. Dufrêche 1, G. Ferru 5, G. Fragneto 3, O. Diat 1,* 1Laboratoire: Institut de Chimie Séparative de Marcoule UMR 5257 - (CEA/CNRS/UM/ ENSCM) - Bagnols Sur Ceze (France), 2Materials Synthesis and Integrated Devices,Los Alamos National Laboratory - Los Alamos (United States of America), 3Laue Langevin Institut - Grenoble (France), 4European Synchrotron Radiation Facility - Grenoble (United States of America), 5Argonne National Labororatory - Lemont (United States of America) Among the many solvent extraction technologies, those used for metal recovering are quite challenging due to the poor solubility of inorganic ions in oils. Metal extraction thus requires the use of lipophilic extractant molecules to complex the cations and solubilize the complex in the oil phase. In practice, there is a trade-off between selectivity, kinetics and efficiency, in keeping with cost constraints. Despite all the attention solvent extraction has received, however, the molecular structure of the L-L interface remains quite elusive and, as a result, the mechanisms of complexes (ion + extractant molecules + counterions) formation and transfer, that influence the kinetics of extraction, are not well understood. Ion-extraction can be referred to as a diffusion-limited or a reaction-limited process depending on how high is the energy barrier at the LL interface. To tackle this highly challenging problem, we will buckle down by seeking for coherent structural information of the interface at the nanometer scale, at equilibrium in a first step. X-ray AND neutron reflectivities were used to show the evolution of the interfacial structure and to determine the ion potentials at the LL interface [1,2]. References [1] E. scoppola et al, PCCP 17 15093 – 15097 (2015). [2] E. Scoppola et al , Angewandte Chemie Int. Ed. DOI: 10.1002/anie.201603395

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O2-SMI _366 A COMBINED NEUTRON REFLECTOMETRY AND ATR-FTIR STUDY ON THE EFFECTS OF SHEAR ON LIPID MEMBRANES

SMI - Soft Matter at Interfaces M. Trapp 1,*, F. Schwörer 2, M. Ballauff 1, R. Dahint 2, R. Steitz 1 1Helmholtz-Zentrum Berlin - Berlin (Germany), 2RKU Heidelberg, Applied Physical Chemistry - Heidelberg (Germany) Shear forces play a major role in degenerative joint diseases such as osteoarthritis (OA). Due to abrasion cartilage and surface active phospholipids are removed from the bones which lead to increased friction and shows symptoms such as joint pain, stiffness and inflammation. While there are already many different treatments of OA, the understanding of these treatments on a molecular level is still scarce. Medications may include the intra- articular application of hyaluronic acid, one of the main components of the synovial fluid. In a previous study, we found that solid-supported oligolamellar lipid membranes show an enormous swelling of a factor up to 4 after incubation with HA. In addition, the lipid coating remained on the support even in the liquid phase whereas without HA the coating detached when crossing the main phase transition [1]. In order to investigate shear effects on systems modelling joints, a novel setup was designed and built. We now present first results obtained with this newly developed shear cell which allows the simultaneous measurement of neutron reflectivity and ATR-FTIR data up to shear rates of 6000 rpm [2]. The systems under investigation were again solid-supported oligolamellar lipid membranes incubated with the polyelectrolyte Poly(allylamine hydrochloride) (PAH). After incubation the d-spacing of the system shows an increase of a factor of about 5, similar to the behaviour observed when lipid membranes are incubated with HA [1]. The neutron data reveal a substantially increased water fraction with increasing shear rate. Simultaneously recorded IR data indicate that the applied shear also causes a phase transition into the liquid state. Yet the coating remains attached to the substrate, but changes composition and morphology. This effect can be attributed to the stabilisation introduced through the bridging of individual lipid bilayers by PAH.

Figure 1: Neutron reflectivity curves of a solid-supported oligolamellar lipid hydrogel lining (11 DMPC lamellae in total) interacting with PAH against water as a function of applied shear load. References [1] M. Kreuzer et al., BBA, 1818 (2012) 2648. [2] F. Schwörer et al., Langmuir, 31 (2015), 11539.

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O3-SMI _236 LOADED POLYELECTROLYTE/SURFACTANT MEMBRANES SPREAD FROM NEUTRAL AGGREGATES

SMI - Soft Matter at Interfaces A. Tummino 1,*, R. Campbell 1,*, I. Varga 2, B.A. Noskov 3 1Institut Laue-Langevin, 71 avenue des Martyrs - Grenoble (France), 2Institute of Chemistry, Eötvös Loránd University - Budapest (Hungary), 3Institute of Chemistry, St. Petersburg State University - St. Petersburg (Russian federation) We present a new methodology to prepare efficient membranes of oppositely charged polyelectrolytes and surfactants out of equilibrium conditions at the air/water interface. Our approach consists of exploiting the dynamic dissociation of neutral aggregates of poly(sodium styrene sulfonate) and dodecyltrimethylammonium bromide (NaPSS/DTAB) from an aqueous dispersion onto pure water to form a loaded spread film thanks to the Gibbs-Marangoni effect. A systematic investigation of the interfacial composition as well as the mechanical properties of the films with respect to the sample history has been carried out using ellipsometry and specular neutron reflectometry in combination with surface pressure-area isotherms. We found that the membranes behave like perfectly insoluble Langmuir-like films over five consecutive cycles with an initial surface excess more than four times higher than layers formed from bulk adsorption. The components bind in a one-to-one molar ratio independently of the sample history, which is rationalized in terms of the entropy of counterion release due to the low ionic strength of the solution. To our knowledge, this is the first time in which the dynamic interfacial composition of a binary system has been resolved in situ. We believe that our findings may open up new possibilities in the fields of preparation of films at the air/water interface for coating technologies as well as encapsulation of functional molecules such as drugs.

Figure 1: surface pressure-area isotherms of five cycles of spread NaPSS/DTAB films formed from neutral aggregates where each cycle is displayed darker in shading;

Figure 2: Interfacial composition resolved using NR where the maxima mark full compression and minima mark full expansion.

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O4-SMI _234 VUV TREATMENT AS A RESOURCE SAVING METHOD FOR FIBRE-REINFORCED PLASTIC (FRP) SURFACE PREPARATION PRIOR TO BONDING

SMI - Soft Matter at Interfaces K. Rosanova *, L. Schilinsky, C. Schmüser, C. Dölle Fraunhofer Institute for Manufacturing Technology and Advances Materials IFAM - Bremen (Germany) Fiber-reinforces plastics (FRP) are commonly used in the aerospace, automotive, marine and construction industries. Optimization of the adhesive bonding process of FRP structures, especially the surface preparation prior to bonding, will be of a central importance in forthcoming expansion of FRP use. In this connection the key problem is dependent on the polymer FRP matrix. In the case of duroplastic matrix the main problem is the presence of release agent on the surface of joining components. For the thermoplastic matrix such as polypropylene (PP) , the problem is the low surface energy and the inertness of its surface. In this work the effect of VUV irradiation on the surfaces of carbon-fiber-reinforced polymer with duroplastic epoxy matrix (CFRP) as well as on glass-fiber reinforced polypropylene (PP-GF) is studied and optimized in order to achieve the good adhesive bonding results. For that purpose, substrates irradiated by VUV light at wavelengths of 172 nm (Xe-Excimer lamp) and 185 nm (Mercury low pressure lamp) in air and nitrogen atmosphere were analyzed. XPS measurements show an increase of oxygen containing surface groups by VUV treatment. At the same time, the surface energy measurements demonstrate an increase of the polar component of the surface energy within up to 60 s of irradiation for PP- GF and CFRP surfaces. For longer irradiation times a saturation behavior of the surface energy is observed. The adhesion tests show a good correlation of the adhesion abilities of VUV irradiated surfaces and surface energies values. The adhesive bonding strength increases after short irradiation times for both FRP materials. Longer irradiation time decreases of the adhesion properties due to the formation of a weak boundary layer. Surface damages are observed with the help of a light microscope for long irradiation times (100 – 600 s dependent on the lamp type and the treatment atmosphere). Kinetic of the material removal resulting from the surface damages was measured for both VUV wavelengths.

The influence of the treatment atmosphere (air and N2) during the irradiation process on the resulting surface chemical composition and adhesive properties will also be discussed. The shown improved adhesion abilities demonstrate the practicability of VUV irradiation for surface activation. Thanks The authors thanks the „Forschungsvereinigung DECHEMA Gesellschaft für Chemische Technik und Biotechnologie e.V.“ for the financial sponsorship of this project (ROBUST, IGF-project no. 17854 N).

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O5-SMI _461 REDUCTION IN TENSION AND STIFFENING OF LIPID MEMBRANES IN AN ELECTRIC FIELD REVEALED BY X-RAY SCATTERING

SMI - Soft Matter at Interfaces A. Hemmerle 1,*, T. Charitat 1,*, G. Fragneto 2, J. Daillant 3 1UPR 22/CNRS, Institut Charles Sadron, Université de Strasbourg - Strasbourg (France), 2Institut Laue-Langevin - Grenoble (France), 3SIS2M, CEA - Saclay (France) Electric fields have a strong influence on lipid membrane behavior and are used in many applications in cell biology, biotechnology and pharmacologyi[1, 2]. High electric field can lead to cell hybridization, electroporation, electrofusion [3] and electropermeabilization, opening wide applications in tissue ablation, cancer treatment and gene therapy. Lower electric fields can also induce shape deformation of the lipid bilayer and under certain conditions its destabilization. This electroformation process has become one of the classical methods to form large unilamellar vesicles. The effect of electric fields on membrane elasticity has been investigated using synchrotron grazing incidence x-ray scattering. Using a recently developed method, we are able to precisely determine membrane tension, rigidity and interaction potentials. We show that membrane tension is decreased, possibly down to negative values and that the membrane rigidity is increased. A full analysis of our data as a function of applied potential and frequency shows that it is possible to decouple simple electrokinetic effects from the bilayer elasticity which is affected by the local electric field. The effects on the membrane itself and Debye electrical double bilayer could be fully analysed leading to a fine understanding of AC fields effects. We also demonstrate that only a non-linear theory can describe our data. Finally, an instability was observed at low frequency with a unstable mode in agreement with the size of vesicle obtained in electroformation experiments. References [1]M. Zhao, B. Song, J. Pu, T. Wada, B. Reid, G. Tai, F. Wang, A. Guo, P. Walczysko, Y. Gu, T. Sasaki, A. Suzuki, J.V. Forrester, H.R. Bourne, C.D. Devreotes, P.N. McCaig, and J.M. Penninger, Nature, 442 (7101):457– 460, 2006. [2] U. Zimmermann. Electrical breakdown, electropermeabilization and electrofusion. In Reviews of Physiology, volume 105, pages 175–256. Springer Berlin Heidelberg, 1986. [3] U. Zimmermann and G.A. Neil. Electromanipulation of cells. CRC press, 1996.

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O6-SMI_383 STRUCTURAL CHARACTERIZATION OF MEMBRANES OF INCREASING COMPLEXITY

SMI - Soft Matter at Interfaces G. Fragneto *, R. Delhom * Institut Laue-Langevin - Grenoble (France) Current research in membrane protein biophysics highlights the emerging role of lipids in a large number of biophysical processes including shaping membrane protein function. Cells and organisms have developed sophisticated mechanisms for controlling the lipid composition and many diseases are related to the failure of these mechanisms. Furthermore, lipid bilayers are involved in several mechanisms of exchange form the internal and external parts of a cell, including drug delivery. Neutron scattering techniques like small angle scattering, diffraction, reflectometry are rapidly developing as they allow detecting and characterising sub-nanometer structural changes induced in biomembranes by different bio- related molecules. The talk will review some recent progress in the field and provide perspectives for future developments. It aims at highlighting neutron scattering methods as a versatile tool to tackle questions dealing with the understanding and function of biomembranes and their components. Examples shown will include the use of membrane systems with increasing level of complexity and the study of: the Islet Amyloid PolyPeptide interaction with planar lipid bilayers: neutron scattering helps shedding light on its cytotoxicity mechanism [1]; the fusion of raft-like lipid bilayers operated by a membranotropic domain of the HSV-type I glycoprotein gH occurring through a cholesterol-dependent mechanism [2]; iii) the biochemical and structural characterisation of lipid bilayers from natural yeast extracts [3,4] and the effect of the potent but highly toxic antifungal drug Amphotericin B [5]. Thanks All co-authors of the cited publications and the Institut Laue-Langevin for award of beam- time and use of PSCM facilities. References [1] A. Martel, Y. Gerelli, L. Porcar, I. Kiese, L. Antony, M. Vivaudou, G. Fragneto, De Pablo J. submitted [2] G. Vitiello ,· A. Falanga, · A. Alcides Petruk ,· A. Merlino, · G. Fragneto, · L. Paduano, · S.Galdiero · G. D'Errico Soft Matter, 11, (2015) 3003 [3] Gerelli Y., de Ghellinck A., Jouhet J., Laux. V., Haertlein M., Fragneto G., Acta Crystall. Section D (2014); 70(12):3167 [4] A. de Ghellinck, H. Schaller, V. Laux, M. Haertlein, M. Sferrazza, E. Marechal, H. Wacklin, J. Jouhet, G. Fragneto, et al. PLoS ONE 01/2014; 9(4):e92999 [5] A. de Ghellinck, G. Fragneto, V. Laux, M. Haertlein, J. Jouhet, M. Sferrazza, H. Wacklin, BBA- Biomembranes, 10, (2015) 2317-2325.

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I13_SMI_434 SCATTERING METHODS AND FORCE SPECTROSCOPY REVEAL MOLECULAR LEVEL STRUCTURE AND INTERACTIONS OF LIPID MEMBRANES

SMI - Soft Matter at Interfaces T. Kuhl * Department of Chemical Engineering and Department of Biomedical Engineering University of California at Davis - Davis (United States of America) Over the past several decades, supported lipid membranes have been used as model systems of cellular membranes, to investigate various membrane interactions, and as platforms for development of bio-sensors. Precise structural characterization by x-ray reflectivity and grazing incidence diffraction at the solid-liquid interface coupled to high resolution force spectroscopy offers a wealth of insight into membrane organization, self- assembly, and domain formation as well as how membranes respond to changes in their environment. In this talk, I will discuss some recent advances in our understanding of supported membranes including (1) the role of cholesterol in modifying lipid packing structure through alterations in hydration which includes conclusive evidence for a stoichiometric ratio of cholesterol to saturated lipid; (2) membrane rearrangements during contact and protein binding; (3) and a robust polymer cushioned membrane system for biosensing applications. The talk will particularly highlight the importance of x-ray scattering techniques for single, lipid bilayer structural characterization and direct force measurements of membrane-membrane interactions.

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P1-SMI_18 A STRAIGHTFORWARD APPROACH FOR CONCURRENT PARTICLE FORMATION AND SURFACE MODIFICATION OF BOEHMITE NANOPARTICLES VIA IN-SITU SURFACE MODIFICATION

SMI - Soft Matter at Interfaces G.A. Farzi *, M. Ghamari Hakim Sabzevari University - Sabzevar (Iran, islamic republic of) In this study, in-situ surface modification of boehmite nanoparticles was carried out successfully using a new approach by means of 3-Methacryloxy propyl trimethoxy silane as coupling agent. Simultaneous boehmite formation and surface modification is favored to this study. By using aluminum nitrate as an inexpensive precursor and ammonia solution for adjusting pH, the chemical reactions were carried out at 80oC under vigorous stirring. This is a new route for developing of so-called one-pot process of making advanced nano- materials considering deep understanding of chemical interactions between reactants before and during procedure. The temperature and pH play very important role in this process of particle formation and simultaneous surface modification, at constant concentration of precursor (0.033M). Since the traditional surface modification of nanoparticles is time and energy consuming, the total time and energy spent, diminished by this efficient method in order to achieving an innovate route to fabricate valuable and ready to use nano-particles. The results of FTIR investigations showed that successful particle formation as well as simultaneous surface modification has been properly occurred. Three hydrolysable groups in silane undertook hydrolyze after pH changed, then the bonding between hydroxyl groups of boehmite and silane was formed for the sake of surface modification. The rate of hydrolyze is pH dependent and consequently the rate of reaction can be adjusted by controlling pH so that almost all of the methoxy groups would be hydrolysable and be able to bond to boehmite particles in the next step. Keywords: Surface modification, Boehmite, nanoparticles, one-pot process

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SST - Surface structure

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O1-SST _82 AB INITIO STUDY OF STRUCTURE PHASE TRANSITION IN ATOM-WIDE CO WIRES ON A VICINAL CU(111) SURFACE

SST - Surface structure A. Klavsyuk *, A.G. Syromyatnikov, N.S. Kabanov Faculty of Physics, Moscow State University - Moscow (Russian federation) The bimetallic system Co/Cu(111) has been studied extensively both experimentally and theoretically. From the theoretical point of view, the studies of Co/Cu(111) system are mainly related to ab initio calculations in the framework of Density Functional Theory (DFT). DFT is commonly used method for calculations in condensed matter physics. Usually the results of DFT calculations for condensed matter systems are in a good agreement with the experimental data. Even better results are observed for metal systems [1,2]. The result of recent work [1] was totally unexpected. Based on ab initio calculations Zaki et al. [3] conclude that DFT qualitatively fails to predict the dimerized structural phase for a monatomic Co wire [4]. It was also demonstrated, that the dimerized Co wire exists at low temperature and shows a tip-bias dependency [4]. The ab initio calculations are performed to study the structure of atom-wide Co wire on a vicinal Cu(111) surface. We have found two ferromagnetic states of Co wires. In the first state the Co wire consists of dimers, while in the second state the distance between atoms in Co wire is equal. The low phase transition temperature is explained by small difference in energy between the states. Our results completely refute the conclusion made by Zaki et al. [3] that DFT qualitatively fails to predict the dimerized structural phase for a monatomic Co wire on a vicinal Cu(111) surface. In addition, it was found that the phase transition temperature depends drastically on the length of the wire and the tip bias. In the first instance, tip-bias dependency is related with deformation of wire and surface. Thanks This work was supported by Russian Foundation of Basic Researches (Project number 15- 32-20560). References [1] S.V. Kolesnikov, A.L. Klavsyuk, A.M. Saletsky Surface Science 612, 48 (2013). [2] V.S. Stepanyuk, A.N. Klavsyuk, L. Niebergall, and P. Bruno, Phys. Rev. B 72, 153407 (2005). [3] N. Zaki, H. Park, R.M Osgood, A.J. Millis, and C.A. Marianetti, Phys. Rev. B 89, 205427 (2014). [4] N. Zaki, C.A. Marianetti, D.P. Acharya, P. Zahl, P. Sutter, J. Okamoto, P.D. Johnson, A.J. Millis, and R.M. Osgood, Phys. Rev. B 87, 161406 (2013).

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O2-SST _105 SURFACE STRUCTURE OF (110) TERMINATED MAGNETITE INVESTIGATED BY SCANNING TUNNELING MICROSCOPY AND DENSITY FUNCTIONAL THEORY

SST - Surface structure B. Walls 1,*, O. Lübben 1, K. Palotás 2, K. Fleischer 1, K. Walshe 1, I.V. Shvets 1 1School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin - Dublin (Ireland), 2Department of Theoretical Physics, Budapest University of Technology and Economics, Budafoki út 8, H-1111 Budapest - Budapest (Hungary) We have performed a combined scanning tunneling microscopy (STM) and density functional theory (DFT) study of the (110) surface of single crystalline magnetite. (110) terminated magnetite consists of two alternating planes, namely the A and B planes. Previously, STM studies of Fe3O4(110) have shown a row reconstruction [1,2], and this row reconstruction has recently been explained as periodic faceting which exposes {111}-type planes [3]. STM measurements indicate that the surface morphology depends on the cleaning procedure; annealing in a UHV environment results in the {111}- faceted row reconstruction. However, annealing in an oxygen rich atmosphere results in a surface exhibiting a surprising atomically flat structure. STM image simulations, including tip-surface interactions, of the atomically flat structure show that this is the B-plane terminated (110) surface containing oxygen vacancies. Additionally, we also take a closer look at the atomic structure of the {111}-faceted surface and its termination. References [1] R. Jansen, V. Brabers, and H. van Kempen, Surf. Sci. 328, 237 (1995). [2] G. Maris, O. Shklyarevskii, L. Jdira, J. Hermsen, and S. Speller, Surf. Sci. 600, 5084 (2006). [3] G. S. Parkinson, P. Lackner, O. Gamba, S. Maaß, S. Gerhold, M. Riva, R. Bliem, U. Diebold, and M. Schmid, Surf. Sci. 649, 120 (2016).

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O3-SST _77 COBALT THIN FILMS INTERCALATION UNDER GRAPHENE ON IRIDIUM(111): INTERMIXING EFFECTS AND THE ROLE OF GRAPHENE

SST - Surface structure I. Carlomagno 1,*, J. Drnec 1, S. Vlaic 2, A.M. Scaparro 3, S. Cicia 3, I. Lucarini 3, S. Macis 4, C. Meneghini 3, F. Carlà 1, R. Felici 3 1ESRF - Grenoble (France), 2LPEM-UMR8213/CNRS-ESPCI Paris Tech - UPMC - Paris (France), 3Università Roma Tre - Rome (Italy), 4Università Tor Vergata - Rome (Italy) Ultrathin (<10MLs) Cobalt films show high magnetic anisotropy which could be used to make ultra-dense memory devices. On the other hand, they are extremely reactive and, under ambient pressure, they immediately oxidize resulting into a completely different magnetic response. For this reason, interest has raised into Co films intercalated under Graphene/Iridium. The intercalation procedure allows to include chemical species into layered compounds: such as Graphene on Iridium(111), an easy-to-grow system providing high chemical stability to the intercalant. Interestingly, Gr/Co/Ir systems show an enhanced magnetic response [1] whose origin has been investigated focussing mainly on the Co-C interactions [2, 3]. Nevertheless, given the reduced dimensionality of the system, even small modifications in the film structure can affect the whole system magnetic anisotropy therefore should be taken into account. Using X-Ray Reflectivity (XRR), Grazing Incidence X-Ray Diffraction (GIXD) and X-ray Absorption Spectroscopy (XAS), we characterized the buried Co-Ir interface and the Co chemical surroundings upon intercalation. Furthermore, the comparison of bare Co/Ir(111) to Gr- covered Gr/Co/Ir systems allowed us to identify the role played by Graphene. Investigating bare Co/Ir(111) we evaluated the thermal effects on the local structure of a 8MLs-thick Co film. In agreement with GIXD and XRR analysis [4], X-ray Absorption Near Edge Spectroscopy (XANES) data collected after several annealing treatments show that the film is stable up to 200⁰C but higher temperatures result into a progressive lattice stretching with increasing Co-Ir intermixing. This process has been found to be dependent both on the Co film thickness and on the annealing temperature. Comparing this result to Gr/Co/Ir systems, we have identified the Graphene as an enhancer of the alloying process. It lowers the maximum temperature and increases the minimum thickness at which structural changes start to be detected. In this respect, the Graphene provides a colander effect isolating the Co atoms in the moment when they arrive at the substrate interface. This structural characterization, once complemented by magnetic measurements, will allow to tailor the magnetic response of the system simply tuning the macroscopic intercalation conditions. Thanks The authors wish to thank the whole staff of ID03 for the wonderful support shown in every part of the experiments preparation. References [1] N. Rougemaille et al., Appl. Phys. Lett. 101 (2012) [2] R. Decker et al., Phys. Rev. B 87 (2013) [3] H. Vita et al., Pjhys. Rev. B 90 (2014) [4] J. Drnec, S. Vlaic, I. Carlomagno et al., Carbon 94 (2015)

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O4-SST _390 WETTING LAYER OF COPPER ON THE TANTALUM (001) SURFACE

SST - Surface structure G. Beutier 1,*, M. Dupraz 1,*, R. Poloni 1, K. Ratter 2, D. Rodney 3, M. De-Santis 2, B. Gilles 1, M. Verdier 1 1SIMAP, CNRS & Univ Grenoble Alpes - Grenoble (France), 2Institut Néel, CNRS - Grenoble (France), 3Institut Lumière Matière, Univ Lyon I - Lyon (France) The Cu on Ta system is expected to present a Stransky-Krastanov mode of growth [1]. Previous studies using electron spectroscopy or chemical desorption [2,3] evidenced the presence of a wetting layer of copper on Ta[110] without determining its structure. Here we study the solid state dewetting of copper on the Ta[001] surface using, in addition to usual laboratory methods, in situ surface X-ray diffraction (SXRD) to characterize the hetero-epitaxial interface and ex situ coherent X-ray diffraction (CXD) to characterize the microstructure of the dewetted islands. The latter show a unique crystallographic orientation, and 3D displacement fields measured by CXD showed a highly strained and defect free structure [4]. This presentation will focus on the recent SXRD results [5]: the analysis of the crystal truncation rods reveals the presence of a wetting layer of copper made of two atomic planes pseudomorphic to the tantalum substrate, whose upper most atomic planes are significantly deformed. These findings are in total agreement with the results of Density Functional Theory calculations. The presence of a wetting layer confirms a Stranski-Krastanov growth mode and is thought to explain the extremely fast atomic diffusion of copper during the dewetting process in the solid state at high temperature. Thanks ANR MECANIX is aknowledged for the PhD grant of M. Dupraz. References [1] Rodriguez, J.A. et al (1991), J. Phys. Chem 95, 4196-4206 [2] Kuhn, K. W. et al (1993), J. Phys. Chem 97, 446-453 [3] Venugopal, V. et al (2009), Thin solid Films 517, 5482-5488 [4] Beutier et al. (2012), Thin Solid Films 530, 120-124. [5] Dupraz et al., in preparation.

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O5-SST _249 SURFACE TUG OF WAR: DIRECT QUANTITATIVE IDENTIFICATION OF THE “SURFACE TRANS-EFFECT”

SST - Surface structure D.A. Duncan 1,*, P.S. Deimel 2, M.R. Bababrik 3, B. Wang 3, P.J. Blowey 4, L.A. Rochford 4, P.K. Thakur 1, T.L. Lee 1, M.L. Bocquet 5, J.V. Barth 2, D.P. Woodruff 4, F. Allegretti 4 1Diamond Light Source (United Kingdom), 2Techincal University of Munich (Germany), 3University of Oklahoma (United States of America), 4University of Warwick (United Kingdom), 5ENS (France) The recently proposed “surface trans-effect” (STE)[1] suggests that the interaction of ligands to surface-supported metal-organic complexes can have a complex interplay with the surface through the complex. This interplay, or “tug of war”, between the axial ligand and the underlying substrate could have wide ranging effects on the various fields aiming to utilize such systems, most notably in heterogenous catalysis and gas sensors. However, the current understanding of this effect is incomplete and lacks reliable structural parameters to benchmark theoretical calculations. Using X-ray standing waves, we demonstrate that ligation of ammonia and water to iron phthalocyanine (FePc) on Ag(111) increases the adsorption height of the central Fe atom (shown on the left in the figure); dispersion corrected density functional theory calculations accurately model this structural effect. The calculated charge redistribution in the FePc/H2O electronic structure induced by adsorption shows an accumulation of charge between the surface, the Fe atom and the water molecule along the σ-bonding direction, similar to the redistribution caused by ammonia (shown on the right in the figure). This apparent σ-donor nature of the observed STE on Ag(111) thus strongly implies that it shares physical origin with the trans-effect. Surprisingly, the theoretical calculations further suggest that the Ag(111) substrate has an even stronger trans-effect than either studied molecular ligand. References [1] W. Hieringer, K. Flechtner, A. Kretschmann, K. Seufert, W. Auwärter, J. V. Barth, A. Görling, H. –. Steinrück and J. M. Gottfried, J. Am. Chem. Soc., 2011, 133, 6206.

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I10_SST_456 THREE DECADES OF ATOMIC FORCE MICROSCOPY - WHAT IS IN FOR SURFACE SCIENCE?

SST - Surface structure F. Giessibl * Experimental and Applied Physics, University of Regensburg - Regensburg (Germany) Atomic force microscopy (AFM) and scanning tunneling microscopy (STM) image surfaces with atomic resolution and enable local spectroscopies such as of current versus voltage and forces versus distance. In the past, STM and AFM used to be separate techniques that required their own instrumentation. The introduction of the qPlus force sensor [1] enabled combined STM and AFM capability, allowing highly precise imaging and spectroscopy functions and measuring the forces that act during atomic manipulation [2]. While STM had better spatial resolution than AFM in the past, the situation is reversed now with modern AFM [3]. Angular dependencies of chemical bonding forces have been observed before for Si tips interacting with Si surfaces [4], W tips interacting with graphite [5] and similarities exist between metal tips interacting with CO molecules on Cu and Si adatoms [6]. In the latter two cases, light atoms such as carbon or oxygen interacted with much heavier and much larger metal atoms. Gross et al. established that CO is an excellent probe for organic molecules. For example, pentacene can be imaged at excellent resolution with CO terminated tips [7], although the softness of CO on tips can lead to image distortions [8,9]. Tips made of permanent magnets such as CoSm allow to resolve the spin order in the antiferromagnetic insulator nickel oxide [10]. Complex surface terminations of the topological insulator TlBiSe2 have been determined by AFM [11]. The stiff cantilever/small amplitude technique used here also allows true atomic resolution in ambient conditions [12], and small iron clusters on Cu (111) are resolved by force microscopy [13]. Very recently, AFM has provided important insights into inelastic tunneling spectroscopy [14]. In summary, we see many exciting avenues in nanoscience research that open up with combined STM and AFM. Fig 1 : AFM image of a Fe trimer next to a Fe dimer on Cu(111) [13]. References [1] F. J. Giessibl, Appl. Phys. Lett. 73, 3956 (1998). [2] M. Ternes et al., Science 319, 1066 (2008). [3] J. Welker, F. J. Giessibl, Science 336, 444 (2012). [4] F. J. Giessibl, S. Hembacher, H. Bielefeldt, J. Mannhart, Science 289, 422 (2000). [5] S. Hembacher, F. J. Giessibl, J. Mannhart, Science 305, 380, (2004). [6] J. Welker, J. Weymouth, F. J. Giessibl, ACS Nano, DOI: 10.1021/nn403106v (2013). [7] L. Gross et al. Science 325, 1110 (2009). [8] A. J. Weymouth, Th. Hofmann, F. J. Giessibl, Science 343, 1120 (2014). [9] M. Neu et al., Phys. Rev. B 89, 205407 (2014). [10] F. Pielmeier, F. J. Giessibl, Phys. Rev. Lett. 110, 266101 (2013). [11] F. Pielmeier et al., N. J. Phys. 17, 023067 (2015). [12] D. Wastl, J. Weymouth, F. J. Giessibl, Phys. Rev. B 87, 245415 (2013). [13] M. Emmrich et al., Science 348 308 (2015). [14] N. Okabayashi et al., Phys. Rev. B 93, 165415 (2016).

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O6-SST _340 THE SURFACE STRUCTURE OF V2O3(0001)

SST - Surface structure F. Feiten 1,*, J. Seifert 1, J. Paier 2, H. Kuhlenbeck 1, H. Winter 3, J. Sauer 2, H.J. Freund 1 1Fritz Haber Institute of the Max Planck Society - Berlin (Germany), 2Humboldt University, Chemistry Department - Berlin (Germany), 3Humboldt University, Physics Department - Berlin (Germany)

Thin films (~10 nm) of V2O3(0001) on Au(111) catalyze oxidation reactions, for example the partial oxidation of methanol to formaldehyde. In previous studies, the reactivity has been explained using a fully vanadyl (V=O) covered model for the surface structure. [1] Recent ion scattering studies have challenged this view and instead proposed a reconstructed oxygen trilayer (O3) surface termination. [2,3]

Using I/V-LEED in direct succession with STM we show that the surfaces of V2O3(0001) films prepared under typical conditions in UHV are indeed terminated by a full layer of V=O groups with some local defects. The Pendry R-factor for several preparations is ~ 0.1 for a vanadyl terminated model structure while RPendry for O3 terminated structural models is always > 0.2. STM images of the V2O3(0001) surfaces show hexagonal patterns of round protrusions typical for a vanadyl terminated surface. While some local defects can always be seen in STM, their number can be reduced by careful preparation and a coexistence of different extended surface structures was never observed. [4] Fast atom diffraction led to experimental curves that match calculated curves for a V=O terminated model structure well, while calculations for an O3 terminated model structure fail to reproduce the experimental data. Density functional theory calculations using the HSE hybrid functional describe V-O bonding more accurately than previously employed pure GGA functionals and predict an increased range of oxygen chemical potentials at which the V=O terminated surface is thermodynamically favored. [5] The figure shows STM images of three different V2O3(0001) films with the Pendry R-factor for a vanadyl terminated structural model resulting from the corresponding I/V-LEED calculations inset into each of the three images. References [1] Y. Romanyshyn, S. Guimond, D. Göbke et al. Top. Catal. 2011, 54, 669–684. [2] A. J. Window, A. Hentz, D. C. Sheppard et al. Phys. Rev. Lett. 2011, 107, 016105 [3] J. Seifert, E. Meyer, H. Winter and H. Kuhlenbeck, Surf. Sci. 2012, 606, L41 [4] F. E. Feiten, H. Kuhlenbeck, H.-J. Freund, J. Phys. Chem. C 2015, 119, 22961 [5] F. E. Feiten, J. Seifert, J. Paier et al. Phys. Rev. Lett. 2015, 114, 216101

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O8-SST _72 THE NEW GENERATION OF THE HEMISPHERICAL ENERGY ANALYSER IN THE NOVEL SURFACE SCIENCE RESEARCH

SST - Surface structure C. Kirschfeld * R&D Department, PREVAC sp. z o.o. - Rogów (Poland) Complexity and the range of materials and their surface studied will be expanded across a wide range of topics, including surface science, catalysis, corrosion, semiconductors research, photoelectrochemical energy conversion, battery technology, or energy-saving technologies [1-4]. An unique and exceedingly flexible analysis cluster with a detection system is needed for these fundamental and applied research. Here it will be described a new energy and angle resolved analyser for photoelectron spectroscopy. The analyser has a hemispherical shape with a mean radius of 150 mm and is based on combining an advanced focusing electron lens system, which can be operated in different modes, transmission, spatial resolution or angular resolution. An angular resolution of better than 0.06° and spatial resolution 100 µm can be obtained. The spectrometer includes highly stable 6 kV power supply, where each independent voltage module achieves temperature stability below 0.5 ppm of the voltage span per degrees Celsius. The modern 2-D low noise CCD-MCP assembly with a noise level of < 0.01 cps/channel and a 70 fps fast camera are used. Fully automation and environmental software system make it a user-friendly tool for the conducted researches. It will be presented combination of the new generation hemispherical energy analyser with modular PREVAC surface analysis system as part of multi-technique surface analysis systems to fully characterize the surface structure via XPS, UPS, ISS and APRES mapping. We will report the first results from these techniques, using our analyser and induced by four sources, X-ray, UV, electron or ion impact. UV excited Xe5p spectra recorded in the gas phase show that the energy resolution is better than 3 meV at 2eV analyser pass energy. Some measurements for photovoltaic materials, graphene, or self-assembled organic monolayers of organic molecules will be presented as studied on our system. This analyser opens up new possibilities for angular/spatial resolved electron spectroscopy, band-mapping and other applications. References [1] S. Bengió, et. al, Surf. Sci. 646, 126-131 (2016) [2] B. Eren el. al, Science 29, 475-478 (2016) [3] Z. Duan et. al, J. of Solid St. Electrochem. 19, 2265-2273 (2015) [4] N. Tomaszewska et. al, Surf. Sci. 632, 103-110 (2015)

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O9-SST _363 STRUCTURE OF A MODEL DYE/TITANIA INTERFACE: GEOMETRY OF BENZOATE ON RUTILE-TIO2 (110)(1×1)

SST - Surface structure R. Lindsay 1,*, W. Busayaporn 2,*, D.A. Duncan 3, F. Allegretti 3, A. Wander 4, M. Bech 5, P. Møller 5, B. Doyle 6, N. Harrison 7, G. Thornton 8 1University of Manchester - Manchester (United Kingdom), 2Synchrotron Light Research Institute - Nakhon Ratchasima (Thailand), 3Technische Universität München - Garching (Germany), 4Daresbury Laboratory - Warrington (United Kingdom), 5University of Copenhagen - Copenhagen (Denmark), 6IOM CNR Laboratorio TASC - Basovizza (Italy), 7Imperial College - London (United Kingdom), 8University College London - London (United Kingdom) Motivated to a large extent by the employment of the carboxyl (-COOH) containing molecules as solar harvesters in TiO2-based dye-sensitized solar cells, there is significant ongoing activity seeking to elucidate the interaction of such species with single crystal TiO2 surfaces. To date, most progress has been achieved for the simplest –COOH containing molecule, namely formic acid (HCOOH), on the prototypical rutile TiO2(110)(1×1) surface, including high precision quantification of the adsorption geometry1,2. Currently, however, similar structural information is largely absent for other –COOH containing species with geometrical details typically being restricted to angular orientation from near edge X-ray absorption fine structure (NEXAFS) data and lateral location from scanning probe microscopy (SPM) images. Here, we address this issue, employing scanned-energy mode photoelectron diffraction (PhD) and ab initio density functional theory (DFT) calculations to investigate the adsorption geometry of benzoate ([C6H5COO]-) on rutile- TiO2(110)(1×1). The PhD data indicate that the benzoate moiety binds to the surface through both of its oxygen atoms to two adjacent five-fold surface titanium atoms in an essentially upright geometry. Moreover, its phenyl (C6H5-) and carboxylate ([-COO]-) groups are determined to be coplanar, being aligned along the [001] azimuth (see figure below). This experimental result is consistent with the benzoate geometry emerging from DFT calculations conducted for laterally rather well separated adsorbates. At shorter inter-adsorbate distances, the theoretical modeling predicts a more tilted and twisted adsorption geometry, where the phenyl and carboxylate groups are no longer coplanar, i.e. inter-adsorbate interactions influence the configuration of adsorbed benzoate. Notably, in contradiction to an earlier assertion3,4, overlayer structures comprised of benzoate species with their phenyl groups displaying more than one angular orientation are found to be energetically unfavorable. References 1. D.I. Sayago et al., J. Phys. Chem. B 2004, 108, 14316-14323. 2. R. Lindsay et al., J. Phys. Chem. C, 2008, 112, 14154-14157. 3. Q. Guo et al., Surf. Sci. 1999, 433-435, 322-326. 4. J. Schnadt et al., Surf. Sci. 2003, 540, 39-54.

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O10-SST _364 GOLD-PALLADIUM NANOPARTICLES ON TIO2 (110): CORRELATION BETWEEN MORPHOLOGY/STRUCTURE AND UV-VIS RESPONSE

SST - Surface structure A. Abisset *, Y. Soldo, A. Coati, S. Garaudée, A. Bailly, Y. Garreau, M. De Santis, M.C. Saint- Lager Institut Néel - Grenoble (France) Recent experiments [1,2] have shown an important increase of the catalytic activity for chemically synthesized gold or gold alloyed nanoparticles under visible light exposition. Such phenomenon has been attributed to surface plasmon resonance modes localized on nanoparticles (LSPR, local surface plasmon resonance). It is extremely relevant in the context of energy-efficient processes using solar light, in particular in order to transform visible light into chemical energy via photocatalytic reactions. In this context, the combination of gold, known for its LSPR, with palladium, characterized by important catalytic properties, is very promising but very little is known about the plasmonic properties of Au-Pd bimetallic NPs. However, a deep comprehension of these LSPR-assisted processes, especially at the nano/atomic level, is a key step in order to allow large scale development of plasmon assisted photocatalysis. In the aim of exploring the link between plasmonic properties and structure of the NPs, our approach consists in studying model systems [3], namely AuxPd1-x nanoclusters deposited by molecular beam epitaxy (MBE) onto TiO2(110). For the first time, we succeeded in performing in situ coupled measurements of the morpho-structural and optical properties during the growth of few nanometers sized bimetallic nanoparticles. This was done at SOLEIL synchrotron (France) by means of Grazing Incidence Small Angle X-ray Scattering (GISAXS), providing size, shape and interparticle distance, Grazing Incidence X-ray Diffraction (GIXRD) for crystallographic properties and UV-Vis surface differential reflectivity spectroscopy (SDRS) for optical response. We will present the results obtained during the growth of the NPs obtained by sequential and co-deposition for several compositions. Our results show a great influence of palladium on the NPs growth mechanisms, as well as on their optical response that critically depends not only on the NPs composition but also on their chemical configuration (core-shell, alloy, Janus particle,…). References [1] Sarina et al, JACS 135 (2013) 5793. [2] Mukerjee et al, Nano Lett. 13 (2013) 240. [3] Laoufi et al, J. Phys. Chem. C 115 (2011) 4673.

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O11-SST _233 IDENTIFICATION OF SURFACE STRUCTURES OF TITANIA NANOPARTICLES BY PHOTOEMISSION SPECTROSCOPY

SST - Surface structure P. Borghetti 1,*, E. Meriggio 2, G. Rousse 3, G. Cabailh 1, R. Lazzari 1, J. Jupille 1 1Institut des Nanosciences de Paris - Paris (France), 2Dipartimento di Fisica, Università degli Studi di Genova - Genova (Italy), 3Chimie du Solide et de l’Energie, Collège de France - Paris (France) The innumerous properties of titanium dioxide relies on its various polymorphs and crystallographic orientations, and quite often on mixtures of these [1,2]. It is therefore crucial to set out surface-sensitive methods that allow the in situ structural identification. The present work reports on the ability of photoemission-based techniques to identify the phase and surface orientation of TiO2 nanostructured samples. Ti LMV Auger reference spectra of TiO2 rutile (110), anatase (101) and anatase (001) single-crystals are singled out, by taking advantage of the presence of a valence level in the Auger transition. Indeed, differences in the Ti LMV transition, which mostly originate from the way Ti 4s and Ti 4p states hybridize with the O 2p valence states, derive from intrinsic structural aspects of the different titanium dioxide polymorphs and orientations. Ti LMV templates allow a quantitative analysis of phases and orientations involved in nanoparticle samples. As an example, the case of standard Degussa P-25 powder is analyzed, both in its as-received form and during the anatase-to-rutile transformation upon annealing. Comparison to X-ray diffraction measurements demonstrates the reliability of the Auger analysis and highlights its ability to detect crystallographic orientations and composition gradients. References [1] M. Kapilashrami, Y. Zhang, Y.-S. Liu, A. Hagfeldt, and J. Guo, Chem. Rev. (2014) 114, 9662−9707. [2] T. Ohno, K. Sarukawa, K. Tokieda, and M. Matsumura, Journal of Catalysis (2001) 203, 82–86.

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O12-SST _38 STRUCTURAL AND MORPHOLOGICAL CHANGES OF CO AND RH NANOPARTICLES ON CEO2 AND AL2O3

SST - Surface structure E. Varga *, P. Pusztai, A. Oszkó, A. Erdohelyi, J. Kiss * University of Szeged - Szeged (Hungary) Noble metal promoted cobalt particles on oxide supports have gained attention due to their outstanding activity in the stream reforming of ethanol and the hydrogenation of CO and 2 CO2.1 The properties of Co can be further tuned by the support. Al2O3 and Co can form hardly reducible CoAl2O4 and over CeO2 the reduction of Co is hindered, too, because of the high oxygen mobility of the support.3, 4

We examined Al2O3 and CeO2 supported Co, Rh and Rh-Co samples, focusing on the chemical states after the catalyst pretreatment. XPS revealed that 2% Co on both supports appeared in +2 oxidation state after oxidation, proving the strong metal-support interaction. 2+ On 10% Co/Al2O3 XPS clearly verified the presence of Co corresponding to CoO or CoAl2O4, but Co3O4 formed over CeO2. When 0.1% Rh was added to 10% Co/Al2O3, Co3O4 was detected, indicating that Rh release the interaction between Co and Al2O3. Rhodium enhanced the reduction of Co on both supports and retarded its dissolution into the CeO2.

On CeO2, Rh was well dispersed after preparation but significant particle size increase was observed after reduction at 773 K that was hindered in the presence of Co. Here we demonstrate that Rh can be reduced under mild conditions without sintering. References 1. L. Guczi, G. Boskovic and E. Kiss, Catal. Rev., 2010, 52, 133-203. 2. Z. Ferencz, A. Erdőhelyi, K. Baán, A. Oszkó, L. Óvári, Z. Kónya, C. Papp, H. P. Steinrück and J. Kiss, ACS Catal., 2014, 4, 1205-1218. 3. Z. Ferencz, K. Baán, A. Oszkó, Z. Kónya, T. Kecskés and A. Erdőhelyi, Catal. Today, 2014, 228, 123-130. 4. E. Varga, P. Pusztai, L. Óvári, A. Oszkó, A. Erdőhelyi, C. Papp, H.-P. Steinrück, Z. Kónya and J. Kiss, Phys. Chem. Chem. Phys., 2015, 17, 27157-25166.

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P1-SST_20 GIANT FLEXOELECTRIC INDUCED SURFACE LAYER IN BIFEO3 THIN FILM

SST - Surface structure T. Yang 1,*, X. Li 1, C. Wang 2 1Shanghai Institute of Applied Physics, Chinese Academy of Sciences - Shanghai (China), 2Institute of Physics, Chinese Academy of Sciences - Shanghai (China) Surface double-layer structure different from the interior was found in BiFeO3 thin film grown on SrRuO3 covered SrTiO3 (111) substrate by pulsed laser deposition. It was shown that BiFeO3 film exhibits epitaxial phase with single domain. X-ray reflectivity and X-ray photoelectron spectroscopy results revealed a skin layer of less than 1 nm with a reduced electron density and different surface state. Grazing incidence x-ray diffraction convinced a surface multi-domain structure of several nm beneath the surface skin layer. The double- layer near surface structure would be originated from the large depolarization field produced by the single-domain structure with strain. we revealed that this layer exhibits giant strain gradient about 107 m-1, which was 2 or 3 orders of magnitude larger than the values inside the film. By combining in-situ x-ray reflectivity and grazing incidence x-ray diffraction, we found that an abrupt structure transition happens at 500K, which show a thinner surface layer and a released stain gradient profile. Our results suggest the coupling between surface structure and flexoelectricity, implied that the surface layer and properties would be controlled by the strain gradient in ferroelectric films. Thanks The authors thank the staff at beamline BL14B1 of Shanghai Synchrotron Radiation Facility. This work was financially supported by the National Natural Science Foundation of China (Nos. 11405253, 11205235, 11174355 and U1332205), and the Youth Innovation Promotion Association CAS. References T. Y. Yang, C. Wang, X. M. Zhang, Y. Feng, H. Z. Guo, K. J Jin, X. Y. Gao, Z. Li, and Xiaolong Li, Appl. Phys. Lett. 105, 202901 (2014).

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P2-SST_146 DFT AND STM STUDY OF RECONSTRUCTED AU(100) SURFACE

SST - Surface structure B. Pieczyrak *, A. Trembulowicz *, L. Jurczyszyn, G. Antczak University of Wroclaw (Poland) The massive reconstruction of Au(1 0 0) surface has been studied for decades (Ref. 1–5) and still the details of top-layer arrangements are not completely resolved. Current understanding of the phenomenal arrangement is the following: the system lowers the surface energy by developing the complicated quasi-hexagonal reconstructed first layer on a square, weakly reconstructed, second layer. In addition to the reconstruction, the top-layer can rotate up to ±0.83° with respect to the second layer. This rotation is responsible for various structural arrangements of the reconstruction. We use the scanning tunneling microscopy (STM) and the density functional theory (DFT), as implemented in the Vienna Ab-initio Simulation Package (VASP), to investigate the structural and electronic properties of this surface. We investigate two types of hex-reconstructed surfaces: unrotated and rotated and their response to the formation of surface monovacancies. References [1] F. Ercolessi et al., Phys. Rev. Lett. 57 (1986) 719. [2] O.K. Binnig et al., Surf. Sci. 144 (1984) 321. [3] P. Havu et al., Phys. Rev. B 82 (2010) 161418. [4] A. Trembulowicz et al., Phys. Rev. B 84 (2011) 245445. [5] R. Hammer et al., Phys. Rev. B 90 (2014) 035446.

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P3-SST_338 ORDERING IN SELF-ORGANIZED PD-AU ARRAYS OF NANOPARTICLES STUDIED BY IN SITU GRAZING INCIDENCE X-RAY SCATTERING

SST - Surface structure A. Bailly 1,*, G. Sitja 2, M.C. Saint-Lager 1, S. Le Moal 3, F. Leroy 2, M. De Santis 1, C.R. Henry 2, O. Robach 4 1CNRS, Institut Néel - Grenoble (France), 2CINaM - Marseille (France), 3Institut des Sciences Moléculaires d'Orsay - Orsay (France), 4CEA, INAC/NRS - Grenoble (France) Bimetallic nanoparticles (NPs) supported on oxides usually exhibit better catalytic properties compared to the pure metal counterparts[1]. The understanding of the mechanisms underlying such improved performances requires quantifying the impact of each parameter (size, shape, crystallographic structure, composition, oxidation degree and so on) on the catalytic efficiency. The changes undergone by the catalyst during a reaction must thus be characterized in operando conditions. This calls for the use of perfectly controlled systems. In this frame, model catalyst surfaces consisting of long-range ordered NPs arrays are invaluable candidates. As a preliminary study, the growth of Pd-Au NPs arrays has been examined by small angle X-ray scattering and X-ray diffraction in grazing incidence (GISAXS, GIXRD)[2]. An ultrathin alumina film obtained by the oxidation of a Ni3Al(111) single crystal surface is used as a template for initiating the NPs self-organization[3]. Several compositions have been explored (from pure palladium to almost pure gold) up to a total equivalent thickness of one monolayer in each case. GISAXS is performed in situ during the growth and allows the determination of the thickness limit above which the NPs arrays start to exhibit disorder. The growth behaviour is clearly different as a function of the Au/Pd ratio: the lower the ratio, the better the organization of the nanoparticles array. We underline that the limit for gold corresponds to one additional atomic layer deposited on top of the pre-formed Pd seeds. Above this limit, the NPs arrays show disordering. This phenomenon is evidenced by the occurrence of a diffuse scattering contribution in the GISAXS images that co-exists with narrow scattering rods arising from the persistence of a long-range order. Below this threshold we can consider that the NPs size and composition are strongly correlated. The quantitative GISAXS analysis allowed us to obtain the mean morphological parameters of the ordered NPs (diameter, aspect ratio and correlation length) and the GIXRD provided structural information such as the epitaxial relationships and interatomic distances within the nanoparticles as a function of the relative gold content. Thanks We thank Olivier Geaymond and Olivier Ulrich for their valuable help during beamtime and the CRG review committee for attributing beamtime. References [1] N. El Kolli, L. Delannoy, C. Louis, Journal of Catalysis 297 (2013) 79. [2] A. Bailly, G. Sitja, M.-C. Saint-Lager, S. Le Moal, F. Leroy, M. De Santis, C.R. Henry, O. Robach, in preparation. [3] M. Marsault, G. Sitja, C.R. Henry, Phys.Chem.Chem.Phys. 16 (2014) 26458.

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P4-SST_347 STRAIN ENGINEERING ACROSS THE H-, O- AND OH-PT(111) SYSTEMS

SST - Surface structure I. Shuttleworth * Nottingham Trent University - Nottingham (United Kingdom) Key elements in the oxygen reduction reaction (ORR) are the H, O and OH intermediates that interact with one another across a catalytic surface. In the current work [1] the behaviour of each of these intermediates on a strained Pt(111) surface is investigated, and the results show that H changes binding position from on-top (compressive strain) to FCC (tensile). Coincidentally, the binding position of the O and OH intermediates remains unchanged suggesting that delocalised bonding plays a significant role in modifying the binding position. This suggestion is quantified through a crystal orbital overlap population (COOP) investigation of the H s-Pt s and H s-Pt d bonds across the range of strained surfaces. Thanks This research used the computational resources of the Supercomputing Laboratory at the King Abdullah University of Science & Technology (KAUST) in Thuwal, Saudi Arabia. References [1] Controlled FCC/on-top binding of H/Pt(111) using surface stress I. G. Shuttleworth, Applied Surface Science 378 (2016) 286-292 DOI: 10.1016/j.apsusc.2016.03.173

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P5-SST_379 RICH INTERFACIAL FILMS FORMED FROM AGGREGATES IN ALFA- CYCLODEXTRIN SOLUTIONS

SST - Surface structure R. Campbell 1,*, Á. Piñeiro 2, J. Ruso 2, N. Hassan 2, J. Campos-Terán 3, J. Hernandez- Pascacio 4, M. Costas 4 1Instiut Laue-Langevin - Grenoble (France), 2University of Santiago de Compostela - Santiago De Compostela (Spain), 3Universidad Autónoma Metropolitana - Ciudad De México (Mexico), 4Universidad Nacional Autónoma de México - Ciudad De México (Mexico) Cyclodextrins (CDs) are cyclic oligosaccharides formed by six (α), seven (β), or eight (γ) 1,4-linked α-D-glucopyranoside units. They are probably the first family of molecules that spring to mind when one looks to encapsulate small hydrophobic species [1]. CDs meet a number of characteristics that are not easy to bring together in a family of compounds, namely low toxicity, biocompatibility, chemical stability, and ease of synthesis and purification [2,3] Additionally, CDs are good targets for chemical modifications, which can enhance further their various attributes [4]. Nevertheless, the fundamental behavior of CDs in aqueous solutions and at interfaces is not yet fully understood. In the present work [5], the spontaneous aggregation of α-CD molecules in aqueous solution and the interactions of the resulting aggregates at the liquid/air interface have been studied at 283 K and 298 K using a battery of experimental techniques: transmission electron microscopy, dynamic light scattering, isothermal titration calorimetry, surface tensiometry, Brewster angle microscopy, neutron reflectometry and ellipsometry. We show that molecules spontaneously form aggregates in the bulk that grow in size with time. These aggregates adsorb to form films at the water/air interface with their size in the bulk determining the adsorption rate. The material that reaches the interface coalesces laterally to form two-dimensional organized domains on the micrometer scale with a layer thickness on the nanometer scale. These processes are affected by the ages of the bulk and the interface and the temperature, e.g., see the ellipsometry data of the adsorption rate in the figure where the temporal fluctuations imply lateral inhomogenities on the micrometer scale. The resulting film morphology is far from equilibrium, locked in a kinetically-trapped state. Our results reveal a surprising complexity of the parallel physical processes taking place in what might have seemed at first like a rather simple system. References [1] M. Messner et al. Int. J. Pharm. 2011, 407, 174 // [2] K. Connors, Chem. Rev. 1997, 97, 1325 // [3] J. Szejtli, Chem. Rev. 1998, 98, 1743 // [4] R. Challa et al. AAPS PharmSciTech 2005, 6, E329–E357 // [5] J. Hernandez-Pascacio et al. Langmuir 2016, under review.

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P6-SST_408 STUDY OF EFFECT OF ALUMINA ON ALUMINIUM CHARACTERISTIC PROPERTIES IN COMPOSITE ALLOYS

SST - Surface structure A. Bourbia 1,*, M. Debili 2 1preparatory school for science and technique (EPST) - Annaba (Algeria), 2Laboratory of Magnetism and Spectroscopy of Solids (LM2S), Department of Physics, Faculty of Science, Badji-Mokhtar Uni- versity - Annaba (Algeria) This article focuses on crystalline microstructure and intrinsic hardness properties of Al- Al2O3 alloys solidified by an electromagnetic high frequency (hf) melting process from cold compacted mixtures of pure aluminium and alumina (α-Al2O3) powders. The crystalline microstructure characteristics were investigated by X-ray diffraction (XRD) spectra measures, optical micrography observations. The hardness was evaluated by Vickers microhardness tests. It was found that the crystalline microstructure of the as-melted Al- Al2O3 alloys appear as a mixture of the fcc Al solid solution and the rhomboedric α-Al2O3 alumina phases. The surface morphologies exhibit a refined texture. The measured microhardness Vickers Hv0.2 gives a constant value of around 300 MPa. This observed strengthening of Al by Al2O3 in Al-Al2O3 composite alloys is essentially due to fine Al2O3 particles reinforcement of Al matrix. Keywords: Elaboration processes, Al alloys, Microstructure, Strengthening. References [1] A. Bourbia, M, Draissia; H, Bedboudi, S. boulkhessaim , Journal of X-ray science and technology 18(2)( 2010). P. 201. [2] M. Draissia, M.Y. Debili, J. of Crystal Growth 270 (2004), p. 250. [3] A. Bourbia, H.Bedboudi, M. Draissia, M.Y. Debili, JnanoR Vol. 3 (2008), p. 33.

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P7-SST_341 ADDRESSING THE VIBRATIONAL AND STRUCTURAL PROPERTIES OF POLYMORPH EXFOLIATED MOS2 PHASES

SST - Surface structure S. Lisi 1,*, S. Dubey 1, G. Nayak 1, N. Bendiab 2, V. Bouchiat 1, J. Coraux 1 1Institut Néel, CNRS - Grenoble (France), 2Institut Néel, CNRS / Université Joseph Fourier - Grenoble - Grenoble (France) Monolayer (ML) transition metal dichalcogenides (TMDs) crystals are 2D sheets built up by a one atom-thick layer of a transition metal sandwiched between two one atom-thick layers of a chalcogen element [1]. Although being known for more than 40 years in their 3D bulk phase, in the last years, they suddenly renewed the interest of the scientific community: the recent advances in the top-down preparation methods, triggered by the rise of graphene, have being rapidly adapted to a variety of layered crystal structure. In particular, MoS2 has emerged as an outstanding candidate for novel optoelectronics applications[2], thanks to its indirect to direct band gap transition, when synthesised as an ultimately thin monolayer[3]. MoS2 possesses further fascinating properties, among which polymorphism, i.e. (meta)stability of distinct crystallographic phases, noteworthy the semiconducting (2H) and metallic (1T') ones[4]. Finely tuning the phase transition is paramount for designing novel data storage devices or metal-semiconducting 1D junctions. In this contribution we will present our preliminary results on the structural and spectroscopic characterization of 2D MoS2 flakes exfoliated on SiO2/Si. In particular: i) atomic force microscopy (AFM) will shed light on the characteristic features of the exfoliated samples, as rippling and folding (Fig1.b and Fig1.c). ii) The current knowledge of the correlation between flakes thickness and the evolution of vibrational properties (Fig1.d and Fig.e) will be further extended, by means of Raman spectroscopy. iii) Our advances in the control of the phase transformation by means of chemical treatment and mechanical stresses will be presented. References [1] K. -A. N. Duerloo et al., Nature Comm. 5, 4214 (2014) [2] S. Cho et al., Science 349, 6248 (2015) [3] K. F. Mak et al., Phys. Rev. Lett. 105, 136805 (2010) [4] Y. -C. Lin et al., Nature Nanotech. 9, 391 (2014)

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TPI - Topological insulators

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O1-TPI _121 DETERMINATION OF THE ATOM-SURFACE INTERACTION POTENTIAL FOR A TOPOLOGICAL INSULATOR: 3HE-BI2TE3(111)

TPI - Topological insulators M. Pusterhofer 1,*, P. Kraus 1, A. Tamtögl 2, A. Ruckhofer 1, W. Allison 2, W.E. Ernst 1 1Institute of Experimental Physics, Graz University of Technology - Graz (Austria), 2Cavendish Laboratory - Cambridge (United Kingdom) Materials with peculiar electronic surface effects such as the novel group of topological insulators pose an especially interesting topic for truly surface sensitive measurement methods such as helium atom scattering (HAS). Since the diffractive interaction of low- energy atoms with surfaces depends on a multitude of parameters, the total interaction profile between the helium atom and the surface under investigation must be known with a high degree of certainty. Although several atom scattering experiments have been performed on topological surfaces [1,2], surface preparation of complicated layered materials is difficult at best and angular scattering spectra are therefore often too noisy to gather important surface parameters. Recent 3He diffraction experiments from in-situ cleaved single crystals of Bi2Te3(111) revealed a multitude of distinct resonance features in between the diffraction peak maxima. Using the angular positions of these features and an extended analysis over several measurement cycles, we were able to identify ten distinct 3 bound-state energies of the He-Bi2Te3(111) interaction potential. Using these eigenvalues as the source for a potential fit, a full three-dimensional interaction profile can be fitted to an azimuthal scan via an extended close-coupling (CC) calculation. Modelling the scattering intensities via an elastic CC calculation provides a quantum mechanically accurate way of testing a provided interaction profile against measured intensity data [3,4,5]. With our fitting 3 procedure we obtain an accurate three-dimensional He-Bi2Te3(111) interaction profile which will pave the way for a better understanding of topological insulator surfaces. References [1] X. Zhu et al., PRL 107 (2011), 186102 [2] C. Howard et al., PRB 88 (2013), 035402 [3] A. S. Sanz et al., Phys. Rep. 451 (2007), 37 [4] M. Mayrhofer-Reinhartshuber et al., PRB 88 (2013), 205425 [5] P. Kraus et al., JPC-C 119 (2015), 17235-17242

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O2-TPI_471 TOPOLOGICAL QUANTUM PHASE TRANSITION FROM WEAK TO STRONG TOPOLOGICAL INSULATOR IN PBSNBISE

TPI - Topological insulators O. Rader 1,*, P.S. Mandal 1, G. Springholz 2, G. Bauer 2, V.V. Volobuev 2, V.V. Volobuev 3, O. Caha 4, A. Varykhalov 1, E. Golias 1, J. Sánchez-Barriga 1 1Helmholtz-Zentrum Berlin - Berlin (Germany), 2Institut for Semiconductor and Solid State Physics, JKU - Linz (Austria), 3National Technical University "KhPI" - Kharkiv (Ukraine), 4Masaryk University - Brno (Czech republic)

Time-reversal symmetry protects strong topological insulators of the Z2 class which possess an odd number of Dirac-cone surface states. Topological crystalline insulators are merely protected by individual crystal symmetries and are classified as weak topological insulators because of their even number of Dirac cones. Here we present measurements of the system Pb-Sn-Bi-Se which reveal a composition-dependent phase transition from topological crystalline insulator to time-reversal-symmetry protected Z2 topological insulator and, therefore, from weak to strong. Moreover, a temperature-dependent phase transition from trivial to Z2 topological insulator is demonstrated. We investigate (111) epitaxial films of Pb-Sn-Bi-Se by angle-resolved photoemission and identify the Z2 topological insulator phase from a gapped Dirac cone at G while the three cones at the M points remain intact. We interpret this as caused by a lattice distortion and suggest that the new Z2 phase is ferroelectric. This finding is highly interesting because it makes topological insulators in principle switchable electrically.

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O4-TPI _213 IV-VI MONOLAYERS WITH ALKALINE-EARTH CHALCOGENIDE SUPPORTS

TPI - Topological insulators K. Kobayashi * Department of Physics, Ochanomizu University - Tokyo (Japan) Topological crystalline insulator (TCI) is a new concept of topologically non-trivial matters defined by point group symmetries of crystals [1]. SnTe and IV-VI compounds are the first materials that have experimentally been identified as TCIs. It was theoretically proposed that SnTe thin films are two-dimensional TCIs [2,3]. But, it seems not experimentally being confirmed. It was also theoretically proposed that IV-VI monolayers including SnTe are also 2D TCIs [4,5]. However, it seems also that IV-VI monolayers have not been materialized. We present a theoretical study on IV-VI monolayers with alkaline-earth chalcogenide supports. In a previous paper we showed a theoretical study of IV-VI monolayers with alkali halide supports [6] and following results are found. First, planar structures of free-standing IV-VI monolayers are not stable. TCI states are lost by buckling. Second, planar structures of monolayers are maintained by sandwiching them between alkali halide surfaces, and TCI states are preserved. One problem in that system is that the interaction between monolayers and alkali halide surfaces is weaker that between monolayers. It is expected that this property prevent monolayers from stably existing on surfaces. Therefore we study the system of IV-VI monolayers on alkaline-earth chalcogenide surfaces in this study. Since alkaline-earth chalcogenides are divalent ionic crystals, it is expected that the interaction between monolayers and alkaline-earth chalcogenide surfaces is stronger than that between monolayers and alkali halide surfaces. We performed density-functional calculations for various combinations of IV-VI monolayers and alkaline-earth chalcogenide surfaces, and found that the interaction between them is stronger that between monolayers and alkali halide surfaces. This result suggests possibility of realization of IV-VI monolayers on surfaces. References [1] L. Fu, Phys. Rev. Lett. 106, 106802 (2011). [2] J. Liu, T. H. Hsieh, P. Wei, W. Duan, J. Moodera, and L. Fu, Nature Mat. 13, 178 (2014). [3] H. Ozawa, A. Yamakage, M. Sato, and Y. Tanaka, Phys. Rev. B 90, 045309 (2014). [4] E. O. Wrasse and T. M. Schmidt, Nano Lett. 14, 5717 (2014). [5] J. Liu and X. Qian and L. Fu, Nano Lett. 15, 2657 (2015). [6] K. Kobayashi, Surf. Sci. 639, 54 (2015).

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P2-TPI_244 ASSESSING TOPOLOGICAL PROTECTION IN REAL SPACE

TPI - Topological insulators H. Dil 1,*, R. Queiroz 2, F. Pielmeier 3, G. Landolt 4, S. Muff 1,*, J. Osterwalder 4, V. Strocov 5, F. Giessibl 3, A. Schnyder 2 1Institute of Physics, Ecole Polytechnique Fédérale de Lausanne - Lausanne (Switzerland), 2Max- Planck-Institut für Festkörperforschung - Stuttgart (Germany), 3Institute of Experimental and Applied Physics, Universita¨t Regensburg - Regensburg (Germany), 4Physik-Institut, Universität Zürich - Zurich (Switzerland), 5Swiss Light Source, Paul Scherrer Institut - Villigen (Switzerland) One of the reasons that topological insulators have received so much attention in recent years is the fact that the edge states are protected by the topology of the bulk band structure and the change in topology at an interface. The unique spin texture of the topological surface states is a direct consequence of this topological protection, because the only way to guarantee the existence of a state crossing a gap is when it is spin polarised. Therefore, the spin texture of the surface states as measured by spin- and angle-resolved photoemission has been successfully used to prove whether a material is a topological insulator in many instances. In literature the reverse argument, that the spin polarisation causes the topological protection through the suppression of backscattering, can often be found. However, this is only valid for the 1D edge states of a 2D topological insulator, and not for the 2D edge states of a 3D system. It is thus of importance to study the microscopic mechanism behind topological protection. Using the combination of a variety of experimental techniques and theoretical models we have addressed the issue of how topological protection works in real space. From the comparison of AFM, STM and ARPES measurements with density functional theory calculations on the topological insulator TlBiSe2 we found that the 50% defect density on the surface quenches all trivial surface states, but a clear topological surface state remains [1]. Furthermore, a light sputtering of the prototypical topological insulator Bi2Se3 renders the topological surface state invisible in UV ARPES, but induces a clearer and sharper topological surface state when measured by soft X-ray ARPES [2]. This apparent discrepancy can be explained by considering the different influences of gaussian and unitary disorder on the surface state combined by the enhanced probing depth. Adsorbates on the surface cause a smearing of the state, whereas the defects induced by sputtering cause the state to relocate to deeper layers. Thus in both cases the topological protection mechanism can be explained by the topological surface state moving away from regions with high defect density and further into the bulk. This can be loosely interpreted as a shift of the topological transition towards deeper layers. Thanks This work is supported by the Swiss National Science Foundation References [1] F. Pielmeier et al. New Journal of Physics 17, 023067 (2015). [2] R. Queiroz et al. Physical Review B 93, 165409 (2016).

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Special sessions

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O01-ASC_475 SEE ATOMS MOVE IN REAL TIME: ULTRAFAST ELECTRON DIFFRACTION

ACS Nano session Award P. Rudolf * Zernike Institute for Advanced Materials, University of Groningen (Netherlands) Time-resolved electron diffraction is a unique tool for providing direct and detailed information on the structural dynamics of solid surfaces, nano-sized materials, molecules and atomically thin layers, thanks to the high cross section for interaction between electron and matter. Femtosecond lasers are used to generate ultrashort light and electron pulses. Light initiates a process in the sample - a phase transition, an electronic excitation or simply a temperature jump - and by recording snapshots of the electrons diffracted from the sample in a stroboscopic fashion, one can image the photo-induced motion of the structure. In this talk I shall try to give a taste of the immense possibilities of ultrafast electron diffraction, illustrating how this novel technique opens the door to physical understanding of many aspects of light-matter interaction such as out of equilibrium structural phase transitions, heat transport through interfaces and the creation of coherent phonons. Specific examples that will be discussed are the martensite to austenite phase transition in a Ni-Mn- Ga foil, which is a magnetic shape memory Heusler alloy, and the structural dynamics of a Cr/Au bi-layer foil after photo-excitation by a near-infrared femtosecond laser pulse. For the latter we directly followed atomic disorder caused by the generation of hot electrons, the subsequent transfer of energy to phonons and the diffusion of both electrons and phonons through the Cr/Au interface. For the Heusler alloy instead, after the initial change of the material from the low temperature martensite phase to the high temperature austenite phase, oscillations are observed, indicating a strong tendency in the lattice to go back to the low-temperature martensite phase.

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O02-ASC_476 FROM MOLECULAR SELF-ASSEMBLY TO ON-SURFACE CHEMISTRY

ACS Nano session Award L. Chi * Institute of Functional Nano & Soft Materials (FUNSOM) Soochow University - Suzhou (China) Surfaces provide platforms for self-assembly of well-defined molecular structures. By adjusting the subtle balance of molecul-molecule interactions and molecule-surface interactions, diverse molecular patterns can be created. Beyond molecular self-assembly, “on-surface covalent coupling” or “surface assisted reaction” under ultrahigh vacuum (UHV) became a new concept in the recent years to create robust, ordered molecular structures that may exhibit novel properties.1,2 While some products are not possible to be synthesized by standard synthesis in solutions because of high reaction barrier or low solubility,3 some others undergo different reaction pathways compared with traditional reactions. Our recent progresses in this research area will be summarized in this lecture, particularly emphasizing the significant impacts of metal single crystal surfaces.4-9 Important breakthroughs give a clear signal for the opening of a new avenue in realizing robust functionalized molecular surfaces, and it may offer ideas for designing new catalysts for unusual chemical reactions. References 1) L. Grill, M. Dyer, L. Lafferentz, M. Persson, M.V. Peters, S. Hecht, S. Nat Nano 2007, 2, 687-691. 2) J. Cai, P. Ruffieux, P. Jaafar, M. Bieri, T. Braun, S. Blankenburg, M. Muoth, A.P. Seitsonen, M. Saleh, X.L. Feng, K. Mullen, R. Fasel, R. Nature 2010, 466, 470-473. 3) D.Y. Zhong, J.H. Franke, S. Kumar Podiyanachari, T. Blömker, H.M. Zhang, G. Kehr, G. Erker, Harald Fuchs, Lifeng Chi, Science, 2011, 334, 213-216. 4) B. Yang, J. Björk, H.P. Lin, X.Q. Zhang, H.M. Zhang, Y.Y. Li, J. Fan, Q. Li, L.F. Chi, J. Am. Chem. Soc. 2015, 137, 4904-4907. 5) H.M. Zhang, H.P. Lin, K.W. Sun, L. Chen, Y.L. Zagranyarski, N. Aghdassi, S. Duhm, Q. Li, D.Y. Zhong, Y.Y. Li, K. Müllen, H. Fuchs, L.F. Chi, J. Am. Chem. Soc, 2015, 137, 4022-4025. 6) Z. Gong, B. Yang, H.P. Lin, Y.Y. Tang, Z.Y. Tang, J.J. Zhang, H.M. Zhang, Y.Y. Li, Y.S. Xie, Q. Li and L.F. Chi, ACS Nano 2016, 10, 4228–4235. 7) Li, B. Yang, H.P. Lin, N. Aghdassi, K.J. Miao, J.J. Zhang, H.M. Zhang, Y.Y. Li, S. Duhm, J. Fan, and L.F. Chi, J. Am. Chem. Soc., 2016, 138 (8), 2809–2814. 8) B. Yang, H.P. Lin, K.J. Miao, P. Zhu, L.B. Liang, K.W. Sun, H.M. Zhang, J. Fan, V. Meunier, Y.Y. Li, Q. Li, L.F. Chi, Angew. Chem. Int. Ed. 2016, DOI: 10.1002/anie.201602414. 9) H.M. Zhang and L.F. Chi, Adv. Mater, 2016, Accepted.

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O03-ASC_477 SOLUTION PROCESSED 2D CRYSTALS FOR ENERGY AND (OPTO)ELECTRONIC APPLICATIONS

ACS Nano session Award F. Bonaccorso * Istituto Italiano di Tecnologia, Graphene Labs - Genova (Italy) New materials and processes1 are needed to improve the performance of existing devices or enable new ones,1-6 which are also environmentally benign. In this context, graphene and other 2d crystals, thanks to their excellent and complementary properties, are emerging as next-generation materials.1-6 In particular, the assembly of such 2d crystals in vertical heterostructures will provide a rich toolset for the creation of new, customised materials.1,2 However, a key requirement for applications such as flexible (opto)electronics and energy storage and conversion is the development of industrial-scale, reliable, inexpensive production processes,2 while providing a balance between ease of fabrication and final material quality with on-demand properties. Liquid-phase exfoliation2,4 is offering a simple and cost-effective pathway to fabricate various 2d crystal-based (opto)electronic and energy devices, presenting huge integration flexibility compared to conventional methods. Here, I will show our scaling up approach for the solution processing of 2d crystal based on the wet-jet milling of layered materials. Moreover, I will present an overview of 2d crystals for flexible and printed (opto)electronic and energy applications, from the fabrication of large area electrodes3 to devices integration.6-12 References 1. A. C. Ferrari, et al., Nanoscale 7, 4598 (2015). 2. F. Bonaccorso, et al., Mater. Today 15, 564 (2012). 3 .F. Bonaccorso, et. al., Nature Photon. 4, 611 (2010). 4. F. Bonaccorso, et. al., Adv. Mater. DOI:10.1002/adma.201506410 (2016). 5. G. Fiori, et al., Nature Nanotech. 9, 768 (2014). 6. F. Bonaccorso, et. al., Science 347, 1246501 (2015). 7. J. Hassoun, et al. Nano Lett. 14, 4901 (2014). 8. F. Bonaccorso, et al. Adv. Funct. Mater. 25, 3870 (2015). 9. A. Capasso, et al. Adv. Ener. Mater. DOI:10.1002/aenm.201600920 (2016). 10. S. Casaluci, et al. Nanoscale 8, 5368 (2016). 11. H. Sun, et al., J. Mater. Chem. A 4, 6886 (2016). 12. A. L. Palma, et al., Nano Energy 22, 349 (2016).

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O04-ASC_478 BUILDING ELECTRONIC AND OPTICAL DEVICES FROM COLLOIDAL NANOCRYSTALS

ACS Nano session Award C.R. Kagan * Department of Electrical and Systems Engineering, Department of Materials Science and Engineering, Department of Chemistry, University of Pennsylvania - Philadelphia (United States of America) Semiconductor and plasmonic nanocrystals are known for their size- and shape-dependent electronic and localized surface plasmon resonances respectively. In this talk, I will describe the use of semiconductor and plasmonic nanocrystals as building blocks of mesoscale materials for semiconductor electronics and optoelectronics and plasmonic optical metamaterials. Chemical exchange of the long ligands used in nanocrystal synthesis with more compact ligand chemistries brings neighboring nanocrystals into proximity and increases interparticle coupling. In semiconductor nanocrystal solids, we show strong electronic coupling in combination with doping allows us to control the carrier type and concentration and design high mobility n- and p-type materials. I will give examples where n- and p-type nanocrystal solids are used to construct field-effect transistors and integrated circuits and solar photovoltaics. In metal nanocrystals, ligand-controlled coupling allows us to tailor a dielectric-to-metal phase transition seen by a 1010 range in DC conductivity and a dielectric permittivity ranging from everywhere positive to everywhere negative across the whole range of optical frequencies. We realize a "diluted metal" with optical properties not found in the bulk metal analog, presenting a new axis in plasmonic materials design and the realization of optical properties akin to next-generation metamaterials. We harness the properties of metal NCs by using nanoimprint lithography to print large-area metamaterials on glass and plastics with widely tailorable optical properties that are used to realize near- infrared optical devices.

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O05-ASC_479 BUILDING WITH ARTIFICIAL ATOMS: THE DESIGN OF MULTIFUNCTIONAL NANOMATERIALS AND DEVICES THROUGH NANOCRYSTAL SELF-ASSEMBLY

ACS Nano session Award C. Murray * University of Pennsylvania, Departments of Chemistry and Materials Science and Engineering (United States of America) The synthesis of monodisperse colloidal nanocrystals (NCs) with controlled composition, size and shape and surface functionalization now yeld ideal building blocks for the assembly of new thin films and devices. Monodisperse colloidal NCs are in a sense "artificial atoms" with tunable electronic, optical, magnetic and catalytic properties, and they are allowing the development of a new periodic table with which we can design materials and devices at the Mesoscale. In this talk, I will briefly outline the current state of the art in synthesis, purification, and integration of size and shape controlled single phase NCs as well as core- shell and herterodimer particles (heterostructures). I will emphasize the role of chemical tailoring of NC shape and ligand structure in programming the assembly of NC thin films and 3D supercrystals. These NCs can be induced to assemble into single-component, binary, and even ternary NC superlattices providing a scalable route to the production of multi-functional thin films. The power of NC hetero-integration I will be illustrated by progress in the co-assembly of plasmonic resonators and nanoscale emitters to fabricate MetaMaterials with novel linear and non-linear optical properties. The modular assembly of these NCs allows the desirable features of their underlying quantum character to be retained, or even enhanced as the interactions between the NCs drive the emergence of new delocalized properties. Semiconductor NCs (Quantum Dots) solids that exhibit strong electronic, optical coupling will be emphasized. We are pushing to realize solution processable NC solids with a new 3D band structure and high carrier mobilities (>30 cm2V- 1S-1) and harness these in disctrete devices and complex circuits.

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O06-ASC_480 ADVANCES IN RAMAN SPECTROSCOPY OF GRAPHENE AND LAYERED MATERIALS

ACS Nano session Award A. Ferrari * Cambridge Graphene Centre, University of Cambridge (United Kingdom) Raman spectroscopy is an integral part of graphene research [1]. It is used to determine the number and orientation of layers, the quality and types of edges, and the effects of perturbations, such as electric and magnetic fields, strain, doping, disorder and functional groups[2,3]. I will review the state of the art, future directions and open questions in Raman spectroscopy of graphene and related materials, focussing on the effect of disorder[3,4], doping[5,6] and deep UV laser excitation[7]. I will then consider the shear [8] and layer breathing modes(LBMs)[9], due to relative motions of the planes, either perpendicular or parallel to their normal. These modes are present in all layered materials[10,11]. Their detection allows one to directly probe the interlayer interactions [10,11]. They can also be used to determine the elastic constants associated with these displacements: the shear and out-of-plane elastic moduli[12]. This paves the way to the use of Raman spectroscopy to uncover the interface coupling of two-dimensional hybrids and heterostructures[10-12]. References 1. A. C. Ferrari et al. Phys. Rev. Lett. 97, 187401 (2006) 2. A.C. Ferrari, D.M. Basko, Nature Nano. 8, 235 (2013) 3. A.C. Ferrari, J Robertson, Phys. Rev. B 61, 14095 (2000) 4. G. Cancado et al. Nano Lett. 11, 3190 (2011) 5. M. Bruna et al. ACS Nano 8, 7432 (2014) 6. A. Das et al. Nat. Nanotechnol. 3, 210 (2008) 7. A.C. Ferrari et al. (2016) 8. P. H. Tan et al. Nature Materials 11, 294 (2012) 9. X. Zhang et al. Phys. Rev. B 87, 115413 (2013) 10. J. B. Wu et al. Nature Comms 5, 5309 (2014) 11. J.B. Wu et al. ACS Nano 9, 7440 (2015) 12. S. Milana et al. submitted (2016)

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NANOCAR_472 THE NANOCAR RACE USING SINGLE MOLECULE-VEHICLES

NanoCar Race Project X. Bouju 1,*, C. Durand 2, D. Martrou 1, J.P. Launay 2, C. Joachim 1 1CEMES-CNRS, UPR 8011 - Toulouse (France), 2CEMES-CNRS, UPR 8011 & Université de Toulouse, UPS - Toulouse (France) The first international race of molecule–vehicles (nano-cars) will be held in Toulouse France in October 2016, as first announced at the beginning of 2013 [1]. This race at the nanoscale will bring together teams with different molecule-vehicles (equipped with or without wheels, or with wings or paddles) on a metallic surface. Contrary to most of molecular manipulations performed by using mechanical forces between the tip and the molecule [2,3], each moleculevehicle has to be driven by an inelastic electronic tunneling current phenomenon, using the tip of a scanning tunneling microscope (STM) at low temperature (LT) and in an ultrahigh vacuum environment (UHV) [4-6]. Four nano-cars will be driven in parallel and on the same surface, thanks to the newly installed LT-UHV 4-STM instrument in Toulouse, built by ScientaOmicron and having four STM heads able to operate independently on the same surface [7]. We will describe the rules of this nanocar race, the six teams already registered and what can be scientifically gained from such a nanoscale competition. References [1] C. Joachim and G. Rapenne. ACS Nano 7, 11 (2013). [2] D. M. Eigler and E. K. Schweizer, Nature 344, 524 (1990). [3] X. Bouju, C. Joachim, and C. Girard. Phys. Rev. B 59, R7845 (1999). [4] B. C. Stipe, M. A. Rezaei, and W. Ho. Science 279, 1907 (1998). [5] S. W. Hla, L. Bartels, G. Meyer, and K.-H. Rieder. Phys. Rev. Lett. 85, 2777 (2000). [6] J. Echevaria, S. Monturet, and C. Joachim. Nanoscale, 6, 2793 (2014). [7] J. Yang, D. Sordes, M. Kolmer, D. Martrou, and C. Joachim, Eur. Phys. J. Appl. Phys. 73, 10702 (2016).

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Authors index

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Antonov V...... O3-SMG_222 A Anzai M...... P1-NAM_53 Apolloner F...... O2-ADS_97 Abadia M...... O31-MOS_47 Apostol N...... I15_GRA_438 Abisset A...... O10-SST_364 Appelfeller S...... O6-ELPS_272 Abramiuc L...... O27-OXI_279 Arab M...... P5-SCR_304 Abufager P...... P18-MOS_298, Arabi N.H...... P19-OXI_407 ...... O10-SMG_247 Arabski J...... O9-SMG_89 Acres R.G...... P12-OXI_250 Arguelles E...... O3-ADS_231, Adam J.P...... O1-SMG_129 ...... P14-MOS_232 Adler H...... O33-MOS_237 Arie Z...... P11-OXI_177 Aeschlimann M...... PL02_427 Arista N...... P4-ELPS_209, Aghavnian T...... P3-SMG_416 ...... P5-GRA_210 Ahlskog M...... P1-GRA_58 Arman M.A...... O1-GRA_296, Ahumada Lazo R...... O7-M4E_292, ...... O11-GRA_391, ...... O1-OXI_256 ...... O6-OXI_387 Akimenko S...... P5-SAS_325 Arnau A...... O1-MOS_119, Albanese E...... O3-OXI_179 ...... P4-SAS_321 Albani M...... O13-RTP_78 Arnaud S...... O11-OXI_56 Aldahhak H...... O8-ADS_152 Arnoux Q...... P4-MOS_50, ...... O4-MOS_362 Alex C...... P5-NAM_395 Arous O...... P1-SMC_14 Alexandrowicz G...... O5-NAM_392 Arruda L.M...... O25-MOS_246 Ali H...... P7-ELC_403 Artaud A...... P14-GRA_286, Alison W...... P4-RTP_394 ...... O13-GRA_289 Alkoby Y...... O5-NAM_392 Assig M...... O7-ELPS_135 Allaberdiev K...... P16-OXI_377 Ast C...... O7-ELPS_135 Allegretti F...... P12-OXI_250, Atli A...... P5-POL_107 ...... O5-SST_249, ...... O9-SST_363 Atodiresei N...... O0-MOS_294 Allison W...... O18-MOS_108, Aubert N...... O8-OXI_131 ...... P26-MOS_458, Auburger P...... O10-OXI_223, ...... O11-RTP_125, ...... P4-SCR_299 ...... O1-TPI_121 Aulbach J...... O9-ELPS_306 Allongue P...... O8-ELC_128, Aulická M...... P4-OXI_54 ...... O1-SMG_129 Aureau D...... O6-ELC_309, Alouani M...... O9-SMG_89 ...... O6-M4E_26, Altass H...... O6-SCR_194 ...... O8-M4E_284 Alves S.A...... P10-OXI_151 Auroux A...... P1-CAT_6 Alyabyeva N...... O17-OXI_255, Avidor N...... O18-MOS_108, ...... O1-SCR_245 ...... P26-MOS_458, Amino S...... P14-MOS_232 ...... O11-RTP_125, ...... P4-RTP_394 Amrous A...... P5-RTP_285, ...... P3-SAS_293 Avvisati G...... O10-MOS_462 Anderson A...... P11-OXI_177 Aydogan P...... O5-LSI_83 Andreazza P...... P4-MAQ_423, Ayuela A...... O2-SMG_133 ...... I01_SCR_428 Azmi R...... P6-M4E_134 Andreazza-Vignolle C...... P4-MAQ_423, Azzolini M...... O10-NAM_35, ...... I01_SCR_428 ...... P7-NAM_422 Angot T...... O11-GRA_391 Antczak G...... P2-SST_146 B

476/499 ABSTRACT BOOK

Baba Y...... P7-OXI_115 Bauer U...... O13-SCR_239 Bababrik M.R...... O5-SST_249 Bauer G...... O2-TPI_471 Baby A...... O5-GRA_368 Baum S...... O2-RTP_203 Bachari K...... P3-CAT_65 Baumann A...... P6-SAS_344 Bachellier N...... P18-MOS_298, Baviloliaei M...... O7-SAS_398 ...... O6-SMG_241, Baynov V...... P1-LSI_94 ...... O10-SMG_247 Beaurepaire E...... O9-SMG_89 Bachmann P...... O13-SCR_239 Bech M...... O9-SST_363 Bachmann J...... O13-SCR_239 Bechgaard K...... P4-POL_59 Baddeley C.J...... O7-CAT_126, Becker C...... O34-MOS_104 ...... O29-MOS_33, ...... P2-MOS_37 Behm R.J...... O4-ADS_139 Badiane K...... O8-ELPS_42 Belete T...... P4-ADS_312 Badjeck V...... P3-SMG_416 Belhadi A...... P8-SMC_278 Bahoosh S...... O9-MOS_268 Belkhou R...... I20_M4E_446, ...... P3-SMG_416 Bahr S...... O8-NAM_8 Bellec A...... O12-GRA_316, Bailly A...... O11-OXI_56, ...... O12-MOS_334 ...... O7-OXI_153, ...... P18-OXI_400, Beloqui A...... P7-POL_168 ...... P3-SST_338, Beltram F...... O4-ELPS_91 ...... O10-SST_364 Benaada M...... P2-POL_16 Balasubramanian T...... O6-BSS_235 Benayad A...... O6-LSI_101, Bali F...... P5-ADS_399 ...... P4-M4E_73 Ballauff M...... P2-ELC_136, Benbalagh R...... O4-CAT_157 ...... O2-SMI_366 Benchettara A...... P6-ELC_376 Balle D...... O33-MOS_237 Bendiab N...... P7-SST_341 Balmes O...... O3-CAT_254 Bendjama Z...... P1-SMC_14 Balog R...... P9-GRA_349, Benedetti S...... O3-OXI_179 ...... O11-GRA_391 Bengone O...... O6-SMG_241 Bandarenka A...... I02_ELC_435 Benitez Lara A...... P6-OXI_80 Bannikov M...... P3-LSI_389 Benlekhal D...... P1-ADS_12, Banzai T...... O9-ELC_227 ...... P1-M4E_13, Barad H.N...... P11-OXI_177 ...... P1-MOS_11 Baraille I...... O2-M4E_36 Benrekia M...... P3-NAM_166 Barbier A...... I20_M4E_446, Bentin J...... P10-GRA_357, ...... P3-SMG_416 ...... P20-MOS_352 Bardeau J.F...... O36-MOS_218 Bergamaschini R...... O13-RTP_78, Barker R...... O6-SAS_397 ...... P7-SMC_160 Barner-Kowollik C...... P7-POL_168 Bergbreiter A...... O2-POL_41 Barret N...... P21-OXI_460 Berger J...... P7-MOS_159, ...... O7-MOS_184 Barreto L...... O8-BSS_360 Berger M.H...... P1-CAT_6 Barrett N...... O13-OXI_76 Berkó A...... P2-ADS_264, Barrow M...... P5-NAM_395 ...... O4-RTP_116 Barsuk D...... P8-M4E_409 Bernard R...... P2-RTP_243, Barth J.V...... P12-OXI_250, ...... O3-RTP_277, ...... O5-SST_249 ...... O4-SMG_143 Bass U...... P6-SAS_344, Bernard M...... O13-OXI_76 ...... P7-SAS_359 Bernardo Gavito R...... O10-ADS_417 Bassat J.M...... O1-M4E_354 Bernien M...... O25-MOS_246 Battiato M...... O4-BSS_144 477/499 ABSTRACT BOOK

Bernot K...... O19-MOS_290 Bouchet R...... O6-LSI_101, Berti G...... O3-BSS_217, ...... P4-M4E_73 ...... P11-SAS_2 Bouchiat V...... P7-SST_341 Bertran F...... O4-GRA_313 Boucly A...... O4-CAT_157, Betti M.G...... O10-MOS_462 ...... O7-LSI_156, ...... P4-MOS_50 Beutier G...... O1-MAQ_343, ...... O4-SST_390 Boudaa F...... O6-RTP_467 Biagioni P...... O10-LSI_3 Boudet N...... O11-OXI_56 Bihlmayer G...... O7-MAQ_405 Boudifa M...... P8-POL_188 Birkhölzer Y...... P5-CAT_142 Boudjemaa A...... P8-SMC_278 Bisson R...... O11-GRA_391 Bouizem Y...... P1-ADS_12, ...... P1-M4E_13, Blanc N...... O11-OXI_56, ...... P1-MOS_11 ...... O6-RTP_467 Bouju X...... NANOCAR_472 Blanchard N...... O9-ADS_358 Boukari S...... O9-SMG_89 Blanco-Rey M...... O2-SMG_133 Bouquey M...... P3-POL_40 Blanquet E...... O8-OXI_131 Bourbia A...... P6-SST_408 Blasco J...... P17-OXI_381 Bourgeois S...... O25-OXI_305, Bliem R...... O24-OXI_318 ...... P15-OXI_314 Blohm J...... P5-NAM_395 Bourgeois O...... P5-M4E_88 Blomberg S...... O3-CAT_254, Bourguignon B...... O1-SCR_245 ...... O23-OXI_114 Bournel F...... O4-CAT_157, Blowey P.J...... P8-SAS_371, ...... O7-LSI_156 ...... O5-SST_249 Bouttemy M...... P4-ELC_288, Blügel S...... O7-MAQ_405 ...... O6-M4E_26, Bluhm H...... O11-GRA_391 ...... O8-M4E_284, Boatner L.A...... P9-MOS_181 ...... O9-M4E_326 Bobrov K...... O2-SAS_320 Bovet N...... P3-ADS_291 Bockstedte M...... O10-OXI_223, Bowen M...... O9-SMG_89 ...... P4-SCR_299 Bozzo B...... P17-OXI_381 Bocquet M.L...... O10-SMG_247, Brahimi R...... P7-ELC_403 ...... O5-SST_249 Brahmi Y...... P1-ADS_12, Bocquet F...... P5-RTP_285, ...... P1-MOS_11 ...... P3-SAS_293 Brambilla L...... O10-LSI_3 Boeglin A...... O16-MOS_275 Bräse S...... P6-POL_113 Bøggild P...... P9-GRA_349 Braun J...... O2-BSS_68, Boichot R...... O8-OXI_131 ...... O6-BSS_235 Bole R...... P8-POL_188 Brimaud S...... O4-ADS_139 Bollmann T.R.J...... P3-RTP_351 Brivio G.P...... O5-GRA_368 Bombis C...... P1-SAS_258 Brongersma H...... O9-NAM_31 Bonaccorso F...... O03-ASC_477 Bronsch W...... O2-RTP_203 Bonn M...... I03_LSI_443 Bronze-Uhle E...... P5-OXI_62 Borca B...... O1-MOS_119 Brune H...... PL04_430 Borensztein Y...... P2-RTP_243, Brüner P...... O9-NAM_31 ...... O3-RTP_277, Bruno C...... P8-POL_188 ...... O4-SMG_143 Bruns M...... P6-M4E_134, Borghetti P...... O4-MAQ_100, ...... P6-POL_113, ...... P24-MOS_242, ...... P7-POL_168 ...... O11-SST_233 Buckley M...... P23-MOS_158, Bouazaoui M...... P19-OXI_407 ...... O11-NAM_167

478/499 ABSTRACT BOOK

Bucur C...... O27-OXI_279 Casarin M...... O31-MOS_47 Bugot C...... O9-M4E_326 Cassidy A...... O1-GRA_296, Bui P...... O16-SCR_150 ...... P9-GRA_349, ...... O11-GRA_391, Bulou H...... O6-MOS_55, ...... P13-GRA_425, ...... O16-MOS_275 ...... P28-MOS_310 Burrield M...... O1-M4E_354 Castiglioni C...... O10-LSI_3 Busayaporn W...... O9-SST_363 Castro Neto A.H...... I28_MOS_465 Bussetti G...... O3-BSS_217, Catena A...... P9-POL_283 ...... O10-LSI_3, ...... P11-SAS_2 Catlow R...... I04_OXI_447, ...... I04_OXI_447 Buttard D...... P5-M4E_88 Ceccato M...... P3-ADS_291, C ...... P4-POL_59 Celeri M...... P11-SAS_2 Cabailh G...... O4-MAQ_100, Celichowski G...... O2-LSI_240 ...... O11-SST_233 Celikbilek O...... O3-M4E_361 Cabo A.G...... O11-GRA_391 Celis J.P...... P10-OXI_151 Cacho C...... O4-BSS_144 Celis A...... O2-GRA_178 Cadete Santos Aires F.J...... P5-POL_107, Ceolin D...... P21-OXI_460 ...... O2-SCR_336 Cepek C...... P3-GRA_120 Caha O...... O2-TPI_471 Cezar J.C...... P18-OXI_400 Calliari L...... O10-NAM_35, Chacon C...... O12-GRA_316, ...... P7-NAM_422 ...... O2-MAQ_324, Calloni A...... O3-BSS_217, ...... O12-MOS_334 ...... P11-SAS_2 Chahed L...... P1-ADS_12, Calvo-Almazan I...... P26-MOS_458 ...... P1-M4E_13, Calzolari A...... P19-MOS_339 ...... P1-MOS_11 Camacho-López S...... P9-OXI_145 Chaker A...... O8-OXI_131 Camilli L...... P9-GRA_349 Champion Y...... P8-M4E_409 Campbell R...... O1-POL_378, Chandola S...... P6-SAS_344 ...... O3-SMI_236, Chang M...... P13-MOS_204 ...... O1-SMI_469, Chang Y.H...... P13-MOS_204 ...... P5-SST_379 Chang H...... P7-M4E_333 Campos-Terán J...... P5-SST_379 Chapelier C...... P4-GRA_199, Cantelli V...... O8-OXI_131, ...... O6-GRA_248, ...... O6-RTP_467 ...... P14-GRA_286, Capoen B...... P19-OXI_407 ...... O13-GRA_289 Caputo M...... I11_MOS_102 Chaplygin P...... P1-MAQ_85 Carapeto A.P...... O4-POL_369 Chaplygina A...... P1-MAQ_85 Cardenas L...... O4-GRA_313 Chapon P...... O6-M4E_26 Carlà F...... O5-ELC_202, Charitat T...... O5-SMI_461 ...... O4-ELC_315, Charra F...... O1-SCR_245 ...... P8-ELC_330, ...... O1-ELC_426, Chassagnon R...... P15-OXI_314 ...... P9-NAM_473, Chassé A...... O33-MOS_237 ...... P3-RTP_351, Chassé T...... O33-MOS_237 ...... O3-SST_77 Chatelier C...... O1-MAQ_343 Carlomagno I...... O3-SST_77 Chatenet M...... P8-M4E_409, Carro P...... O8-MOS_385 ...... P8-M4E_409 Cartas W.C...... O22-OXI_84 Chellal K...... P3-CAT_65 Casari C.S...... O10-LSI_3 Chen H.D...... P6-GRA_212

479/499 ABSTRACT BOOK

Chen M...... O20-MOS_189, Corva M...... P9-SAS_401 ...... O24-MOS_302 Cossaro A...... P4-MOS_50, Chen W.S...... P4-SMC_96 ...... P24-MOS_242 Cheng Y.T...... P4-SMC_96 Costantini G...... P8-SAS_371 Cheng C...... P4-SMC_96 Costas M...... P5-SST_379 Chérioux F...... O13-MOS_345, Cramer J...... P1-SAS_258 ...... P5-RTP_285, Creuze J...... I01_SCR_428 ...... P3-SAS_293 Crisci C...... O8-OXI_131 Cherkez V...... O2-ELPS_332 Croguennec L...... O2-M4E_36 Cheynis F...... O5-RTP_24, Cruguel H...... P2-RTP_243, ...... I16_SAS_454 ...... O3-RTP_277, Chi L...... O02-ASC_476 ...... O1-SAS_367 Chizhik A...... P1-SMG_45 Cubitt R...... P13-OXI_280 Cho Y...... O12-ELPS_111 Cui C...... O37-MOS_182 Choi J...... P7-M4E_333, Curcella A...... P2-RTP_243, ...... O23-OXI_114 ...... O3-RTP_277 Choi D.J...... O6-SMG_241 Curiotto S...... O5-RTP_24, Chong M...... O16-MOS_275 ...... I16_SAS_454 Chu M.H...... O8-OXI_131 Chulkov E...... O7-SMG_57 D Chumakov A...... O4-SAS_418 Da Costa V...... O9-SMG_89 Ciatto G...... O8-OXI_131 Daasbjerg K...... O1-GRA_296 Ciccacci F...... O3-BSS_217, Dahint R...... O2-SMI_366 ...... O10-LSI_3, ...... P11-SAS_2 Dahlem F...... P14-OXI_303 Cicia S...... O3-SST_77 Dähne M...... O6-ELPS_272 Cimatti I...... O19-MOS_290 Dai J.Y...... O24-MOS_302 Claessen R...... O9-ELPS_306 Dai Z...... O4-MAQ_100 Clark P.C.J...... O1-OXI_256 Daillant J...... O3-SAS_382, ...... O5-SMI_461 Clark P...... O7-M4E_292 Dalby K.N...... P3-ADS_291 Claudel A...... O8-OXI_131 D'anna V...... P7-CAT_262, Coati A...... O1-CAT_308, ...... O9-SCR_470 ...... O2-MAQ_324, ...... P4-MAQ_423, Dapor M...... O10-NAM_35, ...... I01_SCR_428, ...... P7-NAM_422 ...... O10-SST_364 Dappe Y...... O12-MOS_334 Coindeau S...... O8-OXI_131 Darlatt E...... P3-M4E_39 Colonna S...... I15_GRA_438 David P...... P14-GRA_286, Contini G...... O4-GRA_313, ...... O13-GRA_289 ...... O14-MOS_464 David C...... O8-ELPS_42 Coraux J...... P14-GRA_286, Davies P...... O6-SCR_194 ...... O13-GRA_289, De Boissieu M...... O1-MAQ_343 ...... I05_GRA_439, De Oteyza D.G...... P24-MOS_242 ...... P7-SST_341 De Santis M...... O3-ELC_365, Corem G...... O5-NAM_392 ...... O11-OXI_56, Correa J...... P9-ELPS_412 ...... O7-OXI_153, Correa-Puerta J...... P9-ELPS_412, ...... P18-OXI_400, ...... O2-MOS_415 ...... P3-SST_338, Corso M...... O8-BSS_360 ...... O10-SST_364 Cortés E...... O8-MOS_385 De Vos W...... O6-SAS_397

480/499 ABSTRACT BOOK

De Weerd M.C...... O1-MAQ_343 Dolle P...... O2-SCR_336 Deak L...... O21-OXI_183 Dölle C...... O4-SMI_234 Debili M...... P6-SST_408 Domenichini B...... O25-OXI_305, Defay E...... P21-OXI_460 ...... P15-OXI_314 Deimel P.S...... P12-OXI_250, Dominguez M...... O31-MOS_47 ...... O5-SST_249 Dominguez Jimenez M.A...... P6-OXI_80 Del Campo V...... P9-ELPS_412, Donsanti F...... O6-M4E_26, ...... O2-MOS_415 ...... O9-M4E_326 Delabrousse E...... P10-GRA_357 Döpper T...... O13-SCR_239 Delaittre G...... P7-POL_168 Döring S...... O7-MAQ_405 Delbos E...... P4-ELC_288, Dos Santos M.C...... O12-GRA_316 ...... O8-M4E_284 Doyle B...... O9-SST_363 Delhom R...... O6-SMI_383 Drera G...... P8-OXI_130 Delorme N...... O36-MOS_218 Dressner J...... O11-ELPS_138 Denecke R...... O4-SCR_348 Dri C...... P9-SAS_401 Denlinger J...... O6-BSS_235 Drnec J...... P5-CAT_142, De-Santis M...... O4-SST_390 ...... P8-ELC_330, Deschanvres J.L...... O8-OXI_131 ...... O1-MAQ_343, ...... O7-NAM_329, Dessemond L...... O1-M4E_354 ...... O3-SST_77 Di N...... O1-SMG_129 Du S...... I28_MOS_465 Di Giovannantonio M...... O4-GRA_313 Dubey S...... P7-SST_341 Di Santo G...... I11_MOS_102 Dubois E...... O7-LSI_156 Diat O...... O1-SMI_469 Duchon T...... P4-OXI_54 Díaz C...... O10-ADS_417 Dufrane T...... P9-NAM_473 Dideriksen K...... P3-ADS_291 Dufrêche J.F...... O1-SMI_469 Diebold U...... P9-MOS_181, Dufresne E...... I08_POL_452 ...... O19-OXI_118, ...... O20-OXI_124, Düll F...... O13-SCR_239 ...... O24-OXI_318 Duncan D.A...... P12-OXI_250, Diekhöner L...... O7-SAS_398 ...... P8-SAS_371, ...... O5-SST_249, Dienel T...... I06_ELPS_437 ...... O9-SST_363 Dil H...... O1-BSS_63, Duò L...... O3-BSS_217, ...... O2-BSS_68, ...... O10-LSI_3, ...... O5-BSS_140, ...... P11-SAS_2 ...... O18-OXI_200, ...... P2-TPI_244 Dupont C...... O25-OXI_305 Ding H...... O1-BSS_63 Dupraz M...... O4-SST_390 Dino W.A...... O3-ADS_231 Durand C...... NANOCAR_472 Diño W...... P14-MOS_232, Duverger E...... P10-GRA_357, ...... O3-SCR_238 ...... P20-MOS_352 Diouma Kobor D...... O26-OXI_60 E Dirany N...... P5-SCR_304 Djadoun A...... P1-CAT_6 Eberhardt W...... P3-M4E_39 Djamila H...... P5-ADS_399 Ebert H...... O2-BSS_68, Djukic U...... O6-BSS_235 ...... O4-BSS_144, Djurado E...... O1-M4E_354, ...... O6-BSS_235, ...... O3-M4E_361 ...... P4-NAM_251 Dmitrii F...... P. Edelmann K...... O9-MOS_268 ...... O4-GRA_313 Edler F...... O6-ELPS_272, Dollase P...... O1-ADS_52 ...... P6-ELPS_274 481/499 ABSTRACT BOOK

Ehrenberg H...... P6-M4E_134, Farkas A.P...... P2-ADS_264, ...... P6-POL_113 ...... O4-RTP_116 Ehret E...... P5-POL_107, Farronato M...... O32-MOS_192, ...... O2-SCR_336 ...... P11-MOS_195 Einstein T...... O7-RTP_388 Farzi G.A...... P1-ELC_127, Eisenhardt A...... O5-ADS_215 ...... P9-ELC_411, ...... P1-SMI_18 El Belghiti H...... P4-ELC_288, ...... O8-M4E_284 Fasolino A...... PL03_431 Ellis J...... P26-MOS_458, Fauser H...... O1-POL_378 ...... O11-RTP_125, Fausto S...... O7-M4E_292 ...... P4-RTP_394 Fauth K...... P7-SAS_359 Ellsworth A...... P3-ELC_205 Federici Canova F...... P5-RTP_285 Eltschka M...... O7-ELPS_135 Fefelov V.F...... P22-MOS_406 Emanuelsson C...... O27-MOS_161 Feiten F...... O6-SST_340 Endres F...... O15-SCR_99 Feldbauer G...... O6-ADS_263, Engelhardt A...... O8-ELC_128 ...... P17-MOS_281 Erdohelyi A...... O12-SST_38 Felici R...... P5-CAT_142, Eriksson S...... P8-NAM_424 ...... O5-ELC_202, ...... P8-ELC_330, Ernst W.E...... O1-TPI_121 ...... O1-ELC_426, Ernst A...... O3-SMG_222 ...... O1-MAQ_343, Erwin S.C...... O9-ELPS_306 ...... P19-MOS_339, Esaulov V...... O2-MOS_415 ...... P9-NAM_473, Eschbach M...... O7-MAQ_405 ...... O3-SST_77 Esparza-García A...... P9-OXI_145 Feng Z...... P9-SAS_401 Esqueda Barrón Y...... P9-OXI_145 Fernandez L...... O2-SMG_133 Esser N...... P6-SAS_344 Ferrari A...... O06-ASC_480 Etcheberry A...... P4-ELC_288, Ferraria A.M...... O4-POL_369 ...... O6-ELC_309, Ferreira De Morais R...... O3-MAQ_141 ...... O6-M4E_26, Ferru G...... O1-SMI_469 ...... O8-M4E_284, Ferstl P...... O6-OXI_387 ...... O9-M4E_326 Fester J...... O4-OXI_346 Etzkorn M...... O7-ELPS_135 Feulner P...... I15_GRA_438, Evertsson J...... O1-ELC_426 ...... P12-OXI_250 Eypert C...... O6-M4E_26, Feya O...... O20-OXI_124 ...... P1-OXI_1 Field D...... P28-MOS_310 Eyrilmez S.M...... P7-MOS_159 Filali L...... P1-ADS_12, ...... P1-MOS_11 F Finazzi M...... O3-BSS_217, ...... P11-SAS_2 Fabre H...... O36-MOS_218 Fischer C...... P9-POL_283 Fagiewicz R...... O4-CAT_157 Flahaut D...... O2-M4E_36 Fagot-Revurat Y...... O4-GRA_313, ...... O13-MOS_345 Flajsman L...... O5-SMG_176 Fairclough S...... O7-M4E_292 Flammini R...... I15_GRA_438 Fan Q.T...... O24-MOS_302 Flavell W.R...... O7-M4E_292, ...... O1-OXI_256 Fanciulli M...... O1-BSS_63, ...... O2-BSS_68, Fleischer K...... O2-SST_105 ...... O18-OXI_200 Floreano L...... O31-MOS_47, Faraggi M...... O10-SMG_247 ...... I11_MOS_102, ...... P24-MOS_242, ...... O25-OXI_305

482/499 ABSTRACT BOOK

Flores M...... O2-MOS_415 Gao D...... P5-RTP_285 Flores Gracia F.J...... P6-OXI_80 Garaudée S...... O11-OXI_56, Fobes D...... O19-OXI_118, ...... O2-SCR_336, ...... O20-OXI_124 ...... O10-SST_364 Fonda E...... I20_M4E_446 Garberoglio G...... O10-NAM_35, ...... P7-NAM_422 Fong D...... O8-OXI_131, ...... I09_RTP_453 Garcia J.L...... P17-OXI_381 Forrer D...... O31-MOS_47 Garcia Salgado G...... P6-OXI_80 Fouquat L...... P3-SCR_207 Gargiani P...... O10-MOS_462, ...... O2-SMG_133 Fournée V...... O1-MAQ_343, ...... O37-MOS_182 Garreau Y...... O1-CAT_308, ...... O2-MAQ_324, Fragneto G...... O3-SAS_382, ...... P4-MAQ_423, ...... O6-SMI_383, ...... I01_SCR_428, ...... O5-SMI_461, ...... I01_SCR_428, ...... O1-SMI_469 ...... O10-SST_364 Francesco D.B...... O4-ELC_315 Gassilloud R...... O13-OXI_76 Franchini C...... O9-OXI_79, Gastaldo M...... O7-SAS_398, ...... O24-OXI_318 ...... O2-SMG_133 Francoual S...... O7-SCR_466 Gaston J...... P1-OXI_1 Franke M...... O3-LSI_259, Gattinoni C...... O7-ELC_323 ...... O11-SCR_226 Gaudry E...... O1-MAQ_343, Franke K.J...... O23-MOS_75, ...... O37-MOS_182 ...... O8-SMG_201 Gavarri J.R...... P5-SCR_304 Franz D...... O7-SCR_466 Gazquez J...... P17-OXI_381 Fratesi G...... O5-GRA_368 Geaymond O...... O6-RTP_467 Frégnaux M...... O6-M4E_26 Gehlmann M...... O7-MAQ_405 Frenken J.W.M...... O2-CAT_311 Geibel C...... O7-SMG_57 Freund H.J...... O15-OXI_228, ...... O6-SST_340 Gellman A...... P6-ADS_372, ...... O8-MAQ_373 Fritton M...... P12-OXI_250 Generalov A...... O7-SMG_57 Fujii S...... P1-ELPS_51, ...... P16-MOS_261 Generosi J...... P3-ADS_291 Fukuda T...... P2-MAQ_273 Gentile P...... P5-M4E_88 Fukutani K...... P2-ELPS_92 Georgarakis K...... P8-M4E_409, ...... P8-M4E_409 Funakubo H...... O17-OXI_255 George A...... P5-OXI_62 G Gerhard L...... O9-MOS_268 Gerstmann U...... O8-ADS_152 Gaberle J...... O28-MOS_282, Gervasoni J...... P3-ELPS_185, ...... P5-RTP_285, ...... P4-ELPS_209, ...... P3-SAS_293 ...... P7-ELPS_297, Gahl C...... O2-RTP_203 ...... P5-GRA_210 Gaiaschi S...... O6-M4E_26 Geurts J...... P6-SAS_344, Galeotti G...... O4-GRA_313 ...... P7-SAS_359 Gallardo J...... P3-ELPS_185 Ghalgaoui A...... O9-LSI_137 Gallet J.J...... O4-CAT_157, Ghamari M...... P1-SMI_18 ...... O7-LSI_156 Gharbi T...... P20-MOS_352 Galtayries A...... O36-MOS_218 Gholhaki S...... P3-MAQ_420 Gao D.Z...... O28-MOS_282, Giaccherini A...... O4-ELC_315 ...... P3-SAS_293 Giampietri A...... P8-OXI_130 Gao H.J...... I28_MOS_465 483/499 ABSTRACT BOOK

Gibson J...... P2-LSI_164, Grenet G...... O12-NAM_342, ...... O11-NAM_167 ...... O4-NAM_474, Giessibl F...... I10_SST_456, ...... P3-SCR_207 ...... P2-TPI_244 Grenier S...... O11-OXI_56, Gilles B...... P14-GRA_286, ...... O7-OXI_153, ...... O4-SST_390 ...... P18-OXI_400 Ginsburg A...... P11-OXI_177 Grillo F...... O7-CAT_126 Giordano M...... O4-ELC_315 Grobelny J...... O2-LSI_240 Giorgi J.B...... O8-SCR_317 Grönbeck H...... O23-OXI_114 Giovanni C...... P5-NAM_395 Groot I.M.N...... O2-CAT_311 Girard J.C...... O8-ELPS_42 Grosso D...... O2-POL_41 Girard L...... O1-SMI_469 Groves M...... O11-GRA_391 Girard Y...... O12-GRA_316, Gruber S...... O5-OXI_30 ...... O2-MAQ_324, Gruber M...... O9-SMG_89 ...... O12-MOS_334 Grützmacher D...... O7-MAQ_405 Glaser M...... O33-MOS_237 Guan X...... P3-SCR_207 Glavic A...... P28-MOS_310 Guan S...... O6-SCR_194 Gleeson M...... P4-ADS_312 Gubó R...... P2-ADS_264, Gleichweit C...... O4-SCR_348 ...... O4-RTP_116 Gloss J...... O5-SMG_176 Gueye I...... P21-OXI_460 Godec M...... P7-ELPS_297 Guichet C...... O8-OXI_131 Godsi O...... O5-NAM_392 Guillemot L...... O2-SAS_320 Goiri E...... P24-MOS_242 Guissart S...... O6-SMG_241 Goldoni A...... P3-GRA_120, Guisset V...... P14-GRA_286, ...... I11_MOS_102 ...... O13-GRA_289 Golias E...... O2-TPI_471 Gulseren O...... P11-GRA_374 Gomez-Rodriguez J.M...... O8-GRA_355, Guo Q...... P10-SAS_413 ...... I12_GRA_441 Guo Y...... P8-M4E_409 Gonçalves A.M...... P4-ELC_288, Guo D...... O2-ELC_74 ...... O6-ELC_309 Guo L...... P10-SAS_413 Goniakowski J...... PL01_429 Gustafson J...... O3-CAT_254, Gonzalez J...... P1-SMG_45 ...... O23-OXI_114, González D.L...... O7-RTP_388 ...... O2-OXI_186, Goodman J.M...... P12-MOS_198 ...... O6-OXI_387 Gorbunov V...... P5-SAS_325 Gutfreund P...... P13-OXI_280 Görling A...... O13-SCR_239 Gutzler R...... O1-MOS_119 Gospodaric P...... O7-MAQ_405 H Gösweiner C...... O2-ADS_97 Gothelf K...... P2-SAS_270 Häberle P...... P9-ELPS_412, Gothelf K.V...... P1-SAS_258 ...... O2-MOS_415 Gotterbarm K...... O4-SCR_348 Hadjadj A...... P8-POL_188 Gottfried M...... O38-MOS_172, Hagman B...... O3-CAT_254 ...... O24-MOS_302 Hakkel O...... O6-CAT_90 Gottwald A...... P3-M4E_39 Halbig B...... P6-SAS_344, Grånäs E...... O2-OXI_186 ...... P7-SAS_359 Granet J...... O13-MOS_345 Halbwax M...... P19-OXI_407 Grehl T...... O9-NAM_31 Halkjær S...... O11-GRA_391, ...... P13-GRA_425 Halperin A...... O3-SAS_382

484/499 ABSTRACT BOOK

Halwidl D...... O19-OXI_118, Hilt G...... O24-MOS_302 ...... O20-OXI_124 Himmerlich M...... O5-ADS_215 Hamada I...... O15-MOS_224 Hinch B.J...... P26-MOS_458 Hamamatsu H...... P1-POL_15 Hingerl K...... O17-MOS_5 Hamamoto Y...... O7-GRA_117, Hirao N...... P7-OXI_115 ...... O15-MOS_224, Hirayama T...... P1-NAM_53 ...... O3-MOS_225 Hirsch A...... O13-SCR_239 Hamane D...... P1-SMC_14 Ho M.Y...... P12-MOS_198 Hammer B...... O11-GRA_391, ...... P1-SAS_258 Hobza P...... P7-MOS_159 Hammer L...... O6-OXI_387 Hofer W.A...... I28_MOS_465 Hammiche-Bellal Y...... P1-CAT_6 Höfft O...... O39-MOS_155, ...... O15-SCR_99 Hamoudi H...... O2-MOS_415 Hofhuis K...... P5-CAT_142 Hao X...... O9-OXI_79 Hofmann P...... O8-BSS_360, Hapala P...... P5-ELPS_257 ...... O11-GRA_391 Harrington D.A...... P8-ELC_330 Hokkanen M...... P1-GRA_58 Harrison N...... O9-SST_363 Holländer B...... O7-MAQ_405 Hasegawa Y...... P21-MOS_393 Hollerer M...... O12-OXI_187 Hassan N...... P5-SST_379 Holtgreve K...... O6-ELPS_272 Hassanine A...... P1-CAT_6 Homberg J...... O9-MOS_268 Hassenkam T...... P3-ADS_291 Hong M...... P4-SMC_96 Hasumi M...... O4-M4E_28, Honkimäki V...... O7-NAM_329 ...... P2-OXI_17 Hoppe H...... P3-M4E_39 Hatter N...... O8-SMG_201 Horky M...... O5-SMG_176 Heard C...... O23-OXI_114 Hornekær L...... O1-GRA_296, Heckel W...... P17-MOS_281 ...... P9-GRA_349, Heckmann O...... O4-BSS_144, ...... O11-GRA_391, ...... O6-BSS_235 ...... P13-GRA_425 Hegemann D...... O9-ADS_358 Hoshi N...... O9-ELC_227 Heinrich B...... O8-SMG_201 Hosokai T...... P21-MOS_393 Heinzmann U...... O2-BSS_68 Hricovini K...... O4-BSS_144, Hejral U...... O7-SCR_466 ...... O6-BSS_235 Hemmerle A...... O5-SMI_461 Hsia Y.Y...... P6-CAT_169 Henda N...... P1-CAT_6 Hsu P.W...... O5-CAT_165 Henríquez R...... O2-MOS_415 Huder L...... P4-GRA_199 Henry C.R...... P3-SST_338 Hüger E...... P2-ELC_136 Hensley A.J.R...... O4-SCR_348 Hughes T...... P12-MOS_198 Hernández C...... O8-MOS_385 Huhn T...... O23-MOS_75 Hernandez De La Luz A.D...... P6-OXI_80 Hulva J...... O24-OXI_318 Hernandez-Pascacio J...... P5-SST_379 Humblot V...... O1-SAS_367 Herper H...... P4-NAM_251 Hung T.C...... O5-CAT_165 Herrera L...... O1-SMG_129 Hurdax P...... O12-OXI_187 Herrera Zaldivar M...... P9-OXI_145 Hurtado Salinas D...... P4-SAS_321 Herrero J...... P17-OXI_381 Hutter H...... O5-OXI_30 Herritsch J...... O20-MOS_189 Heuberger M...... O9-ADS_358 I Heun S...... O4-ELPS_91 Iachella M...... O3-MAQ_141 Hibino H...... O4-ELPS_91 Ibrahim F...... O9-SMG_89

485/499 ABSTRACT BOOK

Ikeuchi J...... P1-POL_15 Jethwa S...... P1-SAS_258, Ilin M...... O2-SMG_133 ...... P2-SAS_270 Imbert G...... P13-OXI_280 Ji G.W...... O30-MOS_21 Imhoff L...... P15-OXI_314 Jiamei Q...... O5-SCR_149 Inagaki K...... O7-GRA_117, Jiang T...... P10-MOS_190 ...... O15-MOS_224, Jiang Y.H...... I28_MOS_465 ...... O3-MOS_225, Joachim C...... NANOCAR_472 ...... O16-SCR_150 Johansson L.S.O...... O7-BSS_175, Inoue K...... P8-ELPS_331 ...... O27-MOS_161 Iratni A...... P19-OXI_407 Johansson D.B...... P4-POL_59 Irkha V...... O5-ADS_215 Joly L...... O9-SMG_89, Isern H...... P5-CAT_142, ...... O10-SMG_247 ...... P9-NAM_473 Joly Y...... O11-OXI_56 Isohashi A...... O16-SCR_150 Jones R...... P2-LSI_164, Ito T...... P8-ELPS_331 ...... P23-MOS_158, Ito M...... P8-ELPS_331 ...... O11-NAM_167 Ivanov S...... P1-LSI_94 Jorge Jr. A.M...... P8-M4E_409, ...... P8-M4E_409, Iversen B...... P28-MOS_310 ...... P8-M4E_409 Iversen J...... P13-GRA_425 Jørgensen M...... P28-MOS_310 Iwane M...... P1-ELPS_51 Jørgensen J...... O1-GRA_296, ...... P9-GRA_349, J ...... O11-GRA_391, ...... P28-MOS_310 Jabeen N...... P7-GRA_230 Joucken F...... O12-GRA_316 Jaeck B...... O7-ELPS_135 Juan A...... P7-ELPS_297 Jaloustre L...... P14-OXI_303 Jubault M...... O6-M4E_26 Jamet M...... P18-OXI_400 Jungsuttiwong S...... P9-M4E_219 Jancarík A...... O10-SCR_173 Jupille J...... O4-MAQ_100, Jandke J...... O11-ELPS_138 ...... O25-OXI_305, Jang H...... P7-M4E_333 ...... O11-SST_233 Jankowski M...... P5-CAT_142, Jurczyszyn L...... O5-SAS_46, ...... O3-CAT_254, ...... P2-SST_146 ...... P9-NAM_473, Jurdi D...... P2-ADS_264 ...... P3-RTP_351 Jux N...... O3-LSI_259 Jansen L...... P4-GRA_199 Jany B.R...... O16-OXI_300 K Jaouen N...... P18-OXI_400 Jauffres D...... O3-M4E_361 Kabanov N.S...... O1-SST_82 Jedrecy N...... P3-SMG_416 Kaden W.E...... O15-OXI_228 Jelinek P...... O13-ELPS_193, Kagan C.R...... O04-ASC_478 ...... P5-ELPS_257 Kahng S.J...... P13-MOS_204 Jelínek P...... P7-MOS_159, Kalashnyk N...... O37-MOS_182, ...... O7-MOS_184, ...... O2-SAS_320 ...... O10-SCR_173 Kalita G...... O9-GRA_208 Jenkins S.J...... O10-ELPS_196, Kaminski D...... P3-RTP_351 ...... P12-MOS_198 Kampen T...... O8-NAM_8 Jenko M...... P7-ELPS_297 Kaneko S...... P15-MOS_253, Jensen V.F...... P1-SAS_258 ...... O26-MOS_353 Jerliu B...... P2-ELC_136 Kaouah F...... P1-SMC_14 Karayel A...... P11-GRA_374 486/499 ABSTRACT BOOK

Karthäuser S...... O0-MOS_294 Knudsen J...... O1-GRA_296, Kasai H...... P14-MOS_232, ...... O11-GRA_391, ...... O3-SCR_238 ...... O6-OXI_387 Kaufmann B...... O34-MOS_104 Kobayashi K...... O4-TPI_213 Kawaguchi N...... O15-MOS_224 Kocabas C...... O5-LSI_83 Kawai M...... PL05_432, Kocán P...... P3-MOS_43, ...... PL05_432 ...... O8-RTP_122, ...... O5-SAS_46 Kawamura T...... O13-NAM_64 Koishi A...... O7-LSI_156 Kaya D...... P10-SAS_413 Kojima K...... O3-SCR_238 Kazar Mendes M...... O13-OXI_76 Kolbe M...... P3-M4E_39 Kebab A...... P1-M4E_13 Kolesnikov S...... O10-GRA_180 Keller D...... P11-OXI_177 Komori F...... O3-SMG_222 Kellner J...... O7-MAQ_405 Komoto Y...... P16-MOS_261 Kerdja Y...... O6-LSI_101 Kondo T...... O2-ELC_74, Kerdjoudj H...... P1-SMC_14 ...... O5-SCR_149 Kern K...... O7-ELPS_135, Kongsfelt M...... O1-GRA_296 ...... O1-MOS_119, ...... P4-SAS_321 Konishi T...... P1-NAM_53 Kettner M...... P4-CAT_81 Konovalov O...... O4-SAS_418, ...... O1-SMI_469 Khalal-Kouache K...... P3-NAM_166 Kónya Z...... P2-ADS_264, Kiel S...... O7-SAS_398 ...... O21-OXI_183, Kierren B...... O4-GRA_313, ...... O4-RTP_116 ...... O13-MOS_345 Koopmans B...... O3-NAM_191 Kiguchi M...... P1-ELPS_51, Köppen M...... O1-ADS_52 ...... P15-MOS_253, ...... P16-MOS_261, Kosmider K...... O7-MOS_184 ...... O26-MOS_353 Kover L...... P3-ELPS_185 Kil D...... P7-M4E_333 Kozarashi T...... O5-SCR_149 Kim Y.H...... P13-MOS_204 Kraffert K...... O25-MOS_246 Kim Y...... PL05_432 Kraft U...... O1-MOS_119 Kim H...... P7-M4E_333, Krasteva A...... O9-RTP_265 ...... P13-MOS_204 Kratzer M...... O34-MOS_104 Kimura S...... O4-M4E_28 Kraus P...... O2-ADS_97, Kipgen L...... O25-MOS_246 ...... O1-TPI_121 Kirschfeld C...... O8-SST_72 Krellner C...... O7-SMG_57 Kishida I...... P2-MAQ_273 Krempasky J...... O5-BSS_140 Kiss J...... P2-ADS_264, Krischok S...... O5-ADS_215 ...... O4-RTP_116, Krivec S...... O5-OXI_30 ...... O12-SST_38 Krizakova V...... O5-SMG_176 Kivala M...... O35-MOS_67 Kroeger D...... P9-ELPS_412 Kizaki H...... P6-MOS_110, Krok F...... O16-OXI_300 ...... O3-MOS_225, ...... O16-SCR_150 Kronlund D...... O2-POL_41 Kjeldsen N.D...... P1-SAS_258 Kropman D...... P3-SMC_69, ...... P5-SMC_70, Klappenberger F...... O8-ADS_152 ...... P6-SMC_71 Klauk H...... O1-MOS_119 Krüger D...... O25-MOS_246 Klavsyuk A...... O1-SST_82 Krüger P...... O38-MOS_172 Klein B.P...... O38-MOS_172, Krzyzewski F...... P6-RTP_252, ...... O24-MOS_302 ...... O9-RTP_265 Kliemt K...... O7-SMG_57

487/499 ABSTRACT BOOK

Kucera M...... O8-RTP_122 Lazzeri M...... P2-RTP_243, Kuch W...... O25-MOS_246 ...... O3-RTP_277 Kucharczyk R...... O6-MAQ_260, Le Bahers T...... O10-SMG_247 ...... P1-RTP_171 Le Denmat S...... P14-OXI_303 Kuehn T...... O6-NAM_269 Le Fevre P...... O4-GRA_313, Kuhl T...... I13_SMI_434 ...... O25-OXI_305 Kuhlenbeck H...... O6-SST_340 Le Moal S...... P3-SST_338 Kumar A...... P3-GRA_120 Le Quang T...... O6-GRA_248, ...... O13-GRA_289 Kummer K...... O7-SMG_57 Le Rhun G...... P21-OXI_460 Kungwan N...... O12-SCR_221 Le Van-Jodin L...... P4-M4E_73 Kurnosikov O...... O3-NAM_191 Leandersson M...... O6-BSS_235 Kutanov V.M...... P22-MOS_406 Lebedev M...... P1-LSI_94 Kuttner J...... O24-MOS_302 Ledieu J...... O1-MAQ_343, Kwo J...... P4-SMC_96 ...... O37-MOS_182 Kyhl L...... O11-GRA_391, Lee H...... P2-CAT_9, ...... P13-GRA_425 ...... O5-CAT_165 L Lee S.H...... P13-MOS_204 Lee T.L...... P23-MOS_158, Laas T...... P5-SMC_70, ...... O11-NAM_167, ...... P6-SMC_71 ...... P8-SAS_371, ...... O5-SST_249 Laas D...... P3-SMC_69 Lemoine A...... P4-MAQ_423, Lacovig P...... I15_GRA_438 ...... I01_SCR_428, Lagoute J...... O2-MAQ_324, ...... I01_SCR_428 ...... O12-MOS_334 Leone A...... P5-CAT_142 Lamare S...... O13-MOS_345, Léoni T...... O34-MOS_104, ...... P5-RTP_285, ...... O4-SMG_143 ...... P3-SAS_293 Leontiadou M.A...... O1-OXI_256 Lamirand A.D...... O7-OXI_153 Leroy F...... O5-RTP_24, Lamirand A...... O11-OXI_56, ...... I16_SAS_454, ...... P18-OXI_400, ...... P3-SST_338 ...... O1-SMG_129 Li X...... P1-SST_20 Lammich L...... P2-SAS_270 Li Y...... P15-MOS_253 Landolt G...... O18-OXI_200, ...... P2-TPI_244 Li H.Y...... O30-MOS_21 Langlais V...... O7-OXI_153 Li J...... O3-ELPS_61 Languille M.A...... O2-SCR_336 Li Bassi A...... O10-LSI_3 Lanius M...... O7-MAQ_405 Liang L...... O4-GRA_313 Larciprete R...... I15_GRA_438 Liao Z.H...... O5-CAT_165 Larrea C...... O29-MOS_33, Libuda J...... I17_M4E_445, ...... P2-MOS_37 ...... O13-SCR_239 Lasne J...... P28-MOS_310 Liebhaber M...... P6-SAS_344 Lau J.A...... P26-MOS_458 Liljeroth P...... I18_GRA_442 Launay J.P...... NANOCAR_472 Limelette P...... O17-OXI_255 Lauritsen J.V...... O4-OXI_346 Limot L...... P18-MOS_298, ...... O6-SMG_241, Lauter V...... P28-MOS_310 ...... O10-SMG_247 Lay S...... O8-OXI_131 Lin Y.H...... P4-SMC_96 Lazzari R...... O4-MAQ_100, Lin K.Y...... P4-SMC_96 ...... O11-SST_233 Lin C.Y...... P6-GRA_212

488/499 ABSTRACT BOOK

Lin H...... O5-GRA_368 Lybye D...... P4-POL_59 Lin J...... P2-SCR_112 Lytken O...... O3-LSI_259, Lin D...... P6-GRA_212 ...... O11-SCR_226 Lincot D...... O6-M4E_26, ...... O9-M4E_326 M Lindén M...... O2-POL_41 Maaß S...... O24-OXI_318 Linderoth T.R...... P1-SAS_258, Maccherozzi F...... I20_M4E_446 ...... P2-SAS_270 Macis S...... O3-SST_77 Lindsay R...... O9-SST_363 Madsen M...... P2-SAS_270 Lingenfelder M...... P4-SAS_321 Maehata Y...... O9-ELC_227 Linsmeier C...... O1-ADS_52 Magana A...... O2-SMG_133 Lipton-Duffin J...... O4-GRA_313 Magaud L...... O6-GRA_248, Lisboa-Filho P...... P5-OXI_62, ...... P14-GRA_286, ...... P10-OXI_151 ...... O13-GRA_289 Lisi S...... O10-MOS_462, Magnan H...... I20_M4E_446, ...... P7-SST_341 ...... P3-SMG_416 Liu L.W...... I28_MOS_465 Magnussen O.M...... P8-ELC_330, Lizzit S...... I15_GRA_438 ...... O7-NAM_329 Llevot A...... P6-POL_113 Magrez A...... O1-BSS_63 Lo R...... P7-MOS_159 Magrini A...... O5-ELC_202 Lobo-Checa J...... O8-BSS_360 Majer K...... P8-MOS_170 Loffreda D...... O3-MAQ_141 Majhi K...... P11-OXI_177 Longo D...... O32-MOS_192, Majidi F.Z...... P27-MOS_459 ...... P11-MOS_195 Malcioglu O...... O10-OXI_223 Loppacher C...... P5-RTP_285, Mallet P...... O2-ELPS_332 ...... P3-SAS_293 Malterre D...... O4-GRA_313, Lorente N...... P18-MOS_298, ...... O13-MOS_345 ...... O10-SMG_247 Manchon G...... P14-OXI_303 Lorenzo E...... O11-OXI_56 Mandal P.S...... O2-TPI_471 Loubat A...... O6-M4E_26 Mannini M...... O19-MOS_290 Lourdin P...... P5-POL_107 Mansour A...... P3-NAM_166 Lovat G...... O31-MOS_47 Mao Z...... O19-OXI_118, Lübben O...... O2-SST_105 ...... O20-OXI_124 Luca F...... P4-MOS_50 Marchini F...... O3-LSI_259 Lucarini I...... O3-SST_77 Marconot O...... P5-M4E_88 Luches P...... I19_OXI_450 Marie J.B...... O2-MAQ_324 Lüftner D...... O12-OXI_187 Mariot J.M...... O4-BSS_144, Lukas M...... O9-MOS_268 ...... O6-BSS_235 Luna Lopez J...... P6-OXI_80 Maroun F...... O8-ELC_128, Lundgren E...... O3-CAT_254, ...... O7-NAM_329, ...... O1-ELC_426, ...... O1-SMG_129 ...... O22-OXI_84, Marry V...... O7-LSI_156 ...... O23-OXI_114, Marschewski M...... O39-MOS_155 ...... O6-OXI_387 Martel R...... I21_SCR_455 Lungu A...... O27-OXI_279 Marthe J...... P8-POL_188 Luo M...... O5-CAT_165, ...... P6-CAT_169 Martin C.L...... O3-M4E_361 Luysberg M...... O7-MAQ_405 Martín F...... O10-ADS_417 Lvova T...... P1-LSI_94 Martinez E...... O12-NAM_342, ...... O13-OXI_76

489/499 ABSTRACT BOOK

Martin-Recio A...... O8-GRA_355 Michel C...... P7-CAT_262, Martrou D...... NANOCAR_472 ...... O8-SCR_317 Marty A...... O13-OXI_76 Michez L...... O4-SMG_143 Mashanov V...... P2-SMC_29 Michl A...... O6-ADS_263 Mashoff T...... O4-ELPS_91 Michnowicz T...... O1-MOS_119 Massimo I...... O4-ELC_315 Michot L...... O7-LSI_156 Masson L...... O34-MOS_104, Miller J...... O8-MAQ_373 ...... O4-SMG_143 Miller A...... O10-ELPS_196 Mathevet F...... O16-MOS_275 Minár J...... O2-BSS_68, Mathew M...... P5-OXI_62, ...... O5-BSS_140, ...... P10-OXI_151 ...... O4-BSS_144, ...... O6-BSS_235 Matkovic A...... O34-MOS_104 Minkowski M...... O12-RTP_98 Matvija P...... P3-MOS_43, ...... O5-SAS_46 Mirolo M...... P5-CAT_142, ...... P3-RTP_351 Maus-Friedrichs W...... O39-MOS_155 Miskovic Z...... P5-GRA_210 Mayor M...... O9-MOS_268 Mittendorfer F...... O19-OXI_118, Mayou D...... O6-GRA_248 ...... O20-OXI_124 Mayr-Schmölzer W...... O19-OXI_118, Miwa J...... O11-GRA_391 ...... O20-OXI_124 Miyamachi T...... O3-SMG_222 Mazzola F...... O8-BSS_360 Miyamoto T...... P1-POL_15 Mc Ewen J.S...... O4-SCR_348 Mlynczak E...... O7-MAQ_405, Mccoustra M...... P28-MOS_310 ...... O7-MAQ_405 Mcguirk G...... O1-MAQ_343 Mocuta C...... P3-SMG_416 Mears L...... O6-SAS_397 Mohamadpour Nazarabady M...... Meddour A...... P1-CAT_6 ...... P1-ELC_127, Meddour-Boukhobza L...... P1-CAT_6 ...... P9-ELC_411 Meeprasert J...... O12-SCR_221 Mohamed F...... P9-SAS_401 Megginson R...... O7-CAT_126 Mohr S...... O13-SCR_239 Meier M...... O24-OXI_318 Molitor S...... O6-NAM_269 Meier M.A.R...... P6-POL_113 Møller P...... O9-SST_363 Mekhtiche A...... P3-NAM_166 Mollica F...... O6-M4E_26 Meneghini C...... O3-SST_77 Mom R...... O2-CAT_311 Ménétrier M...... O2-M4E_36 Mondelli P...... O10-MOS_462 Menzel D...... I15_GRA_438, Monshi A...... O5-MAQ_86 ...... I15_GRA_438 Montalenti F...... O13-RTP_78, Mercier D...... O36-MOS_218 ...... P7-SMC_160 Meriggio E...... O11-SST_233 Montanari G...... I11_MOS_102 Merneche F...... P1-CAT_6 Moock D...... P6-POL_113 Merte L...... O23-OXI_114 Morales J...... O6-LSI_101 Merte L.R...... O3-CAT_254, Morales-Cifuentes J...... O7-RTP_388 ...... O22-OXI_84, Moreau L...... O4-GRA_313 ...... O6-OXI_387 Moreno-Lopez J.C...... O3-ELPS_61 Mesot J...... O1-BSS_63 Morgenstern M...... O7-MAQ_405 Méthivier C...... O1-SAS_367 Morikawa Y...... O7-GRA_117, Meunier V...... O4-GRA_313 ...... P6-MOS_110, Meyer G...... O4-ELPS_91 ...... O15-MOS_224, Miccio L.A...... O8-BSS_360 ...... O3-MOS_225, Miccoli I...... O6-ELPS_272, ...... O16-SCR_150 ...... P6-ELPS_274 Morin P...... P4-M4E_73 490/499 ABSTRACT BOOK

Morresi T...... O10-NAM_35, Ndioukane R...... O26-OXI_60 ...... P7-NAM_422 Nefedov A...... P3-GRA_120 Mossang E...... P18-OXI_400 Nehasil V...... P4-CAT_81 Motobayashi K...... PL05_432 Neo D...... O7-M4E_292 Motoki T...... P2-OXI_17 Neufeld S...... P6-SAS_344 Motte L...... O26-OXI_60 Neumann E...... O7-MAQ_405 Mottet C...... P4-MAQ_423 Ngandjong C...... I01_SCR_428 Moumen S...... O3-POL_154, Nguyen M.T...... O35-MOS_67 ...... O3-POL_154 Nickel F...... O25-MOS_246 Moussaoui S...... P6-ELC_376 Nicolaï L...... O6-BSS_235, Mrah L...... P2-POL_16 ...... P4-NAM_251 Muenzing B...... O8-NAM_8 Niefind F...... O20-MOS_189 Muff S...... O1-BSS_63, Nikiforov A...... P2-SMC_29 ...... O2-BSS_68, Nilius N...... O3-OXI_179 ...... O18-OXI_200, ...... P2-TPI_244 Ning Y...... P1-SAS_258 Mugnaini V...... O8-LSI_174 Niu C...... O7-MAQ_405 Muhsin B...... P3-M4E_39 Noei H...... O2-OXI_186 Müllegger S...... O8-ADS_152 Nogajewski K...... O2-ELPS_332 Müller P...... O38-MOS_172, Noguera C...... PL01_429 ...... O5-RTP_24, Noirez L...... O4-LSI_19 ...... O6-RTP_467, Nony L...... P5-RTP_285, ...... I16_SAS_454 ...... P3-SAS_293 Müller S...... O6-ADS_263, Noskov B.A...... O3-SMI_236 ...... P17-MOS_281 Novak R...... O1-SMG_129 Murata Y...... O4-ELPS_91 Nuermaimaiti A...... P1-SAS_258 Murray C...... O05-ASC_479 Muryn C.A...... O1-OXI_256 O Mussler G...... O7-MAQ_405 Muttaqien F...... O15-MOS_224, Ogawa S...... P2-ELPS_92 ...... O3-MOS_225 Ogawa T...... O5-SCR_149 Myshlyavtsev A.V...... P22-MOS_406, Ogura S...... P2-ELPS_92 ...... P5-SAS_325 Ohresser P...... O9-SMG_89, ...... O10-SMG_247, N ...... P3-SMG_416 Oka K...... O3-SCR_238 Nagatsuka N...... P2-ELPS_92 Okada M...... P14-MOS_232, Naghavi N...... O6-M4E_26 ...... O3-SCR_238 Naimark O...... P3-LSI_389 Okada K...... P8-ELPS_331 Naitabdi A...... O4-CAT_157 Okhrimenko D...... P4-POL_59 Nakamura M...... O9-ELC_227 Olivieri G...... O4-CAT_157 Nakamura T...... P2-OXI_17 Olschewski M...... O15-SCR_99 Nakamura J...... O2-ELC_74, Ondrácek M...... O13-ELPS_193, ...... O5-SCR_149 ...... P5-ELPS_257, Namuangruk S...... P6-NAM_220, ...... P7-MOS_159 ...... O12-SCR_221 Onoda J...... O13-ELPS_193 Narayanan M...... O2-GRA_178 Orbeck J...... O14-SCR_206 Nardin M...... P3-POL_40 Ormaza M...... P18-MOS_298, Navarrete F...... P4-ELPS_209 ...... O2-SMG_133, Nayak G...... P7-SST_341 ...... O6-SMG_241, ...... O10-SMG_247 491/499 ABSTRACT BOOK

Ortega J.E...... O8-BSS_360, Pavelec J...... O24-OXI_318 ...... P24-MOS_242, Pavlicek N...... O4-ELPS_91 ...... O2-SMG_133 Pawlak D...... O2-LSI_240 Oštádal I...... P3-MOS_43, Payne M...... O8-MAQ_373 ...... P8-MOS_170, ...... O8-RTP_122, Pedersen S...... O1-GRA_296 ...... O5-SAS_46 Pedio M...... P3-GRA_120, Osterwalder J...... P2-TPI_244 ...... P19-MOS_339 Oszkó A...... O12-SST_38 Peisert H...... O33-MOS_237 Otero E...... O19-MOS_290 Peng J...... O19-OXI_118, ...... O20-OXI_124 Otrokov M...... O7-SMG_57 Pensa E...... O8-MOS_385 Otto C...... O39-MOS_155 Pentegov I...... O1-MOS_119 Ouldhamou C...... O8-SCR_317 Penuelas J...... P3-SCR_207 Ouled T...... O8-OXI_131 Perdigao L...... P5-NAM_395 Outemzabet R...... P7-ELC_403 Peressi M...... P9-SAS_401 Ouvrard A...... O1-SCR_245 Perez R...... O8-GRA_355 Ouyang M...... I28_MOS_465 Peter M...... O9-SMG_89 Óvári L...... P2-ADS_264, ...... O4-RTP_116 Petrovykh D...... O8-LSI_174 Pétuya R...... O1-MOS_119 P Pfisterer J...... P12-OXI_250 Pfnür H...... O6-ELPS_272, P. Andersson M...... P3-ADS_291 ...... P6-ELPS_274 Pacchioni G...... O3-OXI_179 Pham V.D...... O12-MOS_334 Pacilè D...... O10-MOS_462 Pham V...... O12-GRA_316 Padilla J...... P17-OXI_381 Pham T.A...... O35-MOS_67 Paier J...... O6-SST_340 Philippe S...... P7-CAT_262 Palmer R.E...... P10-SAS_413 Pi T.W...... P4-SMC_96 Palmino F...... P5-RTP_285, Picaud F...... P10-GRA_357, ...... P3-SAS_293 ...... P20-MOS_352 Palotás K...... O2-SST_105 Pieczyrak B...... O5-SAS_46, Panagiotopoulos N.T...... P8-M4E_409 ...... P2-SST_146 Panighel M...... P3-GRA_120, Pielmeier F...... P2-TPI_244 ...... I11_MOS_102 Pignedoli C.A...... I11_MOS_102 Papp C...... O13-SCR_239, Pilet N...... O18-OXI_200 ...... O4-SCR_348 Pimpinelli A...... O7-RTP_388 Para F...... P5-RTP_285, Piñeiro Á...... P5-SST_379 ...... P3-SAS_293 Pinfold H...... P5-NAM_395 Parkinson G...... I22_CAT_433 Piquero-Zulaica I...... O8-BSS_360 Parkinson G.S...... O24-OXI_318 Pirart J...... P4-MAQ_423, Parmigiani F...... O4-BSS_144 ...... I01_SCR_428 Pascual J.I...... O8-SMG_201 Pisarra M...... O10-ADS_417 Paßens M...... O0-MOS_294 Plach T...... O17-MOS_5 Passerone D...... I11_MOS_102 Plucinski L...... O7-MAQ_405 Passoni M...... O10-LSI_3 Plumb N.C...... O8-BSS_360, Paszkiewicz M...... O8-ADS_152 ...... O18-OXI_200 Pászti Z...... O6-CAT_90 Pobegen G...... O5-OXI_30 Patel S...... P10-OXI_151 Podda N...... P9-SAS_401 Patt M...... P8-NAM_424 Pohlenz D...... O6-NAM_269 Pauly F...... O9-MOS_268 492/499 ABSTRACT BOOK

Pointillart F...... O19-MOS_290 Ramos A...... O11-OXI_56, Polak M...... O7-ADS_49 ...... O7-OXI_153, ...... P18-OXI_400 Polek M...... O33-MOS_237 Ramsey M...... O12-OXI_187 Politano A...... I15_GRA_438 Ranguis A...... O34-MOS_104, Poloni R...... O4-SST_390 ...... O4-SMG_143 Polyak Y...... O2-NAM_25 Räthel J...... P6-SAS_344 Pomp S...... O15-OXI_228 Ratter K...... P14-GRA_286, Ponard A...... P13-OXI_280 ...... O4-SST_390 Popov V...... P2-GRA_93 Rauls E...... O8-ADS_152 Popova H...... O9-RTP_265 Ravelosona D...... O1-SMG_129 Portet D...... O36-MOS_218 Ravikumar A...... O5-GRA_368 Potemski M...... O2-ELPS_332 Rebhan B...... O17-MOS_5 Potin V...... P15-OXI_314 Redinger J...... O19-OXI_118, Pou P...... O8-GRA_355 ...... O20-OXI_124 Pradier C.M...... O1-SAS_367 Reecht G...... O6-MOS_55, Prescott S...... O6-SAS_397 ...... O23-MOS_75, Previdello B...... O3-ELC_365 ...... O16-MOS_275 Prévot G...... P2-RTP_243, Rego A...... O4-POL_369 ...... O3-RTP_277, Reikowski F...... P8-ELC_330, ...... O4-SMG_143 ...... O7-NAM_329 Priimets D...... P3-SMC_69 Reiß S...... O5-ADS_215 Priimets J...... P5-SMC_70, Renard V.T...... P4-GRA_199 ...... P6-SMC_71 Renard V...... O6-GRA_248 Provost B...... P12-MOS_198 Renaud G...... O6-RTP_467 Psarski M...... O2-LSI_240 Renault O...... O12-NAM_342, Pugno N...... O10-NAM_35, ...... O4-NAM_474, ...... P7-NAM_422 ...... O13-OXI_76, Puschnig P...... O12-OXI_187 ...... P21-OXI_460 Pusterhofer M...... O1-TPI_121 Renevier H...... O8-OXI_131 Pusztai P...... O12-SST_38 Reocreu R...... O8-SCR_317 Repain V...... O12-GRA_316, Q ...... O12-MOS_334 Resta A...... O1-CAT_308, Queiroz R...... P2-TPI_244 ...... P19-MOS_339 Quesne-Turin A...... O2-M4E_36 Reticcioli M...... O9-OXI_79 Revol B...... P3-POL_40 R Rhyim Y...... O1-NAM_7 Richard M.I...... O8-OXI_131 Raabe J...... O4-MOS_362 Richardson R...... O6-SAS_397 Rader O...... O2-TPI_471 Richter M...... P3-M4E_39 Radovic M...... O18-OXI_200 Richter M.C...... O4-BSS_144, Rafaj Z...... P4-CAT_81 ...... O6-BSS_235 Rahn B...... P8-ELC_330 Ridder B...... P6-POL_113 Rai R...... O22-OXI_84 Rietwyk K...... P11-OXI_177 Raible I...... O3-POL_154 Rijnders G...... P3-RTP_351 Rakhimova O...... P1-LSI_94 Rioult M...... I20_M4E_446, Ramachandran A...... P5-OXI_62 ...... I20_M4E_446 Risse S...... P2-ELC_136 Risterucci P...... O4-NAM_474

493/499 ABSTRACT BOOK

Ristic Z...... O18-OXI_200 Rungnim C...... P6-NAM_220 Rius G...... P20-OXI_457 Ruppenthal L...... O20-MOS_189 Robach O...... O2-SCR_336, Ruso J...... P5-SST_379 ...... P3-SST_338 Ruyter A...... O17-OXI_255 Roberto F...... O4-ELC_315 Rybácek J...... O10-SCR_173 Robles R...... P18-MOS_298 Rysz J...... O16-OXI_300 Rocha L...... P10-OXI_151 Rochet F...... O4-CAT_157, S ...... O7-LSI_156, ...... P4-MOS_50, S. Stipp S.L...... P3-ADS_291 ...... O4-MOS_362 Sabba N...... P5-ELC_307 Rochford L.A...... P8-SAS_371, Sadi F...... P3-CAT_65 ...... O5-SST_249 Sadowski J...... O6-BSS_235, Rodary G...... O8-ELPS_42 ...... P9-GRA_349 Rodenbücher C...... O16-OXI_300 Sainctavit P...... O19-MOS_290 Rodney D...... O4-SST_390 Saint-Lager M.C...... O2-SCR_336, Rodriguez-Blanco J.D...... P3-ADS_291 ...... P3-SST_338, Rogero C...... O31-MOS_47, ...... O10-SST_364 ...... P24-MOS_242 Sakai J...... O17-OXI_255 Romeo M...... O10-SMG_247 Sakata O...... O9-ELC_227 Romero-Muniz C...... O8-GRA_355 Salehi M...... O5-MAQ_86 Ronci F...... I15_GRA_438 Saletsky A...... O10-GRA_180 Ronneburg A...... P2-ELC_136 Salluzzo M...... I23_OXI_451 Rosanova K...... O4-SMI_234 Salvarezza R...... O8-MOS_385 Rösch R...... P3-M4E_39 Sameshima T...... O4-M4E_28, Rosei F...... O4-GRA_313 ...... P2-OXI_17 Rosenow P...... O38-MOS_172 Samia O...... P5-ADS_399 Rosmi M.S...... O9-GRA_208 Sánchez-Barriga J...... O2-TPI_471 Rosu-Finsen A...... P28-MOS_310 Sangaletti L...... P8-OXI_130 Roth F...... P3-M4E_39 Sanna S...... O6-ELPS_272, ...... P6-SAS_344 Rountree C.L...... P3-SMG_416 Sano Y...... O16-SCR_150 Rousse G...... O11-SST_233 Santini C...... O6-LSI_101 Rousset S...... O12-GRA_316, ...... O2-MAQ_324, Sarasola A...... P4-SAS_321 ...... O12-MOS_334 Sasaki M...... P21-MOS_393 Rovaris F...... P7-SMC_160 Sauer J...... O6-SST_340 Rozboril F...... P3-MOS_43, Saun S.B...... O1-NAM_7 ...... P8-MOS_170 Sautet P...... O8-SCR_317, Ruano G...... P4-SAS_321 ...... O9-SCR_470 Rubinovich L...... O7-ADS_49 Savio L...... I24_GRA_440 Rubio J...... P17-OXI_381 Sawa H...... P1-NAM_53 Ruby M...... O8-SMG_201 Scaparro A.M...... O3-SST_77 Ruch F...... P3-POL_40 Schaefer A...... O3-CAT_254, Ruckhofer A...... O2-ADS_97, ...... O22-OXI_84, ...... O1-TPI_121 ...... O2-OXI_186 Rudolf P...... O01-ASC_475 Schaefer J...... O9-ELPS_306 Rueff J.P...... P21-OXI_460 Schaff O...... O8-NAM_8 Ruge M...... P8-ELC_330 Scheiba F...... P6-POL_113 Rullik L...... O1-ELC_426 Schendel V...... O1-MOS_119

494/499 ABSTRACT BOOK

Scheurer F...... O6-MOS_55, Setvin M...... O9-OXI_79 ...... O16-MOS_275, Ševcíková K...... P4-CAT_81 ...... O9-SMG_89, Shakhmin A...... P1-LSI_94 ...... O10-SMG_247 Sharma S...... O9-GRA_208 Schilinsky L...... O4-SMI_234 Sharma R...... O1-M4E_354 Schiller F.M...... O8-BSS_360, ...... O2-SMG_133 Shen K.C...... O30-MOS_21 Schilling M...... O4-ADS_139 Shi Z...... O14-OXI_211 Schlickum U...... O1-MOS_119 Shi M...... O1-BSS_63 Schmid M...... O38-MOS_172, Shimoyama I...... P7-OXI_115 ...... P9-MOS_181, Shipilin M...... O3-CAT_254, ...... O20-MOS_189, ...... O22-OXI_84, ...... O20-OXI_124, ...... O23-OXI_114 ...... O24-OXI_318 Shirakashi J...... P8-ELPS_331 Schmidt H...... P2-ELC_136 Shluger A...... O28-MOS_282, Schmidt W.G...... O8-ADS_152, ...... P5-RTP_285, ...... O6-ELPS_272, ...... P3-SAS_293 ...... P6-SAS_344 Shokuhfar T...... P10-OXI_151 Schmidt A...... O39-MOS_155 Shuttleworth I...... P4-SST_347 Schmüser C...... O4-SMI_234 Shvets I.V...... O2-SST_105 Schneck E...... O3-SAS_382 Siahaan T...... O3-NAM_191 Schneider A...... O6-OXI_387 Sib J.D...... P1-ADS_12, Schneider C.M...... O7-MAQ_405, ...... P1-MOS_11 ...... O4-NAM_474 Sib D.D...... P1-M4E_13 Schneider N...... O9-M4E_326 Sibert E...... O3-ELC_365 Schnyder A...... P2-TPI_244 Sicot M...... O4-GRA_313, Schöfberger W...... O8-ADS_152 ...... O13-MOS_345 Schöniger M...... O38-MOS_172 Sidorenkov A...... O10-GRA_180 Schüffelgen P...... O7-MAQ_405 Siebert E...... O3-M4E_361 Schull G...... O6-MOS_55, Silly M...... O4-CAT_157, ...... O16-MOS_275 ...... O7-M4E_292, Schulte K...... O6-OXI_387 ...... P4-MOS_50 Schusser J...... P4-OXI_54 Silly M.G...... O1-OXI_256 Schwab S...... O5-OXI_30 Simon P...... P15-OXI_314, ...... O6-SMG_241 Schwarz M...... O13-SCR_239 Simon S...... P5-POL_107 Schwörer F...... O2-SMI_366 Singhal D...... P5-M4E_88 Scoppola E...... O1-SMI_469 Siri O...... O34-MOS_104 Sébilleau D...... P4-NAM_251 Sirotti F...... O7-LSI_156, Sedlák R...... P7-MOS_159 ...... P4-MOS_50, Sedova I...... P1-LSI_94 ...... O1-OXI_256 Segui S...... P4-ELPS_209, Sirotty F...... O4-CAT_157 ...... P5-GRA_210 Sitja G...... P3-SST_338 Segura-Ruiz J...... P13-OXI_280 Skopin E...... O8-OXI_131 Seidel P...... O9-LSI_137 Slaoui A...... O8-M4E_284 Seidlhofer B...... P2-ELC_136 Smått J.H...... O2-POL_41 Seifert H.J...... P6-M4E_134 Smogunov A...... O12-MOS_334 Seifert J...... O6-SST_340 Soares M.M...... P18-OXI_400 Sennour M...... P1-CAT_6 Sobotík P...... P3-MOS_43, Serkovic L...... O1-MAQ_343 ...... P8-MOS_170, Sessoli R...... O19-MOS_290 495/499 ABSTRACT BOOK

...... O8-RTP_122, Stöckmann J.P...... P6-ELPS_274 ...... O5-SAS_46 Stöger B...... O19-OXI_118 Soldo Y...... O10-SST_364 Stöhr M...... O3-ELPS_61, Soldo-Olivier Y...... O3-ELC_365 ...... O35-MOS_67 Solianyk L...... O3-ELPS_61 Stoot A...... P9-GRA_349 Song B.Q...... I28_MOS_465 Strafela M...... P6-M4E_134 Song S.R...... I28_MOS_465 Strempfer J...... O7-SCR_466 Song F...... O30-MOS_21, Strocov V...... O5-BSS_140, ...... O35-MOS_67 ...... P2-TPI_244 Song B...... O30-MOS_21 Studniarek M...... O9-SMG_89 Songmuang R...... P14-OXI_303 Stupakiewicz A...... P1-SMG_45 Späth F...... O13-SCR_239 Sugawara T...... O4-M4E_28 Speiser E...... P6-SAS_344 Sugimoto Y...... O13-ELPS_193 Spencer B.F...... O7-M4E_292, Sukotjo C...... P10-OXI_151 ...... O1-OXI_256 Sun H.L...... O30-MOS_21 Springholz G...... O5-BSS_140, Suran-Brunelli S...... I11_MOS_102 ...... O2-TPI_471 Suzer S...... O5-LSI_83 Spychala B...... O2-LSI_240 Suzuki Y...... O5-ELPS_214 Stanescu S...... I20_M4E_446, Svane K.L...... P1-SAS_258 ...... O4-MOS_362 Švec M...... P7-MOS_159, Stanescu D...... I20_M4E_446, ...... O7-MOS_184, ...... P3-SMG_416 ...... O10-SCR_173 Stara I...... O10-SCR_173 Swagten H...... O3-NAM_191 Starfelt S...... O7-BSS_175 Swaraj S...... O4-MOS_362 Starostenkov M...... P1-MAQ_85 Swart I...... O6-NAM_269 Stary I...... O10-SCR_173 Syres K...... P23-MOS_158, Stefano G...... O3-ELPS_61 ...... O11-NAM_167 Steinmüller S...... P6-POL_113 Syromyatnikov A.G...... O1-SST_82 Steinmüller S.O...... P6-M4E_134 Sysoiev D...... O23-MOS_75 Steinrück H.P...... O3-LSI_259, Szenti I...... O21-OXI_183 ...... O11-SCR_226, Szíjjártó G.P...... O6-CAT_90 ...... O13-SCR_239, ...... O4-SCR_348 Szot K...... O16-OXI_300 Steitz R...... P2-ELC_136, ...... O2-SMI_366 T Stempel T...... O8-NAM_8 Tabeshfar M...... O5-MAQ_86 Stephens I.E.L...... I25_ELC_436 Tache C...... O27-OXI_279 Sterrer M...... O9-LSI_137, Tachibana T...... P1-NAM_53 ...... P9-MOS_181, ...... O12-OXI_187, Tainoff D...... P5-M4E_88 ...... O15-OXI_228 Taioli S...... O10-NAM_35, Stetsovych O...... P7-MOS_159, ...... P7-NAM_422 ...... O7-MOS_184, Tajiri H...... O9-ELC_227 ...... O10-SCR_173 Takagi N...... PL05_432 Stettner J...... O7-NAM_329 Takagi Y...... O3-SMG_222 Stevens J...... O1-LSI_4 Takahashi C...... O9-GRA_208 Stierle A...... O2-OXI_186, Takahashi Y...... O3-SMG_222 ...... O7-SCR_466 Takamura M...... O4-ELPS_91 Stipp S.L.S...... P4-POL_59 Taleb M...... P5-ELC_307 Stishenko P.V...... P22-MOS_406 Taleb-Ibrahimi A...... O2-GRA_178

496/499 ABSTRACT BOOK

Tamtögl A...... O2-ADS_97, Tortech L...... P4-MOS_50, ...... P4-RTP_394, ...... O4-MOS_362 ...... O1-TPI_121 Tosoni S...... O3-OXI_179 Tanaka S...... P1-POL_15 Totani R...... O1-SAS_367 Tanase L...... O27-OXI_279 Tougaard S...... O12-NAM_342, Tanemura M...... O9-GRA_208 ...... O4-NAM_474 Taner Camci M...... O5-LSI_83 Touré M...... O26-OXI_60 Tara A...... P8-POL_188 Tournerie N...... O8-ELC_128 Tariq Q...... O11-SCR_226 Townsend P.S.M...... P26-MOS_458, Tarsang R...... P9-M4E_219 ...... O11-RTP_125, ...... P4-RTP_394 Tas H...... O39-MOS_155 Trambly De Laissardière G...... O6-GRA_248 Tebi S...... O8-ADS_152 Tran B...... O35-MOS_67 Tegenkamp C...... O6-ELPS_272, ...... P6-ELPS_274 Trapp M...... P2-ELC_136, ...... O2-SMI_366 Teichert C...... O34-MOS_104 Trari M...... P7-ELC_403, Tejeda A...... O2-GRA_178 ...... P1-SMC_14, Teodorescu C...... O27-OXI_279 ...... P8-SMC_278 Tesson S...... O7-LSI_156 Trautmann M...... I16_SAS_454 Testemale D...... P18-OXI_400 Trembulowicz A...... P2-SST_146 Teys S...... P2-SMC_29 Trino L...... P5-OXI_62 Thakur P.K...... P23-MOS_158, Trouillet V...... P7-POL_168 ...... O11-NAM_167, Tsai A.P...... O37-MOS_182 ...... O5-SST_249 Tsukahara N...... PL05_432 Thissen A...... O8-NAM_8 Tuktamyshev A...... P2-SMC_29 Thomas O...... O8-OXI_131 Tummino A...... O3-SMI_236 Thomas A.G...... O1-OXI_256 Thomas A...... O34-MOS_104 U Thomassey M...... P3-POL_40 Thomssen A.B...... P4-POL_59 Ueba H...... PL05_432 Thornton G...... O9-SST_363 Ueda Y...... O5-ELPS_214 Tian L...... O8-OXI_131 Uhlig M...... O1-POL_378 Tijani G...... P10-GRA_357 Uihlein J...... O33-MOS_237 Timofeev V...... P2-SMC_29 Ules T...... O12-OXI_187 Tine D...... O26-OXI_60 Ulgut B...... O5-LSI_83 Tissot H...... O4-CAT_157 Ulrich O...... O6-RTP_467 Tolentino H.C.N...... P18-OXI_400 Ulrich S...... P6-M4E_134 Tommasini M...... O10-LSI_3 Ulrike D...... O9-OXI_79 Tonchev V...... O9-RTP_265 Umezawa K...... P2-MAQ_273 Tonner R...... O38-MOS_172, Uozumi M...... O3-SMG_222 ...... O20-MOS_189 Urbanek M...... O5-SMG_176 Tonnerre J.M...... P18-OXI_400 Urpelainen S...... O11-GRA_391 Topolnicki R...... O6-MAQ_260, ...... P1-RTP_171 V Torii S...... O3-MOS_225 Torrelles X...... P19-MOS_339, Vacek J...... O10-SCR_173 ...... O8-MOS_385, Vacek Chocholoušová J...... O10-SCR_173 ...... O7-OXI_153, Valasek M...... O9-MOS_268 ...... P17-OXI_381 Valbuena M.A...... O2-SMG_133 Torres A...... O12-NAM_342 Valeri S...... O3-OXI_179 497/499 ABSTRACT BOOK

Vallverdu G...... O2-M4E_36 Walker A...... P3-ELC_205, Valvidares M...... O10-MOS_462 ...... O14-OXI_211, ...... O14-SCR_206 Van De Sanden M.C.M...... P4-ADS_312 Walls B...... O2-SST_105 Varga E...... O12-SST_38 Walshe K...... O2-SST_105 Varga I...... O3-SMI_236 Walton A.S...... O1-OXI_256, Varga P...... O5-SMG_176 ...... O4-OXI_346 Vári G...... P2-ADS_264, Wander A...... O9-SST_363 ...... O4-RTP_116 Wang Z...... O1-BSS_63 Varykhalov A...... O2-TPI_471 Wang Y...... O4-SCR_348 Vasseur G...... O4-GRA_313 Wang L...... O3-ELC_365, Vazquez De Parga A...... O10-ADS_417 ...... O11-MOS_356 Veillerot M...... O13-OXI_76 Wang B...... O5-SST_249 Veltruská K...... P4-OXI_54 Wang C...... P1-SST_20 Verdier M...... O4-SST_390 Wansleben M...... O2-RTP_203 Verdini A...... I11_MOS_102, Ward D.J...... P26-MOS_458, ...... P24-MOS_242, ...... O11-RTP_125, ...... O25-OXI_305 ...... P4-RTP_394 Vergeer K.H...... P3-RTP_351 Warr D...... P5-NAM_395, Vergnaud C...... P18-OXI_400 ...... P8-SAS_371 Verlhac B...... O10-SMG_247 Waser R...... O0-MOS_294 Vérot M...... O10-SMG_247 Watanabe S...... O26-MOS_353 Verstraete M.J...... O2-SMG_133 Watanabe K...... O5-ELPS_214 Vesselli E...... P9-SAS_401 Watkins M...... O28-MOS_282, Veuillen J...... O2-ELPS_332 ...... P5-RTP_285, Vigneron J...... O6-M4E_26, ...... P3-SAS_293 ...... O9-M4E_326 Watkins E.B...... O1-SMI_469 Vilcot J.P...... P19-OXI_407 Watt A...... O7-M4E_292 Vincent R...... O2-MAQ_324 Watts B...... O4-MOS_362 Vinogradov N...... O1-ELC_426 Weaver J.F...... O22-OXI_84, Vitali L...... O2-SMG_133 ...... O23-OXI_114 Vittadini A...... O31-MOS_47 Weber W...... O9-SMG_89 Vlad A...... O1-CAT_308 Weber A...... O1-BSS_63 Vladimir E...... P10-MOS_190 Weber-Bargioni A...... O1-ELPS_10 Vlaic S...... O3-SST_77 Wechsler D...... O11-SCR_226 Vobornik I...... O6-BSS_235 Wehner S...... P9-POL_283 Volfová H...... O2-BSS_68 Wei G.J...... P4-SMC_96 Volkov S...... O7-SCR_466 Wei C.H...... P4-SMC_96 Volobuev V.V...... O2-TPI_471, Weinelt M...... O2-RTP_203 ...... O2-TPI_471 Weiß S...... O12-OXI_187 Von Klitzing R...... O1-POL_378 Wella S.A...... O7-GRA_117, Vyalikh D...... O7-SMG_57 ...... O15-MOS_224 Wells J.W...... O8-BSS_360 W Wendt S...... I26_OXI_448 Widdra W...... I27_OXI_449 Wagner M...... P9-MOS_181 Wiegmann T...... O7-NAM_329 Wahl P...... O1-MOS_119 Wiemann C...... O4-NAM_474 Wakayama Y...... P21-MOS_393 Williams F...... O3-LSI_259

498/499 ABSTRACT BOOK

Williamson A.I...... O7-M4E_292, Yusop M.Z...... O9-GRA_208 ...... O1-OXI_256 Winter H...... O6-SST_340 Z Witkowski N...... O32-MOS_192, ...... P11-MOS_195 Zadick A...... P8-M4E_409 Wöckel C...... O4-SCR_348 Zakaria A...... O1-SCR_245 Woellenstein J...... O3-POL_154 Zaluska-Kotur M...... O12-RTP_98, ...... P6-RTP_252, Wolf T...... O11-ELPS_138 ...... O9-RTP_265 Wolfgang E...... O2-ADS_97 Zanfoni N...... P15-OXI_314 Wolfman J...... O17-OXI_255 Zborowski C...... O12-NAM_342, Won S...... O1-NAM_7 ...... O4-NAM_474 Woodruff D.P...... P8-SAS_371, Zelsmann M...... P5-M4E_88 ...... O5-SST_249 Zetterberg J...... O3-CAT_254 Wormeester H...... P5-CAT_142 Zeudmi Sahraoui F...... P1-M4E_13 Wrana D...... O16-OXI_300 Zhang C...... O3-CAT_254, Wuest K.N.R...... P7-POL_168 ...... O11-MOS_356 Wulfhekel W...... O11-ELPS_138, Zhang H.M...... O7-BSS_175, ...... O9-MOS_268, ...... O27-MOS_161 ...... O9-SMG_89 Zhang F...... O23-OXI_114 Würger T...... P17-MOS_281 Zhang L...... O11-SCR_226 X Zhou T...... O6-RTP_467 Zhou J...... O3-CAT_254 Xiao W.D...... I28_MOS_465 Zhu J.F...... O24-MOS_302 Xie L...... O11-MOS_356 Zhukov A...... P1-SMG_45 Xing S...... O4-GRA_313 Zielke K...... O2-RTP_203 Xu W...... O11-MOS_356 Zimmermann P...... P8-MOS_170 Xu N...... O1-BSS_63 Zinner M...... P7-SAS_359 Xu B...... O2-SMG_133 Znaiguia R...... P9-NAM_473 Zugermeier M...... O38-MOS_172, Y ...... O20-MOS_189, ...... O24-MOS_302 Yaakob Y...... O9-GRA_208 Yamada Y...... P21-MOS_393 Yamashita Y...... O12-NAM_342, ...... O13-OXI_76, ...... P1-POL_15 Yamasue K...... O12-ELPS_111 Yamauchi K...... O16-SCR_150 Yan Z...... P11-OXI_177 Yang K...... I28_MOS_465 Yang T...... P1-SST_20 Yang Z.X...... P2-SCR_112 Yivlialin R...... O10-LSI_3 Yokoyama T...... O3-SMG_222 Yoshidomi S...... O4-M4E_28 Yoshigoe A...... O3-SCR_238 Yoshikawa H...... P1-POL_15 Yu B...... O1-LSI_4 Yun Y...... P6-ADS_372 499/499