Faculty of Natural Sciences II Chemistry, Physics, Mathematics Research Portfolio of the Faculty of Natural Sciences II (NF II)

Photos: Michael Deutsch | MLU

Research portfolio

Faculty of Natural Sciences II Chemistry, Physics, Mathematics Research portfolio of the Faculty of Natural Sciences II (NF II)

With this research portfolio, we present an overview of In each area, the individual groups’ research is document- the research topics pursued at our faculty, as represented ed by large-scale collaborative projects, often funded by by the different research groups in the institutes of the German Research Foundation (DFG), the Ministry Chemistry, Physics and Mathematics, research facilities of Education and Research (BMBF), the Horizon 2020 and connected research institutes. With Materials Science of the European Union, and many other Third Party- being one of Martin Luther University’s main research Funders, including industry. Our dedication to educating fields, our activities center on Nanostructured Materials. young scientists and school teachers is reflected in a Concentrated on three research foci (Synthetic and Bio- number of (under)-graduate and postgraduate-study logical Macromolecules, Solid State Interfaces and programs, where students meet science early on in their Nanostructures and Materials for Energy Conversion studies. and Storage), the faculty provides a vibrant, sustainable and attractive environment in education and research. The interconnectedness of the three research foci occurs via the topics Molecules, Materials and Models. There are many links to other main research areas at Martin Luther University, especially to Molecular Biosciences.

Table of contents

04 _ Address of the Dean 38_ Materials for energy conversion and storage 69 _ Prof. Dr. Dr. Ludger Wessjohann 40 _ Prof. Dr. Michael Bron 70 _ Prof. Dr. Bernhard Westermann 06 _ Research Projects 41 _ Prof. Dr. Stefan Ebbinghaus 06 _ DFG Collaborative Research Center CRC/TRR 227 42 _ Prof. Dr. Martin Goez 72 _ Research in education and history of science 08 _ DFG Collaborative Research Center SFB-TRR 102 43 _ Prof. Dr. Jörg Kressler 73 _ Prof. Dr. Thorid Rabe 10 _ DFG Research Training Group RTG/GRK 2670 44 _ Prof. Dr. Robert Langer 12 _ BMBF center SiLi-nano 45 _ Jun.-Prof. Dr. A. Wouter Maijenburg 74 _ Emeriti 14 _ BMBF center HALOmem 46 _ Prof. Dr. Roland Scheer 47_ Prof. Dr. Ralf B. Wehrspohn 76 _ Undergraduate, graduate and 16 _ Solid state interfaces and nanostructures postgraduate education 18 _ Prof. Dr. Konstantin Amsharov 48_ Synthetic and biomacromolecules 19 _ Prof. Dr. Martin Arnold 50_ Prof. Dr. Kirsten Bacia 78 _ Studying at the Faculty of Natural Sciences II 20 _ Prof. Dr. Jamal Berakdar 51 _ Prof. Dr. Jochen Balbach 79 _ Postgraduate research 21 _ Prof. Dr. Tomáš Dohnal 52_ Prof. Dr. Michael Bartke 22 _ Prof. Dr. Kathrin Dörr 53 _ Prof. Dr. Wolfgang H. Binder 80 _ Impressum 23 _ Prof. Dr.-Ing. Thomas Hahn 54_ Prof. Dr. René Csuk 24 _ Prof. Dr. Reinhard Krause-Rehberg 55 _ Prof. Dr. Marcus A. Glomb 25 _ Prof. Dr. Raphael Kruse 56_ Prof. Dr. Kai-Uwe Goss 26 _ Prof. Dr. Ingrid Mertig 57 _ Prof. Dr. Dariush Hindenberger 27 _ Prof. Dr. Kurt Merzweiler 58_ Prof. Dr. Jan Laufer 28 _ Prof. Dr. Stuart Parkin 59 _ Prof. Dr. Miguel Marques 29 _ Jun.-Prof. Dr. Martin Redmann 60 _ Prof. Dr. Wolfgang Paul 30 _ Prof. Dr. Joachim Rieger 61 _ Prof. Dr. Reinhard Paschke 31 _ Prof. Dr. Jörg Schilling 62 _ Prof. Dr. Detlef Reichert 32 _ Prof. Dr. Georg Schmidt 63 _ Prof. Dr. Kay Saalwächter 33 _ Prof. Dr. Carsten Tschierske 64 _ Prof. Dr. Daniel Sebastiani 34 _ Prof. Dr. Rebecca Waldecker 65 _ Prof. Dr. Christiane Tammer 35 _ Prof. Dr. Nils Waterstraat 66 _ Prof. Dr. Thomas Thurn-Albrecht 36 _ Prof. Dr. Wolf Widdra 67 _ Prof. Dr. Daniel Wefers 37 _ Prof. Dr. Georg Woltersdorf 68 _ Jun.-Prof. Dr. Martin Weissenborn Photo: Maike Glöckner | MLU

MLU Chemistry

MLU Physics

MLU Chemistry

MLU Physics

Leibniz

MLU Mathematics

UFZ Max-Planck IZM Fraunhofer

Local collaboration partners

A significant part of our research is performed Max-Planck-Institute of Microstructure Physics Prof. Stuart Parkin in collaboration with the external partner Prof. Joyce Poon institutions located on Halle’s “Weinberg

Campus.” The close proximity enables quick Interdisciplinary Center of Materials Sciences (IZM) and efficient exchange and personal inter- (central institution of Martin Luther University) Prof. Georg Schmidt action. A part of our faculty, named here, are co-appointed with our partner institutes. Fraunhofer Institute for Microstrucure of Materials and Systems (IWMS), Fraunhofer Center for Silicon-Photovoltaics (CSP), and Fraunhofer Pilot Plant Center for Polymer Synthesis and Processing (PAZ) Beurlaubt: Prof. Ralf Wehrspohn (IMWS / CSP / PAZ) Prof. Michael Bartke (PAZ)

Leibniz Institute of Plant Biochemistry Prof. Ludger Wessjohann Prof. Bernhard Westermann

Helmholtz Center for Environmental Research Prof. Kai-Uwe Goss Faculty of Natural Sciences II (Chemistry, Physics, Mathematics)

Address of the Dean Halle as a bustling and modern city of ¼ million inhabit- Located at a modern and integrative campus, students ants hosts the Martin Luther University Halle-Witten- can experience education and science on one place, well berg (MLU) together with many external research insti- connected to the historic, old town of Halle, also known tutes. Located in the middle of Germany, MLU covers as “Händelstadt”, Georg Friedrich Händel’s birthplace. the full spectrum of science, philosophy and theology. Our study-programs address the Bachelor-, Master- and Founded in the year 1502 MLU has a longstanding tradi- PhD-level, enabling students to either chose science tion in science and mathematics, with the Nobel Prize programs in chemistry, physics or mathematics, or Laureates Gustav Hertz (Physics), Hermann Staudinger reach education in interdisciplinary fields such as medi- (Chemistry), Carl Ziegler (Chemistry) and the Mathema- cal physics, polymer materials science, renewable energies tician Georg Cantor as prominent alumni. and economical mathematics. With this Research Port- folio we provide an overview on research-topics and the Research at the Faculty of Natural Sciences II covers involved researchers, hoping to meet you here and stay both, theoretical and experimental science in the areas in touch. of Chemistry, Physics and Mathematics. Striving to impact modern scientific research we address the growing and advancing needs of a dynamic society. Within the three main areas of research, solid materials interfaces, (bio-)macromolecules and energy storage, central aspects of materials science and molecular science are investigated. Together with 1000 students high-level research is conducted, in addition to many national and interna- Prof. Dr. Wolfgang H. Binder, Dean tional collaborations. Photo: Michael Deutsch | MLU

Contact: Faculty of Natural Sciences II – Chemistry, Physics and Mathematics von-Danckelmann-Platz 3 D-06120 Halle (Saale)

Email: [email protected] Phone: +49 (0)345 5525501 Fax: +49 (0)345 5527158 www.natfak2.uni-halle.de www.natfak2.uni-halle.de/forschung 6_ Research Projects

DFG Collaborative Research Center CRC/Transregio 227 Ultrafast Spin Dynamics

Project Description

The electron spin is one of the key quantum properties determin- spin-based technology. Our research consortium employs and de- ing structure and dynamics of matter. It has large potential for ap- velops a comprehensive portfolio of experimental and theoretical plications in future magnetic memory and logic devices with sim- methods that is ideally suited to study ultrafast spin dynamics and ple architecture and reduced power consumption. Two fundamental train our graduate students in this scientifically exciting and tech- spin-dependent interactions, exchange and spin-orbit coupling, nologically promising field of condensed matter physics. allow for a spin response down to ultrafast time scales. Likewise, when reaching the nanoscale, electron and spin transport become ballistic and can occur ultrafast within femtoseconds. However, while future applications require such high speed and terahertz (THz) bandwidths, most spin-based magnetoelectronic devices are currently operating at 100-1000 times lower clock rates.

The goal of our CRC/TRR 227 is to establish a fundamental understanding of ultrafast spin dynamics, thereby laying the founda- tions for spin-based information technology that can be operated at THz clock rates. Our concerted research effort comprises cut- Ultrafast optically induced inter site transfer of ting-edge experiments in ultrafast spectroscopy and multiscale angular momentum theoretical modeling of spin dynamics. This science-driven approach promises a wealth of new results as well as the progress and buildup of our fundamental knowledge beyond technical applica- Participating Institutions tions. To study ultrafast spin dynamics, we will make use of the fastest stimuli and probes available: ultrashort optical and electro- › Freie Universität Berlin magnetic pulses with center frequencies ranging from the THz to › Martin Luther University Halle-Wittenberg the ultraviolet spectral range. Our research will focus on novel phe- › Fritz-Haber-Institut der Max-Plack-Gesellschaft nomena in state-of-the-art spintronic materials. In addition, we › Helmholtz Zentrum Berlin will address a few new, promising materials and explore nanoscale › Max Born Institut structures to localize and enhance incident electromagnetic fields. The analysis and control of ultrafast spin dynamics form the basis for our long-term goal: To transfer the understanding of femtosec- Budget: 11 Mio € (4 Mio € Halle share) ond spin dynamics into novel functionalities for future ultrafast Funding periods: January 2018 - December 2021 Research Projects _7

Projects and Project Leaders (First Funding Period) Integrated Research Training Group (iRTG)

• A01: Ultrafast spin dynamics and its signature in the The iRTG offers a structured qualification program in scientific and transient electronic structure key skills to all PhD students financed and associated to the CRC/ Prof. Martin Weinelt (FU Berlin) TRR. Its training is divided into research training in several labora- • A02: Eisebitt Ultrafast spin dynamics in heterogeneous tories and in different research contexts, as well as an external magnetic systems training program, which offers courses for key skills. The PhD stu- Clemens von Korff Schmising (Max Born Institute) dents have many occasions to actively learn about the works of • A03: Element-specific view on ultrafast spin and angular their colleagues in the CRC, to communicate science and to discuss momentum redistribution their own scientific results. The scientific exchange is fostered by a Dr. Niko Pontius, Prof. Alexander Föhlisch (HZB) set of opportunities, such as training in other than their own labs, • A04: Theoretical simulation of the probe in pump-probe tutorials, seminars and a retreat. experiments: MOKE, MCD, and PES Dr. Sangeeta Sharma (MBI) Candidates are offered courses on transferable skills in collabora- • A05: Elementary terahertz spin interactions in magnetic solids tion with the Dahlem Research School Berlin (DRS) and the Inter- Prof. Tobias Kampfrath (FU-Berlin) national Graduate Academy Halle (InGrA) RTG • A06: Nanometer-resolved ultrafast spin and electron dynamics at magnetic surfaces Dr. Chen-Tien Chiang, Prof. Wolf Widdra (MLU-Halle) • A07: Bridging the time scales between ultrafast and precessional magnetization dynamics Prof. Wolfgang Kuch (FU-Berlin) • A08: Multiscale modeling of ultrafast spin dynamics Dr. Unai Atxitia (FU-Berlin) • A09: Ultrafast magnetization dynamics and spin transport in magnetic oxide heterostructures Dr. Laurenz Rettig (FHI)

• B01: Ultrafast spin currents and spin torques studied by (non-) linear magneto-optics Dr. Alexey Melnikov, Prof. Georg Woltersdorf (MLU-Halle) • B02: Ultrafast spintronic devices Prof. Tobias Kampfrath (FU-Berlin), Prof. Georg Woltersdorf, Prof. Georg Schmidt (MLU-Halle) • B03: Time-dependent spin dynamics and electron transport Prof. Piet Brouwer (FU-Berlin) • B04: Spin-dependent transport in inhomogeneous systems Contact Prof. Ingrid Mertig, Dr. Jürgen Henk (MLU-Halle) • B05: Spin dynamics in atomically-precise nanostructures CRC/TRR 227 Prof. Katharina Franke, Prof. Tobias Kampfrath (FU-Berlin) Freie Universität Berlin - Fachbereich Physik • B06: Imaging and control of spatio-temporal spin dynamics in Arnimallee 14 nanostructures 14195 Berlin Prof. Jamal Berakdar (MLU-Halle) • B07: Momentum-resolved dynamics of relaxation processes Prof. Dr. Martin Weinelt (Spokesperson) and control of spins and pseudospins in TMDC-based Email: [email protected] spintronic heterostructures Dr. Ralph Ernstorfer, Prof. Marin Wolf (FHI) Dr. Christian Frischkorn (Coordinator) • B08: Ultrafast spin transport at the interface between Email: [email protected] TMDCs and metals Phone: +49 (0) 30 838 75081 Prof. Kirill Bolotin, Dr. Cornelius Gahl (FU-Berlin) • B09: Real-time (pseudo-)spin transport and dynamics in https://www.trr227.de/ transition metal dichalcogenides Prof. Miguel Marques (MLU-Halle) 8_ Research Projects

DFG Collaborative Research Center SFB/Transregio 102: Polymers under Multiple Constraints – Restricted and Controlled Molecular Order and Mobility

Third funding period: July 2019 – June 2023 Budget: 8,8 Mio. € (6,7 Mio. € Halle share)

Project Description Projects and Project Leaders

The rich versatility and the variable properties and functions of • A1: Effects of topological constraints in polymer melts on macromolecules are based on the one hand on a large variety of dif- crystallization and structure formation ferent monomers but on the other hand on the fact that polymers Prof. Thomas Thurn-Albrecht, Prof. Kay Saalwächter (Physics, are able to self-assemble in organized structures, encoded in the MLU Halle) chemical sequence of the polymer chains. In simple cases of self- • A3: Crystallization and cooperativity in dynamic supramolecu- assembly. the only constraint is the chain connectivity, leading to lar polymers the existence of largely universal properties independent of the Prof. Wolfgang H. Binder (Chemistry, MLU Halle) specific chemistry. But there are many important open and chal- • A6: NMR investigations of the self-organization and dynamics lenging problems in polymer science which are characterized by of amyloid protein fibrils strong correlations between local structure and global conforma- Prof. Daniel Huster (Medicine, U Leipzig) tion of the chain. In the CRC TRR 102 we investigate such processes • A7: Intra- and intermolecular structure formation in the of structure formation and self-assembly of chain molecules, for presence of specific interactions which the formation of molecular structures and the molecular dy- Prof. Wolfgang Paul (Physics, MLU Halle) namics are affected in addition to connectivity by constraints, such • A8: Organization and interactions of eye-lens crystallins: as specific internal interactions, external forces, geometrical con- native states and cataract formation finement, crowding or topological restrictions. Prof. Kay Saalwächter, Prof. Jochen Balbach (Physics, MLU Halle) Two prominent examples for such processes and central topics of • A9: Structure formation and aggregation of solvated peptides the CRC are crystallization in the area of synthetic polymers and and polymers in the presence of ions the formation of amyloids in the area of biopolymers. In both cases Prof. Daniel Sebastiani (Chemistry, MLU Halle) larger scale structures form, driven by the formation of local mo- • A12: Assembly of PTH/polymer hybridmolecules lecular order and constrained by the connectivity of the chains. The Prof. Jochen Balbach (Physics, MLU Halle), Prof. Wolfgang Binder resulting structures are thus only partially ordered and of nano- (MLU Halle) scopic size in one or several directions. Both processes have univer- • B1: Aggregation and self-assembly of amyloid systems and sal features, but different from crystallization, amyloid formation functionalized peptides near interfaces - towards molecular is connected to specific interaction. In the CRC we study these and mechanisms and smart materials other related processes of structure formation and the properties Prof. Bernd Abel (Chemistry, U Leipzig) of the resulting structures with the aim to work out and under- • B3: Substrate-induced molecular order and nucleation in thin stand the fundamental, underlying physical principles. To achieve films of semicrystalline polymers this aim we combine expertize from chemistry, experimental and Prof. Thomas Thurn-Albrecht (Physics, MLU Halle) theoretical physics, and biophysics using a large variety of experi- B4: Nanopatterns of macromolecules mental techniques and theoretical approaches based on simula- Prof. Wolfhardt Janke (Physics, U Leipzig) tions on different scales and levels of complexity. • B7: Semicrystalline homopolymers and block copolymers at the air/water interface and in Langmuir-Blodgett films on solid supports Prof. Jörg Kreßler (Chemistry, MLU Halle) • B8: Refined infrared spectroscopy to study molecular orientation and order in heterogeneous polymer systems Prof. Friedrich Kremer (Physik, U Leipzig) • B10: Interactions of single polymer chains and amyloid fibrils in a thermophoretic trap Prof. Frank Cichos (Physics, U Leipzig) • B12: Mechanisms of early amyloid formation and the confining influence of macromolecular crowding Figure 1: Central research topics of the CRC are the crystallization in synthetic Dr. Maria Ott (Biochemistry, MLU Halle) polymers and the amyloid formation in proteins. There are obvious structural • B14: Structure formation in linear precision and comb-like similarities between the semicrystalline morphology of a polymer (a) and the polymers under external constraints: Influence of shear fields amyloid fibrils of peptides and proteins (b). Amyloids fibrils often feature a rigid and interfaces sheet motif in the core and mobile terminal chains. Within the SFB we attempt to β Prof. Mario Beiner (Chemistry, MLU Halle and FhI Halle) connect both research fields by transferring methods and concepts. Research Projects _9

Participating Institutions

Martin Luther University Halle-Wittenberg University of Leipzig Fraunhofer Institute for Mechanics of Materials Halle Leibniz Institute of Surface Engineering Leipzig Max Planck Institute of Colloids and Interfaces Potsdam

Contact:

Figure 3: Group picture of the members of the CRC TRR 102 taken at the 6th retreat SFB-TRR 102 in Bad Schandau in March 2020. Martin Luther University Halle-Wittenberg Institute of Physics

• B15: Dynamics and association in individualized macromol- Von-Danckelmann-Platz 4 ecules D-06120 Halle (Saale) Dr. Martin Tress (Physics, U Leipzig) Email: [email protected] • B16: Crystallization of polymer chains under anisotropic confinement in liquid crystals Prof. Thomas Thurn-Albrecht (spokesperson SFB) Dr. Tiago Mendes Ferreira (Physics, MLU Halle) Email: [email protected] • B17: Force-induced transitions in coiled coil structures Dr. Kerstin Blank (Biochemistry, MPIKG Potsdam) Prof. Kay Saalwächter (spokesperson iRTG) • Z1: Synthesis of labeledα-β and unlabeled peptides with difficult Email: [email protected] sequences in large scales Dr. Sven Rothemund (Medicine, U Leipzig) Dr. Ann-Kristin Flieger (scientific coordinator) Email: [email protected]

Nicole Haak (administration and accounting) Email: [email protected]

Beate Horn (administration and event management) Email: [email protected] Phone: +49 (0) 345-55-25 342

Figure 2: As a third class of materials, hybrid systems are studied in the CRC. The www.natfak2.uni-halle.de/sfbtrr102 combination of elements typical for synthetic polymers and proteins in one hybrid blogs.urz.uni-halle.de/irtgpolymers/ macromolecule leads to new functions and material properties.

Integrated Research Training Group “Polymers: Random Coils and Beyond”

The graduate program provides in-depth training in interdisciplinary soft matter research, including the design and preparation of specific materials, their characterization, and their theoretical understanding. A thorough command of the basic principles of chemistry, physics and engineering of polymers and soft matter are aims of the training within our graduate school. Common projects, mutual support by, e.g., measurements in other research groups and seminars lead to active exchange between the doctoral students. Highlights are full two-days advanced training modules giving an introduction to selected research methods. In addition, the faculty offers lectures on several polymer topics and lecture series by international guest researchers. Besides the scientific education, doctoral students are supported in their transferable skills, such as writing publications Figure 4: In the integrated Research Training Group “Polymers: random coils and and giving persuasive talks. The scientific progress and the current beyond” about 30 doctoral students obtain additional training in (bio)polymer research activities are discussed regularly during meetings with science. In this interdisciplinary research field, questions related to physical, supervisor and mentor. The English language is the common basis biophysical, chemical and materials science are in the focus, combining experi- for communication within the graduate school. ments and theory of synthetic and biological polymers. 10_ Research Projects

DFG Research Training Group (RTG/GRK) 2670

Beyond Amphiphilicity: Self-Organization of Soft Matter Via Multiple Noncovalent Interactions

First funding period: 2021-2025 (4.5 years) Budget: 4.53 Mio. €

Project Description

Amphiphilicity is a well-established qualitative concept contribut- This RTG combines existing competencies in simulation, design ing to the understanding of self-assembly processes of molecules and synthesis, characterization and understanding of new materi- composed of two inherently incompatible units (hydrophilic and als and their properties. The research and educational concepts of hydrophobic) in aqueous systems. Polyphilic molecules are more the RTG go beyond the classical division into disciplines of chemis- complex molecules, from small molecules to macromolecules, that try and will offer doctoral researchers an excellent and broad edu- have interaction patterns with at least two types of interactions, cation combining many facets of modern chemical, physical and one of them based on amphiphilicity. Self-assembled soft matter mathematical methods. The RTG’s educational program will em- systems attain their complexity through noncovalent interaction power its doctoral researchers to become well-qualified scientists patterns of their molecular constituents with their environment, in academia and industry alike – with a unique combination of sci- solvents, biomolecules, membranes, and surfaces. entific training, professional training and strategic research train- With this RTG “Beyond Amphiphilicity” (BEAM), we aim at a re- ing elements. search and training consortium that takes the vast and scattered knowledge and work on noncovalent interactions further to develop a research training that centers on dynamic structuring of polyphilic soft matter through multiple non-covalent interactions. The relevant self-assembly is dynamic on the pico- to microsecond scale but may often dominate the macroscopic length scale and time scales. This translates into the creation of order on multiple length scales in the presence of dynamics. We want to advance the understanding of the emergence of complexity in molecular systems, in the long run we aim at uncovering design principles for nanostructured materials or aspects of self-assembly in biological systems. All studied systems are in or close to thermodynamic equilibrium or at least in long-lived metastable states. From the training perspective for our students, it is highly illustrative to build research on complex structuring on soft matter on the often- Schematic of structure formation to ionoids and anisotropic ionic clusters starting from used and seemingly simple concept of amphiphilicity. We then go ion clouds, as studied in project A2. It also shows the main methods of characterization beyond amphphilicity as a concept by extending the interaction of the ten-day incubation period in ion clouds (CW EPR) and after ten days (DLS). patterns to understand and finally design complexity in soft matter.

Structure and dynamics during self-assembly through multiple interactions of soft matter that has properties between simple (ideal) liquids and solid-state crystalline materials. On the left-hand side, different types of interactions and physical-chemical properties that lead to effective interactions (or forbid certain others) are exemplified. These interactions cause dynamic structuring in soft matter systems depicted on the right-hand side. Research Projects _11

Projects and Project Leaders Participating Institutions

Project area A – Self-organization of small and medium-sized Institute of Chemistry, Institute of Physics, Institute of synthetic molecules through multiple interactions Mathematics (all of Faculty of Natural Sciences II at MLU) Institute of Biochemistry and Biotechnology (Faculty of Natural • A1: Systematic multidimensional quantification of multiple Sciences I at MLU) interaction patterns between polyphilic molecules Prof. Dr. Daniel Sebastiani (Chemistry, MLU Halle) HALOmem: Interdisciplinary Research Center ZIK HALOmem • A2: Dynamic yet defined self-assembly of small molecules in IPB: Leibniz Institute of Plant Biochemistry solution: colloid-like ionic clusters (ionoids) Prof. Dr. Dariush Hinderberger (Chemistry, MLU Halle; HALOmem), Prof. Dr. Daniel Sebastiani (Chemistry, MLU Halle) • A3: Design of liquid quasicrystals and their approximants Contact Prof. Dr. Carsten Tschierske (Chemistry, MLU Halle), Prof. Dr. Rebecca Waldecker (Mathematics, MLU Halle) GRK 2670 • A4: Characterizing the interaction of proteins with polyphilic Martin Luther University Halle-Wittenberg detergents and lipids and their impact on membrane self-assembly Institute of Chemistry Prof. Dr. Carla Schmidt (Biochemistry and Biotechnology, MLU Halle; HALOmem) Von-Danckelmann-Platz 4 • A5: Studying amino acid interactions with non-natural 06120 Halle (Saale) polyphilic substrates Homepage: www.beam.uni-halle.de Prof. Dr. Martin Weissenborn (Chemistry, MLU Halle and IPB) Email: [email protected]

Prof. Dr. Dariush Hinderberger (spokesperson) Project area B – Self-organization of (bio-)polymeric Email: [email protected] polyphilic molecules through multiple interactions

• B1: Thermodynamics of fluorophilicity, lipophilicity, hydrophilicity, and their combination in polymers Prof. Dr. Jörg Kreßler (Chemistry, MLU Halle) • B2: Cluster-formation and interfacial function in polymeric ionic liquids Prof. Dr. Wolfgang H. Binder, (Chemistry, MLU Halle) • B3: Tuning protein and nanocolloid diffusion and (transient) assembly through polyphilic interactions: the role of patchiness and charges Prof. Dr. Kay Saalwächter, (Physics, MLU Halle) • B4: Diffusional and co-diffusional analysis of polyphilic protein–protein and protein–membrane Interactions Prof. Dr. Kirsten Bacia, (Chemistry, MLU Halle; HALOmem)

Molecules of different philicity (regular, semi-fluorinated and perfluorinated alkanes and alcohols), simulated in a lipid bilayer and studied as in project A1. 12_ Research Projects

BMBF Center for Innovation Competence (ZIK): SiLi-nano – Silicon and Light: from Macro to Nano

Budget of current funding period (2016-2021): 7,07 Mio EUR Additional strategic Investments (2020-2021): 3,998 Mio. EU

Project Description Project Groups

Light-matter interaction is the basis for many interesting and Silicon-to-Light technologically relevant processes, and the ability to create nano- Although silicon represents a formidable material for integrated structures with dimensions on the order and below the wavelength photonics due to its high refractive index, light emission and non- of light allows now to manipulate this interaction in new and fasci- linear optical processes are largely impeded by its indirect bandgap, nating ways. Therefore, the Centre of Innovation competence SiLi- centrosymmetric crystal structure and high two-photon absorp- nano (ZIK SiLi-nano) was established in 2009 with the two junior tion. The research of the group “Silicon-to-Light” aims to overcome research groups “Light to Silicon” and “Silicon to Light”. During the these challenges by either modifying the optical properties of sili- first period the research mainly focused on the interaction of light con itself or combining silicon with different materials of desired with silicon – especially the generation of electricity by silicon optical functionality creating hybrid photonic devices for “optics based photovoltaics and the control of light emission, transforma- on the chip”. This includes the generation of a second order nonlin- tion and propagation in silicon photonic circuits. Adapting to new earity ( (2)) in silicon based on symmetry breaking by an applied research challenges and with the addition of the two new groups electric field, third order nonlinear optical processes in hybrid pho- “Light-for-High-Voltage-Photovoltaics” and “Light-for-Hydrogen” tonic devices, Purcell luminescence enhancement in Mie-resonanc- in 2016 the range of investigated material systems broadened. es and plasmonic metamaterials for ultra-tight focussing and However the focus of the research on light-matter interaction in SERS. nanostructures for technologically relevant processes and applications remained. Today the research at the ZIK SiLi-nano includes Light-to-Silicon topics ranging from laser ablation and hybrid photonics to ferro Femto- and picosecond laser ablation offers the possibility for se- electric photovoltaics and photocatalytic water splitting. lective layer removal without causing thermal damage to the surrounding material. Currently spatial and temporal pulse shaping techniques are studied to optimize areal ablation and material selectivity. Furthermore focussing intensive femtosecond laser puls- Publications es inside materials like glass starts an interplay of nonlinear defo- cusing and refocusing resulting in long intensity “filaments” and a D.S. Knoche, Y. Yun, NR. Gowda, L. Mühlenbein, X. Li and A. Bhatnagar: local internal refractive index change. Extended periodic index Domain and Switching Control of the Bulk Photovoltaic Effect in Epitaxial BiFeO3 gratings could be “written” into glass in this way. Short pulse laser Thin Films. Scientific Reports 9, 13979 (2019) irradiation is also used to locally melt-ablate nano-volumes of different materials, which then form perfectly smooth spheres due to H. Zhang, X. Li, A. Hähnel, V. Naumann, C. Lin, S. Azimi, S.L. Schweizer, A.W. the surface tension in the liquid state before re-solidifying and re- Maijenburg and R.B. Wehrspohn: Bifunctional heterostructure assembly of NiFe depositing at a new substrate. LDH nanosheets on NiCoP nanowires for highly efficient and stable overall water splitting. Advanced Functional Materials 28, 1706847 (2018) Light-for-High-Voltage-Photovoltaics V. Rutckaia, F. Heyroth, A. Novikov, M. Shaleev, M. Petrov, The anomalous photovoltaic effect (APV) in ferroelectric / multi- and J. Schilling: Quantum Dot Emission Driven by Mie Resonances in Silicon ferroic materials results in an open circuit voltage (Voc, in volts) Nanostructures. Nano Lett. 17, 6886 (2017) which is far greater than the bandgap (in eV) of the illuminated material. This distinguishes the effect from junction based classic M. Muchow, T. Buchner, A. Sprafke, G. Seifert: Femtosecond laser-written semiconductor photovoltaics. However the generated photocur- high-efficiency blazed phase gratings in the volume of soda lime glass for light rent of the APV is usually far smaller than in traditional solar cell management in solar modules. OPTICS EXPRESS 23, 33540-33549 (2015) materials. The research of the group aims to improve on this point and is actively pursuing the following strategies:

1. Growth of multiferroic and complex oxide material systems in the form of Superlattices, and heterostructures.

2. Band gap engineering of oxides via substitutional doping and strain from the substrate.

Furthermore the interplay between photovoltaic and ferroic properties are investigated. High resolution transmission electron microscope image and model of atomic ordering of a ferroelectric superlattice cell. Research Projects _13

Project Partners

Light-for-Hydrogen Local: When specific photocatalytic materials are immersed in water and Fraunhofer CSP irradiated with sunlight the photo(electro) chemical water splitting Fraunhofer IMWS reaction occurs resulting in the formation of hydrogen gas in an Max Planck Inst. of Microstructure Physics environmentally friendly way. The group aims to develop specifically Smart Membranes GmBH designed nanostructures to increase the light-to-hydrogen effi- Interdisciplinary Centre for Materials science (IZM) of the MLU ciency for this photocatalytic water splitting reaction. In particular Several Research groups at the Institutes of Physics and Chemistry Metal Organic Frameworks (MOFs), template based nanostructures of the MLU as well as electrospun photocatalytic nanofibers are investigated. The investigation of the physical and chemical suitability of different National: types of nanostructures and their combination in photocatalytic Laserzentrum Hannover/FH Bremen cells for improved photoelectrochemical and autonomous water Fraunhofer IST Braunschweig splitting completes these studies. Fraunhofer IKTS Hermsdorf MPI for Solid State Research Stuttgart Leibniz Inst. für Oberflächen Modifikation Leipzig Fraunhofer ISIT Itzehoe Friedrich Schiller University Jena TU Darmstadt University Leipzig University Bochum University Köln University Giessen

International: University of Warwick (UK) University Twente (NL) Illustration of optimized photoelectrochemical water University of Pennsylvania (USA) splitting device using quasi one-dimensional nanostructures: IBM/Lumiphase Zürich (Switzerland) a maximum of solar light can be absorbed over the nanowire ICMAB Barcelona (Spain) length, while the nanowire diameter is small enough for IIT Banaras (India) efficient electron and hole diffusion. ITMO St. Petersburg (Russia) IMP RAS Nishni Novgorod (Russia) Chungnam Nat. Univ. (South Korea) Project Leaders University Donhua (China)

• Prof. Jörg Schilling Since 2009 leader of the group “Silicon-to-Light” Contact Email: [email protected] Centre for Innovation Competence SiLi-nano® • Dr. Paul Miclea Martin Luther University Halle-Wittenberg Since 2017 leader of the group “Light-to-Silicon” Karl-Freiherr-von-Fritsch-Str. 3 Email: [email protected] D - 06120 Halle (Saale)

• Dr. Akash Bhatnagar www.sili-nano.de Since 2016 leader of the group “Light-for-High-Voltage-Photovoltaics” Email: [email protected]

• Jun. Prof. Wouter Maijenburg Since 2016 leader of the group “Light-for-Hydrogen” Email: [email protected] 14_ Research Projects

BMBF Center for Innovation Competence (ZIK): HALOmem – Membrane Protein Structure and Dynamics

Budget: 24 Mio. € Funding period: 2009 - 2022

Project Description

HALOmem is an interdisciplinary research center at the Martin mental methods of HALOmem by cryo-EM and mass spectrometry Luther University Halle-Wittenberg (MLU). We focus on the structure and the scientific focus towards membrane protein complexes sup- of membrane proteins and their interactions with the surrounding ported by substantial investments into instrumentation by the membrane. Membrane proteins direct and regulate a wide range of BMBF and the state Sachsen-Anhalt. In 2020, HALOmem associated essential cellular functions, being responsible for such diverse Prof. Dr. Dariush Hinderberger from our Institute of Chemistry for processes as inter- and intracellular communication, neurotrans- EPR spectroscopic studies of complex self-organization of membrane mission, transport of nutrients and generation of energy. Their vital proteins. nature is reflected by the fact that up to 70% of current drug targets are membrane proteins. Collaboration Partners

• Protein crystallography Prof. Dr. Milton T. Stubbs, Institute of Biochemistry and Biotechnology, MLU • NMR and protein dynamics Prof. Dr. Jochen Balbach, Institute of Physics, MLU • Fluorescence correlation spectroscopy Prof. Dr. Kirsten Bacia, Institute of Chemistry, MLU • Protein mass spectrometry Jun.-Prof. Dr. Carla Schmidt, HALOmem • Cryo-Electron microscopy Jun.-Prof. Dr. Panagiotis L. Kastritis, HALOmem

Contact Four junior research groups (RG I – IV) investigate molecular details of membrane proteins and their complexes by various methods of basic research and for drug Center for Innovation Competence HALOmem industry transfer. Martin Luther University Halle-Wittenberg Charles Tanford Protein Center Kurt-Mothes-Str. 3a HALOmem was founded by Prof. Dr. Milton T. Stubbs and Prof. Dr. 06120 Halle(Saale) Jochen Balbach as a joint effort of the Institute of Biochemistry & Biotechnology (Faculty of Natural Sciences I) and the Institutes of Dr. Ulla Niesbach-Klösgen (scientific coordinator) Physics and Chemistry (Faculty of Natural Sciences II). The research [email protected] center brings together resources and special expertise from those Phone: +49 (0) 345-55-24866 institutes, such as recombinant protein production, biophysical methods for studying membranes, and protein structure determina- www.halomem.de tion by mass spectrometry, cryo-electron microscopy, crystallography and NMR. Within the first phase of funding of the HALOmem research center (2009 - 2015), the two independent tenure-track junior research groups Membrane Protein Biochemistry (RG I Dr. Mikio Tanabe) and Biophysical Chemistry of Membranes (RG II Prof. Dr. Kirsten Bacia) were established. In 2015, Kirsten Bacia became a full professor (W2) of Biophysical Chemistry at our faculty. Within the second phase of funding (2016 – 2022), two additional independent tenure-track junior research groups joined HALOmem: Cryo-Electron Microscopy of Membrane Complexes (RG III Jun.-Prof. Dr. Panagiotis L. Kastritis) and Biophysical Characterisation of Medically Relevant Proteins (Jun.-Prof. Dr. Carla Schmidt). They extended the experi- Research Projects _15 Solid state interfaces and nanostructures

Photo: R B. | pixelio.com Gaining control over structure formation on the nano studied. This involves research in their catalytic, elec- scale opens tremendous possibilities to enhance, alter tronic and optical properties as well as their impact on or even create new materials properties. These can be electronic/spintronic transport, photonic, magnonic employed for future applications ranging from chemical and plasmonic wave propagation and the associated synthesis to new nano-optical and -electrical devices. switching and modulation dynamics. Nanostructures Moreover in composite- and super-structures with in- and surfaces of ferromagnetic and ferroelectric materi- dividual elements of nanoscale dimensions the surface als are of particular interest in this respect. and interface regions start to play a crucial role affecting These activities are supported by mathematical model- basic electronic transport properties and giving rise to ling and several network initiatives like the SFB “Func- unexpected new phenomena. tionality of oxidic interfaces”, the SFB “Ultra fast spin Our investigated nanostructures range from individual dynamics”, the international Max-Planck-research school carbon based complexes and metal-organic/anorganic for “Science and Technology of Nano-Systems” and the clusters to solid state oxides. Besides the natural struc- Centre of innovation competence (ZIK) SiLi-nano have ture formation and self-assembly of the nanostructures been and are continuing to foster the research in this field. their particular chemical and physical properties are

Molecules

MECS

Models

SSIN Solid state interfaces and SBM nanostructures

Materials 18_ SOLID STATE INTERFACES AND NANOSTRUCTURES

Institute of Chemistry Organic Chemistry

Fields of Research: Current Projects and Future Goals:

Our main goal is to find and to develop alternative Carbon-carbon bond formation synthetic approaches suitable for preparative The development of effective technique allowing ef- Prof. Dr. production of various carbon based nanostructures fective intramolecular carbon-carbon (carbon-het- Konstantin Amsharov in isomerically pure form. Our research group is eroatom) bond formation is one of the main focus of 2002 working on the rational synthesis of sp2-carbon the current research. Particular interest lies in the Ph.D from the Institute of Macro based nanostructures which includes the rational field of intramolecular Aryl-Aryl coupling reactions molecular Compounds, Russian synthesis of higher and non-classical fullerenes, which can be performed in domino fashion. This in- Academy of Science geodesic polycyclic hydrocarbons, buckybowls, clude investigation in the field of C-F bond activa- 2005 graphene nanoribbons, nanographenes, carbon tion (cyclodehydrofluorination), surface assisted Max-Planck Institute for Solid State nanotubes and other related systems. Our syn- cyclodehydrogenation and dehydrative π-extension Research, Stuttgart thetic strategy is based on the synthesis of pre- (DPEX). cursor molecules – polycyclic aromatic hydrocar- 2012 bons, containing the carbon framework required synthesis of carbon based nanostructures habilitation in Organic chemistry at for the formation of the target nanostructure. Currently we also working on development of alter- the Institute of Organic Chemistry, University of Stuttgart The respective precursor molecule can be trans- native synthetic approaches allowing effective C-C formed to the desired carbon nanostructure by coupling on metal oxide surfaces. The respective 2014-2019 intramolecular Aryl-Aryl domino-coupling. For this synthetic methods will open facile asses to the syn- FAU Erlangen-Nürnberg leading an purpose specially designed precursor molecules thesis of carbon based nanostructures directly on independent research group are synthesized and investigated for controlled technologically relevant non-metallic templates. Since 2019 synthesis of the respective carbon nanostructures. We believe that our synthetic approaches will pro- Full Professor of Organic Chemistry The characteristic feature of the approach is a vide many interesting carbon based material in rel- at the Martin Luther University zipper mechanism of cyclization (regiospecific evant for further investigation amounts. Halle-Wittenberg condensation in a domino fashion) by which the regiospecifity of each condensation step is unam- biguously predefined by the specially “designed” Contact precursor structure. konstantin.amsharov@chemie. uni-halle.de

https://www.chemie.uni-halle.de/ bereiche_der_chemie/ organische_chemie/33685_42633/

Selected publications:

M.Kolmer, A.K. Steiner, I. Izydorczyk , W. Ko, M. Engelund, M. Szymonski, A.P.Li, K.Amsharov. Rational synthesis of atomically precise graphene nanoribbons directly on metal oxide surfaces. Science 2020, 369, 571-575.

M. Kolmer,R. Zuzak, A.K.Steiner, L. Zajac, M. Engelund, S. Godlewski, M. Szymonski, K. Amsharov. Fluorine-programmed nanozipping to tailored nanographenes on rutile TiO2 surfaces. Science 2019, 363, 57-60.

J. R. Sanchez-Valencia, T. Dienel, O. Gröning, I. Shorubalko, A. Mueller, M. Jansen, K. Amsharov, P. Ruffieux, R. Fasel. Controlled synthesis of single-chirality carbon nanotubes. Nature 2014, 512, 61-64

K. Amsharov, M. A. Kabdulov, M. Jansen. Facile Bucky-Bowl Synthesis by Regiospecific Cove-Region Closure by HF Elimination. Angew. Chem. Int. Ed. 2012, 51, 4594-4597. SOLID STATE INTERFACES AND NANOSTRUCTURES _19

Institute of Mathematics Numerical Mathematics

Fields of Research: Current Projects and Future Goals:

› Time integration of constrained and coupled Numerical Modelling of Highly Prof. Dr. Martin Arnold systems of differential equations Flexible Structures › Geometric integration, Structure preserving Highly flexible slender structures like yarns, ca- 1990 PhD in Numerical Mathematics , coarse grid discretizations of differential bles, hoses or ropes are essential parts of high- Martin Luther University Halle- equations performance engineering systems. The complex Wittenberg, Germany › Model based simulation and optimization in response of such structures in real operational science and engineering conditions is far beyond the capabilities of cur- 1991–1997 › Numerical methods and software for time rent modelling tools that are at the core of mod- PostDoc and Assistant Professor, dependent problems: Interfaces, constraints, ern product development cycles. In the frame- Rostock University, Germany multi-disciplinary applications work of Horizon 2020, we coordinate the 1997 interdisciplinary network THREAD of 26 Euro- Habilitation in Mathematics, Multi-disciplinary and multi-scale aspects of com- pean universities, research organisations and in- Rostock University, Germany plex phenomena and processes in science and engi- dustrial partners who will develop mechanical 1997–2000 neering result typically in mathematical models of models and numerical methods for designing Research Scientist, DLR German some specific structure that is exploited by prob- highly flexible slender structures. This Marie Aerospace Center, Oberpfaffenhofen, lem adapted numerical methods to improve ro- Skłodowska-Curie ITN is one of the first research Prof. W. Kortüm bustness, numerical stability and efficiency. Such projects that applies systematically the novel

2000–2002 specially tailored numerical solution methods are mathematical concept of geometric numerical in- Head of Computational Methods Team, the backbone of model based simulation and opti- tegration in industrial settings. DLR German Aerospace Center, mization in various fields of application. Oberpfaffenhofen and Privatdozent, Our group focusses on time integration methods Munich University of Technology for coupled systems of differential equations and on the numerical solution of constrained systems Since 2003 Full Professor (C4) of Numerical that result from the use of redundant coordinates Mathematics, Martin Luther University in network approaches for modelling complex Halle-Wittenberg systems. We study typical problem classes in science and engineering to design specially adapted Coarse grid discretization of a geometrically exact time integration methods for constrained sys- beam model. Contact tems that combine numerical stability with numerical efficiency in terms of computing time. Time integration of non-smooth problems martin.arnold@ mathematik. uni-halle.de Software aspects include numerical issues as well Design, analysis and implementation of time in- as the standardization of interfaces in (commer- tegration methods are based on mathematical https://sim.mathematik.uni-halle.de/ cial) simulation software. smoothness assumptions that are frequently vio- arnold Recently, the preservation of structural proper- lated in applied problems from science and engi- ties in coarse grid discretizations of differential neering. We investigate alternative approaches equations has found special interest. We con- being based on precise localization of disconti- Selected publications: struct and analyse Lie group time integration nuities, on analytical regularization of non- S. Hante, M. Arnold, RATTLie: A variational Lie methods for flexible multibody systems that are smooth model components or on a numerical group integration scheme for constrained mechanical systems, Journal of Computational modelled by differential equations on a manifold regularization by so-called time-stepping meth- and Applied Mathematics, 2020 (in press), DOI: with Lie group structure. This novel approach ods. In a joint project with the University of Rije- 10.1016/j.cam.2019.112492. helps to avoid singularities in the simulation of ka (G. Jelenić), these numerical results are vali-

M. Arnold, O. Brüls, A. Cardona, Error analysis systems with large rotations. dated by test rig experiments for a rigid body of generalized- Lie group time integration rocking on a flexible structure. methods for constrained mechanical systems, Numerische Mathematik,α 2015, 129, 149–179. Modular time integration of coupled and H. Lang, J. Linn, M. Arnold, Multibody dynamics constrained systems simulation of geometrically exact Cosserat rods, Multibody System Dynamics, 2011, 25, The modular structure of complex coupled systems 285–312. in science and engineering may be exploited in time integration combining different time integra- M. Arnold, Numerical methods for simulation in applied dynamics. In: M. Arnold, W. Schiehlen tion methods (with different, problem adapted (eds.): Simulation Techniques for Applied time step sizes) for different subsystems and re- Dynamics. Springer Wien New York, 2009. stricting the data exchange between subsystems appropriately. For stiff and for constrained sys- Differential equations on manifolds: tems, the numerical stabilization of these meth- Interpolation in Lie groups. ods is a topic of active research. 20_ SOLID STATE INTERFACES AND NANOSTRUCTURES

Institute of Physics Nonequilibrium Many-Body Systems

Fields of Research: Current Projects and Future Goals:

› Nanophysics Superconductor-magnetic heterostructures › Photonics Superconductors have a wide-range of applica- Prof. Dr. Jamal Berakdar › Nanomagnetism tions in energy-saving devices, sensorics, and 1994 › Ultrafast Optics quantum information circuits. Multilayers com- Dr. rer.nat in Theoretical Physics, posed of magnetic materials deposited on super- University of Freiburg, Germany We develop theoretical concepts and numerical conductors show in addition to the superconduct- codes to understand the behavior of matter un- ing and magnetic properties, further emerging 1995 der external driving fields. The goal is to control features that can be exploited in superconducting/ Research associate, Royal Holloway University of London, UK materials properties in a spatio-temporal way or magnetic tunnel junctions and superconductor- even to generate new features by specific engi- based quantum information science. We are de- 1995–1997 neering of the fields and/or the material under veloping new approaches capable of predicting Feoder-Lynen Humboldt fellow and study. We are particularly interested in magneti- the physical properties of meso- and macroscopic research fellow at the Institute of cally active structures at the nanoscale driven by samples of magnetic/superconducting nanostruc- Advanced Studies, Australian National shaped laser pulses, magnetic fields, elastic de- tures. University, Canberra, Australia formations or heat gradients. With a focus on 1997–2006 technological applications we study how classical Magnonics and ultrafast spintronics Scientific member of the Max-Planck or quantum information can be stored, transmit- Instead of optical signals, excitations in a mag- Institute of Microstructure Physics, ted, and retrieved in terms of certain magnetic netic system (called magnons) also serve as a very Halle, Germany phases. One goal is to design fast and reliable effective carrier of information and can be gene Since 2006 electronic devices that offer new functionalities rated and detected at very low energy cost. We Full professor of Theoretical Physics, and operate with low energy consumption. On seek ways to increase the bandwidth and the effi- Martin Luther University Halle- the other hand, we study the influence of materi- ciency of such information channels by material Wittenberg, Halle, Germany al structuring and modifications of its physical design and/or by shaping the input signals. In ad- properties on the propagation of electromagnetic dition, we also study the possibility of using the waves with the aim to identify suitable optical spin as a key element for the operation of elec- Contact materials for polarization shaping and wave-front- tronic circuits, in particular we study such spin- [email protected] structuring of light fields. We use the structured tronic systems driven by short optical fields to laser fields as building blocks for optical communi- achieve a swift operational speed. http://qft0.physik.uni-halle.de/jber/ cation devices and ultrafast science with a par- index.htm ticular emphasis on low-dimensional quantum Photonics and non-linear optics structures such waveguides, quantum dots, and In addition to the temporal structuring of laser Selected publications: molecular aggregates. pulses, a control on the polarization state as well as on the phase of the wave front opens the way Yu, D., Kang, J., Berakdar, J. et al., Nondestructive ultrafast steering of a for new applications of lasers. We study how po- magnetic vortex by terahertz pulses. NPG larization and wave-front structuring affect the Asia Mater 12, 36 (2020). interaction of laser fields with matter in general. current De Ninno G., Wätzel J., Ribič P.R. et al. Laser pulse In addition, we study the propagation of intense Photoelectric effect with a twist laser pulses in optical devices with the goal of Nature Photonics 14, pp 554 (2020). realizing efficient and reliable optical logic gates. Wätzel J., and Berakdar J., Open-Circuit ferromagnetischSuperconductor Ultrafast Generation of Nanoscopic Toroidal Topology and geometry in quantum matter Moments: The Swift Phase Generator, We study how the space-time structure leads to Advanced Quantum Technologies 2, pp chiral multiferroic 1800096 (2019). the emergence of stable phases or resonances. A Substrate particular focus is put on the influence of topology Jia, C., Ma, D., Schäffer, A.F., Berakdar, J., Twisted magnon beams carrying orbital and geometry of the system on the stability of the angular momentum, Nat Commun 10, 2077 formed states in field-free environment or for (2019). With external fields such as a magnetic field generated by driven systems. Pursehouse J., Murray A. J., Wätzel J., Berakdar a current pulse or the electric field of a short laser pulse we J., Dynamic Double-Slit Experiment in a Single calculate, analyze, and seek to control the behavior of Atom, Phys. Rev. Lett. 122, pp 053204 (2019). nanostructured materials and their compositions such as superconductor/ferromagnetic or ferroelectrics with a Jandieri V., Khomeriki R., Berakdar J., Erni D., Theory of soliton propagation in nonlinear magnetic response (called multiferroics). The aim is to photonic crystal waveguides, Optics Express identify new fast, efficient and energy-saving ways to store 27, pp 29558 (2019). and process classical and quantum information. SOLID STATE INTERFACES AND NANOSTRUCTURES _21

Institute of Mathematics Applied Mathematical Analysis

Fields of Research: Current Projects and Future Goals:

› Wave-packets in heterogenous media Surface Plasmon Wave-Packets in Prof. Dr. Tomáš Dohnal › Rigorous asymptotics of wave-packets, Nonlinear Media envelope equations Surface plasmons are electromagnetic waves at in- 2005 PhD in Applied Mathematics, › Bifurcation of nonlinear waves terfaces of metal and dielectric material layers. Due University of New Mexico, USA › Waves in periodic media and at interfaces to the extremely tight localization to the interface these are often applied in nano-photonics and could 2005–2007 Propagation of waves in heterogenous media, once play a role as bit carriers in optical computing. Postdoc, ETH Zurich, Switzerland along interfaces or through media with defects is of In the presence of nonlinearity surface plasmon 2012 importance in various physical applications ranging pulses are possible. Habilitation in Applied Mathematics, from electromagnetic waves (e.g. in photonic KIT, Karlsruhe, Germany crystals) to elastic waves or density waves. Physi- Being governed by the

2012–2018 cally most relevant are finite energy waves. These (vector valued) quasi- Junior Professor, TU Dortmund, can exist in the form of pulses, i.e. wave-packets. linear Maxwell equa- Germany tions in two or three dimensions, it is of Since 2018 importance to find Full Professor of Applied Analysis, simpler approximate Martin Luther University Halle-Wit- tenberg envelope equations for such pulses. This is surface plasmon pulse typically the Ginz- illustration burg-Landau equation. Contact The justification of the approximation requires wave-packet in a 2D periodic medium, showing long time well-posedness of the quasi- tomas.dohnal@mathematik. (T. Dohnal and D. Rudolf, Applic. Ana. 99, 1685–1723, 2020) uni-halle.de linear Maxwell problem. Moreover, the response of the metal to the field is time-delayed as well as www2.mathematik.uni-halle.de/ Wave propagation is typically dispersive which lossy, resulting in the Maxwell system being non- dohnal leads to a delocalization of wave-packets. This local in time and the spatial operator being non- can be, however, balanced by an intrinsic nonlin- self-adjoint. A boot strap argument can be used earity. A typical task in the analysis of nonlinear for the well-posedness on large time intervals for Selected publications: wave-packets is their approximation on asymp- small initial data. T. Dohnal and L. Wahlers. Coupled Mode totically large time scales via a slowly varying en- Equations and Gap Solitons in Higher Dimensions. J. Differ.Equations (2020), 269, velope ansatz. A rigorous justification of such an Spectral Analysis of Surface Plasmons 2386–2418. approximation involves proving a well-posedness Eigenvalues of the Maxwell problem in frequency of the (nonlinear) error equation and careful esti- domain for the metal dielectric interface corre- T. Dohnal and D. Pelinovsky. Bifurcation of nonlinear bound states in the periodic mates of the residual. spond to linear surface plasmons. For the bifurca- Gross-Pitaevskii equation with PT-symmetry. In special cases standing or moving solitary waves tion analysis it is necessary to understand the Proc. R. Soc. Edinb. A (2020), 150, 171–204. exist. These correspond to a balance between the whole spectrum of the problem. The analysis of T. Dohnal and H. Uecker. Bifurcation of Nonlinear dispersion and the nonlinearity. Their existence the essential spectrum is an open problem. The Bloch Waves from the Spectrum in the can be typically shown via a bifurcation analysis or spectral properties also depend on the geometry Gross-Pitaevskii Equation. J. Nonlin. Sci. (2016), 26, 581–618. via variational methods, e.g. energy minimization of the interface. via concentration compactness. Such solitary waves T. Dohnal, A. Lamacz, and B. Schweizer. are usually found in spectral gaps and are then Gap Solitons in Maxwell Equations for Dispersive homogenized models and coefficient formulas for waves in general periodic media. called gap solitons. Their bifurcation analysis from Two Dimensional Photonic Crystals Asymptotic Analysis (2015), 93, 21–49. spectral edges relies on a restriction to a symmetry In dielectric photonic crystals the spectrum is ob- subspace, like, e.g., the parity-time-symmetric sub- tained by the Bloch analysis and typically in- T. Dohnal, M. Plum and W. Reichel. Surface gap soliton ground states for the nonlinear space: . cludes spectral gaps. No bounded linear waves Schrödinger equation. Comm. Math. Phys. exist in these gaps but nonlinear gap solitons may (2011), 308, 511–542. be found. The bifurcation of these from spectral edges is governed by coupled mode equations des cribing the coupling of modulated linear Bloch waves at the spectral edge. The proof of the bifurcation can be obtained using a fixed point itera- tion for the Maxwell system in a suitable function space and a restriction to a symmetric subspace in order to avoid the kernel of the coupled mode PT-symmetric solution of the Gross-Pitaevskii eq linearization operator. 22_ SOLID STATE INTERFACES AND NANOSTRUCTURES

Institute of Physics Functional Oxide Interfaces

Fields of Research: Current Projects and Future Goals:

› Thin film epitaxy of oxide materials Non-collinear interface magnetism › Physics of transition metal oxides in oxides Prof. Dr. Kathrin Dörr › Magnetism and Ferroelectricity Interfaces of ferromagnetic oxides of ABO3 (per- 1996 › Domains in ferroelectric materials ovskite) type are promising for the formation of PhD in Solid State Physics, TU non-trivial spin textures. An example of a spin Dresden, Germany Our research is aimed at the fundamental under- spring is shown in Fig.1. Strong exchange cou- standing of ferroic ordering and switching in thin pling and lattice distortions govern magnetic an- 2000–2010 films, at interfaces, in nanostructures and bulk isotropy and spin textures in ways unknown Research group leader, IFW Dresden, Ferroic Oxide Films materials. Ferroics are materials with a switchable from metals. Novel transport phenomena benefi- magnetic, electric or elastic polarization. They cial for spintronics applications are expected 2003 find wide-spread application in data storage, as from such oxide thin film systems with engi- Postdoc, Trinity College Dublin, sensors and actuators. The properties of thin neered interface magnetism. Ireland, Prof. J. M. D. Coey films can be controlled utilizing interface effects 2007 and elastic strain. One major goal of our research Habilitation in Solid State Physics, is the discovery of strain-driven effects. In-situ TU Dresden, Germany dynamic strain control is realized by using piezo- Since 2011 electric monocrystalline substrates. The approach Full professor (W3), gives access to direct measurements of strain- Institute of Physics dependent electronic and optical properties. Thin films are grown by pulsed laser deposition (KrF 248 nm). Structural analysis is done by (in-house or synchrotron-based) x-ray diffraction. Contact

[email protected]

www.physik.uni-halle.de Switchable spin spring at an epitaxial interface of ferromagnetic oxides (Das 2019). Selected publications:

S. Das et al., Low-field switching of non-collinear spin texture at La Sr MnO - Ferroelastic domain manipulation 0.7 0.3 3 SrRuO3 interfaces, Phys. Rev. B 99, 024416 in polymers (2019). The flexibility of ferroelectric polymers has re- A. Herklotz et al., Designing morphotropic cently been discovered to enable domain manipu- phase composition in BiFeO3, Nano Lett. 19, lation by tip-induced mechanical strain in a force 1033 (2019). Ferroelectric Landau domain pattern of in-plane microscope (Roth 2018). Strain-driven alignment R. Roth et al., Aligning in-plane polarization polarization written mechanically in a P(VDF-TrFE) of electric polarization vitally improves the elec- multiplies piezoresponse in P(VDF-TrFE) films polymer film on graphite. Writing with a force tric performance parameters such as piezoelec- on graphite, New J. Phys. 20, 103044 (2018). microscopy tip is based on the ferroelastic effect. tric and dielectric coefficients. Fig.2 shows a Lan- E. J. Guo et al., Ferroelectric 180° domain wall dau domain with in-plane polarization aligned in motion controlled by biaxial strain, Adv. four directions in a P(VDF-TrFE) film. Mater. 27, 1615 (2015).

K. Dörr and A. Herklotz, Two steps for a Oxide interfaces with strong magnetoelectric switch. Nature 516, 337 spin orbit coupling (2014). Antiferromagnetic oxides offer fascinating op- A. Herklotz et al., Strain response of magnetic tions for ultrafast optical spin control using light / order in perovskite-type oxide films. Phil. electromagnetic radiation from the visible to the Trans. Roy. Soc. A 372, 20120441 (2014). THz range. While early experiments relied on single-crystalline samples, the advances of oxide epitaxy open pathways for domain control and for the growth of materials previously unaccessible in required quality. SOLID STATE INTERFACES AND NANOSTRUCTURES _23

Institute of Chemistry Industrial Chemistry

Fields of Research: Current Projects and Future Goals:

› Preparation and characterisation of porous Oxygen transfer reactions Prof. Dr.-Ing. Thomas Hahn materials and catalysts Preparation of solid single or multi-component › Reaction engineering – coupling of transport catalysts for partial/total oxidation reactions in 1987 Dr.-Ing. in Chemical Process properties and chemical reaction gas or liquid phase especially for aromatic sub- Engineering, Universität strates, assessment of reaction kinetics (activity, Karlsruhe (TH), Germany More than 85 % of the products of chemical in- selectivity, time on stream) and reaction net- dustry are made in catalytic processes. Especially works for gas-phase reactions with/without oxygen 1994 solid catalysts are indispensable for fuel produc- spillover. In-situ characterization of active com- Habilitation and Venia legendi, tion, bulk and fine chemicals and abatement of ponents by solid-electrolyte-potentiometry. Universität Karlsruhe (TH), Germany pollution in end-of-pipe processes. 1996–1999 Our activities in the field of catalysis starts with Optimisation of heterogeneous catalysts Substitute Professor of Chemical the synthesis of nanoscale catalytically active Preparation, characterization and testing of nano- Process Engineering, Universität materials but also includes the formulation and and mesoporous aluminate spinels for high- Karlsruhe (TH), Germany shaping of different porous solids and catalysts temperature reactions, for example dry reforming Since 1999 for use in an industrial reactor, their functional of methane. Professor of Industrial Chemistry, characterisation and the assessment of transport Martin Luther University Halle- and reaction kinetics. We explore novel processing Catalyst deactivation Wittenberg, Germany options experimentally and by using modeling Using local lignite for catalytic cracking with solid and simulation tools. Reactions under study are acid catalysts can only be cost-effective if the deac- diverse, however, (partial) oxidation and acid- tivated catalysts can be reactivated a sufficient Contact base reactions play a major role. number of times. Dependent of cracking conditions the physical blocking of the catalyst by “coke” [email protected] mainly takes place at the outer surface of the cata- www.chemie.uni-halle.de/bereiche_ lyst body and/or inside the porous structure. This der_chemie/technische_chemie/ can be differentiated by use of physical characteri- ak_prof._hahn zation and model reactions with substrates of diffe rent molecule size to give hints for an optimized regeneration procedure. Selected publications:

F. Marske, J. Martins de Souza e Silva, R. B. Thermal energy storage materials Wehrspohn, T. Hahn, D. Enke, Synthesis of monolitic shape-stabilized phase change Monolithic shape-stabilized phase change materials materials with high mechanical stability via a (ss-PCMs) are one of the most promising materials porogen-assisted in situ sol{gel process to store large amounts of solar energy, waste heat RSC Adv., 10 (2020), 3072. and off-peak electricity as heat in energy-saving M. Rückriem, D. Enke, T. Hahn, Inverse gas buildings, photovoltaics and water-heating systems. chromatography (IGC) as a tool for an energetic However, more than 15 wt% PCM in ss-PCMs leads characterisation of porous materials, Micro. Mesopor. Mat., 209 (2015), 99. shape-stabilized PCM to a loss of the monolithic form, low mechanical stabilities and PCM leakage problems. To over- S. Straube, T. Hahn, H. Köser, Adsorption and Oxidation of Mercury in Tail-end SCR-DeNOx come these problems, over 60 wt% PCM are incor- Plants - Bench Scale Investigations and porated in situ in a highly mechanical stable silica Speciation Experiments, Appl. Catal. B, 79 matrix by a sol-gel synthesis. Pore size effects on (2008) 286. physicochemical properties are analyzed. M. Estenfelder, T. Hahn, H.-G. Lintz, Solid Electrolyte Potentiometry Aided Study of Investigation of phase formation in Oxidic catalysts, Catal. Rev. 46 (2004) 1. silica-free glasses and glass-ceramics in the F. C. Buciuman, F. Patcas, T. Hahn, Synergy Na2O-B2O3-MxOy (M = Fe, Ti) system effect between copper and manganese oxides in hopcalite catalysts, Stud. Surf. Sci. Catal., Fundamental studies of the Na2O-B2O3-MxOy 138 (2001) 315. (M = Fe, Ti) system concerning the complex rela- Controlled pore glass CPG (Enke, Dirk: "Über die anwendungs- tionships between initial glass composition, crys- bezogene Charakterisierung von Katalysatorträgern", tallization conditions, structure formation mecha- Habilitationsschrift, Martin Luther University Halle-Witten- nisms and properties of the resulting porous berg, 2005) glass-ceramics. The aim is to prepare porous and mechanically stable titanium oxide- and/or iron oxide-based glass-ceramic monoliths. Further systematic investigations regarding the control of morphology and the crystallizing species. 24_ SOLID STATE INTERFACES AND NANOSTRUCTURES

Institute of Physics Materials Research by Means of Positron Annihilation

Fields of Research: Current Projects and Future Goals:

› Defect studies in semiconductors, Micro- and meso-porous materials metals and alloys Controlled pore glass can be used as carrier for Prof. Dr. Reinhard › Study of meso- and microporous materials catalysts, molecular filter membranes, carriers Krause-Rehberg

› Study of open-volume in polymers for long-term retard drugs, for sensors, etc. Posi- 1976–1981 and ionic liquids tron annihilation was established to be a new Studies of physics at Martin Luther standard tool for the investigation of such porous University Halle-Wittenberg Positron Annihilation is used for many years as glass systems. Low-k dielectric layers are used in successful tool for the study of different type of ultra-large scale integrated circuits for the reduc- 1985 Ph.D. Thesis in Experimental Physics defects in all kind of crystalline materials such as tion of the product R×C, and can, thus, help to at Martin Luther University Halle- metals, alloys, elemental and compound semi- increase further the clock frequency of CPU’s. The Wittenberg conductors. Vacancies, vacancy clusters, dislo MePS system of EPOS is an ideal tool for the char- cations and precipitates are potential research acterization of these closed micro-porous sys- 1986 and 1990 objects. Moreover, positronium is formed in die- tems and will be used for further investigations. Research visits at Technical University lectric media and can be used to measure the pore Helsinki, Finland size and pore size distribution in a range of 0.5 to Semiconductors 1995 50 nm pore size, even in closed pore systems, like Many defects problems in elemental and com- Habilitation in Experimental Physics low-k materials, controlled pore glass, etc. The pound semiconductors can be studied by posi- at Martin Luther University open-volume between molecular chains in poly- trons. Of particular interest is in the moment the Halle-Wittenberg mers and ionic liquids can also be studied as func- appearance of vacancy-type defects during diffu- since 2002 tion of temperature, sample densification, gas sion of Zn and Cu in III-V compounds. Also the Extraordinary (apl.) Professor at the load etc. study of extended defects in GaN and other semi- Martin Luther University Halle- conductors during ion-splitting (smart cut) is of Wittenberg, Germany Our lab accomodates all relevant methods of the current and future interest. Finally, thin photo- since 2009 positron annihilation technique, such as analog voltaic layers of CuInGaSe2 will be subject of de- Vice-Chairman of the “International and digital positron lifetime and Doppler broade fect investigation. Advisory Committee Positron ning spectroscopy. A positron beam system using Annihilation” monoenergetic positrons allows the investigation Metals of near-surface defects. In addition, we construc Fe-Cr alloys are of interest for use as wall mate- ted an intense, pulsed positron source (EPOS Sys- rial in fusion reactors. The study of defect genera- Contact tem) as a user facility at the Helmholtz Center tion by neutrons and also after ion implantation reinhard.krause-rehberg@physik. Dresden-Rossendorf. is a running project. Moreover, in near future the uni-halle.de role of quenched-in vacancies for the nucleation of precipitation in Al alloys will be studied. http://positron.physik.uni-halle.de

Selected publications:

Stefan Spannenberger, Vanessa Miß, Edda Klotz, Janosch Kettner, Marvin Cronau, Asvitha Ramanayagam, Francesco di Capua, Mohamed Elsayed, Reinhard Krause-Rehberg, Michael Vogel, and Bernhard Roling. Annealing-induced vacancy formation enables extraordinarily high Li+ ion conductivity in the amorphous electrolyte 0.33 LiI+0.67 Li3PS4. Solid State Ionics 2019, 341, 115040 1-7

S. Assal, M. Elsayed, J. Nicolas, M.O. Liedke, A. Wagner, M. Butterling, R. Krause-Rehberg, and O. Moutanabbir. Vacancy complexes in nonequilibrium germanium-tin semiconductors. Applied Physics Letters 2019, 114, 251907 1-5

Wycliffe K. Kipnusu, Mohamed Elsayed, Ciprian Iacob, Sebastian Pawlus, Reinhard Krause-Rehberg, and Marian Paluch. The Glassy Dynamics Predicted by the Mutual Role of the Free and Activation Volumes. Soft matter 2019, 15, 4656−4661

The pulsed, monoenergetic positron beam MePS is part of the intense positron source EPOS at the Helmholtz Center Dresden-Rossendorf. SOLID STATE INTERFACES AND NANOSTRUCTURES _25

Institute of Mathematics Numerical Methods for Stochastic Differential Equations

Fields of Research: Current Projects and Future Goals:

› Numerical analysis of stochastic evolution Galerkin finite element methods for Prof. Dr. Raphael Kruse equations stochastic evolution equations › Galerkin finite element methods for Numerical methods for stochastic evolution 2008 Diploma in Mathematics, Bielefeld stochastic partial differential equations equations in infinite dimensions (such as the University, Germany › Randomized schemes for rough differential stochastic heat or wave equation) are investi- equations gated. The goal is to design more efficient 2012 › Monte Carlo methods for non-smooth methods by better intertwining different strate- Dr. math., Bielefeld University, problems gies, which are used for the discretization of Germany › Stability, complexity and error analysis the evolution equation with respect to the spatial 2012–2014 or temporal variables. For instance, we aim to PostDoc, SAM, ETH Zurich, Evolution equations are a powerful and well- better integrate the Euler-Maruyama method Switzerland established tool to model highly complex phe- and Galerkin finite element methods with 2014–2019 nomena in physics, chemistry, biology, medicine Monte-Carlo methods by making use of adaptive Head of a junior research group, TU and the engineering disciplines. Important ex- strategies, the multi-level Monte Carlo approach Berlin, Germany amples include the porous media equation in fluid or sparse grid techniques. mechanics, the Cahn-Hilliard equation in metal- Since 2019 lurgy, or the FitzHugh-Nagumo equation in neuro- Quasi-linear stochastic partial differential Professor (W2) for Numerical Methods for Stochastic Differential Equations, science. Stochastic evolution equations have equation Martin Luther University Halle- attracted a lot of attention in various mathemati- In recent years, there has been a considerable pro- Wittenberg cal fields such as stochastic analysis, numerical gress in the analysis of quasi-linear stochastic analysis and PDE theory over the last decades. In partial differential equations, e.g., the stochastic Uncertainty Quantification, for instance, one in- porous media equation, based on the application Contact troduces random coefficients or stochastic per- of variational methods. We examine if these ana- turbations into evolution equations to model in- lytical tools can be adapted to also perform an error [email protected] complete knowledge of parameter values or and stability analysis of associated numerical www.mathematik.uni-halle.de/numsde measurement errors. Other processes, such as the methods for these problems. orcid.org/0000-0002-8341-5097 motion of a Brownian particle suspended in a moving fluid or the production, transport and Randomized numerical methods for rough consumption of renewable energy, are intrinsi- differential equations Selected publications: cally random and directly modeled by stochastic It is already well-known that by randomizing M. Eisenmann, M. Kovács, R. Kruse, S. Larsson, differential equations. quadrature rules one can combine the benefits of On a Randomized Backward Euler Method for Nonlinear Evolution Equations with In most cases, the presence of stochastic noises Monte Carlo methods with those of classical nu- Time-Irregular Coefficients. Found Comput leads to a low regularity of the exact solution. In merical integration methods. For instance, the Math 19, 1387–1430 (2019). particular, a solution to a stochastic differential randomized Riemann sum has a higher order of

W.-J. Beyn, E. Isaak, R. Kruse, Stochastic equation is typically nowhere differentiable. convergence than the deterministic Riemann C-Stability and B-Consistency of Explicit and Their mathematical solution therefore requires sum or the standard Monte Carlo method with- Implicit Milstein-Type Schemes. J Sci Comput the development of novel analytical tools. In ad- out increasing the smoothness requirements on 70, 1042–1077 (2017). dition, the accuracy and performance of numerical the integrand. In this project we study how this R. Kruse, Consistency and stability of a methods is often affected severely. Due to the low result can be extended to develop novel numerical Milstein–Galerkin finite element scheme for semilinear SPDE. Stoch PDE: Anal Comp 2, regularity, standard approaches to construct effi- methods for non-smooth, stochastic or rough diffe 471–516 (2014). cient numerical methods, e.g. Runge-Kutta rential equations. methods, are often intractable and their speed of R. Kruse, Strong and Weak Approximation of Semilinear Stochastic Evolution Equations. convergence is typically reduced drastically. Lecture Notes in Mathematics, Vol. 2093, The overall goal of the research activities therefore Springer, (2014). consists in the design and the analysis of more efficient numerical methods for the simulation of evolution equations with random or stochastic perturbations. 26_ SOLID STATE INTERFACES AND NANOSTRUCTURES

Institute of Physics Quantum Theory of the Solid State

Fields of Research: Current Projects and Future Goals:

› Multiferroics and magnetoelectric coupling Multiferroics and magnetoelectric coupling › Spintronics Multiferrioc materials are particularly interesting Prof. Dr. Ingrid Mertig › Topological properties in solids since they show a spontaneous magnetisation 1982 and a spontaneous polarisation in one and the PhD in Theoretical Physics, Our activities are attached to the quantum theo- same system. The interaction of magnetisation TU Dresden, Germany retical description of solids based on density and polarisation is called magnetoelectric coupling functional theory. This means that we start to which offers the opportunity that magnetic in- 1985–1990 model our systems at the atomic level, do not take formation can be influenced by an electric field PostDoc, Joint Institute for Nuclear Research, Russia any free parameter into account, and solve the and vice versa. This is a very attractive concept for Schrödinger and other relevant equations to obtain memory technology. We consider in particular 1995 finally a macroscopic property that can be meas- multiferroic interfaces which occur in artificially Habilitation in Theoretical Physics, ured. To support the experimental developments, grown heterostructures and separate a ferroelectric TU Dresden, Germany to predict new materials for future applications, from a ferromagnetic layer. 1997–2001 and to optimize the effects under consideration, Heisenberg Fellow of the German first-principle electronic structure calculations Spintronics Research Foundation are the most powerful tool. In this way, we gain Spintronics is an emerging field based on the since 2001 insight into the microscopic origin of macroscopic transport properties of electrons exploiting both Full Professor (C4) of Theoretical properties of metals, semi-conductors, and insu- their charge and spin degree of freedom. Most of Physics, Martin Luther University lators in their 3D bulk formation or as 2D sur- the spintronic effects like giant magnetoresist- Halle-Wittenberg, Germany faces and interfaces and 1D wires. The underlying ance and tunneling magnetoreistance occur in methods are particularly useful to describe nano- magnetic materials and are widely used. The next structures of realistic dimension up to thousands step is the search for spintronic devices manipu- Contact of atoms. The formalism is based on Green func- lating pure spin currents. They would play an im- [email protected] tions for the equilibrium and the non-equilibrium portant role in the next generation of low-energy- state. We are particularly qualified for the ab initio consumption electronics. Pure spin currents are www.physik.uni-halle.de/ description of transport properties in the coherent generated by the spin Hall effect. We are looking fachgruppen/qtfk limit based on Landauer theory and in the diffusive for alloys with giant spin currents. limit based on Boltzmann theory. In general, our Selected publications: theory is material specific and has a strong overlap Topological properties in solids with experiments. The next generation of spintronic effects is based B. Göbel, A. Mook, J. Henk, and I. Mertig, Antiferromagnetic skyrmion crystals: on spin currents which occur in metals as well as Generation, topological Hall, and topological in insulators, in particular in topologically non- spin Hall effect. Phys. Rev. B 96, 060406(R) trivial materials. Spin currents are a response to (2017).

an external stimulus – for example an electric A. Mook, J. Henk, and I. Mertig, Edge states in field or a temperature gradient. Topological prop- topological magnon insulators. Phys. Rev. B 90, erties are always related to spin-orbit interaction 024412 (2014). and cause a whole zoo of transversal transport M. Gradhand, D. V. Fedorov, P. Zahn, and I. coefficients: the trio of Hall, Nernst, and quantum Mertig, Extrinsic spin Hall effect from first Hall effects, all in their conventional, anomalous, principles. Phys. Rev. Lett. 104, 186403 (2010). and spin flavour. They offer the possibility for M. Fechner, I. V. Maznichenko, S. Ostanin, A. future low-energy-consumption electronics. Ernst, J. Henk, P. Bruno, and I. Mertig, Magnetic phase transition in two-phase multiferroics predicted from first principles. Phys. Rev. B 78, 212406 (2008).

V. V. Maslyuk, A. Bagrets, V. Meded, A. Arnold, F. Evers, M. Brandbyge, T. Bredow, and I. Mertig, Organometallic benzene-vanadium wires: A one-dimensional half-metallic ferromagnet. Phys. Rev. Lett. 97, 097201 (2006).

Bloch skyrmions – magnetic whirls in a solid SOLID STATE INTERFACES AND NANOSTRUCTURES _27

Institute of Chemistry Molecular and Structural Chemistry

Fields of Research: Current Projects and Future Goals:

› Main group element chemistry Metal complexes and clusters with Prof. Dr. Kurt Merzweiler › Coordination and cluster chemistry functionalized silylamidoligands › X-Ray crystal structure analysis Currently, this work concentrates on the investi- 1986 PhD in Inorganic Chemistry, › Metal complexes and clusters with gation of low valent Cr(II), Mo(II) and V(II) com- University of Karlsruhe (TH) functionalized silylamido ligands pounds. The first results in the case of Mo(II) have › Structural chemistry of metal amides shown, that silylamido ligands support the for- 1991 › Donor-functionalized 2,4-pentandionate mation of Mo-Mo multiple bonds along with Mo Habilitation, University of ligands clusters, depending on the nature of the silyla- Karlsruhe (TH) mide ligand. According to preliminary tests, Since 1994 A main part of our research interests is located at Mo(III) silylamides display catalytic activity to- Full Professor (C3) of Inorganic the interface between main group and transition wards cyclotrimerization of isocyanates. The field of Chemistry, Martin Luther University metal chemistry. At the beginning, the research Cr(II) and V(II) complexes with R2Si(NR´)2 ligands Halle-Wittenberg was focused on mixed main group/transition is practically unexplored, probably due their ex-

metal cluster compounds like [{Cp(CO)2Fe}4Sn4E6] treme air and moisture sensitivity. The goal of this (E = S, Se, Te) and the employment of the related project is to provide an access to this class of com- 3– Contact thiostannates RSnS3 as building blocks for hetero- pounds using "tailor made" silylamide ligands nuclear clusters like [(RSnS ) (CuPR´ ) ]. In order with OR, NR , PR and N-heterocyclic carbene [email protected] 3 2 3 6 2 2 to extend and thus generalize this approach of (NHC) functionalities. Apart from the synthetic www.chemie.uni-halle.de/bereiche_ cluster synthesis, analogous trifunctional silylami- challenge, this study is designed to give insight der_chemie/anorganische_ 3– do ligands RSi(NR´)3 and difunctional deriva- into the magnetic behavior of low-valent Cr and V chemie/33619_91885 2– tives R2Si(NR´)2 were applied. This led to the complexes and the formation of metal-metal bonds. discovery of hitherto unknown copper(I) silylamide clusters with up to 12 copper atoms, e.g. [Cu Structural chemistry of metal amides Selected publications: 8 {Me2Si(NPh)2}], [Cu9{MesSi(NPh)3}2(PhCO2)3], and Nitrogen ligands like amides and imides are of U. Morgenstern, C. Wagner, K. Merzweiler. [Li(THF)4]2[Cu12{MeSi(NPh)3}4]. Generally, Cu(I) considerable interest in coordination chemistry, Dinuclear Molybdenum(II) Complexes with Thioether Functionalized Silylamide Ligands, silylamides exhibit extreme air and moisture both of main group and transition metals. In the Z. Anorg. Allg. Chem. 2019, 645, 1. sensitivity along with very low thermal stability. case of main group elements our research is fo- In order to improve the thermal stability and to cused on alkali metal and group 14 element R. Albrecht, P. Liebing, U. Morgenstern, C. Wagner, K. Merzweiler. Ni(II) complexes with ease the accessability of Cu(I) and other metal deri (Ge(II), Sn(II)) derivatives of anilides bearing ad- thioether-functionalized silylamide ligands. vatives, silylamido ligands bearing auxiliary donor ditional donor functions OR, NR2, SR and PR2. Synthesis and crystal structures of groups were developed. Particularly the introduc- Typically, the solid state structure of sodium and [Ni{Me2Si(N-C6H4-2-S-tBu)2}], [Ni{Ph2Si(N-

C6H4-2-SMe)2}] and [Ni{Ph2Si(N-C6H4-2- tion of thioether functionalities opened the door potassium anilides are characterized by extended SPh) }]. Z. Naturforsch. B. 2019, 74, 233. 2 to new types of silylamide cluster compounds. 3D structures, and in contrast to this Ge(II) and

U. Morgenstern, C. Wagner, K. Merzweiler. Ligand improvement and optimization is by no Sn(II) derivatives tend to form molecular hetero-

Synthesis and crystal structure of the copper means limited to the silyamide area. The concept cubane-type clusters [M4(NR)4]. In the case of re- silylamide cluster compound of side-arm functionalization can be also applied lated Cu(I) compounds, cluster complexes like [Cu9{MesSi(NPh)3}2 (PhCO2)3]. Z. Naturforsch. B. 2018, 11, 953. for classical ligands like amides, amidines and [Cu6X2(NHR´)4] (X= Cl, Br, I; R´= C6H4-2-PPh2) acetylacetonates in order to design new coordina- dominate. Currently, the investigation of the P. Liebing, K. Merzweiler. Gold(I) and Silver(I) tion patterns. Some years ago this approach was structure directing influence of the OR, SR, NR Complexes with Thioether Functionalized 2 Silylamido Ligands. used to modify acetylacetonato ligands with chiral and PR2 functionalization is in focus. Z. Anorg. Allg. Chem. 2017, 643, 1220 amino acid units. Furthermore, donor-functiona

C. Wagner, K. Merzweiler. Novel Dinuclear lized amides of alkali metals and copper(I) were Donor-functionalized 2,4-pentandionate Tin(II) and Lead(II) Compounds with 2-Pyridyl studied. ligands Functionalized Silylamido Ligands. Z. Anorg. Acetylacetonate ligands are widely used in coor- Allg. Chem. 2017, 643, 938. dination chemistry. The reaction of 3-formyl P. Liebing, J. Freudenberg, C. Heiser, acetylacetone with OR, SR or PR2 functionalized K. Merzweiler. Novel Copper(I) Clusters with anilines provides a synthetic path to novel triden- 2-(Diphenylphosphanyl)anilide Ligands. Synthesis and Crystal Structures of tate ligands with N,O,X donor sets (X = O, S, P). First [Cu X (NHR) ] (X = Cl, Br, I; R = C H -2-PPh ). 6 2 4 6 4 2 studies on this type of N,O,P-ligands revealed a Z. Anorg. Allg. Chem. 2017, 643, 203. pincer-type coordination mode in octahedral complexes of Fe2+, Mn2+, Ni2+. In the last years, pincer type ligands have attracted growing interest due to their application in homogenous catalysis. A future goal in this project is the synthesis of Central core of the cluster pincer-type hybrid ligands combining the coordi-

[Cu8{Me2Si(NPh)2}4] nation properties of acetylacetonates and N-heterocyclic carbenes (NHC). 28_ SOLID STATE INTERFACES AND NANOSTRUCTURES

Max Planck Institute of Microstructure Physics Experimental Department II

Fields of Research: Atomically engineered materials Experimental methods to deposit layers just one › Spintronics atom or one unit cell thick include physical › Oxides and Interfaces methods, such as molecular beam epitaxy, pulsed Prof. Dr. Stuart Parkin › Atomically engineered materials laser deposition and magnetron and ion beam Alexander von Humboldt Professor

› Computational Materials Discovery sputtering, as well as chemical methods such as 1981 › Cognitive Devices and Bio-Inspired Materials atomic layer deposition and chemical vapor PhD in Physics (University of deposition. Theoretical methods to simulate the Cambridge, UK) growth of such materials and to calculate their Current Projects and Future Goals: properties are powerful and accurate enough 1980–1981 PostDoc (Université Paris-Sud, France) that, by using these methods in tandem with Spintronics experiment, rapid advances in atomically engi 1981 Spintronics is a field of research that comprises neered materials with novel and technologically PostDoc (IBM San Jose Research the generation, manipulation and detection of relevant properties is currently possible. Atomi- Laboratory, USA) spin-polarized electrons in a wide range of cally engineered materials underpin the fields of 1982–2014 materials including metals, insulators, and semi- spintronics, oxide electronics, cognitive devices IBM Almaden Research Center, conductors. The most important spintronic and routes to room temperature superconductors. San Jose, USA materials are composed of artificially engineered - Research Staff Member atomically layered magnetic thin film structures Computational Materials Discovery - IBM Fellow (since 1999) with spin-dependent transport properties. The The theoretical modelling of structure-property - Manager of Magnetoelecronics Group use of both spin-polarized charge currents and relationships from the nano- to the meso-scale (since 1999) pure spin currents, generated by electric voltages, requires the synergistic use of various simulation since 2014 temperature gradients and / or optical means, to methodologies. Electronic and magnetic proper- Director (Max Planck Institute of excite and manipulate magnetic moments is of ties of, e.g., molecules, nano-wires or oxide layers Microstructure Physics, Halle, great interest from both fundamental and tech- are studied by quantum mechanical methods, Germany) and Alexander von nological perspectives. Spin-orbit interaction via the development and application of electronic Humboldt Professor (MLU) is a principle driving mechanism behind many density functional techniques. Molecular arrange- topical phenomena including spin-orbit torques, ments and properties on longer length scales of, current driven domain-wall motion, perpendicu- e.g., macromolecules or magnetic model systems, Contact lar magnetic anisotropy, spin Hall effect, anoma- are studied by Molecular Dynamics and Monte [email protected] lous and topological Hall effects, and topological Carlo techniques. Heterogeneous structures on magnetic structures including skyrmions. still larger scales are mapped onto field-theoretical www.magnetoresistance.de descriptions and treated with tools of numerical Oxides and Interfaces mathematics. Different techniques are used to Selected publications: Complex oxides display an enormous variety of bridge multiple time- and length-scales to charac- properties, ranging from insulators to metals and terise and understand the functions of complex J. Jeong, N. Aetukuri, T. Graf, T. D. Schladt, M. G. Samant, and S. S. P. Parkin; Suppression of superconductors, from anti-ferromagnetism to structures. The use of such computational methods Metal-Insulator Transition in VO2 by Electric ferromagnetism, and ferroelectric to paraelectric to explore and predict the properties of novel, en- Field–Induced Oxygen Vacancy Formation to name just a few. By forming heterostructures gineered materials is an emerging discipline of Science 339, 1402 (2013) between thin films of distinct oxides, novel considerable current interest. H. Yang, S.-H. Yang, S. Takahashi, S. Maekawa, materials can be engineered with functionalities and S. S. P. Parkin; Extremely long that are not otherwise seen in the individual Cognitive Devices and Bio-Inspired quasiparticle spin lifetimes in superconducting aluminium using MgO tunnel spin injectors materials. One example are magneto-electric Materials Nat. Mater. 9, 586 (2010) phenomena in which magnetic fields can influ- It is clear that nature has devised methods of pre- S. S. P. Parkin, M. Hayashi, and L. Thomas; ence ferroelectric behavior or electric fields can paring materials that we can’t yet replicate and Magnetic Domain-Wall Racetrack Memory control magnetic behavior. with properties that we can’t yet match. However, Science 320, 190 (2008) the very existence of such biological materials and L. Thomas, M. Hayashi, X. Jiang, R. Moriya, C. functionalities serves as inspiration for research Rettner, and S. S. P. Parkin; Oscillatory into novel ways of manufacturing materials and dependence of current-driven magnetic fabricating devices with such properties. A very domain wall motion on current pulse length Nature 443, 197 (2006) A vertical-configuration racetrack important area of research is the development of offers the highest storage density cognitive computing devices that could support S. S. P. Parkin; Systematic variation of the by storing the pattern in a strength and oscillation period of indirect novel computing architectures that could carry magnetic exchange coupling through the 3d, U-shaped nanowire normal to the out computations a million times more efficiently 4d, and 5d transition metals plane of the substrate. than conventional charge based devices. Rev. Lett. 67, 3598 (1991) SOLID STATE INTERFACES AND NANOSTRUCTURES _29

Institute of Mathematics Applied Stochastics

Fields of Research: Current Projects and Future Goals:

› Numerical Approximations to Rough/ Discretizing Rough/Stochastic (Partial) Jun.-Prof. Dr. Stochastic Partial Differential Equations Differential Equations Martin Redmann › Lévy Processes Rough/Stochastic (Partial) Differential Equations

2012–2016 › Stochastic Differential Equations/Stochastic can be used to model applications in different ar- PhD student in mathematics, Max Evolution Equations eas. Usually they cannot be solved analytically. Planck Institute for Dynamics of › Model Reduction for Stochastic Systems Therefore, we investigate and generalize numerical Complex Technical Systems in › Galerkin Schemes for Controlled Stochastic approximation schemes (like finite element meth- Magdeburg Partial Differential Equations with Lévy ods or Runge-Kutta methods) for these equations Noise and subsequently run simulations. 2016–2019 Postdoctoral researcher in mathematics, Weierstraß Institute for Applied The focus of our research is on stochastic (partial) Model Order Reduction for Stochastic Analysis and Stochastics in Berlin differential equations (S(P)DEs) and at the inter- Systems face of analysis, numerics and stochastics. In many real life applications, large dimensional 2018–2019 In particular, efficient solution algorithms for problem occur, especially when stochastic PDE Interim Professor, University of S(P)DEs are investigated and applications with models are discretized in space. We investigate Southern Denmark (Odense): Department of Mathematics and uncertainties in other natural sciences are modeled and study methods to reduce the dimension of the Computer Science by S(P)DEs. This provides links to other disciplines problem leading to a lower computational com- like chemistry and physics as, e.g., in the field of plexity. We are mainly interested in non-linear Since 2020 molecular dynamics or in materials science (data- stochastic systems which are reduced using, e.g., Assistant Professor (W1 with Tenure based modeling and simulation of phenomena are the proper orthogonal decomposition, reduced Track to W2) for Applied Stochastics, under uncertainties: optimization of model pa- basis methods or system-theoretic model reduc- Martin Luther University of Halle-Wittenberg rameters; high-dimensional simulation; model tion. reduction). Option Pricing Contact Current projects of this group deal with the ana We develop and study efficient algorithms to price, lysis and the numerical approximation of stochastic e.g., Bermudan or American options. We are par- martin.redmann@mathematik. uni-halle.de (partial) differential equations that can, e.g., be ticularly interested in problems where existing used in the context of modeling materials and methods fail since they do not provide sufficiently www2.mathematik.uni-halle.de/ their properties. accurate results. Moreover, we apply model order redmann reduction to large-scale asset price models which allows to apply option pricing algorithms to the problem that are usually not feasible in high dimen- Selected publications: sions. M. Redmann, S. Riedel, Runge, Kutta methods for rough differential equations, Submitted 2020. Solving High-Dimensional Partial Differen- tial Equations C. Bayer, D. Belomestny, M. Redmann, S. These equations have applications, e.g., in molecular Riedel, J. Schoenmakers, Solving linear parabolic rough partial differential equations, dynamics and it is usually very complicated to Journal of Mathematical Analysis and solve them since finite element methods cannot Applications, 2020. be applied due to the curse of dimensionality. We M. Redmann, Type II balanced truncation for aim to approximate high-dimensional PDEs by ones deterministic bilinear control systems, SIAM of low order. Here, model reduction for stochastic Journal on Control and Optimization, 2018. nonlinear systems becomes the key, because sto- M. Redmann, Type II singular perturbation chastic representations for the PDE solutions can approximation for linear systems with Lévy be used. Noise, SIAM Journal on Control and Optimization, 2018. The project deals with high dimensional partial differential equations that play a role in molecular P. Benner and M. Redmann, Model Reduction dynamics and in finance, too. for Stochastic Systems, Stochastic Partial Differential Equations: Analysis and Computations, 2015 .

P. Benner, T. Damm, M. Redmann, and Y. R. Rodriguez Cruz, Positive Operators and Stable Truncation, Linear Algebra and its Applications, 2014. 30_ SOLID STATE INTERFACES AND NANOSTRUCTURES

Institute of Mathematics Geometry

Fields of Research: Current Projects and Future Goals:

› Singularities of mappings and of varieties Classification of singularities (classification, deformations and invariants) Most of the classifications of mappings from Prof. Dr. Joachim Rieger › Applications of singularity theory (e.g. to n-space to p-space have been carried out for par- 1988 differential geometry, topology and ticular pairs (n, p) of dimensions, and either list PhD in Singularity Theory, enumerative geometry) the A-orbits up to a certain codimension or up to University of London, England › Bifurcations in families of mappings a certain modality (first the 0-modal, deformation on real algebraic sets, stratifications of finite, singularities, also known as simple singu- 1988–1989 bifurcation varieties larities, next the uni-modal singularities, and so Royal Society Fellowship, University of Warwick, England › Computational aspects of invariants on). We want to extend these classifications in of ideals and modules two directions. (1) We can relate the A-orbits of 1989–1991 modality 0 for dimension pairs (n, p) on certain Postdoc, University of Karlsruhe

Singularity theory is concerned both with singu- lines by three operations called extensions, sus- 1992–1995 larities of smooth mappings between (real or pensions and embedding. (2) We consider a certain DFG Habilitation Fellowship, complex) manifolds and with singular points of subgroup A(E), which replaces the right diffeo- University of Hamburg varieties. Some of the principal questions in this morphisms in the group A by diffeomorphisms field are the classification of singularities (up to preserving the exceptional divisor of the blowing- 1997–1999 Associate Professor of Mathematics, various notions of equivalence), the study of in- up of the source. University of Sao Paulo, Brazil variants associated with a singularity, and the study of deformations of singularities (which sin- Invariants and deformations of singularities Since 1999 gularities are stable and persist under small For singularities of complex analytic mappings Full Professor (C4) of Geometry, deformations, which stable singularities can appear there are analytic and topological invariants de- Martin Luther University Halle-Wit- in a deformation of a given unstable singularity?). scribing the geometry and topology of the image tenberg The most classical singularities are the stable or the discriminant of a stable deformation of an critical points of a smooth real-valued function on a unstable singularity. And one wants to find for- manifold: by a non-linear change of coordinates mulas for these invariants e.g. in terms of certain Contact (a diffeomorphism) the function near each critical multiplicities and also formulas relating various coxeter1.mathematik.uni-halle.de/ point can be transformed to a sum of squares in invariants. The constancy of these invariants in ~rieger the variables (with coefficients +1 and -1), and it is families plays a key role in equisingularity prob- known from Morse theory that the critical points lems. Related are also invariants of complex (ana- www2.mathematik.uni-halle.de provide a lot of information about the manifold. lytic and algebraic) varieties. For example, the The more recent work on singularities arising in jumping numbers associated to multiplier ideals Selected publications: the more general context of smooth mappings of rational surface singularities. and varieties has similar applications in other areas Baumers, H. and Dachs-Cadefau, F., Computing jumping numbers in higher dimensions, of mathematics. Projections of algebraic surfaces Manuscripta Math. 161 (2020), 35–59. Our group is working on the classification of sin- The projection of an algebraic surface M in a projective gularities of mappings, on subgroups of the group space P from a point c in M (or more generally from Domitrz, W. and Rieger, J.H., Volume-preserving subgroups of A and K and singularities in of diffeomorphisms preserving some additional a linear subspace L which intersects M) is a map unimodular geometry, Math. Annalen 345 structure (e.g. some volume form), on the use of from the blow-up of M, rather than from M itself. In (2009), 783–817. invariants for equisingularity problems, and on order to compactify the space of all projections of a Rieger, J.H. et al., M-deformations of A-simple deformations of singularities. We are also interest- given surface M one has to admit such inner projec- germs from Rn to Rn+1, Math. Proc. Cambridge ed in applications of singularity theory to differ- tions of M from points c in M. Outer projections of Phil. Soc. 142 (2008), 181–195. ential geometry, to low dimensional topology M, from points c in the complement of M, are classi- Carter, J.S., et al., A combinatorial description of (knotted surfaces) and to enumerative questions fied by A-equivalence. Inner projections, from knotted surfaces and their isotopies, Advances in projective algebraic geometry. points c in M, are classified by the refined A(E)- Math. 127 (1997), 1–51.

equivalence. And the space P has a natural stratifi- Rieger, J.H., On the complexity and cation by equisingularity strata of projections (the computation of view graphs of piecewise complement of M is stratified by A-types and M by smooth algebraic surfaces, Phil. Trans. Royal Soc. London Ser. A 354 (1996), 1899–1940. A(E)-types). And for a generic algebraic surface M of a given degree d one can study the enumerative Rieger, J.H., Families of maps from the plane to the plane, J. London Math. Soc. 36 (1987), geometry of this stratification of P. 351–369. SOLID STATE INTERFACES AND NANOSTRUCTURES _31

Institute of Physics Nonlinear Nanophotonics

Fields of Research: Current Projects and Future Goals:

The miniaturisation of light propagation on-chip Luminescence enhancement Prof. Dr. Jörg Schilling and integration of a wide variety of optical pro- in nanostructure resonators cesses in micro- and nanostructures represent an An increased density of photonic states (Purcell 2002 PhD in Physics from Martin Luther intriguing possibility for future optical informa- effect) and increased outcoupling of light from University Halle-Wittenberg for tion technology and sensing (“optics on the cylindrical Silicon- Mie resonators is used to en- research on Photonic Crystals carried chip”). The research of the group focuses especially hance the luminescence of embedded Germanium out at Max Planck Institute of on the integration of active processes into silicon quantum dots. Current research focuses on the Microstructure Physics, Halle photonic structures by either trying to mould the further increase in Q-factor of the resonances by optical properties of silicon itself or combining coupling several closely spaced Mie-resonators 2002–2005 Postdoc at California Inst. Of silicon with other materials resulting in hybrid resulting in collective resonances (Fig. 1) enhancing Technology, Pasadena, USA photonic elements. For this, fundamental ques- the luminescence further with the aim to construct with Prof. Axel Scherrer tions like light concentration, light-matter inter- a miniaturised light source on-chip. action in resonators and the control of optical 2005–2009 dispersion in nanostructures play an important Nonlinear wavelength conversion in Royal Society University Research role. Furthermore plasmonic nanostructures micro- and nanophotonic platforms Fellow at the Queen’s University Belfast, UK consisting of more or less regular arrays of metal Using SiN-coated silicon waveguides a remarkable discs and wires are investigated as basis for sur- increase of the SHG signal can be observed due to Since 2009 face enhanced Raman spectroscopy (SERS) and the symmetry breaking introduced by the inho- Group leader at Centre for Innovation hyperbolic metamaterials offering the possibility mogeneoulsy strained Si-lattice as well as by the Competence (ZIK) SiLi-nano, MLU to create artificial optical properties not found in electric fields, which are generated by fixed charg- 2011–2017 nature. The design and simulation of the optical es at the SiN/Si. Futhermore degenerate four wave Juniorprofessor at MLU properties of the involved structures is based on mixing is enhanced in silicon slot waveguide ring commercial finite-element software. For experi- resonators, which are infiltrated with a chalcogenide Since 2017 Full Professor for Nonlinear mental realisation and investigation the following glass by a newly developed nano-injection mould- Nanophotonics, Institute of Physics, methods are applied: electron beam lithography, ing process. In the future intentionally applied MLU focused ion beam milling, reactive ion etching, electric fields will be used to increase the generated electrochemical etching and deposition, cw- and ᵪ(2) in silicon and hybrid nanostructures further, time resolved micro-photoluminescence spectros- so that efficient wavelength conversion processes Contact copy, nonlinear measurements in reflection and can be integrated on-chip. transmission (e.g. SHG), angular resolved trans- [email protected] mission spectroscopy. The group has strong con- Hyperbolic (wire) Metamaterials www.physik.uni-halle.de/ nections and overlapping activities with the Centre Dense arrays of parallel aligned nanowires repre- fachgruppen/nanophotonik/ of Innovation Competence (ZIK) SiLi-nano at the sent metamaterials for light in the visible and in- www.sili-nano.de Martin Luther University. frared, which exhibit a negative dielectric con- stants for electric fields parallel to the wires and a positive one for fields perpendicular to them. Selected publications: This leads to an unusual hyperbolic dispersion V. Rutckaia, F. Heyroth, A. Novikov, M. Shaleev, relation for light propagating through this meta- M. Petrov, and J. Schilling. Quantum Dot Emission Driven by Mie material featuring very large wavevevtors (very Resonances in Silicon Nanostructures. Nano small wavelengths). It is currently investigated Lett. 17, 6886 (2017). how these properties can be used to create a hy-

I.Staude and J. Schilling. Metamaterial-inspired perlens, which could be used vor nanofocussing silicon nanophotonics. invited Review article in light or subwavelength imaging. Nature Photonics 11, 274–284 (2017).

C. Schriever et al. Second order optical Plasmonic nanostructures for SERS nonlinearity in silicon waveguides – inhomoge- Arranging metal nanodiscs in strictly periodic neous stress and interfaces. Advanced Optical Materials 3, 129 (2015). arrays allows to intensify the overall plasmonic oscillation by forming lattice resonances. When J. Kanungo, J.Schilling. Experimental these resonances are tuned to the emission wave- determination of the principal dielectric functions in silver nanowire metamaterials. length of a molecule or the Raman laser wave- Applied Physics Letters 97, 021903 (2010). length, the luminescence or SERS-intensity can be enhanced. The combination of these lattice Enhancement of the luminescence of Ge-quantum resonances with near field hot spots is currently dots embedded in silicon Mie-resonators. Strongest studied. The goal is the creation of regular nano- enhancement is observed for higher Q collective structures, which offer a reproducible, high and Mie-resonances in trimer structure. uniformly distributed Raman enhancement. 32_ SOLID STATE INTERFACES AND NANOSTRUCTURES

Institute of Physics & Interdisciplinary Center of Materials Sciences Nanostructured Materials

Fields of Research: Current Projects and Future Goals:

› Magnonics and spin transport in nanostruc- Oxide interfaces tures The interface between the two insulating oxides Prof. Dr. Georg Schmidt › Complex oxide electronics and spintronics LAlO and SrTiO is known to exhibit an electron 3 3 1996 › Organic spintronics gas with reasonable mobility at low temperature. PhD Physics, RWTH Aachen, Germany › Nanolithography We were able to show that at low temperature the electrons are located at domain walls which ap- 1999–2008 Spintronics and magnonics both make use of the pear due to a structural phase transition in the PostDoc at Würzburg University, Germany, Prof. Laurens W. Molenkamp electron spin to replace the charge of the electron SrTiO3 substrate. In nanostructures which are in novel Post-CMOS electronics. While spintron- fabricated in a proprietary nano patterning pro- 2004 ics mainly relies on the transport of electrons for cess this leads to anomalies in the temperature Habilitation in experimental physics, the transfer of spin information, magnonics uses dependence of the conductivity and in magne- Universität Würzburg, Germany elementary excitations namely spin waves in fer- totransport. Since 2009 romagnetic materials for information transfer Full professor (W3) of Physics, Group of and processing. Our group makes use of metals, 3D magnonics Nanostructured Materials and director organics, and complex oxides to investigate the Using a new deposition and patterning process for of the Interdisciplinary Center for basic physics of spin transport like spin pumping yttrium iron garnet (YIG) we are able to fabricate Materials Science, Martin Luther or the inverse spin Hall effect on one hand. On suspended or free standing YIG nanostructures. University, Halle-Wittenberg, Germany the other hand, new devices are tailored by so- These unique structures can be used for experi- phisticated methods of 3D nanofabrication that ments ranging from low temperature magnonics may allow to couple spin waves, photons, and like coupling between superconducting micro res- Contact phonons for possible use in quantum informa- onators to YIG nano structures to coupling be- [email protected] tion processing. The three pillars of the work are tween mechanical resonances and magnons, both thin film deposition (Pulsed laser deposition, areas which can be relevant for quantum informa- nano.physik.uni-halle.de evaporation, magnetron sputtering and organic tion processing. A similar patterning process can molecular beam deposition), Nano fabrication also be used to create 3D YIG structures for mag- Selected publications: (electron beam lithography, lift-off, and dry etch- non optics which can act as optical elements for ing), and characterization. The characterization focusing spin waves to high intensities. F. Heyroth et al., Monocrystalline Freestanding Three-Dimensional Yttrium-Iron-Garnet ranges from magnetic characterization (SQUID, Magnon Nanoresonators, Physical Review MOKE) to magnetotransport and ferromagnetic Applied 12 (5), 054031 (2019). resonance at low temperature down to mK. C. Hauser et al., Yttrium Iron Garnet Thin Films with Very Low Damping Obtained by Recrystallization of Amorphous Material, Scientific Reports 6, 20827 (2016).

O. Wid et al., Investigation of the unidirectional Simulated spin wave focusing in a YIG based micro device spin heat conveyer effect in a 200 nm thin Yttrium Iron Garnet film, Scientific reports 6, 28233 (2016).

Spin dynamics and spin pumping M Grünewald et al., Vertical organic spin valves in perpendicular magnetic fields, Physical Spin pumping is a reliable method to create pure Review B 88 (8), 085319 (2013). spin currrents. These can be converted into real currents by the inverse spin-Hall effect. We in- M. Grünewald et al., Tunneling anisotropic magnetoresistance in organic spin valves, vestigate the spin pumping efficiency in various Physical Review B 84 (12), 125208 (2011). Free standing YIG resonators material systems ranging from all-metal multi- B. Pigeau et al., A frequency-controlled layers to oxide hybrid structures and organic/fer- magnetic vortex memory, Applied Physics romagnet hybrids. Using these pure spin currents Letters 96 (13), 132506 (2010). spin dynamics can be detected but also spin-currents induced by the spin-Hall effect can be used to reduce the damping in ferromagnetic resonance and to create nano-sized high frequency oscillators for the GHz regime.

Standing spin waves detected by MOKE (top) and simulated patterns (bottom) SOLID STATE INTERFACES AND NANOSTRUCTURES _33

Institute of Chemistry Supramolecular Chemistry and Liquid Crystals

Fields of Research: Current Projects and Future Goals:

› Design and investigation of Complex fluid nanostructures of polyphilic Prof. Dr. Carsten Tschierske new liquid crystals (LCs) mesogens › Dynamic network formation by liquid state Division of space into distinct subspaces is a central 1985 PhD in Organic Chemistry , self-assembly (liquid organic frameworks) feature of life as exemplified by cells and organelles. University Halle › Spontaneous mirror symmetry breaking in Our goal is to understand the fundamental basic soft matter principles of self-assembly of simple molecules into 1990 › E mergence of complexity by soft self-assembly highly complex compartmented LC superstructures. Habilitation, University Halle › Development of polar order and An example is shown in Fig. 1, where the molecules since 1994 ferroelectricity in LCs form the walls of a honeycomb composed of hexagonal Full Professor (C3) of Organic › Photoisomerizable and other functional LCs and triangular cells (the Kagome), which are filled Chemistry, Martin Luther University by different materials, the red triangles by hydro- Halle-Wittenberg Liquid crystals represent a state of matter uniquely carbons and the larger blue hexagons by perfluori- combining fluidity with order. This combination nated hydrocarbons. Both are separated by walls with is essential for numerous technological applica- only one molecule in diameter (black lines). Our fu- Contact tions, the commonly known is the LC display; but ture aim in this area is to find new tiling patterns this state of matter is also of importance in nume with increased complexity, finally leading to quasi [email protected] rous other fields, as for example for the complex crystalline tilings (see S. Poppe 2015, X. Zeng et al.). www.chemie.uni-halle.de self-assembly in biosystems. Our group deals with the synthesis of new materials capable of forming Dynamic Supramolecular Networks such self-assembled ordered fluids with high struc- Networks are the basis of intelligence, metabolic Selected publications: tural complexity and new emergent functionalities. cycles and the open-end development of complex C. Tschierske et al. Mirror Symmetry Breaking We perform the design, the synthesis and the systems. We design molecules capable of self- in Liquids and Their Impact on the Development of Homochirality in Abiogenesis: characterization of new liquid crystalline mole- assembly into dynamic networks with cubic sym- Emerging Proto-RNA as Source of cules. For the investigations various complimentary metry, connected by thee-, four- and higher valence Biochirality? Symmetry, 2020, 12, 1098. methods are employed, among them polarizing junctions into single nets and double or multiply

T. Reppe et al. Spontaneous mirror symmetry microscopy, calorimetric analysis, X-ray diffraction interwoven networks (see S. Poppe et al. 2020). breaking in benzil-based soft crystalline, cubic methods and electro-optical investigations. Fur- These networks are of interest for photonic appli- liquid crystalline and isotropic liquid phases. ther studies are performed in cooperation with cations and can provide conduction pathways in Chem. Sci. 11. 2020, 5902–5908. partners from all over the world. all tree dimensions, which is of importance for S. Poppe et al. Liquid Organic Frameworks: applications in photovoltaics, as ion carriers and The Single-Network “Plumber’s Nightmare” Bicontinuous Cubic Liquid Crystal. J. Am. for other functionalities. Chem. Soc. 2020, 242, 3296–3300. Spontaneous mirror symmetry breaking in M. Alaasar et al. Isothermal Chirality Switching in Liquid-Crystalline Azobenzene fluids and the origin of biochirality Compounds with Non-Polarized Light, Angew. Homogeneous chirality is one of the basic fea- Chem. Int. Ed. 2017, 56, 10801–10805. tures of life and its origin is still unclear. We have S. Poppe et al. Zeolite-like liquid crystals, demonstrated that achiral molecules can sponta- Nature Commun. 2015, 6, 8637. neous develop conglomerates composed of two

C. Dressel, et al. Chiral Self-sorting and chiral liquids with opposite chirality, which are Chirality Amplification in Isotropic Liquids of immiscible and form separate phases (dark/ Achiral Molecules. Nature Chemistry, 2014, 6, bright in Fig. 2, see C. Dressel et al., T. Reppe et 971–977. Electron density map of the liquid crystalline al., M. Alaasar et al.). This synchronization of en- X. Zeng, et al., Complex Multicolor Tilings and kagome pattern (B. Glettner et al). antiomorphic molecular conformers is supported Critical Phenomena in Tetraphilic Liquid by the cooperativity provided by the formation of Crystals. Science, 2011, 331, 1302–1306. highly dynamic helical networks in these perco- B. Glettner et al. Liquid-Crystalline Kagome, lated liquids. We work on the fundamental under- Angew. Chem. Int. Ed. 2008, 47, 9063–9066. standing of these phenomena and their possible implications for the emergence of uniform chirality in prebiotic liquids.

Chiral conglomerate of a mirror symmetry broken liquid, observed with polarized light (C. Dressel et al.). 34_ SOLID STATE INTERFACES AND NANOSTRUCTURES

Institute of Mathematics Algebra

Fields of Research: Current Projects and Future Goals:

› Abstract theory of finite groups Groups acting with low fixity › Applications of the classification of In a number of interesting open problems there is Prof. Dr. Rebecca Waldecker finite simple groups some group action involved on a mathematical 2007 › New algorithms in computational object with high symmetry, for example a network, PhD in Mathematics, University permutation group theory a curve or a surface. Then the goal is to use the of Kiel, Germany › Algebraic and geometric methods in interplay between the structure of the object and chemistry and physics the structure of its symmetry group in order to 2007–2009 understand the object better. Honorary Lecturer and Research Fellow, University of Birmingham, UK Groups arise naturally wherever symmetry is For instance, a compact Riemann surface of genus present, which is why group theory and algebraic at least 2 has a finite automorphism group, and 2009–2015 methods have applications far beyond mathe- fixed points of non-trivial automorphisms can be Junior Professor for Groups and matics. Using the language of group theory helps used to understand the structure of the surface Geometries, Martin Luther University to understand the structure and symmetry of better. Halle-Wittenberg curves and surfaces, it plays a role for virus models, This leads to questions about permutation groups Since 2015 for modelling the self-assembly of molecules or for acting with low fixity. In ongoing research, it has Professor (W2) of Algebra, Martin calculating energy levels of electrons, and recently been possible to prove classification results about Luther University Halle-Wittenberg group theory has played a role in solving difficult finite groups acting with fixity 2 or 3, partial re- algorithmic problems. sults for fixity 4 are available and there is much Algebraic methods have made it possible to develop work in progress in order to classify the Riemann Contact new algorithms for computer algebra software surfaces that exhibit such groups as groups of auto- rebecca.waldecker@mathematik. that have substantially changed the state of the art. morphisms, along with ramification data. This uni-halle.de While some problems can be solved using elemen- work will continue and all results will not only be tary techniques and arguments from geometry or published, but will also be made available in com- www.mathematik.uni-halle.de group theory, others need deep knowledge about puter algebra software. algebra.mathematik.uni-halle.de/ the abstract theory of finite groups. For some ap- rebecca_waldecker plications we need an inductive approach which Algorithms often leads to an investigation of the smallest For many search problems in permutation Selected publications: building blocks of abstract groups: the finite simple groups, a backtrack search method is used. While groups. often good enough in practice, the worst-case P. Salfeld and R. Waldecker, The occurrence of finite simple permutation groups of fixity 2 as Their classification is of crucial importance not performance is so bad that there is a desperate automorphism groups of Riemann surfaces. only for group theory, and much is still left to under- need for new ideas that help to prune the search Journal of Algebra 561 (2020), 402-420. stand in greater detail. tree quickly and substantially. Chr. Jefferson, M. Pfeiffer and R. Waldecker, Many open research problems have been (and After the introduction of new refiners around or- New refiners for permutation groups search. J. still are) solved by direct use of this classification bital graphs, there is now a new approach that of Symb. Comp. 92 (2019), 70–92. result, and much inspiration for further research instead of partitions used stacks of labelled di- Chr. Jefferson, Eliza Jonauskyte, M. Pfeiffer into even more details stems from applications graphs for the organisation of the search procedure and R. Waldecker, Minimal and canonical within and outside of mathematics. (collaboration with Computer Science, St An- images. J. of Alg. 521 (2019), 481–506.

drews). We have also developed new methods for K. Magaard and R. Waldecker, Transitive the calculation of canonical images, and future permutation groups with trivial four point projects include combining our new ideas for even stabilizers. J. Group Theory 18 (2015), no. 5, 687–740. better algorithms and extending the graph stack method in order to solve even harder problems. K. Magaard and R. Waldecker, Transitive permutation groups where nontrivial elements have at most two fixed points. J. of Further applications Pure and Appl. Alg. 219, Issue 4 (2015), Using symmetry, we intend to better understand 729–759.

the tesselations that model the self-assembling I. Toborg and R. Waldecker, Finite simple behaviour of liquid quasi-crystals. 3'-groups are cyclic or Suzuki groups. Archiv der Mathematik 102, No. 4 (2014), 301-312.

R. Waldecker, Isolated involutions in finite groups. Memoirs of the AMS, Volume 226, Number 1061 (2013).

Development of the dodecagonal supertiles at the transition from triangular to square tiling patterns. (M. Poppe, et al., A Periodic Dodecagonal Supertiling by Self-assembly of Star- shaped Molecules in the Liquid Crystalline State, Communi- cations Chemistry volume 3, Article number: 70 (2020), 5). SOLID STATE INTERFACES AND NANOSTRUCTURES _35

Institute of Mathematics Functional Analysis

Fields of Research: Current Projects and Future Goals:

› Topological Methods in Nonlinear Analysis The equivariant spectral flow and bifurca- Prof. Dr. Nils Waterstraat › K-theoretic Methods in Bifurcation Theory tion theory › Selfadjoint Fredholm Operators and the Differential equations often have symmetries, 2011 PhD in Mathematics, University of Spectral Flow which can be described as invariances under the Göttingen › Index Bundles for Families of Fredholm action of a group. Unfortunately, such symmetries Operators can ruin the topological approach when they cause 2011–2013 the vanishing of the invariants. The aim of this DAAD PostDoc Fellow at Politecnico di Topological methods have been used in nonlinear project is to introduce an equivariant spectral Torino, Italy analysis from the very beginning of its systematic flow as an element of the representation ring of 2013–2015 study. The usual task is the search for solutions of the group of symmetries. Like the ordinary spectral Dirichlet Postdoc of the Berlin nonlinear equations in Banach spaces that are ob- flow, which is an integer, its equivariant version Mathematical School tained from differential equations. A common can be estimated by using a partial order on the 2015–2018 strategy is to construct indices that can be assigned representation ring. The ultimate goal of this pro- Lecturer in Analysis at the University to such equations and whose non-triviality pre- ject is to show that a non-vanishing equivariant of Kent, UK dicts the existence of solutions. When constructed spectral flow yields bifurcation just as for the or- by topological methods, such indices sometimes dinary spectral flow in the non-equivariant case. Since 2019 turn out to be invariant under certain deformations Moreover, we apply our theorem to study bifurca- Since 2019 Professor of Functional Analysis at the Martin Luther of the equations, making them well suited for tion phenomena for periodic Hamiltonian systems University of Halle-Wittenberg such an application. having symmetries which cause the ordinary A related problem is the setting of bifurcation spectral flow to vanish. theory, where families of nonlinear equations are considered that are parametrized by one or several Exponential Dichotomies Contact parameters. All of these equations are assumed to We have previously studied topological bifurcation have a “trivial” solution that we already know. invariants for various discrete and continuous nils.waterstraat@mathematik. uni-halle.de Here the above topological methods can be used dynamical systems that were assumed to be asymp- to find parameter values where new solutions totically hyperbolic, i.e., that converge in forward analysis.mathematik.uni-halle.de/ branch off from the known ones. and backward time to a special kind of system. mitarbeiter/nils_waterstraat We mostly study two related kinds of topological The aim of this project is to lift this restrictive indices for bifurcation problems. Firstly, we con- convergence assumption and to require instead sider K-theory classes for families of Fredholm the existence of exponential dichotomies, which Selected publications: operators that were introduced by Jänich and Ati- is a common setting in the theory of dynamical N. Doll, H. Schulz-Baldes, N. Waterstraat, yah in the sixties in connection to family versions systems. This is a joint project with R. Skiba (Torun) Parity as Z_2-valued spectral flow, Bull. Lond. Math. Soc. 51 (2019), 836–852- of the Atiyah-Singer Index Theorem. Their appli- which is funded by a DAAD grant (2020–2021). cability in bifurcation theory was pointed out in N. Waterstraat, Spectral flow and bifurcation the late eighties and this link has since then Several parameter bifurcation invariants for a class of strongly indefinite elliptic systems, Proc. Roy. Soc. Edinburgh Sect. A steadily been developed. Secondly, we focus on for variational problems 148 (2018), 1097–1113. selfadjoint Fredholm operators and consider the Many differential equations are induced by vari- spectral flow, which is an invariant that was in- ational problems. This makes their representing N. Waterstraat, Spectral flow, crossing forms and homoclinics of Hamiltonian systems, troduced by Atiyah, Patodi and Singer in the sev- operators selfadjoint and so the spectral flow is a Proc. Lond. Math. Soc. (3) 111 (2015), 275–304. enties. The spectral flow was first linked to bifur- convenient invariant for studying bifurcation

N. Waterstraat, A family index theorem for cation theory in the late nineties and we have made phenomena in this setting. Unfortunately, the periodic Hamiltonian systems and bifurcation, substantial contributions to this active field of spectral flow is only defined for problems de- Calc. Var. Partial Differential Equations 52 research. We have in particular developed methods pending on a single parameter. The aim of this (2015), 727–753. to estimate spectral flows, which are often good project is to obtain K-theoretic invariants for sev- A. Portaluri, N. Waterstraat, A Morse-Smale enough for applications to bifurcation problems. eral parameter bifurcation problems that gener- index theorem for indefinite elliptic systems alize the spectral flow. These invariants will be and bifurcation, J. Differential Equations 258 (2015), 1715–1748. used to study bifurcation of periodic solutions of autonomous Hamiltonian systems, where one pa- N. Waterstraat, A K-theoretic proof of the Morse index theorem in semi-Riemannian rameter is necessarily reserved for the length of geometry, Proc. Amer. Math. Soc. 140 (2012), the period. 337–349. 36_ SOLID STATE INTERFACES AND NANOSTRUCTURES

Institute of Physics Surface and Interface Science

Fields of Research: Current Projects and Future Goals:

› Surface properties of oxides Oxide nanostructures › Growth and properties of oxide quasicrystals Growth of oxide thin films and oxide hetero- Prof. Dr. Wolf Widdra › Electronic structure of organic thin films structures and their characterization by in-situ 1991 › Surface vibrational spectroscopy microscopy and spectroscopy has been leading PhD in Experimental Physics, › Femtosecond laser spectroscopy the SFB-762 in the past decade. Emerging electronic U Marburg, Germany › Ultrafast photoelectron microscopy properties, new bonding schemes, lattice dynamics and femtosecond dynamics of excited electrons 1992–1994 Surface science is a modern research area within are investigated by complementary techniques. PostDoc, UC St. Barbara, California, USA solid-state physics. The nanometer-controlled material science, where interfaces and surfaces Quasicrystals 2000 dominate device performance, inspires novel ma- Peculiarities and unexpected physical properties of Habilitation, TU Munich, Germany terial concepts for future applications in infor- oxide quasicrystals – highly ordered monolayer 2001 mation and sensor technologies. For the under- films with self-similar structures, but without peri- Professor (C3), TU Berlin and standing of such new concepts, atomically odicity – define the focus of this research field since Head of Department controlled surfaces and interfaces provide an the discovery of oxide quasicrystals in 2013 in Halle. Max-Born Institute, Berlin ideal research environment: Nanostructures are We address the fundamental aspects of quasicrystal Since 2003 assembled atom-by-atom or atomic layer-by-lay- physics, but also aim at application for quasicrystal Professor (C4) of Experimental er; new structures are atomically resolved by thin film coatings. Physics, Martin Luther University scanning tunneling microcopy (STM) in-situ un- Halle-Wittenberg der ultraclean vacuum conditions, and state-of- the-art surface-sensitive spectroscopies directly Since 2010 analyze the new physical or chemical properties. Max-Planck-Fellow, MPI for Microstructure Physics, Halle At the MLU, we developed a variety of methods as scanning tunneling microscopy, high-resolution inelastic electron scatting (HREELS), electron diffraction (LEED), angle-resolved photoelectron Contact spectroscopy (ARPES), photoemission electron [email protected] microscopy (PEEM) and laser-based two-photon photoemission (2PPE). Their combinations allow www.physik.uni-halle.de/surface exceptional resolution in space, time, energy as Square-triangle-rhomb tiling of a dodecagonal oxide well as momentum to address novel interface quasicrystal with STM image as background. Selected publications: phenomena. L. K. Scarbath-Evers, R. Hammer, D. Golze, M. Brehm, D. Sebastiani, and W. Widdra, From Laser-based spectroscopy and microscopy Flat to Tilted: Gradual Interfaces in Organic Femtosecond lasers enable the observation of dy- Thin Film Growth, Nanoscale 12, 3834 (2020). namic processes of electrons on femtosecond time K. Gillmeister, D. Golež, C.-T. Chiang, N. Bittner, scales. Within the SFB/TRR-227, we advance this Y. Pavlyukh, J. Berakdar, P. Werner, and W. field by the use of widely tunable lasers and laser- Widdra, Ultrafast coupled charge and spin based high-harmonics generation at high repetition dynamics in strongly correlated NiO, Nature Comm. 11, 4095 (2020). rates. With this instrumentation, we identify electron decay and transport on intrinsic time scales. A. Trützschler, M. Huth, C.-T. Chiang, R. Kamrla, F. O. Schumann, J. Kirschner, and W. Widdra, Ultimate goal is combination of femtosecond spec- Band-Resolved Double Photoemission troscopy and nanometer microscopy via laser-based Spectroscopy on Correlated Valence Electron electron microscopy. Pairs in Metals, Phys. Rev. Lett. 118, 136401 (2017).

Organic electronics S. Förster et al., Observation and Structure Polymer and organic thin films on solid surfaces Determination of an Oxide Quasicrystal Approximant, Phys. Rev. Lett. 117, 095501 View onto a quasicrystal in an ultra-high vacuum chamber. are key elements in the field of organic electron- (2016). ics. Understanding of their self-organization as S. Förster, K. Meinel, R. Hammer, M. well as their electronic properties is our goal by Trautmann, and W. Widdra, Quasicrystalline combination of STM and photoemission. The as- structure formation in a classical crystalline signment of local electronic states to specific in- thin-film system, Nature 502, 215 (2013). terface-induced structures leads to deeper understanding for charge injection in organic devices. SOLID STATE INTERFACES AND NANOSTRUCTURES _37

Institute of Physics Optics and time resolved spectroscopy

Fields of Research: Current Projects and Future Goals:

› Spin dynamics and spin transport Nanoscale magnetization dynamics Prof. Dr. Georg Woltersdorf › Ultrafast spin dynamics We use time resolved magneto optic microscopy › Time resolved microscopy to obtain snapshots the spin dynamics (spin 2004 PhD Physics at Simon Fraser University, › Magnetic hetero and nano structures waves) in magnetic nanostructures. Here the in- Canada with Prof. Bretislav Heinrich › Spintronics teraction of the magnetic excitations with elec- trically driven spin currents is of particular inter- 2004–2007 The electron spin is a quantum property and de- est as spin transfer torque and spin orbit torque Postdoc at the University of termines structure and dynamics of matter. It effects allow control the dynamics. In order to Regensburg with Prof. Christian Back has a strong influence on light emission and ab- overcome the diffraction limit we currently de- 2007–2013 sorption, allows controlling charge transport velop an optical near field method. Staff scientist at the University of processes, and is essential for the emergence of Regensburg with Prof. Christian Back magnetic order. Consequently, spin physics has a Spin to charge conversion 2013 broad impact on everyday life. Examples are the Spin currents may be created without a ferromag- Habilitation at the University of usage of electron spins to store digital informa- netic material using the spin orbit interaction. Regensburg tion in nanoscale bits and the magnetization de- This effect is known as the spin Hall effect. We pendence of electronic transport in nanoscale use this phenomenon to generate spin transfer since 2013 sensors. Employing the electron’s spin degree of torques in metallic multilayer systems and sam- Full Professor (W3) for Experimental Physics, Martin Luther University freedom has large potential for advanced elec- ple the effect by time resolved microscopy. In our Halle-Wittenberg tronic device concepts with simple architecture experiments, we would like to understand and and reduced power consumption. The field of spin maximize this effect. electronics (spintronics) has enjoyed enormous Contact interest in last three decades due to the discovery Ultrafast spin dynamics of numerous effect linking electrical currents to We use ultrafast (femtosecond) laser pulses to [email protected] the spin and its dynamics. These phenomena al- generate ultrashort and intense spin current www.physik.uni-halle.de/fachgrup- low controlling the magnetization state by charge pulses in spintronic hetero-structures. One aim pen/optik currents and vice versa. is to use these pulses to excite ultrafast spin dy- The research activities in the optics group focus namics in ferrimagnets and achieve ultrafast on understanding spin dynamics and spin trans- spin switching. Alternatively, a material with Selected publications: port on small time (femtoseconds) and length large spin orbit interaction is used to convert the S. Poellath et al., Ferromagnetic Resonance scales (nanometers). Most of the experiments in- ultrafast spin current pulses into intense charge with Magnetic Phase Selectivity by Means of Resonant Elastic X-Ray Scattering on a Chiral volve ultrafast optical methods for the detection current pulses with THz bandwidth via the in- Magnet, Phys. Rev. Lett. 123, 167201(2019). of spin dynamics. In addition to the time resolved verse spin Hall effect. Thereby creating on chip optical experiments our group also prepares of THz source with vast applications ranging from T.S. Seifert et al., Femtosecond formation dynamics of the spin Seebeck effect revealed the most samples (growth and nanofabrication THz imaging to antiferromagnetic spintronics. by terahertz spectroscopy, Nature processes). The goal of our research is an im- Communications 9, 2899 (2018). proved understanding of fundamental processes S. Baierl et al., Terahertz-Driven Nonlinear facilitating the development of novel spin elec- Spin Response of Antiferromagnetic Nickel tronic devices. Oxide, Phys. Rev. Lett. 117, 197201(2016).

H.G. Bauer, P. Majchrak, T. Kachel, C.H. Back, and G. Woltersdorf, Nonlinear spin-wave excitations at low magnetic bias fields, Nature Communications 6, 8274 (2015).

D. Wei, M. Obstbaum, M. Ribow, C. H. Back, and G. Woltersdorf, Spin Hall voltages from a.c. and d.c. spin currents, Nature Communications 5, 3768 (2014).

Time resolved magneto-optic imaging of spin waves in a On-chip generation of THz current pulses with a ferrimagnetic material at a frequency of 5 GHz. spintronic emitter. Materials for energy conversion and storage

Photo: Andreas Struzina Considering the challenges of climate change and the renewable Energy. Current network initiatives include associated transformation towards an environmentally the research cluster Solarvalley Mitteldeutschland friendly energy supply technology our research theme on (since 2009) as well as the consortium HYPOS: Hydrogen “Materials for Energy Conversion and Storage” focuses Power Storage (since 2014) and the ZIK SiLi-nano (since on a highly relevant topic for current and future genera- 2009). The research theme was recently strengthened tions. The aim is the development of a sustainable and by two new professorships within the area. Future pers efficient energy supply for the future. pectives for development– especially with the aim to Within the research theme experimental and theoretical establish new cooperative research networks – lie in the projects are combined, which represent an advancement fields of CO2-fixation, novel lithium-free battery systems, on prior topics formerly investigated within the areas closed material cycles and chemical hydrogen storage of functional solid state interfaces and photovoltaics/ and usage.

MECS Molecules Materials for energy conversion Models and storage

SSIN SBM

Materials 40_ Materials for energy conversion and storage

Institute of Chemistry Materials for Energy

Fields of Research: Current Projects and Future Goals:

› Nanostructured Materials for Carbon-based materials for vanadium Electrochemical Energy Conversion redox-flow batteries (VRFB) Prof. Dr. Michael Bron In redox flow batteries chemical energy is stored in 1998 The conversion of electrical into chemical energy redox reactions of dissolved materials instead of PhD in Physical Chemistry, TU and vice versa is a key process in a renewable en- the electrodes (e.g., vanadium ions). However, for Chemnitz, Germany ergies-scenario, and allows excess electrical energy efficient catalysis of the redox reactions, catalyti- e.g. from wind and solar to be converted and stored, cally active electrode materials are needed. We are 1998–2002 and made available when needed. Electrochemical synthesizing and investigating a variety of carbon Post-Doc at Hahn-Meitner- Institute Berlin, Germany energy conversion devices rely heavily on nanomaterials (carbon nanotubes, graphene, carbon- structured materials, at which the relevant electro- ized polymers, composites of these, etc.) toward 2002–2009 chemical reactions take place. Our group is focusing their activity and stability as electrodes in VRFB Habilitation in Industrial Chemistry, on the development of such materials, their charac- with a focus on the influence of functional surface TU Darmstadt, Germany terization, and an in-depth understanding of the groups as well as porosity. 2007–2010 processes taking place at these materials and the Group leader at Ruhr-University parameters determining their activity and stability. Nickel-based materials for alkaline water Bochum, Germany We are using advanced synthesis approaches in- electrolysis Since 2012 cluding colloidal synthesis, microwave assisted The efficiency of water electrolysers is strongly in- Full professor (W3) of Industrial synthesis and chemical vapor deposition to prepare fluenced by over-potentials required to run the elec- Chemistry, Martin Luther University materials with distinct properties. A detailed ex trochemical reactions at reasonable rates. NiFe ox- Halle-Wittenberg situ characterization using e.g. TEM, XRD, and XPS ides are known active materials for the oxygen on the one hand and an electrochemical charac- evolution, while NiMn compounds catalyze the hy- terization using advanced techniques like imped- drogen evolution with low over-potentials. Both Contact ance spectroscopy helps to establish structure- types of materials are investigated towards the re- [email protected] property-relationships which in turn may be used spective reaction with a focus on structure-activity to develop novel materials. Furthermore, we are relationships, including influence of composition www.chemie.uni-halle.de/bereiche_ actively developing novel experimental techniques and surface structure. der_chemie/technische_chemie/ak_ including in situ-IR- and Raman spectroscopy as bron well as micro-electrochemical methods to unravel CO2 electroreduction processes occurring during electrochemical energy CO2 may be electrochemically reduced to valuable Selected publications: conversion. Finally, to evaluate the properties of products, including CO and lower hydrocarbons. new materials under realistic conditions and to However a major issue is the low selectivity and M. Steimecke et al., Higher-Valent Nickel Oxides with Improved Oxygen Evolution transfer the gained knowledge from basic studies high amount of (in this case unwanted) hydrogen Activity and Stability in Alkaline Media to application, we are performing cell tests at our produced during electroreduction. We are synthe- Prepared by High-Temperature Treatment of fuel cell, electrolysis and battery test benches. sizing size-selected Au-, Ag-, and Cu-nanoparticles Ni(OH)2. ACS Catal. 10 (2020) 3595–3603.

for this reaction to unravel particle size/structural X. Lu et al., Titanium as a Substrate for effects and their influence on activity and selectivi- Three-Dimensional Hybrid Electrodes for ty. Electronic effects and support effects are investi- Vanadium Redox Flow Battery Applications. ChemElectroChem 7 (2020) 737. gated as well. X. Lu et al., Plasma-etched Functionalized Graphene as a Metal-free Electrode Catalyst Fuel cell catalysis in Solid Acid Fuel Cells. J. Mater. Chem. A 8 Current fuel cell related research in our group is mo- (2020) 2445–2452. tivated by recent advances in alkaline exchange M. Steimecke et al., In situ Characterization of membranes, which might preplace the currently Ni and Ni/Fe Thin Film Electrodes for Oxygen used acid membranes. We are investigating the oxy- Evolution in Alkaline Media by a Raman- gen reduction reaction over carbon based materials coupled Scanning Electrochemical Microscope Setup. Anal. Chem. 89 (2017) 10679–10686. Novel setup for in situ-Raman measurements of electrode as well as the oxidation of ethylene glycol and glyc- surfaces under potential control erol over Pt and Au. Besides activity, a major focus is A.B.A.A. Nassr et al., Rapid Microwave- Assisted Polyol Reduction for the Preparation on the long-term stability of the materials, which is of Highly Active PtNi/CNT Electrocatalysts crucial for later application. for Methanol Oxidation. ACS Catal. 4 (2014) 2449–2462.

Polyaniline deposited on carbon cloth as high-surface-area fuel cell electrode Materials for energy conversion and storage _41

Institute of Chemistry Solid State Chemistry

Fields of Research: Current Projects and Future Goals:

› Preparation, structure and physical Functional magnetic materials Prof. Dr. Stefan properties of complex oxides Materials with high and adjustable magnetization Ebbinghaus › Soft-chemistry synthesis of nanoparticles, or exotic spin structures are interesting e.g. for

1998 processing and characterisation of ceramics, power generators and spintronics. To investigate PhD in Inorganic Chemistry, University single crystal growth the (anisotropic) magnetic properties of oxides and of Hamburg, Germany › Structure determination by X-ray and intermetallic phases, high quality single crystals neutron diffraction are grown using the floating zone method or flux 1999–2000 › Magnetic, (di-)electric and thermal transport techniques. PostDoc, Princeton University, properties New Jersey, USA, Prof. Robert J. Cava

2006 Complex oxides are key functional materials for Habilitation in Solid State Chemistry, various applications like data storage devices, solid University of Augsburg, Germany oxide fuel cells, thermoelectric converters, (photo-) since 2008 catalysts, sensors, capacitors etc. Our group deals Full Professor (W3) of Solid State with the synthesis and comprehensive characteri- Chemistry, Martin Luther University sation of new oxides with various morphologies Halle-Wittenberg including crystals, ceramics, powders, thin films, and nano particles. The applied synthesis methods Optical floating zone furnace comprise classical solid state reactions, sintering Contact techniques, single crystal growth, plasma-assisted Mayenite as universal host material reactions as well as soft-chemistry approaches like Due to its unusual cage structure, mayenite shows [email protected] sol-gel synthesis, decomposition of precursors, an excellent oxygen mobility required e.g. for solid www.chemie.uni-halle.de spray drying/spray pyrolysis and spin coating. oxide fuel cells and oxidising catalysts. Upon re- The materials properties are affected by the com- duction, the to date only known temperature and plex interplay of composition, crystal structure, moisture stable electride (Ca Al O :2e–) is for Selected publications: 12 14 32 particle sizes and interfaces. Various complemen- med. This unique material is studied with the aim M. Breitenbach et al. Magnetoelectric and tary characterisation techniques are applied, in- to stabilize exotic ionic species. HR-STEM Investigations on Eutectic CoFe O – 2 4 cluding X-ray and neutron diffraction, X-ray ab- Ba1-xSrxTiO3 Composites, Journal of Physics and Chemistry of Solids (2019), 135, 109076. sorption spectroscopy, different thermal analysis methods, optical spectroscopy and electron mi- N.Quandt et al. Spin Coating of Epitaxial croscopy. For chemical analysis atomic absorption BaTiO3/CoFe2O4 Thin Films on Single

Crystalline (001)-SrTiO3, Materials Chemistry and X-ray fluorescence spectroscopy are used. In and Physics (2019), 229, 453–459. addition, various physical properties like electrical Cage structure of the R.Köferstein et al. Investigations of and thermal conductivity, heat capacity, dielectric oxygen ion conductor Nano-crystalline Sr Ba Nb O and Bulk Ca Al O 0.5 0.5 2 6 behaviour, magnetic and magnetoelectric proper- 12 14 33+δ Ceramics Synthesized by a Polymerization Method Using PEG400, Journal of the ties are investigated. European Ceramic Society (2019), 39, 1156–1163. Anion-substituted perovskites

J.Jacobs et al. Structure, Optical and Oxide ions in perovskites can partially be replaced Photocatalytic Properties of Oxyntride Solid by N3–, F– or H–. Oxynitrides are highly promising Solutions Ca Sr NbO N, CaNb Ta O N, and 1‑x x 2 1‑x x 2 photocatalysts, while oxyfluorides are interesting SrNb1‑xTa xO2N Prepared from Soft-Chemistry Precursors, Zeitschrift für Anorganische und candidates for fluorine-based battery systems Allgemeine Chemie (2018), 644, 1832–1838. and oxyhydrides may serve as hydrogen storage

T.Walther et al. Novel Magnetoelectric materials. Our goal is to identify new phases using Composites of Cobalt Iron Alloy and Barium (in-situ) X-ray and neutron diffraction and to study Titanate, Journal of the American Ceramic their catalytic and physical properties in detail. Society (2017), 100, 1502–1507.

F.Oehler et al. Preparation and Dielectric Prop- Multiferroic heterostructures erties of CaTaO N and SrNbO N ceramics, 2 2 3-3 heterostructure of BaTiO and CoFe O Magnetoelectric multiferroics are potential can- Journal of the European Ceramic Society 3 2 4 (2017), 37, 2129–2136. didates for next-generation data storage and sensor systems. We investigate composites consis

ting of ferroelectrics like BaTiO3 or SrxBa1-xNb2O6 and ferromagnetic alloys or spinels. The effects of stoichiometry, dimensionality and the properties of the oxide interfaces are studied for 0–3-, 2–2-, and 3–3-heterostructures. 42_ Materials for energy conversion and storage

Institute of Chemistry Photochemistry

Fields of Research: Current Projects and Future Goals:

› Mechanistic and kinetic photochemistry Photo-CIDNP spectroscopy › Laser-flash photolysis On one hand, we develop new and improved pulse Prof. Dr. Martin Goez › NMR spectroscopy sequences, on the other hand, we use this spec- 1986 troscopic technique for in-depth mechanistic and PhD in Physical Chemistry (Friedrich– The importance of photochemistry can hardly be kinetic investigations of organic photoreactions. Alexander-Universität Erlangen, overstressed, taking into account the rapidly In collaboration with the group of P. J. Hore at Germany) nearing exhaustion of fossil fuels – which are not Oxford, we apply CIDNP to biorelevant molecules only the world’s energy sources but also the raw and their reactions, such as protein folding. 1986–1988 Research scientist (Philips Research materials for most industrial organic syntheses Laboratory Aachen, Germany) – and the fact that all these fuels originate from photosynthesis. 1988–1995 We investigate the mechanisms and kinetics of PostDoc and Heisenberg fellow photoreactions, using a variety of spectroscopic (Universität Carolo–Wilhelmina, techniques. Our specialized expertise is in the Braunschweig, Germany) areas of two-colour laser-flash photolysis at ex- 1993 tremely high excitation intensities, of magnetic Habilitation in Physical Chemistry field effects, and of photo-CIDNP (photochemi- (Universität Carolo–Wilhelmina, cally induced dynamic nuclear polarizations). In Braunschweig, Germany) the two-colour experiments, we use one laser Since 1995 pulse to prepare a short-lived intermediate, and Full Professor (C3) of Organic then apply a second pulse to do photochemistry Chemistry (Martin Luther University on the latter. This, as well as the high excitation New photoionization mechanisms Halle–Wittenberg, Germany) intensities, opens up completely new reaction We have discovered, and are currently investiga 2000–2001, 2004–2005, 2008 pathways. By the application of magnetic fields, ting, a variety of mechanisms that yield more Visiting Professor (University of Leeds, the product yields can be modified; although a than one electron per molecule, e.g., catalytic University of Oxford) and Visiting seemingly esoteric phenomenon, this is the cycles, where the photoionized intermediate is Fellow (Magdalen College, Oxford, UK) underlying mechanism of the orientational system regenerated by a chemical reaction with a sacrifi- of migratory birds. Photo-CIDNP is basically cial electron donor. A related issue is the strong laser-flash photolysis with NMR detection. This effects that small structural or electronic changes Contact extremely powerful method yields information (e.g., the conversion of a triplet into a radical anion) [email protected] about all stages of a chemical reaction that is often can have on the photoionization efficiency. We aim inaccessible otherwise. to understand such changes, and utilize hydrated www.chemie.uni-halle.de electrons for green photoredox catalysis.

Selected publications:

T. Kohlmann, C. Kerzig, M. Goez. Laser- induced Wurtz-type syntheses with a metal- free photoredox catalytic source of hydrated electrons. Chem. Eur. J. 2019, 25, 9991.

R. Naumann, F. Lehmann, M. Goez. Generating hydrated electrons for chemical syntheses by using a green light-emitting diode (LED). Angew. Chem. Int. Ed. 2018, 57, 1078.

R. Naumann, M. Goez. First micelle-free photoredox catalytic access to hydrated electrons for syntheses and remediations with a visible LED or even sunlight. Chem. Magnetic field effects Eur. J. 2018, 24, 17557. We use magnetic field effects to elucidate the M. Goez. Photo-CIDNP spectroscopy. Annu. details of organic photoreactions and diffusional Rep. NMR Spectrosc. 2009, 66, 77–147. dynamics, especially in microheterogeneous systems (e.g., micelles). A second focus is on the M. Goez et al. Quenching mechanisms and diffusional pathways in micellar systems development of new experimental methods for unraveled by time-resolved magnetic-field measuring magnetic field effects. This project is effects. Chem. Eur. J. 2009, 15 , 6058–6064.

part of an ongoing collaboration with the group K. H. Mok et al. A pre-existing hydrophobic of C. R. Timmel at Oxford. collapse in the unfolded state of an ultrafast folding protein. Nature 2007, 447, 106–109. Materials for energy conversion and storage _43

Institute of Chemistry Physical Chemistry of Polymers

Fields of Research: Current Projects and Future Goals:

› Physical Chemistry of Polymers Polymer Crystallization Prof. Dr. Jörg Kressler › Thermodynamics of Polymer Blends, Ion on the Water Surface Conductivity, Polymer Chrystallisation The crystallization of PCL on the water surface is 1978–1983 Studies of Chemistry at TU Dresden, studied by various experimental techniques. Espe- Germany We deal with thermodynamic properties of poly- cially grazing incidence wide angle X-ray scattering 1983–1997 mers in solution and in bulk. Frequently employed reveals details on the morphology development PhD at TU Dresden and several experimental methods are X-ray scattering (see of PCL crystals which appear during compression PostDoc stays in Amherst, Tokyo, and Figure), NMR- and FTIR spectroscopy, and thermo- of a thin polymer film on a Langmuir trough. Fur- Freiburg analytic methods. Furthermore, we study the ion thermore, the crystallization of PEO on the surface

1993–1997 conductivity of polymer electrolytes. In cooperation of different salt solutions is investigated with re- Research scientist at Freiburg with the pharmacy department, we develop mod- spect to the Hofmeister series. Materials Research Center ern drug release systems. Modification and Characterization of 1997 PEO Networks Habilitation in Physical Chemistry , Different PEO network structures have been syn- TU Dresden thesized by “click” chemistry. The morphology of since 1997 the networks is investigated by scattering tech- Full Professor (C4) on Physical niques and soled state NMR spectroscopy. Addi- Chemistry of Polymers, Martin tionally, the Li-ion conductivity for various network Luther University Halle-Wittenberg structures is studied by impedance spectroscopy.

Biopolyesters for Pharmaceutical Contact Applications Aliphatic biopolyesters have been synthesized by [email protected] enzymatic polycondensation using CAL-B. Thus, www.chemie.uni-halle.de/bereiche_ functional polyesters with OH-groups at the pol- der_chemie/physikalische_chemie/ ymer backbone are obtained. The OH-groups are ag-kressler used for conjugation with drugs or pharmaceutical proteins. A well-defined drug release profile can be achieved. Selected publications:

S.W.H. Shah, C. Schwieger, J. Kressler, A. Crystallization of PEO on the surface of Modified Hydroxyethyl Starch Blume. Monolayer behavior of pure F-DPPC salt solution studied by GI-WAXS. and mixed films with DPPC studied by Hydroxyethyl starch is a biodegradable and bio- epifluorescence microscopy and infrared compatible polymer with various applications in reflection absorption spectroscopy. pharmacy. It is hydrophilic and water soluble. Chem. and Phys. Lip. 230, 104918, 2020. When OH-groups are partially converted with 2N. Hasan, C. Fuchs, C. Schwieger, K. Busse, O. fatty acids, amphiphilic polymers result. They form Dolynchuk, J. Kressler. Crystallization of different nanostructures in water which are em- poly( -caprolactone) at the air-water interface studied by IRRAS and GI-WAXS. ployed for different drug release systems. Polym.� 196, 122468, 2020.

R. Alaneed, T. Hauenschild, K. Mäder, M. Pietzsch, J. Kressler. Conjugation of amine- functionalized polyesters with dimethylcasein using microbial transglutaminase. J. Pharm. Sci. 109, 981-991, 2020.

M.H. Samiullah, M. Pulst, Y. Golitsyn, A. Bui, K. Busse, H. Hussain, D. Reichert, J. Kressler. Tailored melting temperatures and crystallinity of poly(ethylene oxide) induced by designed chain defects. ACS Appl. Polym. Mater. 1, 3130-3136, 2019. 44_ Materials for energy conversion and storage

Institute of Chemistry Field Coordination Chemistry and Homogeneous Catalysis

Fields of Research: Current Projects and Future Goals:

› Preparation and characterization of transi- Novel ligand platforms tion metal complexes and organometallic Novel ligand platforms for transition metal com- Prof. Dr. Robert Langer compounds plexes can lead to new reactivity patterns and trig- 2001–2006 › Synthesis of highly sensitive compounds ger unusual bond activation reactions. Ligands studies in Chemistry at Martin Luther under inert atmosphere based on the element boron were modified in a way University Halle-Wittenberg and › Investigation of reactivity patterns and bond that they act as very strong electron-donating li- University Karlsruhe (TH), Germany activation processes gands in transition metal complexes, which have › Homogeneous catalysis involving been used in various catalytic applications so far. 2009 PhD in Inorganic Chemistry with Prof. H : (de)hydrogenation, hydrogen borrowing, By rational modifications of these ligand platforms 2 Dr. D. Fenske, University Karlsruhe hydrogen isotope exchange we intend to increase the activity of catalysts and (TH), Germany › Catalysis in high pressure autoclaves extent the spectrum of reactions that can be cata- › Quantum Chemical Investigations lyzed. 2009–2011 Postdoc with Prof. Dr. D. Milstein, Catalytic reactions are used in the production of Catalytic reactions involving hydrogen Weizmann Institute of Science, Rehovot, Israel approx. 80 % of the industrially relevant com- Reactions involving dihydrogen are known to be pounds and coordination compounds with tai- atom economic and potentially useful for hydrogen 2011–2019 Independent group leader, Philipps- lored properties are commonly used as homoge- storage as well as the preparation of CO2-neutral fuels, neous catalysts. The research in our group is but they require the presence of a catalyst. Our goal University Marburg, Germany focused on basic aspects in coordination chemis- is to develop more environmentally benign cata- Since 2020 try with a special emphasis on the development lysts, which are, for instance, based on 3d-metals Professor for Coordination Chemistry, of new catalysts and potential materials by the for these reaction. Martin Luther University Halle- utilization of novel ligand-types with tailored Wittenberg properties. This includes the synthesis of new li- Umpolung of Lewis acids Substrates gands and transition metal complexes under in- The reaction of a Lewis acid with a Lewis base usu- ert atmosphere, as well as the investigation of ally yields an adduct or a ‘frustrated’ Lewis pair. Contact their reactivity in bond activation processes and This reactivity can be circumvented in the presence [email protected] catalytic reactions. We focus in our studies on key of certain dimeric metal complex and a reduced species features of these ligands, such as their donor is formed instead, which subsequently may be trans- www.chemie.uni-halle.de/bereiche_ strength or their cooperative interaction with the ferred to unsaturated substrates. In near future the der_chemie/anorganische_chemie/ central metal atom. goal will be to extent this unprecedented reactivity 33619_3267913/ NMR spectroscopy and single crystal X-Ray dif- to a large number of Lewis acids and develop new fraction are essential methods for our research, catalytic reactions based on this reactivity. Selected publications: which are complemented by quantum chemical investigations in addition to other standard spec- ‘Templated‘ substrate activation A. Bäcker et al. Redox-active, boron-based ligands in iron complexes with inverted troscopic methods in molecular chemistry. We study unusual S-O, C-N and C-O multiple bond hydride reactivity in dehydrogenation activation schemes triggered by metal-ligand coop- catalysis, ACS Catalysis (2019), 9, 7300–7309. eration (MLC) in substrates with nitrile-, imine-, Maser et al. Quantifying the Donor Strength and carbonyl groups, as well as SO2 and seek to apply of Ligand-Stabilized Main Group Fragments, the MLC activation sequences in atom-economic J. Am. Chem. Soc. (2019), 141, 7596–7604. coupling reactions (C–C), allowing for waste-free Vondung et al. Ambireactive (R3P)2BH2-groups conjugate addition reactions, circumventing classical facilitating temperature-switchable bond oxidative addition / reductive elimination processes. activation by an iron complex. Chem. Eur. J. (2018), 24, 1358–1364.

Grätz et al. Donor ligands based on tricoordinate boron formed by B-H-activation of bis(phosphine)boronium salts, Chem. Commun (2017), 53, 7230–7233.

Vondung et al. Phosphine-Stabilized Borylenes as Ligands? Redox Reactivity in Boron-Based Pincer Complexes, Angew. Chem. Int. Ed. (2016), 55, 14450–14454.

Schneck et al. Selective Hydrogenation of Amides to Amines and Alcohols Catalyzed by Improved Iron Pincer Complexes. Organometallics (2016), 35, 1931–1943. Donor strength of different ligands in comparison Materials for energy conversion and storage _45

Institute of Chemistry & ZIK SiLi-nano Inorganic Functional Materials – Light for Hydrogen

Fields of Research: Current Projects and Future Goals:

› Nanostructure design for solar water Metal-Organic Frameworks Jun.-Prof. Dr. splitting Using controlled electrochemical oxidation, we can A. Wouter Maijenburg › Photochemical and photoelectrochemical convert metal (oxide) nanostructures into a respec-

2014 water splitting tive Metal-Organic Framework (MOF) and form PhD in Inorganic Materials Science, › H2 evolution reaction (HER) and O2 evolution for instance core-shell Cu2O@Cu3(BTC)2 nanowires University of Twente, Enschede, the reaction (OER) (see figure) with new synergistic properties. Netherlands › Soft-chemical nanostructure synthesis via e.g. electrodeposition and electrospinning 2014–2016 › Photochemical and -physical characterization Postdoc, GSI Helmholtz Centre for Heavy Ion Research, Darmstadt, via e.g. PEC, GC, fs-TAS and PEIS Germany In our group, we are specialized in the preparation Since 2016 of different kinds of nanostructures like nanow- Core-shell Cu2O@Cu3(BTC)2 nanowires. Junior Professor (W1) of Inorganic ires or nanofibers, and investigate their efficiency Functional Materials, Martin Luther for the formation of hydrogen as a renewable and Metal oxide nanowires and nanofibers University Halle-Wittenberg clean energy source via photo(electro)chemical With soft-chemical methods like templated electro- (PEC) water splitting. The unique physical and deposition and electrospinning, we are able to grow chemical properties of quasi-one-dimensional metal oxide nanowires and nanofibers in a con- Contact nanostructures that arise by their high surface-to- trolled fashion. Some examples of metal oxides that volume ratio make these nanostructures very are highly interesting for photo(electro)chemical wouter.maijenburg@chemie. uni-halle.de promising for photo(electro)-chemical applications, applications are CuBi2O4, Cu2O, BiVO4 and CuFeO2. but the physical properties of most semiconductors www.chemie.uni-halle.de also demand the use of such elongated nanostruc- www.sili-nano.de tures. For instance, the diffusion length of charge Chopped-light PEC measurement of a carriers (electrons and electron holes) in Cu2O is CuGaSe film. only 20-100 nm, while the absorption depth near 2 Selected publications: the bandgap is approximately 10 µm. This means, F. Caddeo et al. Tuning the size and shape of that if Cu2O films would be used for photoelec- nanoMOFs via templated electrodeposition and subsequent electrochemical oxidation, ACS trochemical water splitting, fast charge carrier CuGaxSey films Appl. Mater. Interfaces (2019), 11, 25378–25387. transport to the semiconductor surface without In collaboration with Roland Scheer, we recently electron-hole recombination can only be achieved obtained surprisingly high solar-to-hydrogen ef- L. Movsesyan et al. ZnO nanowire networks as photoanode model systems for photoelectro- within the top 1 % of a Cu2O film with optimized ficiencies when using CuGaSe2 and CuGa3Se5 chemical applications, Nanomaterials (2018), 8, thickness for maximum light absorption. On the films. For CuGaSe2, we obtained a photocurrent 693. other hand, with the use of one-dimensional nano- density of -19 mA/cm2 (see figure), corresponding H. Zhang et al. Bifunctional heterostructure structures, an optimum in both the absorption to the conversion of 86 % of the incident solar assembly of NiFe LDH nanosheets on NiCoP depth and charge carrier diffusion length can be light into electrochemical energy. nanowires for highly efficient and stable overall water splitting, Adv. Func. Mater. (2018), 28, found for efficient H2 evolution: i.e. a maximum 1706847. of solar light can be absorbed over the nanowire Atomic Layer Deposition length, while the nanowire diameter is small Atomic layer deposition (ALD) is a powerful A.W. Maijenburg et al. Insight into the origin of enough for efficient electron and hole diffusion method for the deposition of high-quality ul- the limited activity and stability of p-Cu2O films in photoelectrochemical proton reduction, (see figure), and therefore high efficiency. trathin films, which can even be used to confor- Electrochimica Acta (2017), 245, 259–267. mally coat high aspect ratio nanostructures. In

A.W. Maijenburg et al. Preparation and use of collaboration with the MPI of Microstructure photocatalytically active segmented Ag|ZnO Physics, we developed a new ALD recipe for the and coaxial TiO2-Ag nanowires made by templated electrodeposition, J. Vis. Exp. (2014), controlled deposition of CoP, which is a highly in- 87, 51547. teresting HER co-catalyst.

A.W. Maijenburg et al. Ni and p-Cu2O nanocubes with a small size distribution by templated Photophysical characterization electrodeposition and their characterization by To investigate the photophysical processes taking photocurrent measurement, ACS Appl. Mater. place in our samples, we are for instance using Interfaces (2013), 5, 10938–10945. femtosecond Transient Absorption Spectroscopy (fs-TAS) in collaboration with Georg Woltersdorf. Other techniques of interest are Time-Resolved PhotoLuminescence (TPRL), Surface Photovolt- Schematic illustration of optimized photoelectrochemical age Spectroscopy (SPS) and PhotoElectrochemi- water splitting using quasi-one-dimensional nanostructures. cal Impedance Spectroscopy (PEIS). 46_ Materials for energy conversion and storage

Institute of Physics Photovoltaics

Fields of Research: Current Projects and Future Goals:

› Energy converting thin films and complete Ultrathin solar cells solar cell devices Ideally, thin film solar cells can be made thinner if Prof. Dr. Roland Scheer › In-situ growth studies of thin films using light management allows for high absorption and 1994 real-time X-ray diffraction electronic management allows for back contact PhD in Solid State Physics, TU Berlin › Electronic device analysis and computer passivation. We use structured and reflective back simulation contacts for enhanced light absorption in ultrathin 1994–2010 › Novel device concepts devices and we use passivation layers for mini- Staff Scientist at Helmholtz-Centre-Berlin mized recombination. For Cu(In,Ga)(Se,S)2 based Polycrystalline thin film solar cells, also referred solar cells this is done within the framework of the 2002 to as 2nd generation photovoltaics, are highly BMWi funded projects MasterPV and EFFCIS. Research fellow, National Institute complex material systems. Prominent examples for Advanced Industrial Science and Technology, Tsukuba, Japan are Cu(In,Ga)(Se,S)2, CdTe, and Halide Perovs- kites. Cost aspects require their fabrication with 2003–2005 low cost but with high performance (high effi- Lecturer, Physics Department, ciency of solar-to-electrical energy conversion). University Potsdam, Germany In order to fulfil these requirements, the solar Since 2010 cells have to be designed based on deep under- Full professorship (W3) for Photo standing of their functionality and device physics. voltaics at the Institute of Physics, The strategy of our research group is to tailor Martin Luther University Halle- their functionality by employing novel schemes Wittenberg for the management of photons and charge carri- Cross section of ultrathin structured ers, and to analyse their functionality by a combi- Cu(In,Ga)(Se,S)2 solar cell nation of electronic experiments and computer simulation. This strategy requires both thin film Perovskites for tandems Contact preparation with the formation of functional de- Mixed halide perovskite solar cells are interesting [email protected] vices (complete solar cells) as well as sophisticated for tandem devices in combination with Silicon or www.physik.uni-halle.de analysis techniques. We use a unique thin film Cu(In,Ga)(Se,S)2 bottom cells. However, for this growth setup which allows real-time growth con- purpose the perovskite thin films need to be pre- trol by X-ray methods. And we use sophisticated pared by industrially scalable methods. We use Selected publications: electronic analysis and simulation techniques in co-evaporation in vacuum and study the growth order to study the electronic transport in devices mechanisms by in-situ X-ray diffraction in real- T Hölscher, S Förster, T Schneider, M Maiberg, prepared by our group or by research partners time. The goal is to relate different growth paths W Widdra, R Scheer , Light induced degradation of Cu(In,Ga)Se2 thin film from academia and industry. with the electronic properties of the resultant surfaces, Applied Physics Letters (2017) 111 thin film devices. (1), 011604.

E Jarzembowski, B Fuhrmann, H Leipner, W

Digital twin Fränzel, R Scheer, Ultrathin Cu (In, Ga) Se2 In order to optimize the performance of solar cells, solar cells with point-like back contact in experiment and simulation, Thin Solid Films a detailed knowledge of their limiting recombina- (2015) 633, 61–65. tion mechanisms is required. In our group, com- M Maiberg, T Hölscher, S Zahedi-Azad, R plete 3-dimensional device models are built in the Scheer, Theoretical study of time-resolved computer which allow to identify the most rele- luminescence in semiconductors. III. Trap vant recombination sites. This work is performed states in the band gap, Journal of Applied Physics (2015) 118 (10), 105701. in the frame of BMWi and DFG projects. P Pistor, J Borchert, W Fränzel, R Csuk, R Novel cell concepts Scheer, Monitoring the phase formation of coevaporated lead halide perovskite thin films A completely novel method for photon manage- by in situ x-ray diffraction, The journal of False colour plot of X-ray diffraction intensities ment could be the combination of 2 photons for physical chemistry letters (2014) 5 (19), during growth and decomposition of perovskite film one electronic excitation. Thereby much higher 3308–3312. efficient solar cells could be built. The trick is to R Scheer, HW Schock, Chalcogenide introduce a defect band in the semiconductor. In photovoltaics: physics, technologies, and thin film devices, (2011) John Wiley & Sons. the framework of a DFG project our group investigates chalcogenide thin films doped with transition metals and analyses their functionality by optical and electronic methods. Materials for energy conversion and storage _47

Institute of Physics & Fraunhofer Institute for Microstructure of Materials and Systems Solid State Physics

Fields of Research: Current Projects and Future Goals:

› Silicon electrochemistry X-ray microscopy Prof. Dr. Ralf B. Wehrspohn › Photon management We have used this technique to characterize a few › X-ray microscopy for 3D analysis of porous different types of materials in our group, includ- 1997 PhD in Experimental Physics, samples ing protein fleeces, porous silicates and drugs. University Oldenburg & École Recently, we characterized sustainable polymeric Polytechnique, Palaiseau, France Silicon is the element on which most of the yarns in a work performed in collaboration with group’s work is focused on. We use it to create po- researchers from the University of Bayreuth and 1998–1999 rous structures via (photo-)electrochemical etching other partners in Germany, China, and Switzer- Philips Research Laboratories, processes or functionalize it by the deposition of land. Our partners have developed a straightfor- Redhill, England various layer via sputtering, chemical deposition ward method to synthesize yarns consisting of 1999–2003 or atomic layer deposition. Such Si based materials nanofibrils of polyacrylonitrile (PAN) aligned in Group leader, Max Planck Institute are tested for new battery concepts like the sili- the same direction and interconnected via für Mikrostrukturphysik, Halle con air battery because of its high specific energy poly(ethylene glycol) bisazide. The yarns, with Habilitation at the Martin Luther density. high strength in combination with high tough- University Halle-Wittenberg Also more complex structures like transition metal ness, have overall properties similar to dragline 2003–2005 phosphides are used to build electrocatalysts for spider silk. Our characterization using the X-ray Full Professor (C4) of Nanophotonic the efficient direct water splitting. This is part of microscope was key for the visualization of the Materials, University Paderborn our contribution to the production of green hy- orientation of the fibrils. With X-ray imaging, Since 2006 drogen as a future energy carrier. there was no need to cut or destroy the yarns to Full Professor (W3) of Experimental The second research focus of the group is nano- obtain the three-dimensional of the samples. The Physics, Microstructure based photonics, i.e. the interaction of light with artifi- images not only enabled the visualization of the Material Design, Martin Luther cial nanostructures to investigate new ways of yarns non-destructively but also allowed the University Halle-Wittenberg light control. A particular emphasis lies on en- computational analysis to estimate the high degree

Since 2006 hancing performance of optoelectronic devices of uniform orientation of the fibrils. In conjunction with head of Fraunhofer such as solar cells and OLEDs. This also includes Institute for Microstructure of the development of scalable fabrication processes Tailored disorder for a tailored Materials and Systems, Halle to facilitate nanophotonic interfaces on the device optical response level relevant for industrial application. Between the contrary extremes of strictly periodic Since 2020 Since November 2017, our chair has been using the structures (spectrally well-defined optical res In conjunction with executive vice president of Fraunhofer Society, X-ray microscope ZEISS Xradia 810 Ultra, financed ponse) and purely random structures (broadband Munich by the DFG, to study and characterize advanced response) lies the huge configuration space of materials. With our X-ray microscope, we can correlated disorder, which has just started to being produce three-dimensional virtual representations explored. Therein lie configurations of so-called Contact of microscopic samples non-destructively, allow- hyperuniform disorder. Hyperuniformity repre- ing the detailed visualization of internal parts of sents exciting new states of disordered -but not at [email protected] the sample, their morphological characterization all random- matter, giving rise to unforeseen phe- www.physik.uni-halle.de/ and also the estimation of structural parameters nomena not just in the field of optics but for any fachgruppen/mikromd/ using software analysis. wave excitations. Our group investigates hyperuniform configurations of optical scatterers to explore novel ways to tailor light scattering on demand. Selected publications:

X. Liao et al., High strength in combination with high toughness in robust and sustainable polymeric materials, Science (2019) 366,6471, pp. 1376–1379.

Wehrspohn et al., Nanometallurgical Silicon for Energy Production and Storage, Joule 3(5) 1172, 2019.

Zhang et al., Bifunctional Heterostructure Assembly of NiFe LDH Nanosheets on NiCoP Nanowires for Highly Efficient and Stable Overall Water Splitting, Advanced Functional Materials 28(14):1706847, 2018.

Piechulla et al., Fabrication of Nearly-Hyper- uniform Substrates by Tailored Disorder for Photonic Applications, Adv. Optical Mater, 2018, 1701272. Disordered hyperuniform configuration of TiO2 Mie resonators (left) and their scattering spectrum (right) (taken from Piechulla et al., Adv. Opt. Mater. 2018, 1701272) Synthetic and biomacromolecules

Photo: CFalk | pixelio.com (Bio)-Macromolecules are key molecules, indispensable These activities are supported by several national and for modern society. They are not only found in living international network initiatives such as the SFB TRR 102 organisms or used in medicine, but are also needed in (Polymers under Multiple Constraints – Restricted and modern technology such as in structural materials Controlled Molecular Order and Mobility), the RTG/ (aeroplanes, cars) or in modern energy- or information GRK 2670 (Self-Organization of Soft Matter Via Multiple technology. We strive to interface structure, function and Noncovalent Interactions), the International Graduate dynamics of large (bio)-molecules, aiming to design, School AGRIPOLY and the Center of Innovation Compe- prepare and model specific functions of synthetic poly- tence (ZIK) HALOmem. mers and (bio)-macromolecules in view of their micro- and nanostructure. The molecular design, synthesis Being a strongly interdisciplinary oriented research area and assembly processes of (bio)-molecules such as lipids, we address to reach closed material cycles, specifically metal-complexes, cellulose, enzymes, synthetic poly- in the study programs Bachelor and Master in Chemis- mers, proteins or carbon-materials are addressed both, try/Physics or the special Master program “Polymer theoretically and experimentally. Materials Science”.

Molecules

MECS

Models

SBM Synthetic SSIN and biomacromolecules

Materials 50_ SYNTHETIC AND BIOMACROMOLECULES

Institute of Chemistry & BMBF Center HALOmem & Charles Tanford Protein Center Biophysical Chemistry

Fields of Research: Current Projects and Future Goals:

› Protein and membrane biochemistry Fluorescence Correlation Spectroscopy (FCS) › Reconstitutions using model membranes FCS is a powerful, highly selective and highly sensi- Prof. Dr. Kirsten Bacia › Polyphilic interactions with membranes tive optical fluctuation technique that allows to 2001–2007 › Structure and dynamics of membrane protein analyze the mobility, coincident motion and inter- Graduate student and postdoc complexes actions of molecules in reconstituted systems and (MPI-BPC, Göttingen; MPI-CBG, › Membrane lateral organization living cells. We have refined dual-color Fluorescence Dresden; BIOTEC, Dresden, Germany) › Effects of proteins on membrane morphology Cross-Correlation Spectroscopy (dcFCCS) to moni- and organization tor membrane protein reconstitution and to quan 2005 Dr. rer. nat., University of Dresden › Diffusion and binding analysis with titatively analyze protein binding to membranes. fluorescence fluctuation spectroscopy We plan to further advance fluorescence fluctuation 2007–2009 › Fluorescence microscopy and cryo-electron spectroscopy techniques for a yet more detailed Postdoc, UC Berkeley, USA

microscopy description of protein-membrane binding. 2009–2015 HALOmem Junior Group Leader, Cellular membranes have crucial roles in many Martin Luther University Halle- biological functions. We study the interaction be- Wittenberg tween the membrane bilayer and proteins that 2012–2015 form an integral part of the membrane or reversibly Juniorprofessor (W1), Martin associate with it. From a life science perspective, Luther University Halle-Wittenberg we are interested in intracellular trafficking, an essential process that ensures protein and lipid since 2015 transport between cellular compartments in eu- Professor (W2) of Biophysical karyotes. We are interested in the spatial and Chemistry, Martin Luther University Halle-Wittenberg temporal interplay of factors governing transport vesicle formation. In particular, we seek to understand the sculpturing and the separation (fission) of a nascent membrane transport vesicle. Contact

[email protected] We use a broad range of artificial membrane systems to interrogate dynamic lateral organization, www.chemie.uni-halle.de membrane morphology and protein-lipid interactions. Proteins are expressed, purified, fluores- cently labeled and studied in combination with Model membrane systems for Selected publications: various types of model membranes. Biological research and applications function is studied using physicochemical and We develop and apply model membrane techniques M. Grimmer, K. Bacia, Giant Endoplasmic Reticulum vesicles (GERVs), a novel model optical approaches alongside with biochemical to bridge the gap between well-defined, yet sim- membrane tool. Sci. Rep., 2020, 10(1), 3100. and molecular biology techniques. Cryo-electron plistic synthetic lipid bilayer models and natural microscopy and confocal fluorescence microscopy biological complexity. Recently, we have devised a S. Werner et al., A Quantitative and Reliable Calibration Standard for Dual-Color allow us to visualize morphological consequences method to generate giant unilamellar vesicles from Fluorescence Cross-Correlation Spectroscopy. of protein-membrane interactions in reconstituted natural endoplasmic reticulum (ER) membranes, ChemPhysChem, 2018, 19, 1–10. systems. Fluorescence fluctuation spectroscopy providing an accessible model system for functional D. Krüger et al., Measuring Protein Binding to including dual-color Fluorescence Cross-Correla- in vitro studies of the ER. We plan to apply our Lipid Vesicles by Fluorescence Cross-Correla- tion Spectroscopy is used to obtain quantitative reconstitution and binding analysis approaches to tion Spectroscopy. Biophys. Journal, 2017, information on binding and dynamics. Model investigations of further biological systems, such as 113(6), 1311–1320. membrane and fluorescence methods are avanced protein-membrane interactions in plant cells and the C. Schwieger et al. Binding of the GTPase Sar1 to gain new insights into protein-membrane in- uptake of the SARS-CoV-2 virus into human cells. to a Lipid Membrane Monolayer: Insertion and Orientation studied by Infrared-Reflection- teractions. Absorption Spectroscopy. Polymers, 2017, 9, In vitro reconstitution of 612. intracellular processes S. Werner et al., Dendritic Domains with We investigate membrane binding and remodeling Hexagonal Symmetry Formed by X-Shaped activity of the COPII proteins, which are involved Bolapolyphiles in Lipid Membranes. Chem. Eur. in transport vesicle formation at the ER, using J., 2015, 21, 8840–8850. dcFCCS, advanced fluorescence microscopy and G. Zanetti et al., The structure of the COPII cryo-electron microscopy in combination with transport-vesicle coat assembled on membranes. eLife, 2013, 2:e00951. molecular biology. We want to further explore how the hydrolysis of GTP and the membrane remodeling and fission processes are coordinated in space and time. SYNTHETIC AND BIOMACROMOLECULES _51

Institute of Physics Biophysics

Fields of Research: Current Projects and Future Goals:

› High-resolution NMR spectroscopy Protein folding and biophysical methods Prof. Dr. Jochen Balbach › Structural biology of medically relevant The gain of Gibbs free energy (ΔG) drives the pro- proteins tein folding reaction towards the native, biologi- 1994 PhD in Chemistry, TU München › Biophysics of protein folding and stability cally active state. Several thermodynamic parame- › Intrinsically disordered biopolymers ters including the temperature, the chemical 1994–1996 › Amyloid fibril formation potential, or the pressure change ΔG and thus PostDoc, University of Oxford, UK, induce un- or refolding. For several proteins, we Prof. C.M. Dobson Proteins and nucleic acids are the biopolymers, could disclose the molecular folding mechanism 1996–2004 which control all processes in living systems. and found a direct link to the respective biological Senior scientist, Univ. Bayreuth Their function is closely related to their molecular function. structure. Our group uses high resolution NMR 2001 Habilitation in Biochemistry, spectroscopy and various biophysical methods Medically relevant proteins Univ. Bayreuth (including absorption, fluorescence, CD, calorim- We investigate the structural biology of several etry, and in collaborations crystallography, single- human proteins mainly by NMR spectroscopy in- Since 2004 molecule spectroscopy, cryo electron microscopy) to cluding G-protein coupled receptors, hormones, eye Full Professor (W3) in Experimental investigate the structure, dynamics, and function lens crystallins, ankyrin repeat proteins, hub pro- Physics (Biophysics, Medical Physics), of these biomacromolecules as well as function- teins and membrane remodelling proteins, which Martin Luther University Halle- Wittenberg ally relevant interactions with other proteins, are involved in respective diseases including osteo- nucleic acids, low molecular substrates, metal porosis, cataract, cancer, and muscle dystrophies. ions and lipids/membranes. We will extend our studies now to different proteo- Our biophysical tools are employed to follow the forms of transcription factors of plants, involved Contact self-assembly process of the protein chain towards in plant pathology and metabolism. its three dimensional structure, called protein [email protected] folding. Many protein folding events are closely www.physik.uni-halle.de/fachgrup- related to severe diseases and therefore, we inves- pen/biophysik tigate aggregation prone and intrinsically disor- Electron dered proteins and their relation to function and micrograph of dysfunction. We are interested in the fundamental Selected publications: functional amyloid and polymer physical principles driving protein fibrils of the Klamt, A. et al. Hyperbolic pressure-tempera- order and disorder to fulfil their function. human parathyroid ture phase diagram of the zinc-finger protein hormone apoKti11 detected by NMR. J. Phys. Chem. (2019), 123, 792–801. Amyloid fibril forming proteins Evgrafova, Z., et al. Probing polymer chain conformation and fibril formation of peptide Protein folding of soluble, globular proteins is conjugates. Chem. Phys. Chem. (2019), 20, dominated by intramolecular interactions, whereas 236–240. protein aggregation and fibril formation is domi- Kumar, A. et al. Phosphorylation–induced nated by intermolecular interactions between unfolding regulates p19INK4d during the individual peptide and protein chains. The goal is human cell cycle. Proc. Natl. Acad. Sci. USA (2018), 115, 3344–3349. to understand the fundamental, polymer physical principals of fibril formation. Peptides and pro- Kumar, A. et al. Small Molecule Inhibited teins under current investigations include the Parathyroid Hormone Mediated cAMP Response by N–Terminal Peptide Binding. Alzheimer peptide A-beta, poly(A) binding proteins, Scientific Reports (2016), 6, 22533. human eye lens crystallins, and the parathyroid hormone. In the future, conjugates between these Garvey, M. et al. Molecular architecture of A fibrils grown in cerebrospinal fluid solution peptides and synthetic polymers will be studied. and in a cell culture model of A plaque β formation. Amyloid (2016), 23, 76–85. β Intrinsically disordered proteins Dinesh, D.C. et al. Solution structure of the A fascinating new class are intrinsically disor- PsIAA4 dimerization domain reveals dered proteins. Protein NMR is especially suited interaction modes for transcription factors in early auxin response. Proc. Natl. Acad. Sci. to study the conformational remodelling and USA (2015), 112, 6230–6235. dynamics of these proteins. We started and continue in future to correlate molecular properties of this protein class to their function by studying the human Gab1/Grb2 protein system, the para- Protein structure of the p19INK4d protein, thyroid hormone and plant proteins with disor- which regulates the human cell cycle dered domains. 52_ SYNTHETIC AND BIOMACROMOLECULES

Institute of Chemistry Polymer Reaction Engineering

Fields of Research: Current Projects and Future Goals:

The professorship for Polymer Reaction Engineering Kinetic investigations in gas-phase is a joined appointment of Martin Luther University polymerization Prof. Dr. Michael Bartke Halle-Wittenberg, together with the Fraunhofer In coordinative polymerization, the polymerization 2002 Society for Applied Research. Prof. Bartke is also kinetics are catalyst dependent. In the frame of Dr.-Ing. in Industrial Chemistry, responsible for the Fraunhofer-Polymer Pilot Plant an industrially sponsored research project, we in- Technical University of Berlin Center PAZ in Schkopau. vestigate the kinetics of industrial catalyst systems in gas-phase polymerization of propene under 2001–2005 Polymers are with a worldwide, annual production industrially relevant conditions. Senior Scientist, Borealis Polymers Oy, Finland of more than 350 Mio. tons an important class of materials. Polyreactions do exhibit various chal- 2005–2006 lenges in reaction engineering, e.g. not uniform Research Manager Process Research, products, but product distributions are obtained, Borealis Polymers Oy, Finland kinetics of polyreactions are often complex, mass- 2006–2008 and heat transfer can play an important role and Scientific Director Fraunhofer Polymer often there is a significant increase in viscosity Pilot Plant Center (Schkopau, Germany) during a polyreaction. Since 2006 Professor for Polymer Reaction Polymer Reaction Engineering deals with the Engineering, Martin Luther University reaction engineering of polyreactions, in particular: Halle-Wittenberg › analysis, description and optimization of polyreaction kinetics 5l gas-phase reactor for polymerization of propene Since 2008 › development and design of reactors, reactor Director Fraunhofer Polymer Pilot Plant Center PAZ, Schkopau configurations and processes Reaction Calorimetry Reaction calorimetry is a method to monitor the Research focus of our group is in particular reaction rate of exothermic reactions by measuring measurement and modelling of reaction- and pro- the chemical heat flow released by the reaction. Contact cess kinetics of polyreactions. In our group, we have two different setups for re- [email protected] action calorimetry. In frame of an industrial cooperation project, reaction calorimetry is applied www.chemie.uni-halle.de/bereiche_ in order to study kinetics in bulk phase polymeri- der_chemie/technische_chemie/ zation of propene and to monitor, control and polyrt optimize multi-stage polymerization processes, e.g. for the manufacturing of heterophasic poly- Selected publications: proplyme copolymers. Bartke M. Reaktoren für spezielle technisch-chemische Prozesse: Polymerisa- Scale-up of polyreactions tionsreaktoren. In: Reschetilowski W. (eds) Scale-up is a critical step during commercializa- Handbuch Chemische Reaktoren. Springer tion of new products and processes. In close co Reference Naturwissenschaften. Springer Spektrum, Berlin, Heidelberg (2019). Kinetic measurements in heco-PP polymerization operation with the Fraunhofer Polymer Pilot Plant Center PAZ, which is also headed by Prof. Bartke, Kröner, T., Bartke, M. Sorption of Olefins in A further focus area is development, optimization scale-up of new processes and products up to the High Impact Polypropylene – Experimental Determination and Mass Transport Modeling. and modelling of polymerization processes. A tons scale can be carried out. Macromol. React. Eng. (2013), 7, 453–462. highly specialized lab for coordinative polymeri- Kröner, T., Lieske, A., Hahn, M., Bartke, M. zation of olefins is available. Modellbasierte Übertragung von satzweisem- auf kontinuierlichen Betrieb am In cooperation with the Fraunhofer Polymer Pilot Beispiel einer radikalischen Copolymerisation. Chem. Ing. Tech., (2009), 81, 1837–1843. Plant Center in Schkopau, scale-up of polymerization processes as well as sample synthesis up to Bartke, M. Polymer Particle Growth and the tons scale is possible. Process Engineering Aspects. Kapitel 3 in Severn, J.R., Chadwick, J.C., Tailor-Made Polymers, Wiley-VCH (2008).

Bartke, M., Oksman, M., Mustonen, M., Denifl, P. New Heterogenisation Technique for Single-site Polymerization Catalysts. Macromol. Mater. Eng. (2005), 290, 250–255.

Fraunhofer Polymer Pilot Plant Center PAZ, Schkopau SYNTHETIC AND BIOMACROMOLECULES _53

Institute of Chemistry Polymer Chemistry

Fields of Research: Current Projects and Future Goals:

› Synthesis and novel analytical methods of Biomimetic, renewable and self-healing Prof. Dr. Wolfgang H. Binder macromolecular architectures polymers › Biomimetic, renewable and self-healing Reuse and life-cycle-enhancement of polymers are 1995 PhD in Synthetic Organic Chemistry polymers, 3D-printing among the most pressing societal needs. We address (University of Vienna, Austria) › Design of nanoscaled medical imaging novel concepts for reusing thermoplastics and ther- and drug-delivery systems mosets based on vitrimers, self-healing materials 1996–1997 › Develop novel electrolytes for battery and and reusable rubbers, funded by the graduate school PostDoc (Emory University, USA, transistor systems AGRIPOLY, DFG- and EU-projects. Prof. F. M. Menger) › Self-healing concepts for thermoplasts, 1997 elastomers and electrode-materials Novel electrolyte-polymers for battery and PostDoc (University of Vienna, › Study biological folding, aggregation- and transistor systems Austria, Prof. J. Mulzer) chirality transfer-principles Improved charge-transport and the compensation 2004 of volume-changes is crucial in the technology of Habilitation (Vienna University of Macromolecules are key molecules, indispensable for modern batteries, fuel-cells and transistors. Sev- Technology) modern society, present as widely known structural eral EU/DFG-funded projects (Bat4ever within materials in e.g. automobiles or aeroplanes, but also Horizon-2020, DFG) do address the chemical syn- 2004–2007 in biomedicine, modern energy- or information thesis of novel self-healing ionomers and ionogels. Associate Professor (Vienna University of Technology) technology. Research focus in our group is the prepa ration of functional polymers and their application in Study biological folding-, assembly and Since 2007 technology, aiming to design polymers for medi- chirality transfer-principles Full Professor (W3) of Macromolecular cine, as advanced structural materials, or for novel Secondary-structure of proteins and peptides is Chemistry (Martin Luther University batteries and transistors. Based on the polymer’s determining their function in living systems, in Halle-Wittenberg) structural complexity we use all living polymerizations its undesired assembly being responsible for e.g. and modern functionalization strategies known Alzheimer’s disease. Projects deal with amyloid- from synthetic organic chemistry, including proteins to understand and prevent disease- Contact “click”-based methods. Novel polymeric architec- relevant aggregation via synthetic polymers, able tures and the site-specific integration of supra- to fold- and unfold during aggregation. [email protected] molecular interactions (such as hydrogen bonds, www.macrochem.uni-halle.de ionomers, mechanophores) into tailored macro- 3D-printing of materials molecules generate advanced materials in the areas Three dimensional (3D)-printing technology has of biomedicine, modern imaging technology, bat- become societies leading method to form materi- Selected publications: teries, transistors or for self-healing and 3D- als for many applications. We use multimode 3D- J. Freudenberg and W. H. Binder. Chirality printing technologies. printing methods to prepare modern materials, control of screw-sense in Aib-polymers: synthesis and helicity of amino acid with embedded self-healing-, mechanochromic- functionalized polymers, ACS Macro Letters and pharmaceutical function. Material-focus is (2020), 9, 686. placed on novel battery-electrodes, drug-release

S. Chen, S. S. Parkin, W. H. Binder et al. systems, stress-sensing- and (bio)-degradable soft/ Gating effects of conductive polymeric ionic hard interfaces. liquids. J. Mater. Chem. C (2018), 6, 8242–8250.

S. Chen, W. H. Binder et al. Opposing Design of nanoscaled medical imaging Phase-Segregation and Hydrogen-Bonding systems and artificial membranes Forces in Supramolecular Polymers, Angew. Chem. Int. Ed. (2017), 56, 13016. Imaging technology is among the most important technique for the early detection of diseases D. Döhler, W. H. Binder et al. CuAAc Based in humans, allowing to detect and heal diseases Click Chemistry in Self-Healing Polymers, Acc. Chem. Res. (2017), 50, 2610. in tissue. We develop novel concepts of ultrasmall nanoparticles for near-infrared (NIR-)detection, P. Michael and W. H. Binder. A Mechanochemi- able to visualize tissue-morphology via photoa- cally Triggered “Click” Catalyst, Angew. Chem. Int. Ed. (2015), 54, 13918. coustic- and (NIR)-techniques. The method is extended towards tissue-specific detection of meta- S. Chen, W. H. Binder et al. Self-Healing Materials from V- and H-Shaped Supramo- bolic profiles. lecular Architectures, Angew. Chem. Int. Ed. (2015), 54, 10188. 54_ SYNTHETIC AND BIOMACROMOLECULES

Institute of Chemistry Organic Chemistry

Fields of Research: Current Projects and Future Goals:

› Antitumor and antidementia active Natural product derived antitumor active compounds from natural products compounds Prof. Dr. René Csuk › Ancient dyes and modern materials for The extraordinary chemical diversity encom- 1984 photovoltaics passed by natural products continues to be of rel- PhD in Organic Chemistry, Graz, evance to drug discovery. Therapy of cancer by University of Technology, Austria The evolution of complex life is strictly dependent inducing programmed cell death (apoptosis) is in on mitochondria found in all complex cells. Mito- the focus of scientific research. Quite often, in 1986–1989 chondria fuel the metabolic reactions that create cancer cells the sensitivity towards apoptosis is Post-Doc (University Zurich, Switzerland, Prof. A. Vasella) and maintain all other structures of the cells. reduced thus ultimately leading to an inappropriate Cancer is among the top-most causes of death cell survival and malignant progression. These 1992 and one of the most feared diseases. A modern problems can be addressed by developing mito- Habilitation, University of Heidelberg approach to the therapy consists in the triggering chondria-targeted drugs. Recently we could show 1992 of programmed cell death (apoptosis). Mitochon- that natural product derived conjugates holding Full Professor (C3), Pharmaceutical dria-targeted drugs may induce apoptosis and an extra rhodamine B moiety attached to the Chemistry, University Heidelberg overcome problems of drug resistance. Pentacyclic skeleton of the natural product via a suitable triterpenes and their derivatives are useful candi- spacer exhibit cytotoxicity in a nano-molar range Since 1995 Full Professor (C4), Organic Chemistry, dates to reach these aims. Pentacyclic triterpenes while retaining high tumor cell selectivity. Our Martin Luther University Halle- and their structurally simplified derivatives can future activities will focus on the design and syn- Wittenberg also be used to make compounds available that thesis of molecules that act as “mitocanes” (mito- might be effective against age-related dementia. chondrial targeted cytotoxic agents) and at the same time also inhibit other enzymes that are particularly involved in tumor growth. Further- Contact more, the synthesis of cytotoxic molecules is [email protected] planned, which are linked to a molecular switch thus allowing biological activity to be turned on www.chemie.uni-halle.de and off at will.

Selected publications: Novel materials for OLEDs The production of reproducible and closed DSSCs M. Blaess et al., Lysosomes and lysosomotro- (“Dye Sensitized Solar Cells”) was defined as one pism in SARS-CoV-2 infection and COVID-19 of the most important goals. The synthesis of pro- implicate personal risks and new startegies in prietary dyes for use in DSSCs and their subse- prophylaxis and treatment, Intern. J. Mol. Sci. (2020), 21, 4953. quent evaluation is planned. This project, which focuses among other things B. Brandes et al., Design, synthesis and on the synthesis and evaluation of dyes for pho- cytotoxicity of BODIPY FL labelled triterpenoids, Eur. J. Med. Chem. (2020), 185, tovoltaics, is closely related to the development 111858. and application of highly sensitive analytical M. Garcia-Altares et al., Mapping Natural methods. The knowledge gained from these in- Product Dyes in Archeological Textiles by vestigations will also be used to carry out dye Imaging Mass Spectrometry, Sci. Reports analysis on historical materials from all over the (2019), 9, 2331.

world. J. Wiemann et al., An access to a library of novel triterpene derivatives with a promising pharmacological potential by Ugi- and Passerini multicomponent reactions, Eur. J. An additional highlight is the synthesis of func- Med. Chem. (2018), 150, 176–194. tionalized (natural) products using biocatalytic S. Sommerwerk et al., Rhodamine B conjugates reactions as well as advanced catalytic processes of triterpenoic acids are cytotoxic mitocans to perform reactions with high regio-, enantio- even at nanomolar concentrations, Eur. J. Med. and diastereoselectivity using mild reaction con- Chem. (2017), 127, 1–9. ditions and modern concepts of “green chemistry”. K. Miettinen et al., The ancient CYP716 family These syntheses are also used to access novel ma- is a major contributor for the diversification of terials for photovoltaics. eudicot triterpenoid biosynthesis, Nature Commun. (2017), 8, 14153. A further focus is the analysis of old dyes, colorants and pigments. Thereby, the time span of the exa mined samples ranges from about 3000 BC to the early industrial age. SYNTHETIC AND BIOMACROMOLECULES _55

Institute of Chemistry Food Chemistry

Fields of Research: Current Projects and Future Goals:

› Non-enzymatic browning, Maillard Reaction Controlling Maillard Reaction pathways Prof. Dr. rer. nat. › Enzymatic browning Novel mechanistic pathways leading to defined Marcus A. Glomb › Isolation and characterization of food protein modifications can be used to tailor generate Staatl. gepr. Lebensmittelchemiker ingredients foods of specific demands. Idealy this approach › Synthesis of target compounds only involves traditional preparation techniques 1988–1989 › Analytical and preparative chromatography without the need for artificial additives or flavor- Sandoz AG, Nuremberg, Germany ings. It can also be used to generate technical 1990–1992 The term non-enzymatic browning or Maillard products based on targeted modification of bio Georgi GmbH, Stuttgart, Germany reaction describes the amine catalyzed degradation polymers from food processing side streams in- of reducing sugars. Although the reaction in gen- cluding e.g. gelatin. In vivo this knowledge will 1992 eral has been known for a long time, reactive in- help to find cures against late complications of PhD in Food Chemistry, University of Stuttgart, Germany termediates and major reaction pathways still e.g. diabetes and aging. The latter is currently under need to be uncovered. Our group has established investigation within a DFG research training group 1992–1995 all relevant -dicarbonyl structures within the with the focus on the relation of posttranslational PostDoc, Case-Western-Reserve- degradation of major hexoses and disaccharides protein modifications and aging (ProMoAge – University, Cleveland/Ohio, USA including ascorbicα acid. -Dicarbonyl and oxidative RTG 2155). 2001 -dicarbonyl cleavages were found as the major Habilitation, Technical University degradation routes to βexplain almost all frag- Mechanisms of enzymatic browning Berlin, Germany mentationα products and known end products. In The tea related mechanisms were extended to the

Since 2004 addition, these mechanisms lead to a novel class identification of the major brown chromophores Full Professor (C4) of Food Chemistry, of Advanced Glycation Endproducts with amide found in cut salad, which is found among other to- Martin Luther University Halle- structure, which were established as quantitative days convenient preparations in food markets. In Wittenberg important posttranslational protein modifications. contrast, here enzymatic degradation is based on the In contrast, enzymatic browning involves oxida- modification of bitter components including ses- tion of polyphenols and other secondary plant quiterpene lactones rather than that of polyphenols. Contact products and follow-up non-enzymatic reactions This opens new insights to alternative reaction such as oxidative coupling and polymerization pathways based on secondary plant products and to [email protected] ultimatively lead to high-polymeric brown mela- new strategies to prevent unknown browning of www.chemie.uni-halle.de/bereiche_ nins. In this respect the major mechanistic degra- vegetables. Thus, secondary plant products are cur- der_chemie/lebensmittelchemie dation pathways during rooibos tee fermentation rently screened for their browning potential in were unraveled. Different to the chemistry of addition to physiologically positive effects. black tee the dihydrochalcon aspalathin was Selected publications: identified as the key polyphenolic compound. Understanding of fat autoxidation T. Baldensperger et al. Comprehensive Rooibos browning mechanisms include single- mechanisms analysis of posttranslational protein modifications in aging of subcellular electron transfer reactions leading to fragmenta- Although general pathways of fat autoxidation are compartments, Sci. Rep. (2020), DOI: 10.1038/ tion and entail protein modification. known for decades, most research was conducted s41598-020-64265-0. As a general approach of our work group target in simple one-phased model setups. However, the

T. Heymann et al. Influence of -carotene and structures are either isolated from food by the typical situation in foods is extremely complex and lycopene on oxidation of ethyl linoleate in one complete array of chromatographic methods in- brings major constituents as proteins and carbohy- β and disperse phased model systems, J. Agric. cluding counter current setups or are synthesized drates as well as minor constitutents as secondary Food Chem. (2020), DOI: 10.1021/acs. jafc.9b07862. independently. Authentic materials can then be plant products in contact to fats typically in multi- used in independent model incubations to clarify phased systems. We have recently established a N. Mertens et al. Oxidative fragmentation of aspalathin leads to the formation of novel reaction pathways relevant in foods or stable disperse-phased setup to investigate the dihydrocaffeic acid and the related lysine physiological systems on a molecular basis. influences of the various chemical classes on fat amide adduct, J. Agric. Food Chem. (2020), oxidation, and as first results were able to differen- DOI. 10.1021/acs/jafc.9b07689. tiate between radical scavenging and physical T. Jost et al. Efficient analysis of 2-acetyl- quenching reactions of selected carotenoids. 1-pyrroline in foods using a novel derivatization strategy and LC-MS/MS, J. Agric. Food Chem. (2019), DOI: 10.1021/acs. jafc.9b00220.

C. Henning et al. Analysis and chemistry of novel protein oxidation markers in vivo, J. Agric. Food Chem. (2018), DOI: 10.1021/acs. jafc.8b00558.

M. Smuda and M.A. Glomb. Maillard Browning of cut iceberg lettuce degradation pathways of vitamin C, Angew. (Prof. Dr. M.A. Glomb) Chem. Int. Ed. (2013), DOI. 10.1002/ anie.201300399. 56_ SYNTHETIC AND BIOMACROMOLECULES

Institute of Chemistry & Helmholtz Center for Environmental Research Analytical Chemistry of Environmental Processes

Fields of Research: Current Projects and Future Goals:

› Technical and natural occurring sorbents Bioaccumulation › Environmental fate of organic pollutants The assessment of the bioaccumulation potential Prof. Dr. Kai-Uwe Goss › Bioaccumulation of organic pollutants of organic chemicals is part of the chemical legis- 1993 › Physico-chemical properties of lation in all industrialized countries. Currently, PhD in Environmental Chemistry perfluorinated chemicals this assessment is based on the assumptions that (University of Bayreuth, Germany) › Predictive methods for equilibrium a) organic chemicals only accumulate in lipids, partitioning and b) that the octanol-water partition coefficient 1994–1995 can be used to estimate this partitioning to lipids. PostDoc (University of Minnesota, USA, Prof. S. Eisenreich) Today a huge number of man-made and naturally However, this approach neither applies to terres- occurring chemicals exist that are of environmen- trial food chains, nor does it work for compounds 1996–2002 tal concern. This includes organic chemicals, their that accumulate in proteins. It is also meaning- PostDoc/Oberasistent (EAWAG, metabolites and complex mixtures. To protect less for ionic compounds. In order to close these Switzerland, Prof. R. Schwarzenbach) the environment, we need detailed knowledge gaps we have set out to develop a systematic and 2002 about such chemicals – their physical and chemical comprehensive understanding of the equilibrium Habilitation (Swiss Federal Institute of properties, their fate in the environment, their partitioning of a broad range of organic chemicals Technology Zürich (ETH), Switzerland) exposure and toxic effects. A thorough under- into membrane lipids, storage lipids, structure 2002–2006 standing of the environmental fate of organic proteins and serum albumin. Privatdozent (Swiss Federal Institute pollutants has numerous applications: it is re- of Technology Zürich (ETH), quired for the registration of chemicals by the PBPK modelling Switzerland) authorities, it is a prerequisite for remediation or The results of our experimental work on biopar prevention of environmental contaminations, it titioning of organic chemicals will be also be used since 2007 helps in the design of environmental monitoring in a PBPK (physiologically based pharmacokinetic) department head at the Helmholtz Center for Environmental Research strategies and it allows for the development of modelling approach in order to elucidate the rela- (UFZ, Leipzig) optimized analytical methods. tive importance of different processes (equilibrium The goal of our group is an improved understanding partitioning, transport kinetics and metabolism). since 2010 of all those transport and partition processes that This modelling will provide us with concentration Full Professor (W2) of Analytical affect the fate of organic chemicals in the envi- profiles of the chemicals in all organs and can be Environmental Chemistry (Martin ronment. We aim for an integrative view that used to better analyse epidemiological surveys and Luther University Halle-Wittenberg) considers the physico-chemical properties of the toxicological studies. The PBPK modelling results chemicals just as well as the environmental con- are also useful in assessing the occupational ex- ditions that can largely vary in space and time. To posure to hazardous chemicals. Contact this end we combine experimental work in the lab [email protected] with various modelling approaches. Ionic organic chemicals There are numerous commercial organic chemicals www.ufz.de/index.php?de=15884 that can carry a negative or positive charge under environmental conditions (e.g. various pharma- Selected publications: ceuticals, pesticides and surfactants). This charge has a substantial impact on the sorption behavi Ebert, A., Goss, K.-U. Predicting uncoupling toxicity of organic acids based on their our of these compounds. Mineral surfaces as well molecular structure using a biophysical model. as the humic material in soils and sediments typi- Chem. Res. Toxicol. 33 (7) (2020), 1835 - 1844. cally are negatively charged. Consequently, the Ebert, A., Hannesschlaeger, C., Goss, K.-U., cationic form of an organic chemical often sorbs Pohl, P. Passive permeability of planar lipid stronger in soils and sediments than its neutral bilayers to organic anions. species while anionic species sorb less strongly. In Biophys. J. 115 (10) (2018), 1931 - 1941. a current project we try to develop a general model Henneberger, L., Goss, K.-U. Environmental to predict sorption of ionic organic compounds in sorption behavior of ionic and ionizable organic chemicals. Rev. Environ. Contam. soils and sediments based on a large experimental Toxicol. Springer, New York (2019). data set measured in the lab under systematically varied conditions. Krause, S., Goss, K.-U. In vitro–in vivo extrapolation of hepatic metabolism for different scenarios – a toolbox. Chem. Res. Toxicol. 31 (11) (2018), 1195 - 1202.

Krause, S., Ulrich, N., Goss, K.-U. Desorption kinetics of organic chemicals from albumin. Arch. Toxicol. 92 (3) (2018), 1065 - 1074. SYNTHETIC AND BIOMACROMOLECULES _57

Institute of Chemistry Physical Chemistry – Complex Self-Organizing Systems

Fields of Research: Current Projects and Future Goals:

› Structure formation in synthetic and biological The Nanoscale of Responsive Polymers Prof. Dr. Dariush soft matter by non-covalent interactions With simple continuous wave (CW) EPR spectros- Hinderberger › Nanoscopic features in hydrogels from synthetic copy on amphiphilic spin probes we have discov-

2004 and biological macromolecules ered that thermoresponsive polymeric systems PhD Physical Chemistry, Johannes › Structure formation between small molecules in show nano-inhomogeneities in structure und re- Gutenberg University, Mainz, Germany liquids; solvation activity. These nano-inhomogeneities can be stat- › Biological and synthetic molecular transporters ic on an EPR timescale (>~1ns), or dynamic (<~1ns) 2004–2006 › Intrinsically disordered proteins (IDPs) and can basically be found in all kinds of synthetic PostDoc at the Laboratory of Physical › Stimuli-responsive polymeric materials and biological thermoresponsive polymers. Chemistry at ETH Zurich, Switzerland with Prof. Dr. A. Schweiger › Method development in electron paramagnetic resonance (EPR/ESR) spectroscopy Serum Albumin Revisited 2006–2013 Human serum albumin (HSA) is a versatile trans- Staff scientist at the Max Planck Biological and synthetic soft matter has a remark- port protein for various endogenous compounds Institute for Polymer Research (MPIP) able ability to self-assemble into larger, complex and drugs in the human blood. It is the major trans- in Mainz and even functional structures solely using non- port protein for fatty acids (FA) in the circulatory 2009–2013 covalent interactions (e.g. electrostatic and hydro- system. We have devised a new EPR spectroscopic Junior Faculty of the Max Planck phobic forces). Dariush Hinderberger’s research approach to gain information on the functional so- Graduate Center with the Johannes group uses electron paramagnetic resonance (EPR) lution structure of HSA, which has remarkably been Gutenberg University Mainz (MPGC). spectroscopy as its main research tool to study soft found to have a much more symmetric than expected 2011 matter from the underlying fundamental interac- from the crystal structure, indicating increased Habilitation in Physical Chemistry, tions to more applied questions. Research in the surface flexibility and plasticity for HSA in solution. Johannes Gutenberg University, Mainz group currently has a focus on solvation and self- Going beyond fundamental structural studies, assembly of small molecules (e.g. in aqueous solu- our research platform is also excellently suited for since 2013 Full Professor (W3) of Physical tions or ionic liquids), on complex biomedical ques- general studies of protein-solvent interactions, Chemistry, Martin Luther University tions (e.g. abundant transport proteins such as temperature effects and ligand binding and we Halle-Wittenberg albumin or intrinsically disordered proteins (IDP)), have now extended it to study the molecular/ and applications such as understanding interac- nanoscopic level of hydrogels made from albumin tions and dynamics of transported molecules in as well as from synthetic polymers. Contact thermoresponsive polymers for drug delivery. EPR spectroscopy is a magnetic resonance method Structure & Dynamics of IDPs and dariush.hinderberger@chemie. uni-halle.de that is sensitive to molecular motions from the Their Complexes pico- to microsecond regime and to distances be- Intrinsically disordered proteins (IDPs) lack de- www.epr.uni-halle.de tween 0.1 and ~8 nanometers. fined tertiary and often secondary structure but fulfill essential tasks in eukaryotic life. It is their structural flexibility that allows IDPs to adapt to Selected publications: and to interact with different binding partners, J. Hunold, T. Wolf, F. Wurm, D. Hinderberger, making them suited for functioning as hubs bet Nanoscopic hydrophilic/hydrophilic phase-separation well below the LCST of ween several interaction partners. However, this Polyphosphoesters, Chem. Commun., 55, dynamic nature makes IDPs difficult to analyze. 3414–3417 (2019). We tackle the complexity of characterizing a dy-

J. Eisermann, D. Hinderberger, Tuning the namic structural ensemble with EPR spectroscopy, shape anisotropy of loosely bound colloid-like combined with NMR spectroscopy or IR-based ionic clusters in solution, Phys. Chem. Chem. techniques and obtain unique insights into a Phys., 21, 1152–1159 (2019). wide variety of IDPs, including membrane-based S. H. Arabi, B. Aghelnejad, C. Schwieger, A. Local, nanoscopic interactions of small molecules and proteins that we also characterize at the lipid Meister, A. Kerth, D. Hinderberger, Serum thermoresponsive polymers (J. Hunold et al. Chem. Commun.) Albumin Hydrogels in Broad pH and monolayer and in bilayers. Temperature Ranges: Characterization of Their Self-Assembled Structures, Nanoscopic Molecular Self Assembly in Solution and Macroscopic Properties, Biomater. Sci., 6, 478–492 (2018). EPR is complemented by other methods of physical Using our unique approach to soft matter, we ul- investigation like NMR and IR spectroscopy, elec- timately aim at exploring and understanding D. Kurzbach, T. C. Schwarz, G. Platzer, S. Höfler, tron microscopy, atomic force microscopy (AFM), structuring and dynamic principles that simple D. Hinderberger, R. Konrat, Compensatory Adaptations of Structural Dynamics in an and dynamic light scattering (DLS), and by syn- molecules in solution show and that constitute Intrinsically Disordered Protein Complex, thetic chemistry, which allows a unique approach initial steps on the way to more complex assemblies Angew. Chem. Int. Ed. 53, 3840–3843 (2014). to study these classes of complex materials. like proto-cells or crystals. 58_ SYNTHETIC AND BIOMACROMOLECULES

Institute of Physics Medical Physics

Fields of Research: Current Projects and Future Goals:

› Biomedical Photoacoustic Imaging and Electro-optically tuneable Fabry-Pérot Spectroscopy ultrasound sensors for high frame rate PA Prof. Dr. Jan Laufer › Development of experimental and tomography 2000 computational methods for image acquisition Camera-based interrogation an electro-optically PhD in Medical Physics, University and inversion tuneable Fabry-Perót polymer film sensors are College London, UK › Technology development (scanners, being developed to enable high speed 3D imaging. detectors) This technology may provide, high resolution PA 2001–2002 › Reporter genes and exogenous contrast imaging of fast physiological processes, such as Bio-Rad Microscience Ltd, Research & Development, Hemel Hempstead, UK agents neuro-functional and blood flow imaging. › In vivo demonstration and application 2002–2011 Computational and experimental methods Senior Research Fellow, Department of Photoacoustic imaging is a hybrid imaging tech- for the quantitative PA tomography Medical Physics & Bioengineering, nology that combines the high spectral specificity The aim of this project is to develop and experi- University College London, UK of optical methods with the high spatial resolution mentally validate experimental and computa- 2012–2016 of ultrasound imaging. It relies on the generation tional methods the PA inverse problem, i.e. the Research group leader, TU Berlin & of broadband acoustic waves via the absorption recovery of absolute chromophore concentrations Charité Berlin, Germany of intensity modulated light. The acoustic field is and physiological parameters, such as blood oxygen Since 2017 mapped outside the organism using ultrasound saturation, from high resolution multiwave- Professor of Medical Physics, Institute detectors. From the measured data, high resolu- length 3-D images. of Physics, Martin Luther University tion 3D images of the initial pressure are recons Halle-Wittenberg tructed that typically show the vasculature but PA imaging of fluorophores using pump- also optically absorbing contrast agents, such as probe excitation nanoparticles, dyes or genetically expressed pro- We are developing a PA molecular imaging method teins and pigments. Our research activities are for the detection of fluorophores that is based on Contact focussed on the development of new technolo- generating stimulated emission using pump- [email protected] gies, experimental and computational methods, probe excitation. The images show the location of and genetic reporters for molecular and function- the fluorophore while the otherwise overwhelm- www.physik.uni-halle.de/ al photoacoustic imaging through a highly inter- ing endogenous background signal (blood) is fachgruppen/medphysik disciplinary research programme involving phys- eliminated. Pump-probe excitation provides con- icists, engineers and life scientists. trast at fluences below the maximum permissible Selected publications: exposure and is applicable to in vivo deep tissue PA tomography. It also allows the detection of dif- J. Buchmann, B. Kaplan, S. Powell, S. Prohaska, J. Laufer. Three-dimensional ferences in the excited state lifetime. quantitative photoacoustic tomography using an adjoint radiance Monte Carlo model and Development of optically controlled genetic gradient descent. Journal of Biomedical Optics 24(6), 066001 (2019). reporters for PA imaging We are developing genetically expressed reporter J. Märk, H. Dortay, A. Wagener, E. Zhang, J. proteins and pigments that are tailored to the re- Buchmann, C. Grötzinger, T. Friedrich, J. Laufer. Dual-wavelength 3D photoacoustic quirements of PA imaging. For example, we have imaging of mammalian cells using a demonstrated the use of photoswitchable, near- photoswitchable phytochrome reporter infrared reporter proteins based on phyto protein. Communications Physics 1 (2018). chromes in vivo. Phytochromes were detected using J. Märk, F.-J. Schmitt, J. Laufer. Photoacoustic a dual-wavelength excitation and difference im- imaging of the excited state lifetime of fluorophores. J. Optics 18(5), 054009 (2016). aging. J. Märk, F.-J. Schmitt, C. Theiss, H. Dortay, T. PA microscopy of vascularisation Friedrich, J. Laufer. Photoacoustic imaging of fluorophores using pump-probe excitation. We are developing instrumentation for optical- Biomedical Optics Express 6(7), 2522–2535 resolution PA microscopy based on optical ultra- (2015). In vivo image of a subcutaneous tumour expressing sound detection. This technology has the potential A.P. Jathoul, J. Laufer, O. Ogunlade, B. Treeby, photoswitchable phytochrome Agp1 and the vasculature of to be combined with optical microscopy. A future B. Cox, E. Zhang, P. Johnson, A.R. Pizzey, B. the surrounding tissue (Märk et al, Comms Phys [2019].). application is functional PA microscopy of vascular Philip, T. Marafioti, M.F. Lythgoe, R.B. Pedley, M.A. Pule, P. Beard. Deep in vivo photoacous- development. tic imaging of mammalian tissues using a tyrosinase-based genetic reporter. Nature Photonics 9, 239–246 (2015). SYNTHETIC AND BIOMACROMOLECULES _59

Institute of Physics Mesoscopic Quantum Dynamics

Fields of Research: Current Projects and Future Goals:

› Global structure prediction and materials Global structural prediction Prof. Dr. Miguel Marques design and materials design › Materials for energy applications In the field of (global) structural prediction one 2000 PhD Theoretical Physics (Julius › Fundaments of (time-dependent) tries to obtain the lowest energy crystal structure Maximilian University of Würzburg, density functional theory and beyond for a given composition. This is a very difficult Germany) › Attosecond dynamics of electrons in problem, as the number of minima (i.e., meta-stable strong laser fields structures) increases exponentially with the 2000–2004 › Scientific software for high-performance number of atoms in the system. It is also an integral PostDoc at the University of the computing part of any strategy to design materials, as it is Basque Country (with Prof. A. Rubio) and at the Free University of Berlin the only way to assure that the predicted materials (with Prof. E. K. U. Gross) In present days there is a clear shift towards a are the ground-state in some area of the phase- new way of doing physics, which relies strongly diagram and that can therefore be experimentally 2004–2005 on the use of computational means. Computa- synthesized. We are currently using these tech- Marie-Curie fellow at the University tional Physics, which is expanding with the availa- niques to find new materials that have interesting Pierre and Marie Curie – Paris VI (with bility of modern and more powerful computers, properties for energy production and storage. Prof. F. Mauri) has been offering new insights on various natural 2005–2007 phenomena, complementing and going beyond Invited assistant professor (University more traditional visions based on analytical ap- of Coimbra, Portugal) proaches. The cornerstone in the study of hard 2007–2014 matter was the development, in 1965, of density CNRS researcher (University of Lyon, functional theory, certainly one of the most suc- France) cessful theories in Physics for the past 50 years. Nowadays density functional theory allows us to 2009 Habilitation in Theoretical Physics calculate the properties of atoms, molecules, and (University of Lyon, France) solids in a computer with a remarkable accuracy A material designed for hydrogen storage and simplicity. We can also perform “in silico” ex- since 2014 periments that complement and help to interpret New materials for photovoltaic applications Professor (W2), Martin Luther a wealth of experimental data. This is true not only Transparent conductive oxide (TCO) materials, University, Halle-Wittenberg for structural, electronic, and thermodynamic have attracted a considerable amount of interest, properties, but even for dynamical processes especially due to their applications in displays such as the interaction of electrons with fast and and in solar cells. In fact, many new solar cells Contact strong laser fields. technologies, like the CIS and CIGS thin film solar cells, use TCOs as contacts. Our group works to [email protected] provide a reliable theoretical understanding of http://www.tddft.org/bmg the band structures and absorption spectra of these materials. This understanding is achieved by using state-of-the-art self-consistent GW methods Selected publications: (for the band structures) combined with the T.F.T. Cerqueira et al. Density-functional solution of the Bethe-Salpeter equation for the tight-binding study of the collapse of Carbon Probing attosecond electronic motion in small molecules Nanotubes under hydrostatic pressure. evaluation of the absorption. Carbon 69, 355-360 (2014). Development of scientific software Ch. Neidel et al. Probing Time-Dependent Molecular Dipoles on the Attosecond More recently, another major step was given in We are active developers of the computer code Timescale. Phys. Rev. Lett. 111, 033001 (2013). this field: we can now “design” in the computer octopus. This program, which is open source soft- new materials with tailored properties for differ- ware under the GNU general public license (GPL), M. Amsler et al. Conducting boron sheets formed by the reconstruction of the α-boron ent applications ranging from photovoltaics, to simulates the dynamics of electrons and nuclei (111) surface. Phys. Rev. Lett. 111, 136101 energy storage, to crystals with exotic properties. under the influence of time-dependent fields. The (2013). This is made possible by the combination of tech- electronic degrees of freedom are treated quantum- S. Botti and M.A.L. Marques. Strong niques stemming from solid-state physics, artificial mechanically, while the nuclei are considered to renormalization of the electronic band gap intelligence, and high-performance computing. behave as classical point particles. In this code, due to lattice polarization in the GW formalism. Phys. Rev. Lett. 110, 226404 This new interdisciplinary field, nowadays called all quantities are discretized in real space using a (2013). “accelerated discovery of materials” or “materials grid, and the simulations are performed in real design”, is still in its infancy and is expected to time. Over the past years, octopus has evolved revolutionize many areas of Materials Science. into a fairly complex and complete tool, and is now used by more than 150 research groups around the world. 60_ SYNTHETIC AND BIOMACROMOLECULES

Institute of Chemistry Theoretical Polymer Physics

Fields of Research: Current Projects and Future Goals:

› Synthetic and Biological Macromolecules Phase transitions of synthetic polymers In experiments, polymer crystallization is a process Prof. Dr. Wolfgang Paul Polymer science is a highly interdisciplinary field where thermodynamic forces and kinetic con- 1989 with questions ranging from materials science to straints interact in a hardly controllable way, PhD Theoretical Physics, Johannes basic theoretical physics. Rational design of poly- which can, however, be captured by Molecular Gutenberg University, Mainz, mer-based materials needs an understanding of Dynamics simulations of the crystallization pro- Germany structure and dynamics on the molecular scale. cess. Pure thermodynamics is addressable via Computer simulations of chemically realistic as simulations for single chain phase transitions of 1993–1994 Visiting Scientist at the IBM Almaden well as coarse-grained models yield insight into alkanes which we will extend to chains at interfaces Research Center, San Jose, USA molecular processes and help to interpret experi- and under other constraints. Copolymers can un- ments. The hierarchy of length scales and time dergo phase separation and ordering within a sin- 1996 scales inherent in often complex molecular archi- gle molecule and variations of chain topology and Habilitation in Theoretical Physics, tectures and material morphologies lead to the chemical composition lead to a variety of micro- Johannes Gutenberg University, necessity for a multi-scale modeling approach. phase separated structures with always the mo- Mainz, Germany This in turn needs model as well as methods de- lecular scale as the resulting length scale of the 2003–2009 velopment for efficient Molecular Dynamics and macroscopic morphology. Extraordinary Professor, Johannes Monte Carlo simulations. Already single (bio-) Gutenberg University, Mainz, polymers or small aggregates are fascinating ob- Conformations and thermodynamics of Germany jects in themselves which can exhibit phase tran- proteins and their aggregates Since 2009 sition-like phenomena as, e.g., protein folding. Proteins and peptides are able of intra-molecular Full Professor (W3) for Theoretical The search for a basic statistical physical under- structure formation and often need to assume Polymer Physics, Martin Luther standing of these phenomena links polymer theory specific structures to perform their molecular University Halle-Wittenberg to biophysics and biology. function. The same interactions (e.g., hydrophobic or hydrogen bonding) generating these structures can, however, also lead to chain aggregation, e.g., Contact amyloid formation, underlying many neurodege- [email protected] narative diseases. Understanding of the statistical mechanics and the kinetics of these competing www.physik.uni-halle.de/theorie/ag/ structure formation processes can be obtained polymertheorie from advanced Monte Carlo simulations of specifically designed models. At the same time, this Selected publications: yields insight into morphology generation in supramolecular chemistry. E. Lee, W. Paul, Additional Entanglement Effect Imposed by Small Sized Ring Aggregates in Supramolecular Polymer Melts: Quantum Hamilton equations Molecular Dynamics Simulation Study, We recently derived quantum Hamilton equa- Macromolecules 53, 1674 (2020).

tions of motion from the formulation of quantum T. Shakirov, W. Paul, Folded alkane chains and mechanics (QM) as a stochastic optimization the emergence of the lamellar crystal, J. Chem. Folding transition of short alkane chains from a random problem and showed how they can be applied to Phys. 150, 084903 (2019). coil to a highly structured ground state obtain the complete spectrum of bound states of J. Köppe et al., W. Paul, Derivation and a quantum system. The numerical treatment of application of quantum Hamilton equations of motion, Ann. Phys. (Berlin) 529, 1600251 the resulting coupled forward-backward stochastic (2017). The conformations of linear polymers are inti- differential equations needs further improve- mately connected to path integrals or random ment concerning efficiency. We will extend the W. Janke, W. Paul, Thermodynamics and structure of macromolecules from walk theory. The methods for their analytical des theory to include a treatment of particle spin and flat-histogram Monte Carlo simulations, Soft cription link polymer theory to quantum field interactions between spin and positional degrees of Matter 12, 642 (2016). theory (statistical field theory) and the theory of freedom. The stochastic processes based approach M. Solar et al.,The dielectric -relaxation in stochastic processes. Fundamental questions in to quantum mechanics should also be extendable polymer films: A comparison between quantum theory and a stochastic processes based to relativistic quantum mechanics. experiments and atomistic simulations,α understanding of quantum mechanics are research Europhys. Lett. 104, 66004 (2013). interests growing out of these connections. SYNTHETIC AND BIOMACROMOLECULES _61

Medicinal-Pharmaceutical Chemistry Isolation, modification and biological testing of herbal antitumor agents

Fields of Research: Current Projects and Future Goals:

› Plant derived antitumor drugs 01 November 2019 to 31 October 2022 Prof. Dr. Reinhard Paschke › Chemical modification Betulin sulfalate conjugates to overcome the hy- › Biological testing poxic radiation resistance of breast cancer in vit- Since 1993 Head of office of the BioCenter of the ro and in vivo, DFG Martin Luther University and Head of The preclinical development of bioactive natural the Medicinal-Pharmaceutical products and their analogues as chemotherapeutic Chemistry unit. agents is a major objective of our research group. 01 October 2020 to 30 June 2023 Triterpenoids are one of the most important Extraction of exopolysaccharides of the red algae Since 1998 classes of natural products occurring widely in the porphyridium sp. as an active substance for the Managing Director of BioSolutions Halle GmbH (Aninstitut) plant kingdom. The derivatives of triterpenoids treatment of the bee disease Nosemosis; BMEL, have been one of the most interesting areas of re- Fachagentur Nachwachsende Rohstoffe 2010 search in the past few years vested to their broad apl. Professor range of biological and medicinal properties. Betu- 01 June 2020 to 30 April 2022 2004 linic acid and betulin belong to the class of penta- Antibacterial and antifungal effects of ingredi- Habilitation and venia legendi cyclic lupine type triterpenes. ents and extracts from Artemisia for use as antitumor agents and antibiotic alternatives; Land S-A, IB Sachsen-Anhalt Contact 01 October 2019 to 31 January 2022 reinhard.paschke@biozentrum. uni-halle.de CA-InhibiTool Carboanhydrase Inhibitors (CAI) - Development of a diagnostic tool for the rapid www.biozentrum.uni-halle.de/ Betulin Betulinic acid and safe determination of carboanhydrase activ- service/medpharmchem/ ity of antitumor markers and agents; Land S-A, IB The plane tree is one of the substantial source for betulinic acid. Sachsen-Anhalt

01 April 2017 to 30 Sptember2020 Selected publications: TopiDrugHorse Cooperation Project Biocapsule - Weber, Lisa A., Meissner, Jessica, Delarocque, "TopiDrugHorse", Drug Synthesis and Analytics; Julien, Kalbitz, Jutta, Feige, Karsten, Kietzmann, Manfred, Michaelis, Anne, ZIM, VDI/VDE Innovation + Technik GmbH Paschke, Reinhard, Michael, Julia, Pratscher, Barbara, and Cavalleri, Jessika M. V. Betulinic acid shows anticancer activity against equine melanoma cells and permeates isolated equine skin in vitro. BMC Vet.Res. 16[1], 44 (2020).

Vanchanagiri, Kranthi, Emmerich, Daniel, Bruschke, Monique, Bache, Matthias, Seifert, Franziska, Csuk, Rene, Vordermark, Dirk, and Paschke, Reinhard. Synthesis and biological investigation of new carbonic anhydrase IX (CAIX) inhibitors. Chem.-Biol.Interact. 284, 12-23 (2018). Plane Tree Liebscher, G., Vanchangiri, K., Mueller, Th, Feige, K., Cavalleri, J.-M. V., and Paschke, R. In Betulinic acid is one of few such compounds that vitro anticancer activity of Betulinic acid and derivatives thereof on equine melanoma cell have been shown to possess several medicinal lines from grey horses and invivo safety properties including anticancer, antimalarial, anti- assessment of the compound NVX-207 in two horses. Chem.-Biol.Interact. 246, 20-29 (2016). microbial and anti-HIV activities. Betulinic acid was found to cause cancer cell death by induction Kommera, Harish, Kaluderovic, Goran N., of apoptosis through changes in the mitochondrial Kalbitz, Jutta, and Paschke, Reinhard. Lupane Triterpenoids-Betulin and Betulinic acid membrane potential, production of reactive oxy- derivatives induce apoptosis in tumor cells. gen species, and permeability of transition pore Invest.New Drugs 29[2], 266-272 (2011). openings. These processes lead to the release of mitochondrial apoptogenic factors, activation of caspases, and DNA fragmentation. Our research group performs both the isolation of the active ingredients and their chemical modi fication as well as the biological testing of the obtained compounds. 62_ SYNTHETIC AND BIOMACROMOLECULES

Institute of Physics Dynamic Solid-State NMR

Fields of Research: Current Projects and Future Goals:

› Structure and dynamics of solid polymers Dynamics in bulk polymers by NMR A number of factors have influence on the practical Prof. Dr. Detlef Reichert › Structure-dynamic-property relationship in applications of the synthetic polymers. For Semi 1990 pharmaceutical compounds, solid polymers, crystalline polymers one of the most significant PhD Experimental Physics, TU, polymer networks and Solid-Polymer mechanical properties is macroscopic drawability. Merseburg, Germany Electrolytes There is evidence that the underlying microscopic › Method development in solid-state NMR process on the microscopic level is lateral chain 1992 diffusion in the crystallites and that is can be in- PostDoc at Weizmann Institute of Science, Rehovot, Israel, with Z. Luz Solid materials and in particular polymeric systems vestigated by solid-state NMR in very detail. In exhibit an astonishing variety of segmental mo- the past, we investigated the helical jumps of the Since 1993 tions as well as molecular reorientations which crystalline stems of a number of polyolefins. Now, Staff scientist at the Institute of have important effects on mechanical, transport we turned our attention to biodegradable polymers Physics of Martin Luther University and optical properties of polymers, the activity of like poly(lactic acid) and focus in particular on Halle-Wittenberg (since 2013 as proteins, the stability of pharmaceuticals, the the effect of different crystalline structures. apl. Professor) transport properties in zeolites, behavior of 2003 amorphous materials near the glass transition, Structure-dynamics-properties Habilitation in Experimental Physics, ion transport in organic and inorganic ionic con- relationship in Solid-Polymer Electrolytes Martin Luther University Halle- ductors, and other structural properties of organic The aim of these studies is a molecular under- Wittenberg and inorganic systems. Solid-state NMR provides standing of chain mobility, polymer crystallization Since 2013 powerful techniques for elucidating details of and of the hierarchical structure formation in the Extraordinary (apl.) Professor, segmental dynamics and local conformation in polymer networks made of poly(ethylene oxide). Martin Luther University Halle- solid materials]. These methods allow detailed Besides new fundamental insides into the crys- Wittenberg studies of dynamics occurring over a wide range tallization process in networks, these networks of frequencies and correlate these information on might serve as a material for polymer electrolytes. the microscopic level with structural data as well Thus, the interactions of the polymer chains with Contact as on the macroscopic level with application salts will be a future scope of this project. [email protected] properties. http://www.physik.uni-halle.de/ Fachgruppen/nmr/reichert.html

Selected publications:

Y. Golitsyn et al., Crystallization in PEG networks: The importance of network topology and chain tilt in crystals, Polymer, 165, 72–82 (2019).

Y. Golitsyn et al., Molecular Dynamics in the Crystalline Regions of Poly(ethylene oxide) Containing a Well-Defined Point Defect in the Middle of the Polymer Chain, J. Phys. Chem. B 121, 4620–4630 (2017).

C. Hackel et al., The trehalose coating effect on the internal protein dynamics, PCCP 14, 2727 (2012).

Time-scales of Dynamic Solid-State NMR methods Schematic picture of polymer network chains in A. Krushelnitsky et al., Direct Observation of Millisecond to Second Motion in Proteins by crystallites. (Y. Golitsyn et al., 2019). Dipolar CODEX NMR. JACS 131, 12097 (2009).

D. Reichert et al., Slow Dynamics in Glassy Methyl -L-Rhamnopyranoside Studied by 1D NMR Exchange Experiments PCCP 10, 542 (2008).α SYNTHETIC AND BIOMACROMOLECULES _63

Institute of Physics Nuclear Magnetic Resonance Spectroscopy

Fields of Research: Current Projects and Future Goals:

Molecular-level structure and dynamics New aspects in polymer crystallization Prof. Dr. Kay Saalwächter in soft materials: While being a seemingly well-understood pheno menon, the crystallization of polymers has 1991–1997 Studies of Chemistry at the › Physics of synthetic and biological moved into the focus again, thanks to new experi- Universities of Mainz, Germany, macromolecules and liquid crystals mental and theoretical tools. In a collaborative Freiburg, Germany, and › Polymer melts, elastomers and hydrogels project with the Thurn-Albrecht group, we study Massachusetts, Amherst, USA › Dynamics and interface phenomena in the so far underestimated influence of intracrys- (nano)composites talline chain dynamics and the accumulation of 1997–2000 › Polymer crystallization entanglements in the amorphous phase, both Doctorate at the MPI for Polymer Research, Mainz, Germany with H. W. › Self-organization and dynamics in functional quantified by NMR. These turn out to have a deci- Spiess, Dr. rer. nat. in Physical polymers sive influence on the semicrystalline morphology. Chemistry (U. of Mainz, Germany) › Method development in solid-state NMR Segmental and chain dynamics in func- 2001–2004 The function and rational design of modern poly- tional polymers and nanocomposites Habilitation at the Institute for meric and other “soft” materials rests on their often The fascinating mechanical behavior of long-chain Macromolecular Chemistry, U. of Freiburg, Germany, self-organized microstructure and the molecular polymer melts, and related materials such as supra- with H. Finkelmann dynamics. Our group focuses on molecular-level molecular elastomers or nanocomposites, rests probes of structure and dynamics in soft matter, upon classical concepts such as de Gennes’ “repta- 2004–2005 mainly (bio)polymers and liquid crystals, in order tion” model, the more general tube model, and Lecturer, U. of Freiburg, Germany to link up molecular processes with structure and variants that take into account additional cons Since 2005 function on the meso- and macroscopic scales. traints to the dynamics. We apply advanced proton Full Professor (W2) of Experimental This concerns for instance the mechanical behavior NMR techniques on inexpensive benchtop spec- Physics, Martin Luther University of polymer melts and elastomers, their thermo- trometers to probe segmental and chain dynamics, Halle-Wittenberg dynamic behavior, nanoscale morphologies arising investigating in particular the modifications arising from self-assembly including partial crystalliza- from “sticky” functional groups or confinement tion, or structure-function relationships in tran- due to the presence of interfaces. Our usually col- Contact sient (self-healing) networks. laborative efforts combine NMR spectroscopy with Our main method is NMR spectroscopy as one of scattering techniques, dielectric and mechanical [email protected] the most versatile molecular probes of structure spectroscopy, and computer simulations. www.physik.uni-halle.de/nmr and dynamics. Modern multi-dimensional NMR at high as well as low field provides access to diverse Molecular-level characterization of observables such as interatomic distances, rota- elastomers Selected publications: tional dynamics covering many decades in time, Tire materials have a unique mechanical property A. Mordvinkin et al., Hierarchical Sticker and translational diffusing (using pulsed field gradi- profile arising from entropic elasticity of crosslinked Sticky Chain Dynamics in Self-Healing Butyl Rubber Ionomers. Macromolecules 2019, 52, ents) and structure on the nanoscale (employing and entangled chains, and from additional synergistic 4169. the spin-diffusion effect). We seek to apply, and effects related to inorganic fillers. We investigate newly develop, different NMR experiments, com- the relations between internal structure, inhomo- A. Naumova et al., Microscopic State of Polymer Network Chains upon Swelling and plemented by a variety of other techniques in order geneous molecular dynamics, and the mechanical Deformation. Macromolecules 2019, 52, 5042. to validate and improve our conceptual under- properties of unfilled and filled elastomers by standing in soft-matter physics. comparing industrially relevant rubbers with model R. Kurz et al., Intracrystalline Jump Motion in Poly(ethylene oxide) Lamellae of Variable networks and nanocomposites. Our goal is to iden- Thickness: A Comparison of NMR Methods. tify and validate the most suitable of the many Macromolecules 2017, 50, 3890. theoretical models that are available. This range of M. Roos et al., Coupling and Decoupling of activities is again a showcase of the great poten- Rotational and Translational Diffusion of tial of inexpensive low-field NMR methodologies. Proteins under Crowding Conditions. J. Am. Chem. Soc. 2016, 138, 10365.

A. Papon et al., Glass-Transition Temperature Gradient in Nanocomposites: Evidence from Nuclear Magnetic Resonance and Differential Scanning Calorimetry. Phys. Rev. Lett. 2012, 108, 065702.

K. Saalwächter., Proton multiple-quantum Fig. above: Molecular dynamic processes in a side-chain NMR for the study of chain dynamics and modified self-healing elastomer (Mordvinkin et al.) structural constraints in polymeric soft materials. Progr. Nucl. Magn. Reson. Spectrosc. 2007, 51, 1. Fig. right: Low-field NMR study of chain stretching in deformed elastomers to (in)validate elasticity models (Naumova et al.) 64_ SYNTHETIC AND BIOMACROMOLECULES

Institute of Chemistry Theoretical Chemistry

Fields of Research:

› Proton and Lithium conduction in solids › Novel solvents (ionic liquids) for biopolymers Prof. Dr. Daniel Sebastiani › Lithium-Sulfur batteries 2001 › Theoretical Spectroscopy PhD Theoretical Physics at the Max › Ab-initio molecular dynamics simulations Planck Institute for Solid State Research, Stuttgart There is a lot of molecular “life” in liquids but also in crystalline and amorphous solids. Small ions 2001–2009 Project leader at the Max Planck such as protons and lithium nuclei are very mobile, The motion of a lithium ion in an amorphous Institute for Polymer Research, Mainz which is important for designing high-performance thiophene matrix during a short time (100ps) is ion conductors (as fuel cell membranes) and bat- shown here as superposition of all visited loca- 2002 teries. The simulation of molecular dynamics on tions. The direct simulation of this ionic dynamics Visiting Scientist at the ETH Zurich, the basis of Theoretical Chemistry allows the direct helps to understand how the (slow) motion of the Rothlisberger Group, Zurich, modeling of ion mobility in such complex con- thiophene molecules controls the (fast) motion of Switzerland densed phase systems. Here, the quantum- the solvated Li ions. Such thiophene compounds 2004 mechanical orbitals (the “chemical bonds”) are are interesting as diffusion inhibitors for sulfur Visiting Scientist at Princeton the driving forces behind the atomic motion. molecules within Lithium-Sulfur batteries. University, Car Group, Princeton, USA We compute the electronic orbitals on large-scale computers, and subsequently we model the mo- 2009–2012 lecular and atomic motion based on these orbitals. Heisenberg Group leader at the Physics This gives access to atomic/ionic mobility proper- Department, Free University Berlin ties, spectroscopic parameters as function of local since 2012 morphologies, as well as the properties of a com- Professor for Theoretical Chemistry, pound as a solvent for different types of solutes. Martin Luther University Halle- Several atomic properties determine which types Wittenberg of molecules are dissolved in which other types of molecules (solutes and solvents). The resulting behavior is often categorized via different “phi- Contact licities” such as hydro-, lipo-, silano- or fluoro- [email protected] philic characteristics of a compound. Our simulations can predict the philicities of novel molecules www.chemie.uni-halle.de with taylored functional groups of several philicity classes. This is of special importance for “difficult” The direct simulation of atomic and molecular Selected publications: solutes such as cellulose: mobility is powerful but inherently restricted to short timescales, due to the enormous computa- Ch. Dreßler, G. Kabbe, M. Brehm, D. Sebastiani, tional effort required for the explicit calculation Dynamical matrix propagator scheme for of all chemical bonds (i.e. all electronic orbitals) large-scale proton dynamics simulations, J. of the entire system. Coarse-grained simulations Chem. Phys. 2020, 152, 114114.

have the potential for simulating longer time in- M. Brehm, M. Pulst, J. Kressler, D. Sebastiani, tervals at the expense of a reduced detail level. Triazolium-Based Ionic Liquids: A Novel Class of We have developed a multi-scale method for the Cellulose Solvents, J. Phys. Chem. B, 2019, 123, 18, 3994–4003. simulation of ion mobility that combines atomistic resolution with very long simulation timescales. P. Partovi–Azar, D. Sebastiani, Mechanism of Lithium Cation Hopping between Tetragonal To this end, we combine molecular dynamics simu- Thiophene Cages, Batteries & Supercaps 2019, lations of the local atomic structure with a lattice 2, 695–700. Monte-Carlo simulation of the ion dynamics. M. Ekimova, F. Hoffmann, G. Bekçioğlu-Neff, A. No conventional solvent is able to dissolve the This give access to mobility phenomena with Rafferty, O. Kornilov, E. Nibbering, D. hydrogen-bonded biopolymers of this type. How- characteristic timescales of up to microseconds. Sebastiani, Ultrafast Proton Transport between ever, we have discovered that a novel solvent All molecular dynamics simulation can be com- a Hydroxy Acid and a Nitrogen Base along Solvent Bridges Governed by the Hydroxide/ (triazol/acetate, an ionic liquid) is indeed able to bined with the quantum chemical calculation of Methoxide Transfer Mechanism, J. Am. Chem. disrupt this highly stable hydrogen bond network several kinds of spectra, such as infrared-, Raman-, Soc.2019, 141, 37, 14581–14592. and thus dissolve cellulose materials. NMR, UV/vis- and VCD spectra within the phase S. Jähnigen, A. Scherrer, R. Vuilleumier, D. space covered by the molecular dynamics simula- Sebastiani, Chiral Crystal Packing Induces tion. We have recently computed how weak inter- Enhancement of Vibrational Circular Dichroism, Angewandte Chemie, 2018, 57, 1–6. molecular coupling interactions within a molecular crystal determines the shape of the VCD spectrum. SYNTHETIC AND BIOMACROMOLECULES _65

Institute of Mathematics Variational Methods

Fields of Research:

› Optimization under uncertainty posed variational inequalities, inverse problems, Prof. Dr. Christiane Tammer › Optimal control problems and split-feasibility problem, among others. Espe- › Variational inequalities, regularization cially, our methods can be applied in complex fluids 1984 Doctoral thesis, methods, inverse problems theoretical polymer physics, like in equilibrium Technical University Merseburg › Lagrange multiplier rules behaviour of nanostructured polymeric systems › Duality theory and polymer fluid dynamics. 1991 › Approximation theory Habilitation, Technical University › Locational analysis Variational principles and Merseburg equilibrium problems 1997 Variational methods are important tools for de- Variational principles are important instruments Visiting professorship, riving optimality conditions and corresponding in variational analysis and nonsmooth optimiza- University Leipzig algorithms for solving optimization problems. We tion, especially for deriving optimality conditions 1998 derive new minimal point theorems in product and corresponding algorithms for solving opti- Visiting professorship, Royal Military spaces and corresponding variational principles. mization problems. We are dealing with several College of Canada, Kingston Furthermore, we are dealing with several applica- applications of the variational principles, espe- tions of the variational principles, especially in cially in approximation theory and optimal con- 1998–1999 approximation theory and optimal control. In this trol. Furthermore, variational principles and Kovalevskaja-Visiting professorship, University Kaiserslautern context we study variational inequalities, regulari- equilibrium problems are useful in the study of zation methods and inverse problems. Moreover, oxidic interfaces. The interactions between metals Since 1998 we consider optimization problems under uncer- and oxides are key factors to study the perfor- Professor of Variational Methods, tainty and develop concepts of robustness. mance of metal/oxide heterojunctions, especially Martin Luther University Halle- in nanotechnology, where the miniaturization of Wittenberg devices down to the nanostructure leads to a Current Projects and Future Goals: strong increase in the density of interfaces. One important issue of concern in engineering metal/ Contact Variational inequalities, oxide interfaces is to understand and control regularization methods, inverse problems these interactions. This could be supported by christiane.tammer@mathematik. uni-halle.de An ill-posed quasi variational inequality with variational methods. contaminated data can be stabilized by employ- www.mathematik.uni-halle.de ing the elliptic regularization. Under suitable Mathematical methods in physics conditions, a sequence of bounded regularized and economics solutions converge strongly to a solution of the Many processes in physics, especially entropy Selected publications: original quasi variational inequality. Moreover, problems, can be formulated as approximation C. Tammer, P. Weidner, Scalarization and the conditions that ensure the boundedness of problem or control problem. Separation by Translation Invariant Functions, Springer, New York, 2020. regularized solutions, become sufficient solvabil- For these problems we derive necessary optimality ity conditions. It turns out that the regulariza- conditions, duality assertions and solution proce- T. Q. Bao, C. Tammer, Scalarization tion theory is quite strong for quasi variational dures. Furthermore, we are dealing with optimi- Functionals with Uniform Level Sets in Set Optimization. Journal of Optimization Theory inequalities with set-valued monotone maps but zation problems under uncertainty. Especially, and Applications (2019) 182:310–335. restrictive for generalized monotone maps. The we develop concepts of robustness in locational results are quite general and applicable to ill- analysis and corresponding solution methods. K. Klamroth, E. Köbis, A. Schöbel, C. Tammer, A unified approach to uncertain optimization. European Journal of Operational Research 260 (2017) 403–420.

B. Jadamba, A. A. Khan, M. Sama, C. Tammer, On convex modified output leastsquares for elliptic inverse problems: stability, regularization, applications, and numerics, Optimization 66 (6) (2017) 983–1012.

A. Khan, C. Tammer, C. Zalinescu, Set-valued Optimization - An Introduction with Applications, Springer, New York, 2015.

A. Göpfert, H. Riahi, C. Tammer, C. Zalinescu, Variational Methods in Partially Ordered Spaces. Springer, New York, 2003.

Software FLO (Facility Location Optimizer), www.project-flo.de , OpenStreetMap 66_ SYNTHETIC AND BIOMACROMOLECULES

Institute of Physics Experimental Polymer Physics

Fields of Research: Current Projects and Future Goals:

› Crystallization of polymers The overall aim of our research is to understand › Structure and mechanical properties of on a fundamental level, how the morphology of Prof. Dr. nanostructured polymers semicrystalline polymers is generated during crys- Thomas Thurn-Albrecht

› Polymers for organic photovoltaics tallization and how it determines the mechanical 1994 › Scattering Methods, Scanning Force and electrical properteis of these important class PhD Physics, University of Freiburg, Microscopy, Rheology, Calorimetry of materials. Germany

Polymers or chain molecules are very versatile Crystallization and 1995–1998 PostDoc/staff scientist at the materials. Their special mechanical, optical or elec- Molecular Dynamics of Polymers Max-Planck-Institute for Polymer trical properties are at the basis of many different Polymers typically crystallize in a semicrystal- Research, Mainz, Germany applications in which we encounter polymers in line structure, consisting of layerlike crystallites daily life. Due to their macromolecular character with a thickness on the nanoscale separated by 1998–1999 polymers display a variety of typical and special disordered amorphous regions. The resulting na- PostDoc at the University of properties like e.g. viscoelasticity, rubber elasticity nostructure strongly determines the macroscopic Massachusetts, Amherst, US or semicrystallinity. Corresponding to their typical mechanical properties. It is therefore important 2000–2003 size in the nanometre range polymers often form to have a precise understanding of the crystalli- Staff scientist and lecturer at the structures on the nanoscale. In our research we zation process and the accompanying structure Institute for Physics, University of investigate the mechanisms of structure formation formation. We understand polymer crystallization Freiburg, Germany and self-assembly (e.g. microphase separation or as a complex interplay of the (macro)molecular Since 2003 crystallization), develop methods to produce well dynamics in the melt, the growth kinetics of the Full Professor of Experimental defined, nanostructured materials, and investigate lamellae, and possible intracrystalline chain Physics, Martin Luther University their properties. dynamics. We use SAXS, DSC, Flash DSC, and Halle-Wittenberg For structural analysis we use a variety of scattering rheology for investigation. Since 2011 techniques including small and wide angle X-ray Coordinator of the SFB Tranregio 102 scattering. Grazing incidence techniques are used Interface Induced Crystallization Polymers under multiple constraints: for thin film characterization. Scanning force mi- It is well known that crystallization of liquids most restricted and controlled molecular croscopy serves as a complementary tool to image often starts at an interface to a solid. In general, a order and mobility structures on the nanoscale in real space. The solid surface can induce crystallization by either complex mechanical properties of polymers are heterogeneous nucleation or prefreezing. Our un- studied by mechanical spectroscopy or rheology derstanding of these processes on a microscopic Contact and the thermal behaviour by (fast scanning) level is very limited. By combining experimental thomas.thurn-albrecht@physik. calorimetry. and theoretical approaches, our aim is to under- uni-halle.de stand the material parameters that affect the thermodynamics of prefreezing and the kinetics www.physik.uni-halle.de/fachgrup- of heterogeneous nucleation. We investigate crys- pen/polymer_physics_group tallization of thin films and isolated droplets of semicrystalline polymers on solid substrates using Selected publications: in-situ atomic force microscopy (AFM), optical microscopy, and X-ray scattering. Schulz, M., et al. The effect of intracrystalline chain dynamics on melting and reorganization during heating in semicrystalline polymers. Structure Formation in Polymer 196 (2020): 122441. Semiconducting Polymers Tariq, M., et al. Effect of Substrate Interaction We investigate structure formation in semicon- on Thermodynamics of Prefreezing. ducting polymers, which are of interest for organic Macromolecules 52(23) (2019): 9140–9148. photovoltaics. A nanostructured morphology is Dolynchuk, O., et al. Phenomenological Theory necessary for an efficient charge separation in of First-Order Prefreezing. J Phys Chem Lett 10 this class of materials, which we realize by diblock (2019): 1942–1946.

copolymer self-assembly. Since semiconducting Schulz, M., et al. The Underestimated Effect of polymers usually have an additional crystalline Intracrystalline Chain Dynamics on the or liquid crystalline order, the structure forma- Morphology and Stability of Semicrystalline Polymers. Macromolecules 51(21) (2018): tion in these materials is complex. We investigate 8377–8385.

AFM image of a prefrozen film of PCL on MoS2 partially covered how different influencing factors affect structure by a liquid droplet. The film is stabilized above the melting formation and ultimately the optoelectronic Balko, J. et al. Surface induced orientation and vertically layered morphology in thin films of temperature by the substrate and in equilibrium with the liquid properties. poly(3-hexylthiophene) crystallized from the droplet. Upon cooling it acts as a nucleus and induces fast and melt. Journal of Materials Research 32(10) oriented crystal growth. (2017): 1957–1968. SYNTHETIC AND BIOMACROMOLECULES _67

Institute of Chemistry Food Chemistry – Functional Food

Fields of Research: Current Projects and Future Goals:

› Structural characterization of Production and advanced structural Prof. Dr. Daniel Wefers polysaccharides from bacteria and algae analysis of dextrans › Production, enzymatic synthesis and Dextrans are -glucans which are enzymatically 2016 modification of polysaccharides synthesized from sucrose by various food-born PhD in Food Chemistry, Karlsruhe α Institute of Technology, Germany › Development of analytical methods for lactic acid bacteria. Depending on source and syn- polysaccharide analysis thesis conditions, dextrans have a high structural 2016 › Synthesis and characterization of complexity which results in varying functional PostDoc, University of Illinois carbohydrate conjugates properties. We aim to improve the understanding Urbana-Champaign, USA, › Exploration of carbohydrate-active enzymes of dextran structural architecture and to improve Prof. Isaac Cann the methods to analyze these polysaccharides. 2016–2019 Functional polysaccharides are complex macro- For this purpose, we use recombinant glucansu- Junior Research Group Leader, molecules which influence the physiological, tech- crases and glucanases for polysaccharide synthesis, Karlsruhe Institute of Technology, nological, and biological properties of foods as well modification, and analysis. Germany as other products. The functionality of these biopoly- Since 2019 mers is mainly determined by their molecular Fine structures of insoluble glucans Associate Professor (W2) of Food structure. Therefore, our research is focused on Some lactic acid bacteria are able to enzymatically Chemistry, Martin Luther University structural characterization of polysaccharides, es- synthesize insoluble -glucans which contain Halle-Wittenberg pecially those from bacteria or algae. varying portions of -1,3-linked glucose units. To develop a detailed understanding of polysac- The formation of suchα polymers is, for example, charide structures, we apply a wide range of ana- important for the biofilmα formation of cariogenic Contact lytical methods such as gas chromatography, ion bacteria. However, less information is available chromatography, size exclusion / gel permeation on the detailed structural composition of insoluble [email protected] chromatography, and nuclear magnetic reso- glucans from different sources. Therefore, we are flm.chemie.uni-halle.de nance spectroscopy. We also use these approach- using partial enzymatic hydrolysis and several es to develop enzyme-based methods for routine analytical approaches to gain detailed insights structural analysis, which allow a detailed and into the structures of different insoluble glucans. Selected publications: fast analysis of polysaccharides in model systems F. Münkel et al. Structural characterization of or foods. Because the establishment of structure- Structure-function relationships of mixed-linkage -glucans produced by mutants of Lactobacillus reuteri TMW 1.106 function relationships requires samples with a carrageenans dextransucrase.α Carbohydr. Polym. (2020), defined structure, another focus of our work lies Carrageenans are structurally heterogeneous 231, 115697. on the synthesis and modification of polysaccha- sulfated polysaccharides from red algae which are

T. Klingel et al. Enzymatic synthesis and rides. For this purpose, we use microorganisms as commonly used as gelling agents. However, some characterization of mono-, oligo-, and well as recombinant enzymes which allow for carrageenans have also been shown to inhibit the polyglucosylated conjugates of caffeic acid specific polysaccharide hydrolysis and modifica- recrystallization of ice. To investigate which struc- and gallic acid. J. Agric. Food Chem. (2019), 67, 13108–13118. tion as well as the production of tailor-made poly- tural elements are responsible for this function- saccharides. Furthermore, we investigate how ality, we are using different chemical, enzymatic, F. Münkel et al. Detailed structural characterization of glucans produced by enzymes or chemical modifications can be used to and analytical approaches to obtain tailor-made glucansucrases from Leuconostoc citreum synthesize novel polysaccharides and polysaccha- and well characterized carrageenans. TMW 2.1194. J. Agric. Food Chem. (2019), 67, ride conjugates with unique properties. 6856–6866. Structural characterization of hetero- A. Fischer and D. Wefers. Chromatographic exopolysaccharides analysis of alginate degradation by five Lactic acid bacteria but also other microorganisms recombinant alginate lyases from Cellulophaga algicola DSM 14237. Food Chem. are able to form highly complex exopolysaccha- (2019), 299, 125142. rides. These polymers are promising candidates

R. M. Prechtl et al. Structural characterization as functional ingredients or materials. We are in- of the surface associated heteropolysaccha- vestigating the structure of these polymers and ride of Lactobacillus plantarum TMW 1.1478 work with other groups to correlate structural and genetic analysis of its putative biosynthesis cluster. Carbohydr. Polym. and functional properties. (2018), 202, 236–245.

L. Fels et al. Structural characterization of the exopolysaccharides from water kefir. Carbohydr. Polym. (2018), 189, 296–303.

Fig.: Reactions catalyzed by glucansucrases from lactic acid bacteria. 68_ SYNTHETIC AND BIOMACROMOLECULES

Institute of Chemistry & Leibniz-Institute of Plant Biochemistry Employing and engineering enzymes for chemically challenging transformations

Fields of Research: Current Projects and Future Goals:

› Directed evolution in yeast-based systems Enzymatic Hydroxylations › Enzymatic degradation of polymers and One of the chemically challenging transformations Jun.-Prof. Dr. mycotoxins is the selective functionalisation of C—H bonds to Martin Weissenborn

form alcohol products. Fungal unspecific peroxy 2009–2012 Despite the growing ‘toolbox’ of commercially genases (UPOs) solely rely on hydrogen peroxide as Dissertation (funded by Marie-Curie- available enzymes, which are capable of catalysing co-substrate and show impressive total turnover Fellowship), Manchester Institute of functional group interconversions with unpa numbers (TTN) of up to 300,000 for sp3-carbon hy- Biotechnology, United Kingdom ralleled regio- and stereoselectivity, biocatalysts droxylations. We were able to heterologously express (Advisor: Prof. Flitsch) mediating the formation of C—X bonds and a range of peroxygenases in yeast and are currently 2012–2016 those enabling convergent synthesis remain engineering them by directed evolution for enanti- Post-Doc, University Stuttgart, mostly undeveloped. Expansion of the biocata- oselective hydroxylation reactions. Germany (Advisor: Prof. Hauer) lytic toolbox to incorporate such enzymes, as well as the development of biocatalysts which mediate Method development for directed evolution 2016 reactions not seen in nature, would allow us to Directed evolution requires the analysis of multiple Post-Doc, ETH Zürich, Switzerland (Advisor: Prof. Hilvert) approach synthetic design in an entirely different hundreds of samples a week and hence necessitates way. a rapid screening system. We have developed a high Since 2016 throughput GC-MS system, which allows the sam- Jun.-Prof. Organic Chemistry at the Besides the inherent or promiscuous activity of ple injection in 33 s intervals, thereby substantially Martin Luther University Halle-Wit- enzymes for chemically challenging reactions, shortening the analysis time. This method enables tenberg and Junior-Research Group the feasibility of these transformations for spe- us to engineer our enzymes towards any substrate Leader at the Leibniz-Institute of Plant Biochemistry, Halle (Saale), cific molecule classes with high turnovers and of interest, which can be analysed by GC-MS. Germany yields is pivotal. The enzymes, therefore, ought to be engineered to fulfil these properties. The Discovering novel enzymatic reactivities method of choice is here directed evolution that Since proteins carry inherent promiscuity, each allows the design of tailor-made catalysts for spe- enzyme can perform a multitude of different Contact cific purposes and was awarded the Nobel Prize “new-to-natural” reactions. Therefore, screening [email protected] in Chemistry in 2018. thousands of different proteins and protein classes for chemically challenging reactions in one ex- www.ipb-halle.de/en/research/ perimental setup with a high-sensitive detection independent-junior-research-groups/ device is a powerful tool. This system is solely dis- research-groups/bioorganic-chemistry covering protein scaffolds, cofactors or active site architectures, which enhance or catalyse the reac- Selected publications: tion of interest. The aim is not to discover a hidden, natural protein activity, but protein’s—and na- Knorrscheidt et al., Identification of novel unspecific peroxygenase chimeras and unusual ture’s—diversity is harvested to randomly identify YfeX axial heme ligand by a versatile novel protein reactions, which will then serve as high-throughput GC-MS approach ‘starting points’ for directed evolution endeavours. ChemCatChem, (2020) 10.1002/ cctc.202000618.

Polymer degrading enzymes K. J. Hock et al., Tryptamine synthesis by Apart from building molecules, enzymes could iron-porphyrin catalysed C—H functionalisation of indole with diazoacetonitrile Angewandte prove to be excellent tools for the degradation of Chemie 58, 3630-3634 (2019). polymers. We are engineering enzymes to im- P. Püllmann, C. Ulpinnis et al. (Collab. Koenigs prove their activity towards the cleavage of poly- Group), Golden Mutagenesis: An efficient mer chains to recycle them. multi-site saturation mutagenesis approach by Golden Gate cloning with automated primer design Scientific Reports, 9, (2019).

M. J. Weissenborn, S. A. Lowet al., Enzyme-Catalysed carbonyl olefination by the E. coli protein YfeX in the absence of phosphines, ChemCatChem. 8, 1636–1640 (2016).

M. J. Weissenborn, R. Castangia, et al., Oxo-ester mediated native chemical ligation on microarrays: an efficient and chemoselective coupling methodology, Chem. Commun. 48, 4444–4446 (2012). SYNTHETIC AND BIOMACROMOLECULES _69

Institute of Chemistry & Leibniz Institute of Plant Biochemistry Natural Products & Bioorganic Chemistry

Fields of Research: Current Projects and Future Goals:

› Biologically active natural products and Isolation and synthesis of Prof. Dr. Dr. Ludger metabolomic profiling bioactive compounds Wessjohann › Total synthesis and medicinal chemistry Plants and fungi are prominent producers of bio

1990 › Multi-component reactions , rapid synthesis, active molecules. We develop new methods for the PhD in Organic Chemistry and peptoids discovery of active ingredients with a current em- (U Hamburg, Prof. A. de Meijere) › Biotransformations phasis on anticancer drugs, fungicides, and taste › Chemoinformatics modulators. This work often is done in close coope 1990 / 1993 / 1995 ration with international partners in South-East Lecturer, U Federal Santa Maria, Brazil Our research focuses on the identification and Asia, Arabia, Latin America and Africa, and with 1991–1992 understanding of small molecules and their effects industrial partners. Based on the natural lead Feodor-Lynen-Postdoctoral Fellow, within biological systems, and on the application structures, we develop total synthesis routes to Stanford U, USA (Prof. P. Wender) of such compounds to probe and modify biological the natural product and its derivatives. In order to 1998 systems monitored by bioassays, computational, optimize the desired properties and to understand Habilitation, LMU Munich metabolomic and proteomic techniques. the drug-protein interaction, we integrate the Three main lines of research are followed to achieve chemical research with biochemical or biological 1998–2000 this: (1.) We try to learn from nature’s chemistry assays and computational methods like molecular Full Prof. Bioorganic Chemistry, Vrije through both elucidation of natural structures as modelling or bioinformatics. As an example, we U. Amsterdam, NL well as understanding basic principles of nature’s recently synthesized and patented new peptides Since 2000 application of chemistry in a biological context; with picomolar cytotoxicity, i.e. they belong to the Full Prof. (C4) of Natural Prod. Chem., (2.) We use total and diversity oriented synthesis most active anticancer compounds known to date. MLU Halle, and Director of Dept. of natural products and derivatives, including bio- Bioorganic Chem., Leibniz Inst. of transformations, for applications in biology, medi- Plant Biochemistry cine, nutrition and agrochemistry; (3.) We try to 2010–2017 increase our understanding of molecular interac- Managing Director of the Leibniz tion and construction processes and develop new Institute of Plant Biochemistry tools, probes and recognition compounds to study these. The analysis, isolation, characterization, and modi Highly potent anticancer Tubugi-peptide (left), and its effect Contact fication of natural products and enzymes from on a human cancer cell (right). (MCR: multicomponent reaction; plants and higher fungi is the basis of our efforts green: microtubules; blue: chromosomes) [email protected] to understand the properties of these biomolecules www.ipb-halle.de/de/forschung/ or to disclose their function in nature, and finally Enzyme biotechnology natur-und-wirkstoffchemie/ to explore their use in chemistry, biology and The chemical industry currently undergoes a rapid medicine. Applications are driven by the discovered change that sees a considerable increase in bio- properties and include such diverse areas as agro- based chemical production technology. Biocatalysts Selected publications: chemicals, lead structures in medicinal chemistry play a crucial role in this transformation process M. G. Ricardo et al. Improved Stability and or novel food ingredients, biological research tools, as they often allow otherwise difficult or impos- Tunable Functionalization of Parallel -Sheets via MulticomponentN-Alkylation of the Turn or the utilization of enzymes as biocatalysts. This sible reactions, or give more efficient, environ- Moiety. Angewandte Chemie (2020) 132:β is backed by the development of analytical tools, mentally benign or acceptable processes. We focus 265-269; Angew. Chem. Int Ed. (2020), 59: e.g. for metabolic and affinity based protein pro- on the discovery, mechanistic understanding, and 259-263. filing, by a synthesis program to increase com- application of biocatalysts with a focus on methyl, L. Holzmeyer et al. Evaluation of plant sources pound availability and molecular diversity, and prenyl, and glycosyl transfer reactions. This will for antiinfective lead compound discovery by by computational methods to aid the under- lead to new processes for the production of im- correlating phylogenetic, spatial, and bioactivity data. Proc. Nat. Acad. Sci. – PNAS standing and design processes through theoretical portant plant products of terpenoid or flavonoid (2020). 117(22): 12444-12451. models. Advanced projects usually proceed with origin which are important, e.g. in the fine chemi

M. Dippe et al. Coenzyme A-conjugated additional collaboration with external academic cals and flavor & fragrance industries. cinnamic acids–enzymatic synthesis of a or industrial partners. CoA-ester library and application in Multiple multicomponent reactions (MCRs) biocatalytic cascades to vanillin derivatives. Adv. Synth. Cat. (2019), 361: 5346-5350. MCRs are unrivalled for the speedy construction of complex molecules. This is potentiated if multiple B. Michels et al. Memory enhancement by or sequential MCRs are applied. The theoretically ferulic acid ester across species.Science Advances (2018), 4: eaat6994. quite demanding processes are often simple in practice and allow hitherto unknown possibilities M.A. Farag et al. Comparative Metabolomics Approach Detects Stress-Specific Responses for the construction of molecules of a complexity during Coral Bleaching in Soft Corals.J. otherwise only found in nature’s proteins or poly- Proteome Res. (2018) 17: 2060-2071. One pot assembly of igloo-type macromulticycles by multiple MCRs saccharides. 70_ SYNTHETIC AND BIOMACROMOLECULES

Institute of Chemistry & Leibnitz Institute of Plant Biochemistry Organic Chemistry Biofunctional Synthesis

Fields of Research: Current Projects and Future Goals:

› Natural product synthesis Multi-Component Reactions › Diversity oriented synthesis Multicomponent reactions (reactions of three Prof. Dr. › Multi-component reactions and more components at the same time) are very Bernhard Westermann

› Probes for protein profiling efficient due to their high atom- and step econo- 1989 my. Among these, isonitrile-based MCRs (Passer- PhD in Organic Chemistry, University In close collaboration with partners from the ini-, Ugi-, Ugi-Smiles-reaction) are suited best to of Paderborn, Germany Leibniz-Institute of Plant Biochemistry, the MLU accomplish the synthesis of natural-like peptoids and internationally with collaborators mainly and depsipeptides. These reactions will be done in 1990–1991 PostDoc University of Toronto, Canada from Cuba and Brasil, we want to gain insight the context of approaches to the synthesis of (group of Prof. J. B. Jones) into the formation and action of secondary me- chemical probes, where they provide dual read tabolites from plants and fungi. These findings out probes (fluorescence, EPR-spectroscopy). Par- 1996 will be applied for plant- as well for human health allel monitoring of biological processes will be Habilitation in Organic Chemistry, issues. made possible, such as the localization and the University of Paderborn, Germany determination of e.g. reactive oxygen species 1997–2004 (ROS). Some of these studies are carried iterative- Assistant and Associate Professor at ly with the biological departments of the IPB. University of Paderborn, Germany

since 2004 Ligations, click-chemistry Group leader Biofunctional Synthesis, Studying click-reactions beyond the well-known Leibniz-Institute of Plant Biochemistry copper-catalyzed alkine-azide cycloadditions (CuAACs) as well as strain-promoted (SPAACs) since 2010 will be developed. These reactions are very useful Prof. (apl; Organic Chemistry) at the Martin Luther University Halle- tools for ligations and bioconjugation. Recently, Wittenberg, Germany we have explored a new strategy, which is based on the Sakai reaction generating triazoles in highly chemo- and regioselective manner. We have begun to study this method as bioorthogo- Contact nal reaction providing modified compounds in [email protected] vitro and in vivo. Specifically, we want to synthesize with our Cuban colleagues protein adducts www.ipb-halle.de amenable for vaccination studies. In addition, we also examine in collaboration with our Brasilian Selected publications: partners photo-chemical reactions for hitherto unknown ligations. The main challenge of all of B. Westermann et al. Natural products from fungi provide provide in- these reactions is the necessity to run them in Discovery of potent and selective inhibitors of teresting synthetic challenges and intriguiung aqueous solutions at ambient temperatures. the Escherichia coliM1-aminopeptidase via biological features (example: natural products multicomponent solid-phase synthesis of tetrazole-peptidomimetics from Hygrophorus-species provide strong fungi- Eur. J. Med. Chem. 2019, 163, 481 – 499. cidal compounds). B. Westermann et al. Diversity Driven Decoration and Ligation of The biofunctional synthesis of plant- and fungi- Fullerene by Ugi and Passerini Multicomponent derived natural products is necessary for several Reactions reasons: i) conformation of relative and absolute Chem. Eur. J. 2018, 24, 9788 – 9793. stereochemistry, ii) synthesis of derivatives to D. Hinderberger, B. Westermann et al. carry out structure-activity relationships, iii) Spin-labelled diketopiperazines and peptide-peptoid chimera by Ugi-multi-compo- combination with dyes/spin labels to study cellu- nent-reactions lar uptake and structural features. To allow for an Org. Biomol. Chem. 2016, 14, 11336 11341. efficient synthesis of these products, we are de- B. Westermann et al. veloping new synthetic methodologies, with mul- Highly Stereoselective Synthesis of Natural ti-component reactions in the focus. These proto- Product-like Hybrids by an Organocatalytic/ Multicomponent Reaction Sequence cols provide access in very low number of Angew. Chem., Int. Ed. 2015, 54, 7621-7625. synthetic steps and can be carried out in “green” and sustainable fashion. B. Westermann et al. Isolation and Asymmetric Total Synthesis of Fungal Secondary Metabolite Hygrophorone B12 Eur. J. Org. Chem. 2015, 2357–2365.

Research in education and history of science

Photo: Prof. Dr. Andreas Kleinert RESEARCH IN EDUCATION AND HISTORY OF SCIENCE _73

Institute of Physics Physics Education

Fields of Research: Current Projects and Future Goals:

Identity work and educational choices Identity work and educational choices Prof. Dr. Thorid Rabe Decisions on educational pathways are relevant It can be assumed that attitudes towards physics both for individuals and society. The investigation are formed at an early age and that physics lessons 2007 PhD Physics Education, University of of identity work on physics allows in depth analy- at school play an important role in this. Therefore, Potsdam, Germany ses of how adolescents relate themselves to physics the perspectives of the pupils in the first physics and how this is reflected in their educational deci- lessons in the 6th grade are examined in a qualita- 2007–2009 sions. Physics identity is defined as the perception tive interview study. Teacher Preparation Service at a by others and the self-perception as well as the A particularly important phase of identity work and Secondary School (linguistic) behaviour of individuals with regard educational choices is the transition from school 2010–2014 to physics-related contents, topics and activities. to university or vocational training. In the project Assistant professor of Physics So called “identity work” – the negotiation of one ‘helpING!’ (cf. https://www.helping.academy; Education (W1), University of or more identities – takes place in an interplay of promoted by the German Ministry of Education) Potsdam, Germany individual acting and the influence of social ‘orientation academies’ are organized addressing Since 2014 structures. young women at the end of their school time. Th Professor of Physics Education (W2), academies aim at providing orientation about Martin Luther University Halle-Wit- Teacher education possible career paths into science and technology. tenberg, Germany How to prepare future teachers so that they can A longitudinal interview study with the partici- plan and conduct their lessons in a professional pating young women will provide a deeper insight and reflective way is an important question for into the complexity of educational decisions at Contact physics education. In addition to competencies in the transition from school to further education. the sense of skills, affective aspects such as self- [email protected] efficacy expectations, orientations on physics and Teacher education http://www.physik.uni-halle.de/ on educational topics are also relevant. Both the In the field of teacher education, the following fachgruppen/didaktik development of survey instruments and the in- three specific issues are examined: vestigation of the development of self-efficacy, › Orientations of physics teachers on responsibility orientations and identities of teacher students and technology in the context of physics teaching. Selected publications: and teachers in the course of their study and career › Casuistic teaching in university courses that Rabe, T. (2020), Wie viel Fach muss sein? Eine are part of the research interest. supplement practical phases with a focus on lin- (kritische) Annäherung an die Modellierung professioneller Handlungskompetenz aus guistic aspects of inclusive teaching-learning physikdidaktischer Perspektive. In U. Hericks, settings M. Keller-Schneider, W. Meseth, & A. › physics teachers’ self-efficacy beliefs for teach- Rauschenberg (Eds.), Fachliche Bildung und Professionalisierung von Lehrerinnen und ing physics, specifically in the fields of “experi- Lehrern (pp. 49–76). Bad Heilbrunn: menting”, “dealing with students’ conceptions”, Klinkhardt. “analyzing and preparing physics content” and Meinhardt, C., Rabe, T., & Krey, O. (2018), Student teachers plan and carry out school “implementation of physics tasks” Formulierung eines evidenzbasierten experiments (Photo: Frederik Bub) Validitätsarguments am Beispiel der Erfassung physikdidaktischer Selbstwirksam- keitserwartungen mit einem neu entwickelten Instrument. Zeitschrift für Didaktik der Naturwissenschaften, 24, 131–150.

Bub, F., Rabe, T., & Krey, O. (2018), Views on interrelations between physics and technology in the context of responsibility. In O. E. Finlayson, E. McLoughlin, S. Erduran, & P. Childs (Eds.), Electronic Proceedings of the ESERA 2017 Conference. Research, Practice and Collaboration in Science Education, Part 6 (pp. 787–795). Dublin, Ireland: Dublin City University.

Rabe, T., & Krey, O. (2018), Identitätskon- struktionen von Kindern und Jugendlichen in Bezug auf Physik - Das Identitätskonstrukt als Analyseperspektive für die Physikdidak- tik? Zeitschrift für Didaktik der Naturwissen- schaften, 24(1), 201–216. Emeriti Emeriti _75

Emeriti

Prof. Dr. Alfred Blume Prof. Dr. Wilhelm Lorenz Institute of Chemistry, Institute of Chemistry, Biophysical Chemistry Environmental Chemistry email: [email protected] email: [email protected]

Prof. Dr. Siegfried Carl Prof. Dr. Karin Richter Institute of Mathematics, Institute of Mathematics, Functional Analysis and Applications Education and History of Mathematics email: [email protected] email: [email protected]

Prof. Dr. Bodo Dittmar Prof. Dr. Hans Roggendorf Institute of Mathematics, Institute of Physics, Analysis – Function Theory Inorganic-nonmetallic Materials email: [email protected] email: [email protected]

Prof. Dr. Dr. h. c. Wilfried Grecksch Prof. Dr. Dirk Steinborn Institute of Mathematics, Institute of Chemistry, Stochastics Organometallic Chemistry and Catalysis email: [email protected] email: [email protected]

Prof. Dr. Wolfram Hergert Prof. Dr. Gernot Stroth Institute of Physics, Institute of Mathematics, Computational Physics Algebra email: [email protected] email: [email protected]

Prof. Dr. Dietrich Hesse Prof. Dr. Steffen Trimper Institute of Physics & Max Planck Institute of Microstructure Institute of Physics, Physics Statistical Physics email: [email protected] email: [email protected]

Prof. Dr. Jürgen Kirschner Prof. Dr. Rüdiger Weiner Institute of Physics & Max Planck Institute of Microstructure Institute of Mathematics, Physics, Scientific Computing Magnetism email: [email protected] email: sekrki@ mpi-halle.mpg.de Undergraduate, graduate and postgraduate education The Faculty of Natural Sciences II is committed to a high-quality scientific education in chemistry, physics, mathematics, and related disciplines, which is reflected in our good positions in national rankings. We combine an in-depth eduacation in the three basic scientific disciplines leading to Bachelor, Master and doctoral degrees with the offer of specific interdisciplinary study programs as well as structured programs on the doctoral level. Photo: Matthias Ritzmann | MLU

Studying at the Faculty of Natural Sciences II

Chemistry, physics, mathematics Masters study The faculty offers education at undergraduate, masters Different Master programs are set up to provide a full and postgraduate level in the classical fields of chemistry, education in science, paving the path for excellent career physics and mathematics and has an additional focus opportunities. The consecutive Bachelor and Master on related interdisciplinary education with Bachelor programs in Chemistry, Physics, Medical Physics, Mathe- and Master programs in Medical Physics, Physics and matics and Economathematics combine the high scien- Digital Technologies, Economathematics, Renewable tific level of traditional German diploma degrees with Energy and Polymer Materials Science. Other programs the benefits of the common European higher education like the studies in food chemistry and the teacher training area according to the Bologna Accords. in chemistry, physics, astronomy and mathematics pre- The consecutive programs are accompanied by an inter- pare students for external final examinations like the nationally oriented Master program in Polymer Mate German Staatsexamen. rials Science taught in English language. The program attracts international as well as German students who Undergraduate study enjoy an interdisciplinary topic and a multi-cultural The faculty offers exciting course programs and optimal learning environment and atmosphere. The Master pro- conditions for learning and studying that are very well gram in Renewable Energies will provide a sound basis recognized in national rankings. The major fields of study are of chemical and physical knowledge and skills on this chemistry, physics and mathematics and their applications very timely topic. in the natural sciences. Specialized Bachelor programs Based on a flexible curriculum, all Master programs offer degrees in Medical Physics and Economathematics. provide structured, graduate-level education in advanced In autumn 2019, a new program Physics and Digital research methods. The graduate students get in close Technologies has been launched, which conveys both a contact with research groups in one of the institutes or general and broad basic physical education and solid in other local research institutions. knowledge of information technology. End of 2020, the new Bachelor course Physics Plus will start, which allows to study at the interface between science and society. Already on the Bachelor level, students get involved in high-level research performed at the different institutes. Photo: Maike Glöckner | MLU

Postgraduate Research

Postgraduate research and qualification Doctoral studies Postgraduate research at the Faculty of Natural Sciences II Doctoral studies at Martin Luther University, like at is typically performed in the framework of a research most German universities, do not involve the strict project in one of the groups at the Institutes of Chemistry, course work that accompanies “PhD programs” in the Physics, Mathematics, or at the different local research Anglo-Saxon system. In the classical German system, institutions. Postgraduate students are commonly em- admission to the doctoral student level requires a Diplo- ployed as regular temporary half- to full-time staff ma or an equivalent Master degree. Applicants on the members and have furthermore access to the post Bachelor level need to pass one of our Master programs graduate qualification program of the International before entering the postgraduate stage. Graduate Academy (InGrA) at Martin Luther University. Structured doctoral programmes International Graduate Academy (InGrA) Depending on their research topic, the postgraduate stu- InGrA is the “roof” for all structured doctoral program dents may, in addition to the thesis-related research mes at Martin Luther University. It supports graduate work, get the opportunity to join a “Graduate School” students in all phases of their studies up to a successful (e.g., within a Research Training Group or a Collaborative start of a professional carrier and aims at gender equality Research Center of the DFG), and thus to participate in and an increasing number of international graduate a dedicated doctoral training programme, for which a students. separate certificate is issued along with the degree. As one example, in a joint initiative of the Max Planck Doctoral degrees Institute of Microstructure Physics, the Institute of Phy The Faculty of Natural Sciences II offers doctoral degrees sics at Martin Luther University Halle-Wittenberg and in Natural Sciences (Dr. rer. nat., Dr.-Ing. or Dr. paed., all the Fraunhofer Institute for Materials Mechanics, the equivalent to a PhD) in the fields of Chemistry, Physics, International Max Planck Research School for Science Mathematics, or a related discipline after submission of and Technology of Nanostructures (Nano-IMPRS) was a suitable doctoral thesis (dissertation) and a doctoral established to support excellent young scientists on their examination (defence). way to a doctorate or PhD degree in this specific area.

Other programmes can be found on our web pages: http://www.natfak2.uni-halle.de/promotion Impressum

Dean’s office Prof. Dr. Christiane Tammer, Vice Dean of Research Faculty of Natural Sciences II - Chemistry, Physics, and Mathematics

Martin Luther University Halle-Wittenberg D-06099 Halle (Saale) [email protected] Phone: +49 (0) 345-55 254 40/31

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