DOCSLIB.ORG

Neutron Scattering Principal Investigators' Meeting

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Neutron Scattering Principal Investigators' Meeting Neutron Scattering Principal Investigators’ Meeting July 22-25, 2012 Gaithersburg Marriott Washingtonian Center Gaithersburg, Maryland Office of Basic Energy Sciences Division of Materials Sciences and Engineering On the Cover Top Left: Predicted density vs. temperature phase diagram of supercooled water in the presence of a first- order high density liquid (HDL) to low density liquid (LDL) phase transition based on the measured densities of confined water at high pressures during heating (the red curve connecting the points) and cooling (the blue curve connecting the points) cycles. The presence of significant hysteresis at high pressures in the measured densities during heating and cooling scans when crossing the transition line points to the putative first order liquid-liquid transition. However, at relatively low pressures, when no first-order line is crossed, there should be no hysteresis as shown with the green curve. (Yang Zhang, Antonio Faraone, W. A. Kamitakahara, Kao-Hsiang Liu, Chung-Yuan Mou, Juscelino B. Leão, Sung Chang, and Sow-Hsin Chen, Density hysteresis of heavy water confined in a nanoporous silica matrix, Proc. National Academy of Sciences, 2011, 108, 12206) Top Middle: A) The fundamental building block of the copper-oxide superconductors is the Cu-O sheet. The well-studied conventional magnetism results from localized spin moments on the Cu atoms. B) Proposed novel magnetism due to circulating charge currents. C) Intensity of scattered neutrons at four wave vectors for the model material HgBa2CuO4+δ. Two magnetic excitations (waves) can be discerned, one at about 40 meV and another at about 55 meV. (Yuan Li, G. Yu, M. K. Chan, V. Balédent, Yangmu Li, N. Bariši´c, X. Zhao, K. Hradil, R. A. Mole, Y. Sidis, P. Steffens, P. Bourges, and M. Greven, Nature Physics, 2012, 8, 404–410) Top Right: The spectrum of low-energy magnetic excitations in an Fe-based superconductor is found to evolve in an unusual way. Contour intensity maps showing the fitted magnetic scattering intensity versus ħω and Q at different temperatures for the superconducting FeTe0.35Se0.65: (a) 4 K, (b) 25 K, (c) 100 K, and (d) 300 K. The change in the distribution of spectral weight between 4 K and 25 K is due to the superconducting transition. The robust spectral weight at all temperatures cannot be explained by conduction electrons alone. (Zhijun Xu, Jinsheng Wen, Guangyong Xu, Songxue Chi, Wei Ku, Genda Gu, and J. M. Tranquada, Phys. Rev. B, 2011, 84, 052506) Bottom Left: Small-angle neutron scattering from a bulk sample of Ni44Co6Mn40Sn10, a precisely engineered off-stoichiometric Heusler alloy, showing the 2D qx-qy small angle scattering intensity map in a strained sample. (Bhatti, El-Khatib, Srivastava, James, and Leighton, Phys. Rev. B, 2012, 85, 134450) Bottom Middle: Frozen phonon calculations evidencing that the most anomalous modes are quantum quartic oscillators, with transverse motions of fluorine atoms – a new mechanism for the negative thermal expansion coefficient of scandium fluoride. (Chen W. Li, Xiaoli Tang, J. A. Muñoz, J. B. Keith, S. J. Tracy, D. L. Abernathy, and B. Fultz, Physical Review Letters, 2011, 107, 195504) Bottom Right: (a) Crystal structure of the ideal kagome lattice compound ZnCu3(OH)6Cl2, also called herbertsmithite. (b) Single crystal synthesized for the magnetic measurements. (T.H. Han, S. Chu, and Y.S. Lee, Physical Review Letters, 2012, 108, 157202) This document was produced under contract number DE-AC05-06OR23100 between the U.S. Department of Energy and Oak Ridge Associated Universities. The research grants and contracts described in this document are supported by the U.S. DOE Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division. Foreword This volume comprises the scientific content of the 2012 Neutron Scattering Principal Investigators' (PI) Meeting sponsored by the Division of Materials Sciences and Engineering (MSED) in the Office of Basic Energy Sciences (BES) of the U.S. Department of Energy (DOE). This meeting on July 22–25, 2012 at the Gaithersburg Marriott Washingtonian Center in Gaithersburg, Maryland, is the third in the series, covering the projects funded by the Neutron Scattering Program. BES MSED has a long tradition of supporting a comprehensive neutron scattering program in recognition of the high impact neutron scattering and spectroscopy tools have in discovery and use-inspired research. The MSED Neutron Scattering Core Research Activity (CRA) supports basic research on the fundamental interactions of neutrons with matter to achieve an understanding of the atomic, electronic, and magnetic structures and excitations of materials and their relationship to materials’ properties. Major emphasis is on the application of neutron scattering and spectroscopy for materials research, primarily at BES-supported user facilities. Development of next-generation instrumentation concepts, innovative optics for time-of-flight instruments and application of polarized neutrons are distinct aspects of this activity. The increasing complexity of DOE mission-relevant materials for various energy applications requires sophisticated scattering and computational tools to investigate the structure and dynamics at relevant length and time scales. Additionally, neutrons allow access to the behavior of matter in extreme environment such as high temperature, pressure and magnetic field. A continuing theme of this program is the integration of material synthesis, neutron scattering measurements and computational modeling as this is vital to obtain controlled samples for experiments and modeling for an in-depth understanding of the structure and dynamics of materials and their relationship to macroscopic properties. The purpose of the BES biannual PI meetings is to bring together all the researchers funded by BES in the neutron scattering area to get a first-hand look at the range of research topics and ongoing activities in the program, to foster an awareness of the research of others in the program, to facilitate the exchange of new results and research highlights, to promote new ideas and collaborations among participants and BES scientific user facilities, and to identify and pursue new scientific opportunities and new frontiers. For BES the PI meetings provide an opportunity to see the entire portfolio/program at one time on a periodic basis, to assess the state of the program and chart new scientific directions, and to turn a 'collection of projects' into a visionary, forward-looking program. We thank all the meeting participants for their active contributions in sharing their ideas and research accomplishments. Sincere thanks are also due to the speakers from other BES programs involved with neutron scattering in multidisciplinary research. We wish to thank Teresa Crockett in MSED and Lee-Ann Talley at the Oak Ridge Institute for Science and Education (ORISE) for their outstanding work in all aspects of the meeting organization. Thiyaga P. Thiyagarajan and Helen Kerch MSED, BES, Office of Science U.S. Department of Energy i ii Table of Contents Foreword ......................................................................................................................................... i Table of Contents ......................................................................................................................... iii Agenda .......................................................................................................................................... ix Session I: High Temperature Superconductors – Cuprates Neutron Scattering Studies of Cuprate Superconductors J. M. Tranquada, G. D. Gu, M. Hücker, G. Y. Xu, and I. A. Zaliznyak ....................................2 Crystal Growth and Scattering Studies of Model Cuprate Superconductors M. Greven .................................................................................................................................6 Neutron and X-ray Scattering Investigation of Electron-Phonon Effects in Cuprate Superconductors and Related Compounds Dmitry Reznik .........................................................................................................................10 Session II: Correlated Electron Systems (I) Quantum Correlated Materials and Phenomena C. Broholm, N. P. Armitage, R. J. Cava, T. M. McQueen, O. Tchernyshyov, and Z. Tesanovic ....................................................................................................................16 Correlations and Competition between the Lattice, Electrons, and Magnetism R. J. McQueeney, V. P. Antropov, A. I. Goldman, B. N. Harmon, A. Kreyssig, D. Vaknin, and J. L. Zarestky .................................................................................................23 Using Neutron as a Probe to Study Magnetic Excitations in Strongly Correlated Electron Materials Pengcheng Dai ........................................................................................................................31 Phase Competition in Bulk Materials: Superconductivity vs Spin and Charge Density Waves R. Osborn, S. Rosenkranz, O. Chmaissem, S. Avci, J.-P. Castellan, and F. Weber ..............36 Session III: Correlated Electron Systems (II) Complex Electronic Materials J. D. Thompson, E. D. Bauer, M. Janoschek, R. Movshovich, F. Ronning, and H. Yasuoka .......................................................................................................................42 iii Neutron Scattering Studies of Fe-Based Superconductors
Load more

Recommended publications
  • A Search for Free Oscillations at the ESS N
    A search for free n → n oscillations at t he ESS π π ? n n π π π D. Milstead Stockholm University Why baryon number violation ? Why baryon number violation ? • Baryon number is not a ”sacred” quantum number – Approximate conservation of BN in SM • ”Accidental” global symmetry at perturbative level – Depends on specific matter content of the SM • BNV in SM by non-perturbative processes –Sphalerons – B-L conserved in SM, not B,L separately. – Generic BNV in BSM theories, eg, SUSY. – BNV a Sakharov condition for baryogenesis Why n→ n ? n→ n • Theory • Baryogenesis via BNV (Sakharov condition) • SM extensions from TeV mass scales scale-upwards • Complementarity with open questions in neutrino physics • Experiment • One of the few means of looking for pure BNV • Stringent limit on stability of matter Neutron oscillations – models • Back-of-envelope dimensional reasoning: cΛ6 6 q operator for ∆B =2, ∆ L = 0⇒ δ m= QCD ⇒ M ∼ 1000 TeV n→ n M 5 • R-parity violating supersymmetry • Unification models: M ∼ 1015 GeV • Extra dimensions models • Post-sp haleron baryogenesis • etc, etc: []arXiv:1410.1100 High precision n→ n search ⇒ Scan over wide range of phase space for generic BNV + ⇒ model constai nts. Extend sensitivity in RPV-SUSY ATLAS multijet ATLAS CMS dijet CMS ESS Arxiv:1602.04821 (hep-ph) Displaced jets RPV-SUSY – TeV-scale sensitivity Neutrino physics ⇔ neutron oscillations Neutrinoless 2β -decay n→ n Eg seesaw mechanism for light ν Eg Unification models ∆L =2, ∆ B = 0, ∆L =0, ∆ B = 2, 2 ∆()B − L = 2 ∆()B − L = Neutrinoless 2β -decay ⇔ nn → linked under BL - viol ation.
    [Show full text]
  • Vortex-Matter in Multi-Component Superconductors
    Vortex-matter in Multi-component Superconductors JOHAN CARLSTRÖM Licentiate thesis Stockholm, Sweden 2012 TRITA-FYS 2012:90 ISSN 0280-316X KTH Teoretisk fysik ISRN KTH/FYS/--12:90--SE AlbaNova universitetscentrum ISBN 978-91-7501-611-5 SE-106 91 Stockholm Sweden Akademisk avhandling som med tillstånd av Kungl Tekniska högskolan framlägges till offentlig granskning för avläggande av teknologie licentiatexamen i teoretisk fysik den 14 Januari 2013 kl 10:00 i sal FA32, AlbaNova Universitetscentrum. c Johan Carlström, December 2012 Tryck: Universitetsservice US AB 3 Abstract The topic of this thesis is vortex-physics in multi component Ginzburg- Landau models. These models describe a newly discovered class of supercon- ductors with multiple superconducting gaps, and posses many properties that set them apart from single component models. The work presented here relies on large scale computer simulations using various numerical techniques, but also some analytical methods. In Paper I, Type-1.5 Superconducting State from an Intrinsic Proximity Effect in Two-Band Superconductors, we show that in multiband supercon- ductors, even an extremely small interband proximity effect can lead to a qualitative change in the interaction potential between superconducting vor- tices by producing long-range intervortex attraction. This type of vortex interaction results in an unusual response to low magnetic fields, leading to phase separation into domains of two-component Meissner states and vortex droplets. In paper II, Type-1.5 superconductivity in multiband systems: Effects of interband couplings, we investigate the appearance of Type-1.5 superconduc- tivity in the case with two active bands and substantial inter-band couplings.
    [Show full text]
  • ICANS XXI Dawn of High Power Neutron Sources and Science Applications
    Book of Abstracts ICANS XXI Dawn of high power neutron sources and science applications 29 Sep - 3 Oct 2014, JAPAN Ibaraki Prefectural Culture Center Update : 12 Oct. 2014 Best photography in 7th Oarai Town Photo Contest. WELCOME TO ICANS XXI ICANS (International Collaboration on Advanced Neutron Sources) is a network for scientists who are involved in developing pulsed neutron sources and accelerator based spallation neutron sources. Since 1st ICANS meetings was held in 1977 at Argonne National Laboratory in the day of dawn of spallation neutron technique, ICANS has been continuously held already 20 times somewhere in the world. Now we are extremely happy to announce that the ICANS, the 21st meeting, will be held at Mito hosted by J-PARC this autumn. We have a large number of topics to be discussed, there are twelve topics, such as futuristic idea of neutron source, rapid progress in facilities, integration issues in target-moderator-development, etc. The details can be found in the agenda. The meeting has a two layered structure, one is plenary session and another is workshop. Two of them are complementary and tightly cooperate each other. In the meeting we would like to enhance "workshop style", which is an original and traditional way of ICANS. Actually 2/3 of topics will be discussed in the workshop sessions. It also will be essentially organized/ lead by the workshop chairs. Plenary session shows overall issues in a relevant workshop, whose details should be talked/discussed in the workshop. The venue for the meeting is Mito city, where the 2nd Shogun Family lived for a long period of time during Edo era from 17th to 19th century, when the Tokugawa shogunate ruled the country.
    [Show full text]
  • Theory of Nematic Fractional Quantum Hall State
    Theory of Nematic Fractional Quantum Hall State Yizhi You,1 Gil Young Cho,1 and Eduardo Fradkin1, 2 1Department of Physics and Institute for Condensed Matter Theory, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080, USA 2Kavli Institute for Theoretical Physics, University of California Santa Barbara, CA 93106-4030, USA (Dated: July 9, 2018) We derive an effective field theory for the isotropic-nematic quantum phase transition of fractional quantum Hall (FQH) states. We demonstrate that for a system with an isotropic background the low-energy effective theory of the nematic order parameter has z = 2 dynamical scaling exponent, due to a Berry phase term of the order parameter, which is related to the non-dissipative Hall viscosity. Employing the composite fermion theory with a quadrupolar interaction between electrons, we show that a sufficiently attractive quadrupolar interaction triggers a phase transition from the isotropic FQH fluid into a nematic fractional quantum Hall phase. By investigating the spectrum of collective excitations, we demonstrate that the mass gap of Girvin-MacDonald-Platzman (GMP) mode collapses at the isotropic-nematic quantum phase transition. On the other hand, Laughlin quasiparticles and the Kohn collective mode remain gapped at this quantum phase transition, and Kohn’s theorem is satisfied. The leading couplings between the nematic order parameter and the gauge fields include a term of the same form as the Wen-Zee term. A disclination of the nematic order parameter carries an unquantized electric charge. We also discuss the relation between nematic degrees of freedom and the geometrical response of the fractional quantum Hall fluid.
    [Show full text]
  • The HIBEAM Experiment for the European Spallation Source
    The HIBEAM Experiment for the European Spallation Source n ? n D. Milstead Stockholm University Outline 1. The aims of the experiment 2. The physics case 3. The proposed program at the ESS 4. Status HIBEAM High Intensity Baryon Extraction and Measurement Search for • 푛 → 푛ത • 푛 → 푛′ (mirror neutrons) Also measurements of weak nucleon-nucleon interactions. Baryon and lepton number violation • BN,LN ”accidental” SM symmetries at perturbative level – BNV, LNV in SM non-perturbatively (eg instantons) – B-L is conserved, not B, L separately. • BNV, LNV needed for baryogenesis and leptogenesis • BNV,LNV generic features of SM extensions (eg SUSY) nn Dimensional reasoning: c6 6q operator for B 2, L 0 m QCD M 1000 TeV nn M 5 R-parity violating supersymmetry Unification theories: M 1015 GeV Extra dimensions models Post-sphaleron baryogenesis etc, etc: arXiv:1410.1100 High precision n n search Scan over wide range of phase space for generic BNV + model constaints. RPV-SUSY Super-K ILL LHC, flavour Constraints vanish for >> TeV masses nnbar@ESS: extends mass range by up to ~400 TeV cf Super-K : pushes into the PeV scale Complementary B,L-violation observables BL 1, BL 2, 0, BL 0, 2, BL 0 BL 2 BL 2 Symbiosis n n , NN decay. Nucleon decay Stable proton. 0 Few pure BNV searches Neutron oscillations – an experimentalist’s view Hypothesis: baryon number is weakly violated. How do we look for BNV? Single nucleon decay searches, eg, pe 0 ? L-violation, another (likely weakly) violated quantity. Decays without leptons, eg, p , impossible due to angular momentum conservation.
    [Show full text]
  • Instrumental Aspects
    EPJ Web of Conferences 155, 00002 (2017) DOI: 10.1051/epjconf/201715500002 JDN 22 Instrumental aspects Navid Qureshi Institut Laue Langevin, 38000 Grenoble, France Abstract. Every neutron scattering experiment requires the choice of a suited neutron diffractometer (or spectrometer in the case of inelastic scattering) with its optimal configuration in order to accomplish the experimental tasks in the most successful way. Most generally, the compromise between the incident neutron flux and the instrumental resolution has to be considered, which is depending on a number of optical devices which are positioned in the neutron beam path. In this chapter the basic instrumental principles of neutron diffraction will be explained. Examples of different types of experiments and their respective expectable results will be shown. Furthermore, the production and use of polarized neutrons will be stressed. 1. Introduction A successful neutron scattering experiment requires a thorough plan of which instrument to use and how to set up its configuration in order to obtain the best possible results. Optimally, the decision of the set-up is taken beforehand, but in many cases the instrument parameters are modified on-the-fly after analyzing the first results. Due to the different experimental tasks – reaching from magnetic or nuclear structure investigation to the mapping of phase diagrams – and the different sample dimensions (both the crystal size and the lattice parameters), which can be investigated at one and the same instrument, it becomes obvious that the versatility of some instruments has to be adjusted to satisfy the experimental tasks. Obviously, the sample state (powder, single crystal, liquid, etc.) limits the choice of instruments, however, you can find powder diffractometers which differ from each other concerning the used neutron wavelength and particular devices in the beam path in order to maximize the efficiency for a type of experiment.
    [Show full text]
  • Media Highlights
    2008 Applied Superconductivity Conference and Exhibition August 17 – 22. 2008 Hyatt Regency Chicago – Chicago, IL USA MEDIA HIGHLIGHTS Conference Website: http://www.ascinc.org PRESS REGISTRATION Members of the media may register by faxing a registration form (found at www.ascinc.org) to ASC 2008 Press at (303) 499- 2599, or register on-site at the Registration desk, located in the North Grand Ballroom Foyer of the Hyatt Regency Chicago. Journalists will be asked to show press credentials/ID to receive complimentary admission to technical sessions, welcome reception and exhibitor’s reception, and Exhibition Hall. Conference program, badges and other conference materials will be available at the registration desk. Tickets for the Thursday conference luncheon may also be purchased at the desk. On-site Press Registration: North Grand Ballroom Foyer – Hyatt Regency Chicago Hours of Operation: Sunday, August 17: 2:00 p.m. – 8:00 p.m. Monday, August 18: 7:00 a.m. – 7:00 p.m. Tuesday, August 19: 7:00 a.m. – 6:00 p.m. Wednesday, August 20: 7:00 a.m. – 6:00 p.m. Thursday, August 21: 7:00 a.m. – 6:00 p.m. Friday, August 22: 7:00 a.m. – 12:00 Noon (For media assistance and additional information, please ask for Dr. Balu Balachandran, Mr. Jim Kerby, Dr. Lance Cooley, Ms. Sue Butler, or Mrs. Paula Pair. Individual interview rooms may also be scheduled.) PLENARY AND OTHER SPECIAL SESSIONS Monday, August 18, 8:00 a.m. - 9:00 a.m. Welcome – Dr. Balu Balachandran, Argonne National Laboratory (Conference Chair); Opening Remarks – Dr.
    [Show full text]
  • Viii-I. Summary of Research Activities
    VIII-I. SUMMARY OF RESEARCH ACTIVITIES VIII-I-1. MEETINGS AND SEMINARS Specialists’ Meetings Held in the FY 2013 1. Issues in Radiogenic Circulatory Disease and Cataracts 2. Proceedings of Workshop on Reactor Physics 3. The Results and Future Prospects of Activation Analysis Using KUR" 4. Workshop on Materials Irradiation Effects and Applications 5. Proceedings of the Specialist Research Meeting on Science and Engineering of Unstable Nuclei and Their Uses on Condensed Matter Physics III 6. Proceedings of the Specialist Research Meeting on “Abnormal Protein Aggregation and the Folding Diseases, and their Protection and Repair System” (VI) 7. Proceedings of the Symposium on Present and Future Statuses of Criticality Safety Research 8. Novel Development of BNCT - From Special to General - 9. Proceedings of the Specialists' Meeting on the Chemistry and Technology of Actinide Elements Proceedings of the Specialist Research Meeting on Science and Engineering of Unstable Nuclei and Their 10. Technological Development, Operation, and Data Analysis of Radiation Mapping Systems in Affected Area of Nuclear Accident 11. Proceedings of the Specialist Meeting on Positron Annihilation Study for Science and Engineering 2013 12. Proceedings of the Specialists' Meeting on Radioactive Wastes Management 13. Neutron Imaging Workshops Organized in the FY 2013 1. Promotion of Leading Research toward Effective Utilization of Multidisciplinary Nuclear Science and Technology 2. Workshop of Next Neutron Source for Beam Utilization after KUR II Special Meeting Held in the FY2013 Meeting on the Future Project of the Kyoto University Research Reactor Institute VIII-I-2. COLLABORATION RESEARCH AND VISITING SCIENTISTS Visiting Scientists The number of project researches .................................................. 11 (The number of allotted research subject) ...............................
    [Show full text]
  • Zlatko Tesanovic
    Zlatko Tesanovic Zlatko was born in Sarajevo (former Yugoslavia) on August 1, 1956 and passed away on July 26, 2012. InsItute for Quantum Maer, Johns Hopkins-Princeton Posions 1994-2012: Professor, Johns Hopkins University 1990-1994: Associate Professor, Johns Hopkins University 1987-1990: Assistant Professor, Johns Hopkins University 1987-1988: Director's Postdoctoral Fellow (on leave from JHU), Los Alamos Naonal Laboratory 1985-1987: Postdoctoral Fellow, Harvard University Educaon 1980-1985: Ph.D. in Physics, University of Minnesota 1975-1979: B.Sc. in Physics (Summa cum Laude), University of Sarajevo, former Yugoslavia Fellowships, Awards, Honors Foreign Member, The Royal Norwegian Society of Sciences and LeLers Fellow, The American Physical Society, Division of Condensed Maer Physics Inaugural Speaker, J. R. Schrieffer Lecture Series, Naonal High MagneIc Field Laboratory, 1997 David and Lucille Packard Foundaon Fellowship, 1988-1994 J. R. Oppenheimer Fellowship, Los Alamos Naonal Laboratory, 1985 (declined) Stanwood Johnston Memorial Fellowship, University of Minnesota, 1984 Shevlin Fellowship, University of Minnesota, 1983 Fulbright Fellowship, US InsItute of Internaonal Educaon, 1980 Zlatko Tesanovic Graduate Students (10) L. Xing (Jacob Haimson Professor, Stanford), I. F. Herbut (Professor, Simon Fraser University, Canada), A. Andreev (Associate Professor, University of Washington), S. Dukan (Professor and Chair of Physics, Goucher College), O. Vafek (Associate Professor, Florida State University and NHMFL), A. Melikyan (Editor, Physical Review B), Andres Concha (Postdoctoral Fellow, Harvard), ValenIn Stanev (Postdoctoral Fellow, Argonne NL), Jian Kang (current), James Murray (current) Postdoctoral Advisees (9) A. Singh (Professor, IIT Kanpur, India), S. Theodorakis (Professor, University of Cyprus, Cyprus), J. H. Kim (Professor and Chair of Physics, University of North Dakota), Z.
    [Show full text]
  • Quantum Critical Behavior in the Superfluid Density of High-Temperature Superconducting Thin Films
    QUANTUM CRITICAL BEHAVIOR IN THE SUPERFLUID DENSITY OF HIGH-TEMPERATURE SUPERCONDUCTING THIN FILMS DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Iulian N. Hetel, Maitrise de Physique et Applications, M.S. Physics ***** The Ohio State University 2008 Dissertation Committee: Approved by Professor Thomas R. Lemberger, Adviser Professor Klaus Honscheid Adviser Professor R. Sooryakumar Physics Graduate Program Professor Nandini Trivedi ABSTRACT A central question in the physics of high-temperature superconductors is how su- perconductivity is lost at the extreme ends of the superconducting phase diagram, underdoping and overdoping. When mobile holes are removed from optimally doped cuprates, the transition temperature TC and superfluid density nS(0) decrease in a surprisingly correlated fashion. I succeeded in producing and measuring homoge- neous underdoped high-temperature superconducting films by partially substituting +2 +3 Ca for Y in Y Ba2Cu3O7−δ films with reduced oxygen concentrations in the CuO chains. I test the idea that the physics of underdoped cuprates is dominated by phase fluc- tuations by measuring the temperature dependence of superfluid density nS(T ) and by changing the dimensionality of the system from 3D thick samples to 2D ultrathin films. Thick Y1−xCaxBa2Cu3O7−δ films are in agreement with previous measure- ments of pure Y Ba2Cu3O7−δ samples and do not show any 2D or 3D-XY critical regimes in the temperature dependence of superfluid density. Moreover, the tran- sition temperature has a square-root dependence on absolute superfluid density at zero temperature, rather than showing the predicted linear dependence in the case of strong thermal phase fluctuations.
    [Show full text]
  • Curriculum Vitae
    Curriculum Vitae Predrag Nikolić George Mason University, School of Physics, Astronomy and Computational Sciences Planetary Hall #209, MSN 3F3, Fairfax, VA 22030 USA Phone: 509-460-9066; E-Mail: [email protected]; www: http://physics.gmu.edu/~pnikolic/ Academic Positions George Mason University, Assistant Professor 08/25/2009 ± present Johns Hopkins University, Adjunct Assistant Professor 09/01/2009 ± present National Institute for Standards and Technology, Guest Researcher 09/01/2009 ± 07/01/2011 Rice University, Keck Postdoctoral Fellow 08/01/2007 ± 07/31/2009 Harvard University, Postdoctoral Fellow 09/01/2005 ± 07/31/2007 Yale University, Postdoctoral Associate 09/01/2004 ± 08/31/2005 Columbia University, Visiting Scientist 09/01/2004 ± 08/31/2005 Education Massachusetts Institute of Technology, Ph.D. in Theoretical Physics 2004 thesis: Geometrically Frustrated Quantum Magnets (advisor: T. Senthil) 09/01/2001 ± 09/15/2004 experimental physics research assistantship (advisor: R. Ashoori) 07/15/1998 ± 08/31/2001 University of Belgrade, Serbia, B.S. in Applied Physics 1998 thesis: Quantum Interference Transistors (advisor: K.Nikolić) 09/01/1993 ± 07/01/1998 Research Grants and Awards NSF Award #1205571 (PI): ªCollaborative Research: 2012 ± 2015 Correlated Superfluids and Insulators of Ultracold Fermionic Atomic Gasesº GMU part: $150,000 for 3 years Publication Award, George Mason University, College of Science November 2011 Johns Hopkins University, IQM summer researcher 2010 ± 2014 Rice University, Keck Fellowship 2007 ± 2009 Madlena
    [Show full text]
  • OSKAR VAFEK Curriculum Vitae Department of Physics and National
    OSKAR VAFEK curriculum vitae Department of Physics and National High Magnetic Field Laboratory tel.(NHMFL A319) : (850) 644-0848 Florida State University tel.(KEEN 309) : (850) 508-7377 Tallahassee, Florida 32306 fax. : (850) 644-5038 USA e-mail: [email protected] Education and Degrees Sep 2003 - Sep 2006 Stanford University, Stanford, CA Postdoctoral Scholar Stanford Institute for Theoretical Physics June 1998 - Aug 2003 Ph.D. Johns Hopkins University (physics) Thesis advisor: Prof. Zlatko Tesanovic Aug 1994 -May 1998 B.A. Goucher College (major: chemistry, minors: physics, mathematics) Positions held: 2012 - present Associate Professor (with tenure) National High Magnetic Field Laboratory Department of Physics, Florida State University 2006 - 2012 Assistant Professor National High Magnetic Field Laboratory Department of Physics, Florida State University 2003 - 2006 Postdoctoral Scholar Stanford University Institute for Theoretical Physics 1998 - 2003 Research Assistant Department of Physics and Astronomy, Johns Hopkins University Research interests Theoretical condensed matter physics and statistical field theory, with an emphasis on the problems in superconductivity and strongly correlated systems Awards and honors 2012 Florida State University PAI Award for excellence in teaching and research 2010 NSF Career Award 2003 Stanford ITP Fellowship (Stanford University) 1998 Ellen E. Swomley Fellowship (Johns Hopkins University) 1998 Stimson-Duvall Scholarship (Goucher College) Luise Kelly Prize in Chemistry (Goucher College) Phi Beta Kappa Membership 1997 NSF Research Opportunity Award for summer research at Johns Hopkins U. 1997 Presidential Scholarship for the senior project (Goucher College) 1994 Merit Foreign Student Scholarship full 4-year scholarship to attend Goucher College Journal publications and preprints: 1. R.M. Fernandes and O.
    [Show full text]