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Schusser J, Bentmann H, Ünzelmann M, Figgemeier T, Min CH, Moser S, Neu JN, Siegrist T, Reinert F. Assessing Nontrivial Topology in Weyl Semimetals by Dichroic Photoemission. Phys Rev Lett 2022; 129:246404. [PMID: 36563241 DOI: 10.1103/physrevlett.129.246404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/26/2022] [Accepted: 11/21/2022] [Indexed: 06/17/2023]
Abstract
The electronic structure of Weyl semimetals features Berry flux monopoles in the bulk and Fermi arcs at the surface. While angle-resolved photoelectron spectroscopy (ARPES) is successfully used to map the bulk and surface bands, it remains a challenge to explicitly resolve and pinpoint these topological features. Here we combine state-of-the-art photoemission theory and experiments over a wide range of excitation energies for the Weyl semimetals TaAs and TaP. Our results show that simple surface-band-counting schemes, proposed previously to identify nonzero Chern numbers, are ambiguous due to pronounced momentum-dependent spectral weight variations and the pronounced surface-bulk hybridization. Instead, our findings indicate that dichroic ARPES provides an improved approach to identify Fermi arcs but requires an accurate description of the photoelectron final state.
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Affiliation(s)
- J Schusser
- Experimentelle Physik VII and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, D-97074 Würzburg, Germany
| | - H Bentmann
- Experimentelle Physik VII and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, D-97074 Würzburg, Germany
| | - M Ünzelmann
- Experimentelle Physik VII and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, D-97074 Würzburg, Germany
| | - T Figgemeier
- Experimentelle Physik VII and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, D-97074 Würzburg, Germany
| | - C-H Min
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
- Ruprecht Haensel Laboratory, Kiel University and DESY, Kiel, Germany
| | - S Moser
- Experimentelle Physik IV and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, D-97074 Würzburg, Germany
| | - J N Neu
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA
- Nuclear Nonproliferation Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - T Siegrist
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, Florida 32310, USA
| | - F Reinert
- Experimentelle Physik VII and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, D-97074 Würzburg, Germany
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2
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Ünzelmann M, Bentmann H, Figgemeier T, Eck P, Neu JN, Geldiyev B, Diekmann F, Rohlf S, Buck J, Hoesch M, Kalläne M, Rossnagel K, Thomale R, Siegrist T, Sangiovanni G, Sante DD, Reinert F. Momentum-space signatures of Berry flux monopoles in the Weyl semimetal TaAs. Nat Commun 2021; 12:3650. [PMID: 34131129 PMCID: PMC8206138 DOI: 10.1038/s41467-021-23727-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 05/12/2021] [Indexed: 11/16/2022] Open
Abstract
Since the early days of Dirac flux quantization, magnetic monopoles have been sought after as a potential corollary of quantized electric charge. As opposed to magnetic monopoles embedded into the theory of electromagnetism, Weyl semimetals (WSM) exhibit Berry flux monopoles in reciprocal parameter space. As a function of crystal momentum, such monopoles locate at the crossing point of spin-polarized bands forming the Weyl cone. Here, we report momentum-resolved spectroscopic signatures of Berry flux monopoles in TaAs as a paradigmatic WSM. We carried out angle-resolved photoelectron spectroscopy at bulk-sensitive soft X-ray energies (SX-ARPES) combined with photoelectron spin detection and circular dichroism. The experiments reveal large spin- and orbital-angular-momentum (SAM and OAM) polarizations of the Weyl-fermion states, resulting from the broken crystalline inversion symmetry in TaAs. Supported by first-principles calculations, our measurements image signatures of a topologically non-trivial winding of the OAM at the Weyl nodes and unveil a chirality-dependent SAM of the Weyl bands. Our results provide directly bulk-sensitive spectroscopic support for the non-trivial band topology in the WSM TaAs, promising to have profound implications for the study of quantum-geometric effects in solids. Weyl semimetals exhibit Berry flux monopoles in momentum-space, but direct experimental evidence has remained elusive. Here, the authors reveal topologically non-trivial winding of the orbital-angular-momentum at the Weyl nodes and a chirality-dependent spin-angular-momentum of the Weyl bands, as a direct signature of the Berry flux monopoles in TaAs.
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Affiliation(s)
- M Ünzelmann
- Experimentelle Physik VII and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, Würzburg, Germany
| | - H Bentmann
- Experimentelle Physik VII and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, Würzburg, Germany.
| | - T Figgemeier
- Experimentelle Physik VII and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, Würzburg, Germany
| | - P Eck
- Theoretische Physik I, Universität Würzburg, Würzburg, Germany
| | - J N Neu
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, FL, USA.,National High Magnetic Field Laboratory, Tallahassee, FL, USA
| | - B Geldiyev
- Experimentelle Physik VII and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, Würzburg, Germany
| | - F Diekmann
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Kiel, Germany.,Ruprecht Haensel Laboratory, Kiel University and DESY, Kiel, Germany
| | - S Rohlf
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Kiel, Germany.,Ruprecht Haensel Laboratory, Kiel University and DESY, Kiel, Germany
| | - J Buck
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Kiel, Germany.,Ruprecht Haensel Laboratory, Kiel University and DESY, Kiel, Germany
| | - M Hoesch
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - M Kalläne
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Kiel, Germany.,Ruprecht Haensel Laboratory, Kiel University and DESY, Kiel, Germany
| | - K Rossnagel
- Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Kiel, Germany.,Ruprecht Haensel Laboratory, Kiel University and DESY, Kiel, Germany.,Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - R Thomale
- Theoretische Physik I, Universität Würzburg, Würzburg, Germany
| | - T Siegrist
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, FL, USA.,National High Magnetic Field Laboratory, Tallahassee, FL, USA
| | - G Sangiovanni
- Theoretische Physik I, Universität Würzburg, Würzburg, Germany
| | - D Di Sante
- Theoretische Physik I, Universität Würzburg, Würzburg, Germany.,Department of Physics and Astronomy, University of Bologna, Bologna, Italy.,Center for Computational Quantum Physics, Flatiron Institute, New York, NY, USA
| | - F Reinert
- Experimentelle Physik VII and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, Würzburg, Germany
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3
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Vidal RC, Bentmann H, Facio JI, Heider T, Kagerer P, Fornari CI, Peixoto TRF, Figgemeier T, Jung S, Cacho C, Büchner B, van den Brink J, Schneider CM, Plucinski L, Schwier EF, Shimada K, Richter M, Isaeva A, Reinert F. Orbital Complexity in Intrinsic Magnetic Topological Insulators MnBi_{4}Te_{7} and MnBi_{6}Te_{10}. Phys Rev Lett 2021; 126:176403. [PMID: 33988442 DOI: 10.1103/physrevlett.126.176403] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 01/09/2021] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
Using angle-resolved photoelectron spectroscopy (ARPES), we investigate the surface electronic structure of the magnetic van der Waals compounds MnBi_{4}Te_{7} and MnBi_{6}Te_{10}, the n=1 and 2 members of a modular (Bi_{2}Te_{3})_{n}(MnBi_{2}Te_{4}) series, which have attracted recent interest as intrinsic magnetic topological insulators. Combining circular dichroic, spin-resolved and photon-energy-dependent ARPES measurements with calculations based on density functional theory, we unveil complex momentum-dependent orbital and spin textures in the surface electronic structure and disentangle topological from trivial surface bands. We find that the Dirac-cone dispersion of the topologial surface state is strongly perturbed by hybridization with valence-band states for Bi_{2}Te_{3}-terminated surfaces but remains preserved for MnBi_{2}Te_{4}-terminated surfaces. Our results firmly establish the topologically nontrivial nature of these magnetic van der Waals materials and indicate that the possibility of realizing a quantized anomalous Hall conductivity depends on surface termination.
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Affiliation(s)
- R C Vidal
- Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany, EU
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
| | - H Bentmann
- Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany, EU
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
| | - J I Facio
- Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstr. 20, D-01069 Dresden, Germany, EU
| | - T Heider
- Peter Grünberg Institut, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany, EU
| | - P Kagerer
- Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany, EU
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
| | - C I Fornari
- Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany, EU
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
| | - T R F Peixoto
- Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany, EU
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
| | - T Figgemeier
- Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany, EU
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
| | - S Jung
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
- Department of Physics, Gyeongsang National University, Jinju 52828, Korea
| | - C Cacho
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - B Büchner
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
- Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstr. 20, D-01069 Dresden, Germany, EU
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany, EU
| | - J van den Brink
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
- Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstr. 20, D-01069 Dresden, Germany, EU
- Institut für Festkörper- und Materialphysik, Technische Universität Dresden, D-01062 Dresden, Germany, EU
| | - C M Schneider
- Peter Grünberg Institut, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany, EU
| | - L Plucinski
- Peter Grünberg Institut, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany, EU
| | - E F Schwier
- Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany, EU
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
- Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-0046, Japan
| | - K Shimada
- Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-0046, Japan
| | - M Richter
- Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstr. 20, D-01069 Dresden, Germany, EU
- Dresden Center for Computational Materials Science (DCMS), Technische Universität Dresden, D-01062 Dresden, Germany, EU
| | - A Isaeva
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
- Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstr. 20, D-01069 Dresden, Germany, EU
- Department of Physics, Gyeongsang National University, Jinju 52828, Korea
- Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, 1098 XH Amsterdam, The Netherlands, EU
| | - F Reinert
- Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany, EU
- Würzburg-Dresden Cluster of Excellence ct.qmat, Germany, EU
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4
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Miao L, Min CH, Xu Y, Huang Z, Kotta EC, Basak R, Song MS, Kang BY, Cho BK, Kißner K, Reinert F, Yilmaz T, Vescovo E, Chuang YD, Wu W, Denlinger JD, Wray LA. Robust Surface States and Coherence Phenomena in Magnetically Alloyed SmB_{6}. Phys Rev Lett 2021; 126:136401. [PMID: 33861118 DOI: 10.1103/physrevlett.126.136401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 01/19/2021] [Accepted: 03/05/2021] [Indexed: 06/12/2023]
Abstract
Samarium hexaboride is a candidate for the topological Kondo insulator state, in which Kondo coherence is predicted to give rise to an insulating gap spanned by topological surface states. Here we investigate the surface and bulk electronic properties of magnetically alloyed Sm_{1-x}M_{x}B_{6} (M=Ce, Eu), using angle-resolved photoemission spectroscopy and complementary characterization techniques. Remarkably, topologically nontrivial bulk and surface band structures are found to persist in highly modified samples with up to 30% Sm substitution and with an antiferromagnetic ground state in the case of Eu doping. The results are interpreted in terms of a hierarchy of energy scales, in which surface state emergence is linked to the formation of a direct Kondo gap, while low-temperature transport trends depend on the indirect gap.
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Affiliation(s)
- Lin Miao
- School of Physics, Southeast University, Nanjing 211189, China
| | - Chul-Hee Min
- Experimentelle Physik VII and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Yishuai Xu
- Department of Physics, New York University, New York, New York 10003, USA
| | - Zengle Huang
- Rutgers Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Erica C Kotta
- Department of Physics, New York University, New York, New York 10003, USA
| | - Rourav Basak
- Department of Physics, New York University, New York, New York 10003, USA
| | - M S Song
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea
| | - B Y Kang
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea
| | - B K Cho
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea
| | - K Kißner
- Experimentelle Physik VII and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - F Reinert
- Experimentelle Physik VII and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Turgut Yilmaz
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Elio Vescovo
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Yi-De Chuang
- Rutgers Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Weida Wu
- Rutgers Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Jonathan D Denlinger
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - L Andrew Wray
- Department of Physics, New York University, New York, New York 10003, USA
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5
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Weinhardt L, Benkert A, Meyer F, Blum M, Hauschild D, Wilks RG, Bär M, Yang W, Zharnikov M, Reinert F, Heske C. Local electronic structure of the peptide bond probed by resonant inelastic soft X-ray scattering. Phys Chem Chem Phys 2019; 21:13207-13214. [PMID: 31179459 DOI: 10.1039/c9cp02481f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Soft X-ray emission spectroscopy and RIXS are used to determine the local electronic structure of the peptide bond.
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6
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Meyer F, Blum M, Benkert A, Hauschild D, Jeyachandran YL, Wilks RG, Yang W, Bär M, Reinert F, Heske C, Zharnikov M, Weinhardt L. Site-specific electronic structure of imidazole and imidazolium in aqueous solutions. Phys Chem Chem Phys 2018. [DOI: 10.1039/c7cp07885d] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electronic structures of aqueous imidazole and imidazolium solutions are studied in an atom- and site-specific fashion using soft X-ray spectroscopy.
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7
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Min CH, Goth F, Lutz P, Bentmann H, Kang BY, Cho BK, Werner J, Chen KS, Assaad F, Reinert F. Matching DMFT calculations with photoemission spectra of heavy fermion insulators: universal properties of the near-gap spectra of SmB 6. Sci Rep 2017; 7:11980. [PMID: 28931836 PMCID: PMC5607333 DOI: 10.1038/s41598-017-12080-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 09/04/2017] [Indexed: 11/11/2022] Open
Abstract
Paramagnetic heavy fermion insulators consist of fully occupied quasiparticle bands inherent to Fermi liquid theory. The gap emergence below a characteristic temperature is the ultimate sign of coherence for a many-body system, which in addition can induce a non-trivial band topology. Here, we demonstrate a simple and efficient method to compare a model study and an experimental result for heavy fermion insulators. The temperature dependence of the gap formation in both local moment and mixed valence regimes is captured within the dynamical mean field (DMFT) approximation to the periodic Anderson model (PAM). Using the topological coherence temperature as the scaling factor and choosing the input parameter set within the mixed valence regime, we can unambiguously link the theoretical energy scales to the experimental ones. As a particularly important result, we find improved consistency between the scaled DMFT density of states and the photoemission near-gap spectra of samarium hexaboride (SmB6).
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Affiliation(s)
- Chul-Hee Min
- Experimentelle Physik VII and Röntgen Research Center for Complex Materials (RCCM), Universität Würzburg, 97074, Würzburg, Germany.
| | - F Goth
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, 97074, Würzburg, Germany
| | - P Lutz
- Experimentelle Physik VII and Röntgen Research Center for Complex Materials (RCCM), Universität Würzburg, 97074, Würzburg, Germany
| | - H Bentmann
- Experimentelle Physik VII and Röntgen Research Center for Complex Materials (RCCM), Universität Würzburg, 97074, Würzburg, Germany
| | - B Y Kang
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Korea
| | - B K Cho
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju, 61005, Korea
| | - J Werner
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, 97074, Würzburg, Germany
| | - K-S Chen
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, 97074, Würzburg, Germany
| | - F Assaad
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, 97074, Würzburg, Germany
| | - F Reinert
- Experimentelle Physik VII and Röntgen Research Center for Complex Materials (RCCM), Universität Würzburg, 97074, Würzburg, Germany
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8
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Bentmann H, Maaß H, Krasovskii EE, Peixoto TRF, Seibel C, Leandersson M, Balasubramanian T, Reinert F. Strong Linear Dichroism in Spin-Polarized Photoemission from Spin-Orbit-Coupled Surface States. Phys Rev Lett 2017; 119:106401. [PMID: 28949177 DOI: 10.1103/physrevlett.119.106401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Indexed: 06/07/2023]
Abstract
A comprehensive understanding of spin-polarized photoemission is crucial for accessing the electronic structure of spin-orbit coupled materials. Yet, the impact of the final state in the photoemission process on the photoelectron spin has been difficult to assess in these systems. We present experiments for the spin-orbit split states in a Bi-Ag surface alloy showing that the alteration of the final state with energy may cause a complete reversal of the photoelectron spin polarization. We explain the effect on the basis of ab initio one-step photoemission theory and describe how it originates from linear dichroism in the angular distribution of photoelectrons. Our analysis shows that the modulated photoelectron spin polarization reflects the intrinsic spin density of the surface state being sampled differently depending on the final state, and it indicates linear dichroism as a natural probe of spin-orbit coupling at surfaces.
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Affiliation(s)
- H Bentmann
- Experimentelle Physik VII and Röntgen Research Center for Complex Materials (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - H Maaß
- Experimentelle Physik VII and Röntgen Research Center for Complex Materials (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - E E Krasovskii
- Departamento de Física de Materiales, Facultad de Ciencias Quíimicas, Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, Apdo. 1072, San Sebastián/Donostia, 20080 Basque Country, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, San Sebastián/Donostia, 20018 Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
| | - T R F Peixoto
- Experimentelle Physik VII and Röntgen Research Center for Complex Materials (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - C Seibel
- Experimentelle Physik VII and Röntgen Research Center for Complex Materials (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - M Leandersson
- MAX IV Laboratory, Lund University, P.O. Box 118, 221 00 Lund, Sweden
| | - T Balasubramanian
- MAX IV Laboratory, Lund University, P.O. Box 118, 221 00 Lund, Sweden
| | - F Reinert
- Experimentelle Physik VII and Röntgen Research Center for Complex Materials (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
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9
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Meyer F, Blum M, Benkert A, Hauschild D, Jeyachandran YL, Wilks RG, Yang W, Bär M, Heske C, Reinert F, Zharnikov M, Weinhardt L. X-ray Emission Spectroscopy of Proteinogenic Amino Acids at All Relevant Absorption Edges. J Phys Chem B 2017; 121:6549-6556. [DOI: 10.1021/acs.jpcb.7b04291] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- F. Meyer
- Experimentelle
Physik VII, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - M. Blum
- Department
of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV), 4505 Maryland Parkway, Las Vegas, Nevada 89154-4003, United States
| | - A. Benkert
- Experimentelle
Physik VII, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- Institute
for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), Hermann-v.-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - D. Hauschild
- Institute
for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), Hermann-v.-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- Institute
for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT), Engesserstr. 18/20, 76128 Karlsruhe, Germany
| | - Y. L. Jeyachandran
- Applied
Physical Chemistry, Heidelberg University, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - R. G. Wilks
- Renewable
Energy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - W. Yang
- Advanced
Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron
Road, Berkeley, California 94720, United States
| | - M. Bär
- Renewable
Energy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
- Institut
für Physik, Brandenburgische Technische Universität Cottbus-Senftenberg, Platz der Deutschen Einheit 1, 03046 Cottbus, Germany
| | - C. Heske
- Department
of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV), 4505 Maryland Parkway, Las Vegas, Nevada 89154-4003, United States
- Institute
for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), Hermann-v.-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- Institute
for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT), Engesserstr. 18/20, 76128 Karlsruhe, Germany
| | - F. Reinert
- Experimentelle
Physik VII, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - M. Zharnikov
- Applied
Physical Chemistry, Heidelberg University, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - L. Weinhardt
- Department
of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV), 4505 Maryland Parkway, Las Vegas, Nevada 89154-4003, United States
- Institute
for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), Hermann-v.-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
- Institute
for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT), Engesserstr. 18/20, 76128 Karlsruhe, Germany
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10
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Medjanik K, Fedchenko O, Chernov S, Kutnyakhov D, Ellguth M, Oelsner A, Schönhense B, Peixoto TRF, Lutz P, Min CH, Reinert F, Däster S, Acremann Y, Viefhaus J, Wurth W, Elmers HJ, Schönhense G. Direct 3D mapping of the Fermi surface and Fermi velocity. Nat Mater 2017; 16:615-621. [PMID: 28272500 DOI: 10.1038/nmat4875] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 02/03/2017] [Indexed: 05/13/2023]
Abstract
We performed a full mapping of the bulk electronic structure including the Fermi surface and Fermi-velocity distribution vF(kF) of tungsten. The 4D spectral function ρ(EB; k) in the entire bulk Brillouin zone and 6 eV binding-energy (EB) interval was acquired in ∼3 h thanks to a new multidimensional photoemission data-recording technique (combining full-field k-microscopy with time-of-flight parallel energy recording) and the high brilliance of the soft X-rays used. A direct comparison of bulk and surface spectral functions (taken at low photon energies) reveals a time-reversal-invariant surface state in a local bandgap in the (110)-projected bulk band structure. The surface state connects hole and electron pockets that would otherwise be separated by an indirect local bandgap. We confirmed its Dirac-like spin texture by spin-filtered momentum imaging. The measured 4D data array enables extraction of the 3D dispersion of all bands, all energy isosurfaces, electron velocities, hole or electron conductivity, effective mass and inner potential by simple algorithms without approximations. The high-Z bcc metals with large spin-orbit-induced bandgaps are discussed as candidates for topologically non-trivial surface states.
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Affiliation(s)
- K Medjanik
- Institut für Physik, Johannes Gutenberg-Universität, StaudingerWeg 7, 55128 Mainz, Germany
| | - O Fedchenko
- Institut für Physik, Johannes Gutenberg-Universität, StaudingerWeg 7, 55128 Mainz, Germany
| | - S Chernov
- Institut für Physik, Johannes Gutenberg-Universität, StaudingerWeg 7, 55128 Mainz, Germany
| | - D Kutnyakhov
- Institut für Physik, Johannes Gutenberg-Universität, StaudingerWeg 7, 55128 Mainz, Germany
- DESY Photon Science, Notkestraße 85, 22607 Hamburg, Germany
| | - M Ellguth
- Institut für Physik, Johannes Gutenberg-Universität, StaudingerWeg 7, 55128 Mainz, Germany
| | - A Oelsner
- Surface Concept GmbH, Am Sägewerk 23a, 55124 Mainz, Germany
| | - B Schönhense
- Department of Bioengineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - T R F Peixoto
- Universität Würzburg, Experimentelle Physik VII, 97074 Würzburg, Germany
| | - P Lutz
- Universität Würzburg, Experimentelle Physik VII, 97074 Würzburg, Germany
| | - C-H Min
- Universität Würzburg, Experimentelle Physik VII, 97074 Würzburg, Germany
| | - F Reinert
- Universität Würzburg, Experimentelle Physik VII, 97074 Würzburg, Germany
| | - S Däster
- Laboratorium für Festkörperphysik, ETH Zürich, Otto-Stern-Weg 1, 8093 Zürich, Switzerland
| | - Y Acremann
- Laboratorium für Festkörperphysik, ETH Zürich, Otto-Stern-Weg 1, 8093 Zürich, Switzerland
| | - J Viefhaus
- DESY Photon Science, Notkestraße 85, 22607 Hamburg, Germany
| | - W Wurth
- DESY Photon Science, Notkestraße 85, 22607 Hamburg, Germany
- Physics Department and Center for Free-Electron Laser Science, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - H J Elmers
- Institut für Physik, Johannes Gutenberg-Universität, StaudingerWeg 7, 55128 Mainz, Germany
| | - G Schönhense
- Institut für Physik, Johannes Gutenberg-Universität, StaudingerWeg 7, 55128 Mainz, Germany
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11
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Dauth M, Graus M, Schelter I, Wießner M, Schöll A, Reinert F, Kümmel S. Perpendicular Emission, Dichroism, and Energy Dependence in Angle-Resolved Photoemission: The Importance of The Final State. Phys Rev Lett 2016; 117:183001. [PMID: 27834988 DOI: 10.1103/physrevlett.117.183001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Indexed: 06/06/2023]
Abstract
Angle-resolved photoemission spectroscopy has been developed to a very high accuracy. However, effects that depend sensitively on the state of the emitted photoelectron were so far hard to compute for real molecules. We here show that the real-time propagation approach to time-dependent density functional theory allows us to obtain final-state effects consistently from first principles and with an accuracy that allows for the interpretation of experimental data. In a combined theoretical and experimental study we demonstrate that the approach captures three hallmark effects that are beyond the final-state plane-wave approximation: emission perpendicular to the light polarization, circular dichroism in the photoelectron angular distribution, and a pronounced energy dependence of the photoemission intensity.
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Affiliation(s)
- M Dauth
- Theoretical Physics IV, University of Bayreuth, D-95440 Bayreuth, Germany
| | - M Graus
- Experimental Physics VII, University of Würzburg, D-97074 Würzburg, Germany
| | - I Schelter
- Theoretical Physics IV, University of Bayreuth, D-95440 Bayreuth, Germany
| | - M Wießner
- Experimental Physics VII, University of Würzburg, D-97074 Würzburg, Germany
| | - A Schöll
- Experimental Physics VII, University of Würzburg, D-97074 Würzburg, Germany
| | - F Reinert
- Experimental Physics VII, University of Würzburg, D-97074 Würzburg, Germany
| | - S Kümmel
- Theoretical Physics IV, University of Bayreuth, D-95440 Bayreuth, Germany
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12
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Abd El-Fattah ZM, Lutz P, Piquero-Zulaica I, Lobo-Checa J, Schiller F, Bentmann H, Ortega JE, Reinert F. Formation of the
BiAg2
surface alloy on lattice-mismatched interfaces. Phys Rev B 2016; 94:155447. [DOI: 10.1103/physrevb.94.155447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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13
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Jeyachandran YL, Meyer F, Benkert A, Bär M, Blum M, Yang W, Reinert F, Heske C, Weinhardt L, Zharnikov M. Investigation of the Ionic Hydration in Aqueous Salt Solutions by Soft X-ray Emission Spectroscopy. J Phys Chem B 2016; 120:7687-95. [PMID: 27442708 DOI: 10.1021/acs.jpcb.6b03952] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Understanding the molecular structure of the hydration shells and their impact on the hydrogen bond (HB) network of water in aqueous salt solutions is a fundamentally important and technically relevant question. In the present work, such hydration effects were studied for a series of representative salt solutions (NaCl, KCl, CaCl2, MgCl2, and KBr) by soft X-ray emission spectroscopy (XES) and resonant inelastic soft X-ray scattering (RIXS). The oxygen K-edge XES spectra could be described with three components, attributed to initial state HB configurations in pure water, water molecules that have undergone an ultrafast dissociation initiated by the X-ray excitation, and water molecules in contact with salt ions. The behavior of the individual components, as well as the spectral shape of the latter component, has been analyzed in detail. In view of the role of ions in such effects as protein denaturation (i.e., the Hofmeister series), we discuss the ion-specific nature of the hydration shells and find that the results point to a predominant role of anions as compared to cations. Furthermore, we observe a concentration-dependent suppression of ultrafast dissociation in all salt solutions, associated with a significant distortion of intact HB configurations of water molecules facilitating such a dissociation.
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Affiliation(s)
- Y L Jeyachandran
- Angewandte Physikalische Chemie, Universität Heidelberg , Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - F Meyer
- Experimentelle Physik VII, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - A Benkert
- Experimentelle Physik VII, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.,Institute for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT) , Hermann-v.-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - M Bär
- Renewable Energy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Hahn-Meitner-Platz 1, 14109 Berlin, Germany.,Institute für Physik und Chemie, Brandenburgische Technische Universität Cottbus-Senftenberg , Platz der Deutschen Einheit 1, 03046 Cottbus, Germany.,Department of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV) , 4505 Maryland Parkway, Las Vegas, Nevada 89154-4003, United States
| | - M Blum
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV) , 4505 Maryland Parkway, Las Vegas, Nevada 89154-4003, United States
| | - W Yang
- Advanced Light Source (ALS), Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, California 94720, United States
| | - F Reinert
- Experimentelle Physik VII, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - C Heske
- Institute for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT) , Hermann-v.-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.,Department of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV) , 4505 Maryland Parkway, Las Vegas, Nevada 89154-4003, United States.,Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT) , Engesserstrasse 18/20, 76028 Karlsruhe, Germany
| | - L Weinhardt
- Institute for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT) , Hermann-v.-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.,Department of Chemistry and Biochemistry, University of Nevada, Las Vegas (UNLV) , 4505 Maryland Parkway, Las Vegas, Nevada 89154-4003, United States.,Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT) , Engesserstrasse 18/20, 76028 Karlsruhe, Germany
| | - M Zharnikov
- Angewandte Physikalische Chemie, Universität Heidelberg , Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
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14
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Graus M, Grimm M, Metzger C, Dauth M, Tusche C, Kirschner J, Kümmel S, Schöll A, Reinert F. Electron-Vibration Coupling in Molecular Materials: Assignment of Vibronic Modes from Photoelectron Momentum Mapping. Phys Rev Lett 2016; 116:147601. [PMID: 27104726 DOI: 10.1103/physrevlett.116.147601] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Indexed: 05/09/2023]
Abstract
Electron-phonon coupling is one of the most fundamental effects in condensed matter physics. We here demonstrate that photoelectron momentum mapping can reveal and visualize the coupling between specific vibrational modes and electronic excitations. When imaging molecular orbitals with high energy resolution, the intensity patterns of photoelectrons of the vibronic sidebands of molecular states show characteristic changes due to the distortion of the molecular frame in the vibronically excited state. By comparison to simulations, an assignment of specific vibronic modes is possible, thus providing unique information on the coupling between electronic and vibronic excitation.
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Affiliation(s)
- M Graus
- University of Würzburg, Experimental Physics VII, 97074 Würzburg, Germany
| | - M Grimm
- University of Würzburg, Experimental Physics VII, 97074 Würzburg, Germany
| | - C Metzger
- University of Würzburg, Experimental Physics VII, 97074 Würzburg, Germany
| | - M Dauth
- University of Bayreuth, Theoretical Physics IV, 95440 Bayreuth, Germany
| | - C Tusche
- Max Planck Institute of Microstructure Physics, 06120 Halle, Germany
- Peter Grünberg Institut (PGI-6), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - J Kirschner
- Max Planck Institute of Microstructure Physics, 06120 Halle, Germany
| | - S Kümmel
- University of Bayreuth, Theoretical Physics IV, 95440 Bayreuth, Germany
| | - A Schöll
- University of Würzburg, Experimental Physics VII, 97074 Würzburg, Germany
| | - F Reinert
- University of Würzburg, Experimental Physics VII, 97074 Würzburg, Germany
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15
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Benkert A, Meyer F, Hauschild D, Blum M, Yang W, Wilks RG, Bär M, Reinert F, Heske C, Weinhardt L. Isotope Effects in the Resonant Inelastic Soft X-ray Scattering Maps of Gas-Phase Methanol. J Phys Chem A 2016; 120:2260-7. [DOI: 10.1021/acs.jpca.6b02636] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A. Benkert
- Experimentelle
Physik VII, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - F. Meyer
- Experimentelle
Physik VII, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - D. Hauschild
- Experimentelle
Physik VII, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - M. Blum
- Department
of Chemistry and Biochemistry, University of Nevada, Las Vegas, 4505 Maryland Parkway, NV 89154-4003, United States
| | - W. Yang
- Advanced
Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron
Road, Berkeley, California 94720, United States
| | - R. G. Wilks
- Renewable
Energy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - M. Bär
- Department
of Chemistry and Biochemistry, University of Nevada, Las Vegas, 4505 Maryland Parkway, NV 89154-4003, United States
- Renewable
Energy, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
- Institut
für Physik und Chemie, Brandenburgische Technische Universität Cottbus-Senftenberg, Platz der Deutschen Einheit 1, 03046 Cottbus, Germany
| | - F. Reinert
- Experimentelle
Physik VII, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - C. Heske
- Department
of Chemistry and Biochemistry, University of Nevada, Las Vegas, 4505 Maryland Parkway, NV 89154-4003, United States
- Institute
for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology, Engesserstr. 18/20, 76128 Karlsruhe, Germany
| | - L. Weinhardt
- Department
of Chemistry and Biochemistry, University of Nevada, Las Vegas, 4505 Maryland Parkway, NV 89154-4003, United States
- Institute
for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology, Engesserstr. 18/20, 76128 Karlsruhe, Germany
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16
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Kang CJ, Denlinger JD, Allen JW, Min CH, Reinert F, Kang BY, Cho BK, Kang JS, Shim JH, Min BI. Electronic Structure of YbB_{6}: Is it a Topological Insulator or Not? Phys Rev Lett 2016; 116:116401. [PMID: 27035312 DOI: 10.1103/physrevlett.116.116401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Indexed: 06/05/2023]
Abstract
To finally resolve the controversial issue of whether or not the electronic structure of YbB_{6} is nontrivially topological, we have made a combined study using angle-resolved photoemission spectroscopy (ARPES) of the nonpolar (110) surface and density functional theory (DFT). The flat-band conditions of the (110) ARPES avoid the strong band bending effects of the polar (001) surface and definitively show that YbB_{6} has a topologically trivial B 2p-Yb 5d semiconductor band gap of ∼0.3 eV. Accurate determination of the low energy band topology in DFT requires the use of a modified Becke-Johnson exchange potential incorporating spin-orbit coupling and an on-site Yb 4f Coulomb interaction U as large as 7 eV. The DFT result, confirmed by a more precise GW band calculation, is similar to that of a small gap non-Kondo nontopological semiconductor. Additionally, the pressure-dependent electronic structure of YbB_{6} is investigated theoretically and found to transform into a p-d overlap semimetal with small Yb mixed valency.
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Affiliation(s)
- Chang-Jong Kang
- Department of Physics, PCTP, Pohang University of Science and Technology, (POSTECH) Pohang 37673, Korea
| | - J D Denlinger
- Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, California 94720, USA
| | - J W Allen
- Department of Physics, Randall Laboratory, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Chul-Hee Min
- Universität Würzburg, Experimentelle Physik VII, 97074 Würzburg, Germany
| | - F Reinert
- Universität Würzburg, Experimentelle Physik VII, 97074 Würzburg, Germany
| | - B Y Kang
- School of Materials Science and Engineering, GIST, Gwangju 61005, Korea
| | - B K Cho
- School of Materials Science and Engineering, GIST, Gwangju 61005, Korea
| | - J-S Kang
- Department of Physics, The Catholic University of Korea, Bucheon 14662, Korea
| | - J H Shim
- Department of Physics, PCTP, Pohang University of Science and Technology, (POSTECH) Pohang 37673, Korea
- Department of Chemistry and Division of Advanced Nuclear Engineering, POSTECH, Pohang 37673, Korea
| | - B I Min
- Department of Physics, PCTP, Pohang University of Science and Technology, (POSTECH) Pohang 37673, Korea
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17
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Meyer F, Blum M, Benkert A, Hauschild D, Nagarajan S, Wilks RG, Andersson J, Yang W, Zharnikov M, Bär M, Heske C, Reinert F, Weinhardt L. “Building Block Picture” of the Electronic Structure of Aqueous Cysteine Derived from Resonant Inelastic Soft X-ray Scattering. J Phys Chem B 2014; 118:13142-50. [DOI: 10.1021/jp5089417] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- F. Meyer
- Experimentelle
Physik VII, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - M. Blum
- Department
of Chemistry, University of Nevada, Las Vegas, 4505 Maryland
Parkway, Las Vegas, Nevada 89154-4003, United States
| | - A. Benkert
- Experimentelle
Physik VII, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - D. Hauschild
- Experimentelle
Physik VII, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - S. Nagarajan
- Angewandte
Physikalische Chemie, Universität Heidelberg, INF 253,69120 Heidelberg, Germany
| | - R. G. Wilks
- Solar
Energy Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - J. Andersson
- Department
of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden
| | - W. Yang
- Advanced
Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron
Road, Berkeley, California 94720, United States
| | - M. Zharnikov
- Angewandte
Physikalische Chemie, Universität Heidelberg, INF 253,69120 Heidelberg, Germany
| | - M. Bär
- Department
of Chemistry, University of Nevada, Las Vegas, 4505 Maryland
Parkway, Las Vegas, Nevada 89154-4003, United States
- Solar
Energy Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
- Institut
für Physik und Chemie, Brandenburgische Technische Universität Cottbus-Senftenberg, Platz der Deutschen Einheit 1, 03046 Cottbus, Germany
| | - C. Heske
- Department
of Chemistry, University of Nevada, Las Vegas, 4505 Maryland
Parkway, Las Vegas, Nevada 89154-4003, United States
- Institute
for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology, Engesserstrasse 18/20, 76128 Karlsruhe, Germany
| | - F. Reinert
- Experimentelle
Physik VII, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - L. Weinhardt
- Department
of Chemistry, University of Nevada, Las Vegas, 4505 Maryland
Parkway, Las Vegas, Nevada 89154-4003, United States
- Institute
for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology, Engesserstrasse 18/20, 76128 Karlsruhe, Germany
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18
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Wießner M, Hauschild D, Sauer C, Feyer V, Schöll A, Reinert F. Complete determination of molecular orbitals by measurement of phase symmetry and electron density. Nat Commun 2014; 5:4156. [DOI: 10.1038/ncomms5156] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 05/19/2014] [Indexed: 11/09/2022] Open
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19
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Min CH, Lutz P, Fiedler S, Kang BY, Cho BK, Kim HD, Bentmann H, Reinert F. Importance of charge fluctuations for the topological phase in SmB(6). Phys Rev Lett 2014; 112:226402. [PMID: 24949780 DOI: 10.1103/physrevlett.112.226402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Indexed: 06/03/2023]
Abstract
Typical Kondo insulators (KIs) can have a nontrivial Z_{2} topology because the energy gap opens at the Fermi energy (E_{F}) by a hybridization between odd- and even-parity bands. SmB_{6} deviates from such KI behavior, and it has been unclear how the insulating phase occurs. Here, we demonstrate that charge fluctuations are the origin of the topological insulating phase in SmB_{6}. Our angle-resolved photoemission spectroscopy results reveal that with decreasing temperature the bottom of the d-f hybridized band at the X[over ¯] point, which is predicted to have odd parity and is required for a topological phase, gradually shifts from below to above E_{F}. We conclude that SmB_{6} is a charge-fluctuating topological insulator.
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Affiliation(s)
- Chul-Hee Min
- Universität Würzburg, Experimentelle Physik VII, 97074 Würzburg, Germany and Karlsruhe Institut für Technologie KIT, Gemeinschaftslabor für Nanoanalytik, 76021 Karlsruhe, Germany
| | - P Lutz
- Universität Würzburg, Experimentelle Physik VII, 97074 Würzburg, Germany
| | - S Fiedler
- Universität Würzburg, Experimentelle Physik VII, 97074 Würzburg, Germany and Karlsruhe Institut für Technologie KIT, Gemeinschaftslabor für Nanoanalytik, 76021 Karlsruhe, Germany
| | - B Y Kang
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Republic of Korea
| | - B K Cho
- School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Republic of Korea
| | - H-D Kim
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 151-747, Republic of Korea and Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Republic of Korea
| | - H Bentmann
- Universität Würzburg, Experimentelle Physik VII, 97074 Würzburg, Germany and Karlsruhe Institut für Technologie KIT, Gemeinschaftslabor für Nanoanalytik, 76021 Karlsruhe, Germany
| | - F Reinert
- Universität Würzburg, Experimentelle Physik VII, 97074 Würzburg, Germany and Karlsruhe Institut für Technologie KIT, Gemeinschaftslabor für Nanoanalytik, 76021 Karlsruhe, Germany
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20
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Reinert F, Roberts A, Wilson JM, De Ribas L, Cardinot G, Griffiths H. Gradation in Nutrient Composition and Photosynthetic Pathways Across the Restinga Vegetation of Brazil. ACTA ACUST UNITED AC 2014. [DOI: 10.1111/j.1438-8677.1997.tb00620.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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21
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Reinert F, Steiner P, Engel T, Hüfner S. Low energy excitations in KMnO4 with 1 eV<=ΔE<=10 eV from electron-energy loss spectroscopy. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s002570050031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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22
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Benkert A, Blum M, Meyer F, Wilks RG, Yang W, Bär M, Reinert F, Heske C, Weinhardt L. Setup for in situ investigation of gases and gas/solid interfaces by soft x-ray emission and absorption spectroscopy. Rev Sci Instrum 2014; 85:015119. [PMID: 24517824 DOI: 10.1063/1.4862059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present a novel gas cell designed to study the electronic structure of gases and gas/solid interfaces using soft x-ray emission and absorption spectroscopies. In this cell, the sample gas is separated from the vacuum of the analysis chamber by a thin window membrane, allowing in situ measurements under atmospheric pressure. The temperature of the gas can be regulated from room temperature up to approximately 600 °C. To avoid beam damage, a constant mass flow can be maintained to continuously refresh the gaseous sample. Furthermore, the gas cell provides space for solid-state samples, allowing to study the gas/solid interface for surface catalytic reactions at elevated temperatures. To demonstrate the capabilities of the cell, we have investigated a TiO2 sample behind a mixture of N2 and He gas at atmospheric pressure.
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Affiliation(s)
- A Benkert
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology (KIT), Hermann-v.-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - M Blum
- Department of Chemistry, University of Nevada, Las Vegas (UNLV), 4505 Maryland Parkway, Nevada 89154-4003, USA
| | - F Meyer
- Universität Würzburg, Experimentelle Physik VII, Am Hubland, 97074 Würzburg, Germany
| | - R G Wilks
- Solar Energy Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - W Yang
- Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
| | - M Bär
- Department of Chemistry, University of Nevada, Las Vegas (UNLV), 4505 Maryland Parkway, Nevada 89154-4003, USA
| | - F Reinert
- Universität Würzburg, Experimentelle Physik VII, Am Hubland, 97074 Würzburg, Germany
| | - C Heske
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology (KIT), Hermann-v.-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - L Weinhardt
- Institute for Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology (KIT), Hermann-v.-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
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23
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Scholz M, Holch F, Sauer C, Wiessner M, Schöll A, Reinert F. Core hole-electron correlation in coherently coupled molecules. Phys Rev Lett 2013; 111:048102. [PMID: 23931410 DOI: 10.1103/physrevlett.111.048102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Indexed: 06/02/2023]
Abstract
We study the core hole-electron correlation in coherently coupled molecules by energy dispersive near edge x-ray absorption fine-structure spectroscopy. In a transient phase, which exists during the transition between two bulk arrangements, 1,4,5,8-naphthalene-tetracarboxylicacid-dianhydride multilayer films exhibit peculiar changes of the line shape and energy position of the x-ray absorption signal at the C K-edge with respect to the bulk and gas phase spectra. By a comparison to a theoretical model based on a coupling of transition dipoles, which is established for optical absorption, we demonstrate that the observed spectroscopic differences can be explained by an intermolecular delocalized core hole-electron pair. By applying this model we can furthermore quantify the coherence length of the delocalized core exciton.
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Affiliation(s)
- M Scholz
- Experimentelle Physik VII and Röntgen Research Center for Complex Material Systems RCCM, Universität Würzburg, 97074 Würzburg, Germany.
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24
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Starowicz P, Schwab H, Goraus J, Zajdel P, Forster F, Rak JR, Green MA, Vobornik I, Reinert F. A flat band at the chemical potential of a Fe1.03Te0.94S0.06 superconductor observed by angle-resolved photoemission spectroscopy. J Phys Condens Matter 2013; 25:195701. [PMID: 23604265 DOI: 10.1088/0953-8984/25/19/195701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The electronic structure of superconducting Fe1.03Te0.94S0.06 has been studied by angle-resolved photoemission spectroscopy (ARPES). Experimental band topography is compared to the calculations using the methods of Korringa-Kohn-Rostoker (KKR) with the coherent potential approximation (CPA) and the linearized augmented plane wave with local orbitals (LAPW+LO) method. The region of the Γ point exhibits two hole pockets and a quasiparticle peak close to the chemical potential (μ) with undetectable dispersion. This flat band with mainly d(z)(2) orbital character is most likely formed by the top of the outer hole pocket or is evidence of a third hole band. It may cover up to 3% of the Brillouin zone volume and should give rise to a Van Hove singularity. Studies performed for various photon energies indicate that at least one of the hole pockets has a two-dimensional character. The apparently nondispersing peak at μ is clearly visible for 40 eV and higher photon energies, due to an effect of the photoionization cross-section rather than band dimensionality. Orbital characters calculated by LAPW+LO for stoichiometric FeTe do not reveal the flat dz(2) band but are in agreement with the experiment for the other dispersions around Γ in Fe1.03Te0.94S0.06.
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Affiliation(s)
- P Starowicz
- M Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland.
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25
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Boariu FL, Bareille C, Schwab H, Nuber A, Lejay P, Durakiewicz T, Reinert F, Santander-Syro AF. Momentum-resolved evolution of the Kondo lattice into "hidden order" in URu2Si2. Phys Rev Lett 2013; 110:156404. [PMID: 25167291 DOI: 10.1103/physrevlett.110.156404] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2012] [Indexed: 06/03/2023]
Abstract
We study, using high-resolution angle-resolved photoemission spectroscopy, the evolution of the electronic structure in URu2Si2 at the Γ, Z, and X high-symmetry points from the high-temperature Kondo-screened regime to the low-temperature hidden-order (HO) state. At all temperatures and symmetry points, we find structures resulting from the interaction between heavy and light bands related to the Kondo-lattice formation. At the X point, we directly measure a hybridization gap of 11 meV already open at temperatures above the ordered phase. Strikingly, we find that while the HO induces pronounced changes at Γ and Z, the hybridization gap at X does not change, indicating that the hidden-order parameter is anisotropic. Furthermore, at the Γ and Z points, we observe the opening of a gap in momentum in the HO state, and show that the associated electronic structure results from the hybridization of a light electron band with the Kondo-lattice bands characterizing the paramagnetic state.
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Affiliation(s)
- F L Boariu
- Lehrstuhl für Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - C Bareille
- CSNSM, Université Paris-Sud and CNRS/IN2P3, Bâtiments 104 et 108, 91405 Orsay Cedex, France
| | - H Schwab
- Lehrstuhl für Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - A Nuber
- Lehrstuhl für Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - P Lejay
- Institut Néel, CNRS/UJF, B.P. 166, 38042 Grenoble Cedex 9, France
| | - T Durakiewicz
- MPA-CMMS, Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - F Reinert
- Lehrstuhl für Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany and Karlsruher Institut für Technologie (KIT), Gemeinschaftslabor für Nanoanalythik, D-76021 Karlsruhe, Germany
| | - A F Santander-Syro
- CSNSM, Université Paris-Sud and CNRS/IN2P3, Bâtiments 104 et 108, 91405 Orsay Cedex, France
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26
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Meyer F, Weinhardt L, Blum M, Bär M, Wilks RG, Yang W, Heske C, Reinert F. Non-equivalent carbon atoms in the resonant inelastic soft X-ray scattering map of cysteine. J Chem Phys 2013; 138:034306. [DOI: 10.1063/1.4774059] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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27
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Dauth M, Körzdörfer T, Kümmel S, Ziroff J, Wiessner M, Schöll A, Reinert F, Arita M, Shimada K. Orbital density reconstruction for molecules. Phys Rev Lett 2011; 107:193002. [PMID: 22181601 DOI: 10.1103/physrevlett.107.193002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Indexed: 05/09/2023]
Abstract
The experimental imaging of electronic orbitals has allowed one to gain a fascinating picture of quantum effects. We here show that the energetically high-lying orbitals that are accessible to experimental visualization in general differ, depending on which approach is used to calculate the orbitals. Therefore, orbital imaging faces the fundamental question of which orbitals are the ones that are visualized. Combining angular-resolved photoemission experiments with first-principles calculations, we show that the orbitals from self-interaction-free Kohn-Sham density functional theory are the ones best suited for the orbital-based interpretation of photoemission.
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Affiliation(s)
- M Dauth
- Theoretical Physics IV, University of Bayreuth, D-95440 Bayreuth, Germany
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28
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Weinhardt L, Fuchs O, Batchelor D, Bär M, Blum M, Denlinger JD, Yang W, Schöll A, Reinert F, Umbach E, Heske C. Electron-hole correlation effects in core-level spectroscopy probed by the resonant inelastic soft x-ray scattering map of C60. J Chem Phys 2011; 135:104705. [DOI: 10.1063/1.3633953] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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29
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Klein M, Nuber A, Schwab H, Albers C, Tobita N, Higashiguchi M, Jiang J, Fukuda S, Tanaka K, Shimada K, Mulazzi M, Assaad FF, Reinert F. Coherent heavy quasiparticles in a CePt5 surface alloy. Phys Rev Lett 2011; 106:186407. [PMID: 21635113 DOI: 10.1103/physrevlett.106.186407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 04/01/2011] [Indexed: 05/30/2023]
Abstract
We report on the results of a high-resolution angle-resolved photoemission study on the ordered surface alloy CePt(5). The temperature dependence of the spectra show the formation of the coherent low-energy heavy-fermion band near the Fermi level. These experimental data are supported by a multiband model calculation in the framework of the dynamical mean-field theory.
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Affiliation(s)
- M Klein
- Universität Würzburg, Experimentelle Physik VII & Röntgen Research Center for Complex Materials RCCM, Germany
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30
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Schöll A, Kilian L, Zou Y, Ziroff J, Hame S, Reinert F, Umbach E, Fink RH. Disordering of an Organic Overlayer on a Metal Surface Upon Cooling. Science 2010; 329:303-5. [DOI: 10.1126/science.1189106] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- A. Schöll
- Universität Würzburg, Experimentelle Physik VII, D-97074 Würzburg, Germany
| | - L. Kilian
- Universität Würzburg, Experimentelle Physik VII, D-97074 Würzburg, Germany
| | - Y. Zou
- Universität Würzburg, Experimentelle Physik VII, D-97074 Würzburg, Germany
| | - J. Ziroff
- Universität Würzburg, Experimentelle Physik VII, D-97074 Würzburg, Germany
| | - S. Hame
- Universität Würzburg, Experimentelle Physik VII, D-97074 Würzburg, Germany
| | - F. Reinert
- Universität Würzburg, Experimentelle Physik VII, D-97074 Würzburg, Germany
- Gemeinschaftslabor für Nanoanalytik, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
| | - E. Umbach
- Universität Würzburg, Experimentelle Physik VII, D-97074 Würzburg, Germany
| | - R. H. Fink
- Universität Würzburg, Experimentelle Physik VII, D-97074 Würzburg, Germany
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31
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Ziroff J, Forster F, Schöll A, Puschnig P, Reinert F. Hybridization of organic molecular orbitals with substrate states at interfaces: PTCDA on silver. Phys Rev Lett 2010; 104:233004. [PMID: 20867234 DOI: 10.1103/physrevlett.104.233004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Indexed: 05/28/2023]
Abstract
We demonstrate the application of orbital k-space tomography for the analysis of the bonding occurring at metal-organic interfaces. Using angle-resolved photoelectron spectroscopy, we probe the spatial structure of the highest occupied molecular orbital and the former lowest unoccupied molecular orbital (LUMO) of one monolayer 3, 4, 9, 10-perylene-tetracarboxylic-dianhydride (PTCDA) on Ag(110) and (111) surfaces and, in particular, the influence of the hybridization between the orbitals and the electronic states of the substrate. We are able to quantify and localize the substrate contribution to the LUMO and thus prove the metal-molecule hybrid character of this complex state.
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Affiliation(s)
- J Ziroff
- Universität Würzburg, Experimentelle Physik VII, 97074 Würzburg, Germany
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32
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Kroha J, Klein M, Nuber A, Reinert F, Stockert O, v Löhneysen H. High-temperature signatures of quantum criticality in heavy-fermion systems. J Phys Condens Matter 2010; 22:164203. [PMID: 21386409 DOI: 10.1088/0953-8984/22/16/164203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We propose a new criterion for distinguishing the Hertz-Millis (HM) and the local quantum critical (LQC) mechanism in heavy-fermion systems with a magnetic quantum phase transition (QPT). The criterion is based on our finding that the complete spin screening of Kondo ions can be suppressed by the Ruderman-Kittel-Kasuya-Yosida (RKKY) coupling to the surrounding magnetic ions even without magnetic ordering and that, consequently, the signature of this suppression can be observed in spectroscopic measurements above the magnetic ordering temperature. We apply the criterion to high-resolution photoemission measurements on CeCu(6 - x)Au(x) and conclude that the QPT in this system is dominated by the LQC scenario.
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Affiliation(s)
- J Kroha
- Physikalisches Institut and Bethe Center for Theoretical Physics, Universität Bonn, Nussallee 12, 53115 Bonn, Germany.
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33
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Stötzel C, Müller FA, Reinert F, Niederdraenk F, Barralet JE, Gbureck U. Ion adsorption behaviour of hydroxyapatite with different crystallinities. Colloids Surf B Biointerfaces 2009; 74:91-5. [PMID: 19640688 DOI: 10.1016/j.colsurfb.2009.06.031] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 06/17/2009] [Accepted: 06/29/2009] [Indexed: 10/20/2022]
Abstract
This study aimed to correlate crystallinity of hydroxyapatite (HA) with the ion adsorption behaviour of the material. Hydroxyapatite powders of various crystallinities (X(c)) and specific surface area (SSA) were prepared by precipitation following heat treatment. Adsorption experiments were carried out by using (i) multi-component ion solutions containing a broad range of light and heavy ions to study competitive adsorption and (ii) lead and zinc solutions with concentrations up to 250 ppm to determine the adsorption isotherms of the material. While as-prepared HA powders of low crystallinity (X(c)=0%) and a high SSA of 170 m(2)/g showed quantitative removal for divalent Pb, Zn, Be, U, Bi, V, Al, Cu and Ga ions, calcined powders with higher crystallinity (X(c)=65-95%) and lower SSA between 5 and 30 m(2)/g led to a quantitative removal only for a few elements (Pb, Bi, Ga). The time and concentration dependant ion removal capacity for Pb(2+) and Zn(2+) single element solutions showed quantitative removal even after short immersion times of less than 10 min for as-prepared HA powders. XRD analysis of the powders after ion adsorption revealed the presence of pyromorphite (Pb(5)(PO(4))(3)OH) and hopeite (Zn(3)(PO(4))(2)) phases, respectively.
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Affiliation(s)
- C Stötzel
- Department for Functional Materials in Medicine and Dentistry, University of Würzburg, Pleicherwall 2, D-97070 Würzburg, Germany
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34
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Klein M, Nuber A, Reinert F, Kroha J, Stockert O, van Löhneysen H. Signature of quantum criticality in photoemission spectroscopy. Phys Rev Lett 2008; 101:266404. [PMID: 19437657 DOI: 10.1103/physrevlett.101.266404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A quantum phase transition in a heavy-fermion compound may destroy the Fermi-liquid ground state. However, the conditions for this breakdown have remained obscure. We report the first direct investigation of heavy quasiparticle formation and breakdown in the canonical system CeCu(6-x)Au(x) by ultraviolet photoemission spectroscopy at elevated temperatures without the complications of lattice coherence. Surprisingly, the single-ion Kondo energy scale T(K) exhibits an abrupt step near the quantum critical Au concentration of x(c) = 0.1. We show theoretically that this step is expected from a highly nonlinear renormalization of the local spin coupling at each Ce site, induced by spin fluctuations on neighboring sites. It provides a general high-temperature indicator for heavy-fermion quasiparticle breakdown at a quantum phase transition.
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Affiliation(s)
- M Klein
- Universitüt Würzburg, Experimentelle Physik II, Am Hubland, D-97074 Würzburg, Germany
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35
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Schwalb CH, Sachs S, Marks M, Schöll A, Reinert F, Umbach E, Höfer U. Electron lifetime in a Shockley-type metal-organic interface state. Phys Rev Lett 2008; 101:146801. [PMID: 18851554 DOI: 10.1103/physrevlett.101.146801] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Indexed: 05/26/2023]
Abstract
The lifetimes of electrons at the interface between 3,4,9,10-perylene-tetracarboxylic acid dianhydride (PTCDA) and Ag(111) have been studied by means of time- and angle-resolved two-photon photoemission. We observe a dispersing unoccupied state 0.6 eV above the Fermi level with an effective electron mass of 0.39m{e} at the Gamma[over ] point. The short lifetime of 54 fs is indicative of a large penetration of the wave function into the metal. Supported by model calculations this interface state is interpreted as predominantly arising from an upshift of the occupied Shockley surface state of the clean metal due to the interaction with the PTCDA overlayer.
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Affiliation(s)
- C H Schwalb
- Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität, D-35032 Marburg, Germany
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36
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Klein M, Zur D, Menzel D, Schoenes J, Doll K, Röder J, Reinert F. Evidence for itineracy in the anticipated Kondo insulator FeSi: a quantitative determination of the band renormalization. Phys Rev Lett 2008; 101:046406. [PMID: 18764349 DOI: 10.1103/physrevlett.101.046406] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Indexed: 05/26/2023]
Abstract
A comparison of high-resolution, angle-resolved photoemission spectroscopy (ARPES) data with ab initio band-structure calculations by density functional theory for the anticipated Kondo insulator FeSi shows that the experimental dispersions can quantitatively be described by an itinerant behavior provided that an appropriate self-energy correction is included, whose real part describes the band renormalization due to interactions of the Fe 3d electrons. The imaginary part of the self-energy, on the other hand, determines the linewidth of the quasiparticle peaks in the ARPES data. We use a model self-energy which consistently describes both the renormalized single-particle dispersion and the energy-dependent linewidth of the Fe 3d bands. These results are clear evidence that FeSi is an itinerant semiconductor whose properties can be explained without a local Kondo-like interaction.
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Affiliation(s)
- M Klein
- Universität Würzburg, Experimentelle Physik II, Am Hubland, D-97074 Würzburg, Germany
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37
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Kilian L, Hauschild A, Temirov R, Soubatch S, Schöll A, Bendounan A, Reinert F, Lee TL, Tautz FS, Sokolowski M, Umbach E. Role of intermolecular interactions on the electronic and geometric structure of a large pi-conjugated molecule adsorbed on a metal surface. Phys Rev Lett 2008; 100:136103. [PMID: 18517971 DOI: 10.1103/physrevlett.100.136103] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2007] [Indexed: 05/03/2023]
Abstract
The organic semiconductor molecule 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) exhibits two adsorption states on the Ag(111) surface: one in a metastable disordered phase, prepared at low temperatures, the other in the long-range ordered monolayer phase obtained at room temperature. Notably, the two states differ substantial in their vertical bonding distances, intramolecular distortions, and electronic structures. The difference is explained by intermolecular interactions, which are particularly relevant for the long-range ordered phase, and which hence require attention.
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Affiliation(s)
- L Kilian
- Universität Würzburg, Experimentelle Physik II, Am Hubland, 97074 Würzburg, Germany
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38
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Bendounan A, Forster F, Reinert F, Kierren B, Fagot-Revurat Y, Malterre D. Comment on "fermi gap stabilization of an incommensurate two-dimensional superstructure". Phys Rev Lett 2006; 96:029701; discussion 029702. [PMID: 16486663 DOI: 10.1103/physrevlett.96.029701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Indexed: 05/06/2023]
Affiliation(s)
- A Bendounan
- Experimentelle Physik II, Universität Würzburg Am Hubland, D-97074 Würzburg, Germany
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39
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Forster F, Hüfner S, Reinert F. Rare Gases on Noble-Metal Surfaces: An Angle-Resolved Photoemission Study with High Energy Resolution. J Phys Chem B 2004. [DOI: 10.1021/jp049215b] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- F. Forster
- Universität des Saarlandes, FR 7.2 Experimentalphysik, D-66041 Saarbrücken, Germany
| | - S. Hüfner
- Universität des Saarlandes, FR 7.2 Experimentalphysik, D-66041 Saarbrücken, Germany
| | - F. Reinert
- Universität Würzburg, Experimentelle Physik II, D-97074 Würzburg, Germany
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40
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Reinert F, Eltner B, Nicolay G, Ehm D, Schmidt S, Hüfner S. Electron-phonon coupling and its evidence in the photoemission spectra of lead. Phys Rev Lett 2003; 91:186406. [PMID: 14611299 DOI: 10.1103/physrevlett.91.186406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2002] [Indexed: 05/24/2023]
Abstract
We present a detailed study of the influence of strong electron-phonon coupling on the photoemission spectra of lead. Representing the strong-coupling regime of superconductivity, the spectra of lead show characteristic features that demonstrate the correspondence of physical properties in the normal and the superconducting state, as predicted by the Eliashberg theory. These features appear on an energy scale of a few meV and are accessible for photoemission only by using modern spectrometers with high-resolution in energy and angle.
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Affiliation(s)
- F Reinert
- Universität des Saarlandes, Fachrichtung 7.2, Experimentalphysik, D-66041 Saarbrücken, Germany.
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41
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Radu G, Memmert U, Zhang H, Nicolay G, Reinert F, Hartmann U. Direct Observation of the Thermal Decomposition of Ligand-Stabilized Clusters. J Phys Chem B 2002. [DOI: 10.1021/jp013409z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- G. Radu
- Institute of Experimental Physics, University of Saarbrücken, P.O. Box 151150, D-66041 Saarbrücken, Germany
| | - U. Memmert
- Institute of Experimental Physics, University of Saarbrücken, P.O. Box 151150, D-66041 Saarbrücken, Germany
| | - H. Zhang
- Institute of Experimental Physics, University of Saarbrücken, P.O. Box 151150, D-66041 Saarbrücken, Germany
| | - G. Nicolay
- Institute of Experimental Physics, University of Saarbrücken, P.O. Box 151150, D-66041 Saarbrücken, Germany
| | - F. Reinert
- Institute of Experimental Physics, University of Saarbrücken, P.O. Box 151150, D-66041 Saarbrücken, Germany
| | - U. Hartmann
- Institute of Experimental Physics, University of Saarbrücken, P.O. Box 151150, D-66041 Saarbrücken, Germany
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42
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Eiguren A, Hellsing B, Reinert F, Nicolay G, Chulkov EV, Silkin VM, Hüfner S, Echenique PM. Role of bulk and surface phonons in the decay of metal surface States. Phys Rev Lett 2002; 88:066805. [PMID: 11863840 DOI: 10.1103/physrevlett.88.066805] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2001] [Indexed: 05/23/2023]
Abstract
We present a comprehensive theoretical investigation of the electron-phonon contribution to the lifetime broadening of the surface states on Cu(111) and Ag(111), in comparison with high-resolution photoemission results. The calculations, including electron and phonon states of the bulk and the surface, resolve the relative importance of the Rayleigh mode, being dominant for the lifetime at small hole binding energies. Including the electron-electron interaction, the theoretical results are in excellent agreement with the measured binding energy and temperature dependent lifetime broadening.
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Affiliation(s)
- A Eiguren
- Departmento de Física de Materiales and Centro Mixto CSIC-UPV/EHU, Facultad de Ciencias Químicas, Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, Apdo. 1072, 20018 San Sebastián/Donostia, Basque Country, Spain
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Reinert F, Ehm D, Schmidt S, Nicolay G, Hüfner S, Kroha J, Trovarelli O, Geibel C. Temperature dependence of the Kondo resonance and its satellites in CeCu2Si2. Phys Rev Lett 2001; 87:106401. [PMID: 11531493 DOI: 10.1103/physrevlett.87.106401] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2001] [Indexed: 05/23/2023]
Abstract
We present high-resolution photoemission spectroscopy studies on the Kondo resonance of the strongly correlated Ce system CeCu2Si2. By exploiting the thermal broadening of the Fermi edge we analyze position, spectral weight, and temperature dependence of the low-energy 4f spectral features, whose major weight lies above the Fermi level E(F). We also present theoretical predictions based on the single-impurity Anderson model using an extended noncrossing approximation, including all spin-orbit and crystal field splittings of the 4f states. The excellent agreement between theory and experiment provides strong evidence that the spectral properties of CeCu2Si2 can be described by single-impurity Kondo physics down to T approximately 5 K.
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Affiliation(s)
- F Reinert
- Universität des Saarlandes, Fachrichtung 7.2-Experimentalphysik, 66041 Saarbrücken, Germany.
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Reinert F, Nicolay G, Eltner B, Ehm D, Schmidt S, Hufner S, Probst U, Bucher E. Observation of a BCS spectral function in a conventional superconductor by photoelectron spectroscopy. Phys Rev Lett 2000; 85:3930-3933. [PMID: 11041963 DOI: 10.1103/physrevlett.85.3930] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2000] [Indexed: 05/23/2023]
Abstract
We present high-resolution photoelectron spectra on the A15-type conventional superconductor V 3Si, where-for the first time-both singularities of the BCS density of states can be resolved by photoemission spectroscopy (PES). With a transition temperature of about T(c) approximately 17 K the gap Delta(gap) of this compound has a magnitude of approximately 5 meV. A measurement by PES on this small energy scale requires a very high energy resolution (DeltaE less, similar5 meV) and sample temperatures significantly below T(c).
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Affiliation(s)
- F Reinert
- Universitat des Saarlandes, Fachrichtung 7.2-Experimentalphysik, D-66041 Saarbrucken, Germany
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Reinert F, Kumar S, Steiner P, Claessen R, H�fner S. The electronic structure of KMnO4 investigated by photoemission and electron-energy-loss spectroscopy. ACTA ACUST UNITED AC 1994. [DOI: 10.1007/bf01317405] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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