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Strocov VN, Lev LL, Alarab F, Constantinou P, Wang X, Schmitt T, Stock TJZ, Nicolaï L, Očenášek J, Minár J. High-energy photoemission final states beyond the free-electron approximation. Nat Commun 2023; 14:4827. [PMID: 37563126 PMCID: PMC10415355 DOI: 10.1038/s41467-023-40432-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 07/26/2023] [Indexed: 08/12/2023] Open
Abstract
Three-dimensional (3D) electronic band structure is fundamental for understanding a vast diversity of physical phenomena in solid-state systems, including topological phases, interlayer interactions in van der Waals materials, dimensionality-driven phase transitions, etc. Interpretation of ARPES data in terms of 3D electron dispersions is commonly based on the free-electron approximation for the photoemission final states. Our soft-X-ray ARPES data on Ag metal reveals, however, that even at high excitation energies the final states can be a way more complex, incorporating several Bloch waves with different out-of-plane momenta. Such multiband final states manifest themselves as a complex structure and added broadening of the spectral peaks from 3D electron states. We analyse the origins of this phenomenon, and trace it to other materials such as Si and GaN. Our findings are essential for accurate determination of the 3D band structure over a wide range of materials and excitation energies in the ARPES experiment.
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Affiliation(s)
- V N Strocov
- Swiss Light Source, Paul Scherrer Institute, 5232, Villigen-PSI, Switzerland.
| | - L L Lev
- Swiss Light Source, Paul Scherrer Institute, 5232, Villigen-PSI, Switzerland
- Moscow Institute of Physics and Technology, 141701, Dolgoprudny, Russia
| | - F Alarab
- Swiss Light Source, Paul Scherrer Institute, 5232, Villigen-PSI, Switzerland
| | - P Constantinou
- Swiss Light Source, Paul Scherrer Institute, 5232, Villigen-PSI, Switzerland
| | - X Wang
- Swiss Light Source, Paul Scherrer Institute, 5232, Villigen-PSI, Switzerland
| | - T Schmitt
- Swiss Light Source, Paul Scherrer Institute, 5232, Villigen-PSI, Switzerland
| | - T J Z Stock
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK
| | - L Nicolaï
- University of West Bohemia, New Technologies Research Centre, 301 00, Plzeň, Czech Republic
| | - J Očenášek
- University of West Bohemia, New Technologies Research Centre, 301 00, Plzeň, Czech Republic
| | - J Minár
- University of West Bohemia, New Technologies Research Centre, 301 00, Plzeň, Czech Republic.
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2
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Yu TL, Xu M, Yang WT, Song YH, Wen CHP, Yao Q, Lou X, Zhang T, Li W, Wei XY, Bao JK, Cao GH, Dudin P, Denlinger JD, Strocov VN, Peng R, Xu HC, Feng DL. Strong band renormalization and emergent ferromagnetism induced by electron-antiferromagnetic-magnon coupling. Nat Commun 2022; 13:6560. [PMID: 36323685 PMCID: PMC9630309 DOI: 10.1038/s41467-022-34254-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 10/13/2022] [Indexed: 11/15/2022] Open
Abstract
The interactions between electrons and antiferromagnetic magnons (AFMMs) are important for a large class of correlated materials. For example, they are the most plausible pairing glues in high-temperature superconductors, such as cuprates and iron-based superconductors. However, unlike electron-phonon interactions (EPIs), clear-cut observations regarding how electron-AFMM interactions (EAIs) affect the band structure are still lacking. Consequently, critical information on the EAIs, such as its strength and doping dependence, remains elusive. Here we directly observe that EAIs induce a kink structure in the band dispersion of Ba1-xKxMn2As2, and subsequently unveil several key characteristics of EAIs. We found that the coupling constant of EAIs can be as large as 5.4, and it shows strong doping dependence and temperature dependence, all in stark contrast to the behaviors of EPIs. The colossal renormalization of electron bands by EAIs enhances the density of states at Fermi energy, which is likely driving the emergent ferromagnetic state in Ba1-xKxMn2As2 through a Stoner-like mechanism with mixed itinerant-local character. Our results expand the current knowledge of EAIs, which may facilitate the further understanding of many correlated materials where EAIs play a critical role.
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Affiliation(s)
- T. L. Yu
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - M. Xu
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - W. T. Yang
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - Y. H. Song
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - C. H. P. Wen
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - Q. Yao
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - X. Lou
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - T. Zhang
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China ,grid.9227.e0000000119573309Shanghai Research Center for Quantum Sciences, 201315 Shanghai, P. R. China ,grid.509497.6Collaborative Innovation Center of Advanced Microstructures, 210093 Nanjing, China
| | - W. Li
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - X. Y. Wei
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - J. K. Bao
- grid.13402.340000 0004 1759 700XDepartment of Physics, Zhejiang University, 310027 Hangzhou, P. R. China
| | - G. H. Cao
- grid.13402.340000 0004 1759 700XDepartment of Physics, Zhejiang University, 310027 Hangzhou, P. R. China
| | - P. Dudin
- grid.18785.330000 0004 1764 0696Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE UK
| | - J. D. Denlinger
- grid.184769.50000 0001 2231 4551Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720-8229 USA
| | - V. N. Strocov
- grid.5991.40000 0001 1090 7501Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, PSI Switzerland
| | - R. Peng
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China ,grid.9227.e0000000119573309Shanghai Research Center for Quantum Sciences, 201315 Shanghai, P. R. China
| | - H. C. Xu
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China
| | - D. L. Feng
- grid.8547.e0000 0001 0125 2443Laboratory of Advanced Materials, State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200438 Shanghai, P. R. China ,grid.9227.e0000000119573309Shanghai Research Center for Quantum Sciences, 201315 Shanghai, P. R. China ,grid.509497.6Collaborative Innovation Center of Advanced Microstructures, 210093 Nanjing, China ,grid.59053.3a0000000121679639Hefei National Laboratory for Physical Science at Microscale, CAS Center for Excellence in Quantum Information and Quantum Physics, and Department of Physics, University of Science and Technology of China, 230026 Hefei, P. R. China
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3
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Elmers HJ, Chernov SV, D'Souza SW, Bommanaboyena SP, Bodnar SY, Medjanik K, Babenkov S, Fedchenko O, Vasilyev D, Agustsson SY, Schlueter C, Gloskovskii A, Matveyev Y, Strocov VN, Skourski Y, Šmejkal L, Sinova J, Minár J, Kläui M, Schönhense G, Jourdan M. Néel Vector Induced Manipulation of Valence States in the Collinear Antiferromagnet Mn 2Au. ACS Nano 2020; 14:17554-17564. [PMID: 33236903 DOI: 10.1021/acsnano.0c08215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The coupling of real and momentum space is utilized to tailor electronic properties of the collinear metallic antiferromagnet Mn2Au by aligning the real space Néel vector indicating the direction of the staggered magnetization. Pulsed magnetic fields of 60 T were used to orient the sublattice magnetizations of capped epitaxial Mn2Au(001) thin films perpendicular to the applied field direction by a spin-flop transition. The electronic structure and its corresponding changes were investigated by angular-resolved photoemission spectroscopy with photon energies in the vacuum-ultraviolet, soft, and hard X-ray range. The results reveal an energetic rearrangement of conduction electrons propagating perpendicular to the Néel vector. They confirm previous predictions on the origin of the Néel spin-orbit torque and anisotropic magnetoresistance in Mn2Au and reflect the combined antiferromagnetic and spin-orbit interaction in this compound leading to inversion symmetry breaking.
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Affiliation(s)
- H J Elmers
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - S V Chernov
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - S W D'Souza
- New Technologies-Research Centre, University of West Bohemia, Univerzitni 8, 306 14 Pilsen, Czech Republic
| | - S P Bommanaboyena
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - S Yu Bodnar
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - K Medjanik
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - S Babenkov
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - O Fedchenko
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - D Vasilyev
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - S Y Agustsson
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - C Schlueter
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - A Gloskovskii
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - Yu Matveyev
- Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
| | - V N Strocov
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland
| | - Y Skourski
- Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - L Šmejkal
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
- Institute of Physics Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Praha 6, Czech Republic
| | - J Sinova
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
- Institute of Physics Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Praha 6, Czech Republic
| | - J Minár
- New Technologies-Research Centre, University of West Bohemia, Univerzitni 8, 306 14 Pilsen, Czech Republic
| | - M Kläui
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - G Schönhense
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
| | - M Jourdan
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
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4
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Ma JZ, Nie SM, Yi CJ, Jandke J, Shang T, Yao MY, Naamneh M, Yan LQ, Sun Y, Chikina A, Strocov VN, Medarde M, Song M, Xiong YM, Xu G, Wulfhekel W, Mesot J, Reticcioli M, Franchini C, Mudry C, Müller M, Shi YG, Qian T, Ding H, Shi M. Spin fluctuation induced Weyl semimetal state in the paramagnetic phase of EuCd 2As 2. Sci Adv 2019; 5:eaaw4718. [PMID: 31309151 PMCID: PMC6625818 DOI: 10.1126/sciadv.aaw4718] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 06/10/2019] [Indexed: 05/22/2023]
Abstract
Weyl fermions as emergent quasiparticles can arise in Weyl semimetals (WSMs) in which the energy bands are nondegenerate, resulting from inversion or time-reversal symmetry breaking. Nevertheless, experimental evidence for magnetically induced WSMs is scarce. Here, using photoemission spectroscopy, we observe that the degeneracy of Bloch bands is already lifted in the paramagnetic phase of EuCd2As2. We attribute this effect to the itinerant electrons experiencing quasi-static and quasi-long-range ferromagnetic fluctuations. Moreover, the spin-nondegenerate band structure harbors a pair of ideal Weyl nodes near the Fermi level. Hence, we show that long-range magnetic order and the spontaneous breaking of time-reversal symmetry are not essential requirements for WSM states in centrosymmetric systems and that WSM states can emerge in a wider range of condensed matter systems than previously thought.
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Affiliation(s)
- J.-Z. Ma
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne, CH-10 15 Lausanne, Switzerland
| | - S. M. Nie
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - C. J. Yi
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physics, University of Chinese Academy of Sciences, Beijing 100190, China
| | - J. Jandke
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - T. Shang
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne, CH-10 15 Lausanne, Switzerland
- Laboratory for Multiscale Materials Experiments, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - M. Y. Yao
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - M. Naamneh
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - L. Q. Yan
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Y. Sun
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physics, University of Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - A. Chikina
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - V. N. Strocov
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - M. Medarde
- Laboratory for Multiscale Materials Experiments, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - M. Song
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Y.-M. Xiong
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
| | - G. Xu
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - W. Wulfhekel
- Physikalisches Institut, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - J. Mesot
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Institute of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne, CH-10 15 Lausanne, Switzerland
- Laboratory for Solid State Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - M. Reticcioli
- Faculty of Physics, Center for Computational Materials Science, University of Vienna, A-1090 Vienna, Austria
| | - C. Franchini
- Faculty of Physics, Center for Computational Materials Science, University of Vienna, A-1090 Vienna, Austria
- Dipartimento di Fisica e Astronomia, Università di Bologna, 40127 Bologna, Italy
| | - C. Mudry
- Condensed Matter Theory Group, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Institute of Physics, Ecole Polytechnique Federale de Lausanne, CH1015 Lausanne, Switzerland
| | - M. Müller
- Condensed Matter Theory Group, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Y. G. Shi
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - T. Qian
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - H. Ding
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physics, University of Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - M. Shi
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
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5
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Yao MY, Xu N, Wu QS, Autès G, Kumar N, Strocov VN, Plumb NC, Radovic M, Yazyev OV, Felser C, Mesot J, Shi M. Observation of Weyl Nodes in Robust Type-II Weyl Semimetal WP_{2}. Phys Rev Lett 2019; 122:176402. [PMID: 31107063 DOI: 10.1103/physrevlett.122.176402] [Citation(s) in RCA: 2] [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: 08/06/2018] [Indexed: 06/09/2023]
Abstract
Distinct to type-I Weyl semimetals (WSMs) that host quasiparticles described by the Weyl equation, the energy dispersion of quasiparticles in type-II WSMs violates Lorentz invariance and the Weyl cones in the momentum space are tilted. Since it was proposed that type-II Weyl fermions could emerge from (W,Mo)Te_{2} and (W,Mo)P_{2} families of materials, a large number of experiments have been dedicated to unveiling the possible manifestation of type-II WSMs, e.g., surface-state Fermi arcs. However, the interpretations of the experimental results are very controversial. Here, using angle-resolved photoemission spectroscopy supported by the first-principles calculations, we probe the tilted Weyl cone bands in the bulk electronic structure of WP_{2} directly, which are at the origin of Fermi arcs at the surfaces and transport properties related to the chiral anomaly in type-II WSMs. Our results ascertain that, due to the spin-orbit coupling, the Weyl nodes originate from the splitting of fourfold degenerate band-crossing points with Chern numbers C=±2 induced by the crystal symmetries of WP_{2}, which is unique among all the discovered WSMs. Our finding also provides a guiding line to observe the chiral anomaly that could manifest in novel transport properties.
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Affiliation(s)
- M-Y Yao
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - N Xu
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
- Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Institute of Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Q S Wu
- Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- National Centre for Computational Design and Discovery of Novel Materials MARVEL, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - G Autès
- Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- National Centre for Computational Design and Discovery of Novel Materials MARVEL, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - N Kumar
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - V N Strocov
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - N C Plumb
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - M Radovic
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - O V Yazyev
- Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- National Centre for Computational Design and Discovery of Novel Materials MARVEL, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - C Felser
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - J Mesot
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
- Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Laboratory for Solid State Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - M Shi
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
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6
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Fu BB, Yi CJ, Zhang TT, Caputo M, Ma JZ, Gao X, Lv BQ, Kong LY, Huang YB, Richard P, Shi M, Strocov VN, Fang C, Weng HM, Shi YG, Qian T, Ding H. Dirac nodal surfaces and nodal lines in ZrSiS. Sci Adv 2019; 5:eaau6459. [PMID: 31058219 PMCID: PMC6499591 DOI: 10.1126/sciadv.aau6459] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 03/21/2019] [Indexed: 05/30/2023]
Abstract
Topological semimetals are characterized by symmetry-protected band crossings, which can be preserved in different dimensions in momentum space, forming zero-dimensional nodal points, one-dimensional nodal lines, or even two-dimensional nodal surfaces. Materials harboring nodal points and nodal lines have been experimentally verified, whereas experimental evidence of nodal surfaces is still lacking. Here, using angle-resolved photoemission spectroscopy (ARPES), we reveal the coexistence of Dirac nodal surfaces and nodal lines in the bulk electronic structures of ZrSiS. As compared with previous ARPES studies on ZrSiS, we obtained pure bulk states, which enable us to extract unambiguously intrinsic information of the bulk nodal surfaces and nodal lines. Our results show that the nodal lines are the only feature near the Fermi level and constitute the whole Fermi surfaces. We not only prove that the low-energy quasiparticles in ZrSiS are contributed entirely by Dirac fermions but also experimentally realize the nodal surface in topological semimetals.
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Affiliation(s)
- B.-B. Fu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - C.-J. Yi
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - T.-T. Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - M. Caputo
- Paul Scherrer Institute, Swiss Light Source, CH-5232 Villigen PSI, Switzerland
| | - J.-Z. Ma
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - X. Gao
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - B. Q. Lv
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - L.-Y. Kong
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Y.-B. Huang
- Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China
| | - P. Richard
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - M. Shi
- Paul Scherrer Institute, Swiss Light Source, CH-5232 Villigen PSI, Switzerland
| | - V. N. Strocov
- Paul Scherrer Institute, Swiss Light Source, CH-5232 Villigen PSI, Switzerland
| | - C. Fang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - H.-M. Weng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Y.-G. Shi
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - T. Qian
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - H. Ding
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
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7
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Schlappa J, Kumar U, Zhou KJ, Singh S, Mourigal M, Strocov VN, Revcolevschi A, Patthey L, Rønnow HM, Johnston S, Schmitt T. Probing multi-spinon excitations outside of the two-spinon continuum in the antiferromagnetic spin chain cuprate Sr 2CuO 3. Nat Commun 2018; 9:5394. [PMID: 30568161 PMCID: PMC6300594 DOI: 10.1038/s41467-018-07838-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [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: 06/13/2018] [Accepted: 11/26/2018] [Indexed: 11/09/2022] Open
Abstract
One-dimensional (1D) magnetic insulators have attracted significant interest as a platform for studying quasiparticle fractionalization, quantum criticality, and emergent phenomena. The spin-1/2 Heisenberg chain with antiferromagnetic nearest neighbour interactions is an important reference system; its elementary magnetic excitations are spin-1/2 quasiparticles called spinons that are created in even numbers. However, while the excitation continuum associated with two-spinon states is routinely observed, the study of four-spinon and higher multi-spinon states is an open area of research. Here we show that four-spinon excitations can be accessed directly in Sr2CuO3 using resonant inelastic x-ray scattering (RIXS) in a region of phase space clearly separated from the two-spinon continuum. Our finding is made possible by the fundamental differences in the correlation function probed by RIXS in comparison to other probes. This advance holds promise as a tool in the search for novel quantum states and quantum spin liquids.
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Affiliation(s)
- J Schlappa
- European X-Ray Free-Electron Laser Facility GmbH, Holzkoppel 4, 22869, Schenefeld, Germany.
- Photon Science Division, Paul Scherrer Institut, 5232, Villigen PSI, Switzerland.
| | - U Kumar
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN, 37996, USA
| | - K J Zhou
- Photon Science Division, Paul Scherrer Institut, 5232, Villigen PSI, Switzerland
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | - S Singh
- Department of Physics, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune, 411008, India
| | - M Mourigal
- École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
- School of Physics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - V N Strocov
- Photon Science Division, Paul Scherrer Institut, 5232, Villigen PSI, Switzerland
| | - A Revcolevschi
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Sud 11, UMR 8182, 91405, Orsay, France
| | - L Patthey
- Photon Science Division, Paul Scherrer Institut, 5232, Villigen PSI, Switzerland
| | - H M Rønnow
- École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| | - S Johnston
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN, 37996, USA.
| | - T Schmitt
- Photon Science Division, Paul Scherrer Institut, 5232, Villigen PSI, Switzerland.
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8
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Xu N, Wang ZW, Magrez A, Bugnon P, Berger H, Matt CE, Strocov VN, Plumb NC, Radovic M, Pomjakushina E, Conder K, Dil JH, Mesot J, Yu R, Ding H, Shi M. Evidence of a Coulomb-Interaction-Induced Lifshitz Transition and Robust Hybrid Weyl Semimetal in T_{d}-MoTe_{2}. Phys Rev Lett 2018; 121:136401. [PMID: 30312078 DOI: 10.1103/physrevlett.121.136401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 07/16/2018] [Indexed: 06/08/2023]
Abstract
Using soft x-ray angle-resolved photoemission spectroscopy we probed the bulk electronic structure of T_{d}-MoTe_{2}. We found that on-site Coulomb interaction leads to a Lifshitz transition, which is essential for a precise description of the electronic structure. A hybrid Weyl semimetal state with a pair of energy bands touching at both type-I and type-II Weyl nodes is indicated by comparing the experimental data with theoretical calculations. Unveiling the importance of Coulomb interaction opens up a new route to comprehend the unique properties of MoTe_{2}, and is significant for understanding the interplay between correlation effects, strong spin-orbit coupling and superconductivity in this van der Waals material.
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Affiliation(s)
- N Xu
- Institute of Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Z W Wang
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - A Magrez
- Institute of Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - P Bugnon
- Institute of Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - H Berger
- Institute of Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - C E Matt
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- Laboratory for Solid State Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - V N Strocov
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - N C Plumb
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - M Radovic
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - E Pomjakushina
- Laboratory for Developments and Methods, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - K Conder
- Laboratory for Developments and Methods, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - J H Dil
- Institute of Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - J Mesot
- Institute of Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- Laboratory for Solid State Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - R Yu
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - H Ding
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100190, China
| | - M Shi
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
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9
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Horio M, Hauser K, Sassa Y, Mingazheva Z, Sutter D, Kramer K, Cook A, Nocerino E, Forslund OK, Tjernberg O, Kobayashi M, Chikina A, Schröter NBM, Krieger JA, Schmitt T, Strocov VN, Pyon S, Takayama T, Takagi H, Lipscombe OJ, Hayden SM, Ishikado M, Eisaki H, Neupert T, Månsson M, Matt CE, Chang J. Three-Dimensional Fermi Surface of Overdoped La-Based Cuprates. Phys Rev Lett 2018; 121:077004. [PMID: 30169083 DOI: 10.1103/physrevlett.121.077004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Indexed: 06/08/2023]
Abstract
We present a soft x-ray angle-resolved photoemission spectroscopy study of overdoped high-temperature superconductors. In-plane and out-of-plane components of the Fermi surface are mapped by varying the photoemission angle and the incident photon energy. No k_{z} dispersion is observed along the nodal direction, whereas a significant antinodal k_{z} dispersion is identified for La-based cuprates. Based on a tight-binding parametrization, we discuss the implications for the density of states near the van Hove singularity. Our results suggest that the large electronic specific heat found in overdoped La_{2-x}Sr_{x}CuO_{4} cannot be assigned to the van Hove singularity alone. We therefore propose quantum criticality induced by a collapsing pseudogap phase as a plausible explanation for observed enhancement of electronic specific heat.
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Affiliation(s)
- M Horio
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - K Hauser
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Y Sassa
- Department of Physics and Astronomy, Uppsala University, SE-75121 Uppsala, Sweden
| | - Z Mingazheva
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - D Sutter
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - K Kramer
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - A Cook
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - E Nocerino
- Department of Applied Physics, KTH Royal Institute of Technology, Electrum 229, SE-16440 Stockholm Kista, Sweden
| | - O K Forslund
- Department of Applied Physics, KTH Royal Institute of Technology, Electrum 229, SE-16440 Stockholm Kista, Sweden
| | - O Tjernberg
- Department of Applied Physics, KTH Royal Institute of Technology, Electrum 229, SE-16440 Stockholm Kista, Sweden
| | - M Kobayashi
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - A Chikina
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - N B M Schröter
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - J A Krieger
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Laboratorium für Festkörperphysik, ETH Zürich, CH-8093 Zürich, Switzerland
| | - T Schmitt
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - V N Strocov
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - S Pyon
- Department of Advanced Materials, University of Tokyo, Kashiwa 277-8561, Japan
| | - T Takayama
- Department of Advanced Materials, University of Tokyo, Kashiwa 277-8561, Japan
| | - H Takagi
- Department of Advanced Materials, University of Tokyo, Kashiwa 277-8561, Japan
| | - O J Lipscombe
- H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, United Kingdom
| | - S M Hayden
- H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, United Kingdom
| | - M Ishikado
- Comprehensive Research Organization for Science and Society (CROSS), Tokai, Ibaraki 319-1106, Japan
| | - H Eisaki
- Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8568, Japan
| | - T Neupert
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - M Månsson
- Department of Applied Physics, KTH Royal Institute of Technology, Electrum 229, SE-16440 Stockholm Kista, Sweden
| | - C E Matt
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
| | - J Chang
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
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10
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Matt CE, Sutter D, Cook AM, Sassa Y, Månsson M, Tjernberg O, Das L, Horio M, Destraz D, Fatuzzo CG, Hauser K, Shi M, Kobayashi M, Strocov VN, Schmitt T, Dudin P, Hoesch M, Pyon S, Takayama T, Takagi H, Lipscombe OJ, Hayden SM, Kurosawa T, Momono N, Oda M, Neupert T, Chang J. Direct observation of orbital hybridisation in a cuprate superconductor. Nat Commun 2018; 9:972. [PMID: 29511188 PMCID: PMC5840306 DOI: 10.1038/s41467-018-03266-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [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: 08/21/2017] [Accepted: 02/01/2018] [Indexed: 11/19/2022] Open
Abstract
The minimal ingredients to explain the essential physics of layered copper-oxide (cuprates) materials remains heavily debated. Effective low-energy single-band models of the copper–oxygen orbitals are widely used because there exists no strong experimental evidence supporting multi-band structures. Here, we report angle-resolved photoelectron spectroscopy experiments on La-based cuprates that provide direct observation of a two-band structure. This electronic structure, qualitatively consistent with density functional theory, is parametrised by a two-orbital (\documentclass[12pt]{minimal}
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\begin{document}$$d_{z^2}$$\end{document}dz2) tight-binding model. We quantify the orbital hybridisation which provides an explanation for the Fermi surface topology and the proximity of the van-Hove singularity to the Fermi level. Our analysis leads to a unification of electronic hopping parameters for single-layer cuprates and we conclude that hybridisation, restraining d-wave pairing, is an important optimisation element for superconductivity. The essential physics of cuprate superconductors is often described by single-band models. Here, Matt et al. report direct observation of a two-band electronic structure in La-based cuprates.
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Affiliation(s)
- C E Matt
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland. .,Swiss Light Source, Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland.
| | - D Sutter
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - A M Cook
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - Y Sassa
- Department of Physics and Astronomy, Uppsala University, SE-75121, Uppsala, Sweden
| | - M Månsson
- Materials Physics, KTH Royal Institute of Technology, SE-164 40, Kista, Stockholm, Sweden
| | - O Tjernberg
- Materials Physics, KTH Royal Institute of Technology, SE-164 40, Kista, Stockholm, Sweden
| | - L Das
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - M Horio
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - D Destraz
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - C G Fatuzzo
- Institute of Physics, École Polytechnique Fedérale de Lausanne (EPFL), Lausanne, CH-1015, Switzerland
| | - K Hauser
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - M Shi
- Swiss Light Source, Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | - M Kobayashi
- Swiss Light Source, Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | - V N Strocov
- Swiss Light Source, Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | - T Schmitt
- Swiss Light Source, Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland
| | - P Dudin
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, UK
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, UK
| | - S Pyon
- Department of Advanced Materials, University of Tokyo, Kashiwa, 277-8561, Japan
| | - T Takayama
- Department of Advanced Materials, University of Tokyo, Kashiwa, 277-8561, Japan
| | - H Takagi
- Department of Advanced Materials, University of Tokyo, Kashiwa, 277-8561, Japan
| | - O J Lipscombe
- H. H. Wills Physics Laboratory, University of Bristol, Bristol, BS8 1TL, UK
| | - S M Hayden
- H. H. Wills Physics Laboratory, University of Bristol, Bristol, BS8 1TL, UK
| | - T Kurosawa
- Department of Physics, Hokkaido University, Sapporo, 060-0810, Japan
| | - N Momono
- Department of Physics, Hokkaido University, Sapporo, 060-0810, Japan.,Department of Applied Sciences, Muroran Institute of Technology, Muroran, 050-8585, Japan
| | - M Oda
- Department of Physics, Hokkaido University, Sapporo, 060-0810, Japan
| | - T Neupert
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - J Chang
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland.
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11
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Chen QY, Xu DF, Niu XH, Peng R, Xu HC, Wen CHP, Liu X, Shu L, Tan SY, Lai XC, Zhang YJ, Lee H, Strocov VN, Bisti F, Dudin P, Zhu JX, Yuan HQ, Kirchner S, Feng DL. Band Dependent Interlayer f-Electron Hybridization in CeRhIn_{5}. Phys Rev Lett 2018; 120:066403. [PMID: 29481263 DOI: 10.1103/physrevlett.120.066403] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 01/02/2018] [Indexed: 06/08/2023]
Abstract
A key issue in heavy fermion research is how subtle changes in the hybridization between the 4f (5f) and conduction electrons can result in fundamentally different ground states. CeRhIn_{5} stands out as a particularly notable example: when replacing Rh with either Co or Ir, antiferromagnetism gives way to superconductivity. In this photoemission study of CeRhIn_{5}, we demonstrate that the use of resonant angle-resolved photoemission spectroscopy with polarized light allows us to extract detailed information on the 4f crystal field states and details on the 4f and conduction electron hybridization, which together determine the ground state. We directly observe weakly dispersive Kondo resonances of f electrons and identify two of the three Ce 4f_{5/2}^{1} crystal-electric-field levels and band-dependent hybridization, which signals that the hybridization occurs primarily between the Ce 4f states in the CeIn_{3} layer and two more three-dimensional bands composed of the Rh 4d and In 5p orbitals in the RhIn_{2} layer. Our results allow us to connect the properties observed at elevated temperatures with the unusual low-temperature properties of this enigmatic heavy fermion compound.
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Affiliation(s)
- Q Y Chen
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Science and Technology on Surface Physics and Chemistry Laboratory, Mianyang 621908, China
| | - D F Xu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - X H Niu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - R Peng
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - H C Xu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - C H P Wen
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - X Liu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - L Shu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - S Y Tan
- Science and Technology on Surface Physics and Chemistry Laboratory, Mianyang 621908, China
| | - X C Lai
- Science and Technology on Surface Physics and Chemistry Laboratory, Mianyang 621908, China
| | - Y J Zhang
- Center for Correlated Matter, Zhejiang University, Hangzhou 310058, China
- Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - H Lee
- Center for Correlated Matter, Zhejiang University, Hangzhou 310058, China
| | - V N Strocov
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - F Bisti
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | - P Dudin
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - J-X Zhu
- Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - H Q Yuan
- Center for Correlated Matter, Zhejiang University, Hangzhou 310058, China
- Department of Physics, Zhejiang University, Hangzhou 310027, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
| | - S Kirchner
- Center for Correlated Matter, Zhejiang University, Hangzhou 310058, China
| | - D L Feng
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
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12
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Schütz P, Di Sante D, Dudy L, Gabel J, Stübinger M, Kamp M, Huang Y, Capone M, Husanu MA, Strocov VN, Sangiovanni G, Sing M, Claessen R. Dimensionality-Driven Metal-Insulator Transition in Spin-Orbit-Coupled SrIrO_{3}. Phys Rev Lett 2017; 119:256404. [PMID: 29303315 DOI: 10.1103/physrevlett.119.256404] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Indexed: 05/27/2023]
Abstract
Upon reduction of the film thickness we observe a metal-insulator transition in epitaxially stabilized, spin-orbit-coupled SrIrO_{3} ultrathin films. By comparison of the experimental electronic dispersions with density functional theory at various levels of complexity we identify the leading microscopic mechanisms, i.e., a dimensionality-induced readjustment of octahedral rotations, magnetism, and electronic correlations. The astonishing resemblance of the band structure in the two-dimensional limit to that of bulk Sr_{2}IrO_{4} opens new avenues to unconventional superconductivity by "clean" electron doping through electric field gating.
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Affiliation(s)
- P Schütz
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - D Di Sante
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - L Dudy
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - J Gabel
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - M Stübinger
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - M Kamp
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Y Huang
- Van der Waals-Zeeman Insitute, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - M Capone
- CNR-IOM-Democritos National Simulation Centre and International School for Advanced Studies (SISSA), Via Bonomea 265, I-34136 Trieste, Italy
| | - M-A Husanu
- National Institute of Materials Physics, Atomistilor 405 A, 077125 Magurele, Romania
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - V N Strocov
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - G Sangiovanni
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - M Sing
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - R Claessen
- Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
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13
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Di Sante D, Das PK, Bigi C, Ergönenc Z, Gürtler N, Krieger JA, Schmitt T, Ali MN, Rossi G, Thomale R, Franchini C, Picozzi S, Fujii J, Strocov VN, Sangiovanni G, Vobornik I, Cava RJ, Panaccione G. Three-Dimensional Electronic Structure of the Type-II Weyl Semimetal WTe_{2}. Phys Rev Lett 2017; 119:026403. [PMID: 28753342 DOI: 10.1103/physrevlett.119.026403] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Indexed: 06/07/2023]
Abstract
By combining bulk sensitive soft-x-ray angular-resolved photoemission spectroscopy and first-principles calculations we explored the bulk electron states of WTe_{2}, a candidate type-II Weyl semimetal featuring a large nonsaturating magnetoresistance. Despite the layered geometry suggesting a two-dimensional electronic structure, we directly observe a three-dimensional electronic dispersion. We report a band dispersion in the reciprocal direction perpendicular to the layers, implying that electrons can also travel coherently when crossing from one layer to the other. The measured Fermi surface is characterized by two well-separated electron and hole pockets at either side of the Γ point, differently from previous more surface sensitive angle-resolved photoemission spectroscopy experiments that additionally found a pronounced quasiparticle weight at the zone center. Moreover, we observe a significant sensitivity of the bulk electronic structure of WTe_{2} around the Fermi level to electronic correlations and renormalizations due to self-energy effects, previously neglected in first-principles descriptions.
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Affiliation(s)
- Domenico Di Sante
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland Campus Süd, Würzburg 97074, Germany
| | - Pranab Kumar Das
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
- International Centre for Theoretical Physics (ICTP), Strada Costiera 11, I-34100 Trieste, Italy
| | - C Bigi
- Dipartimento di Fisica, Universitá di Milano, Via Celoria 16, I-20133 Milano, Italy
| | - Z Ergönenc
- Computational Materials Physics, University of Vienna, Sensengasse 8/8, A-1090 Vienna, Austria
| | - N Gürtler
- Computational Materials Physics, University of Vienna, Sensengasse 8/8, A-1090 Vienna, Austria
| | - J A Krieger
- Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
- Laboratorium für Festkörperphysik, ETH-Hönggerberg, CH-8093 Zürich, Switzerland
| | - T Schmitt
- Paul Scherrer Institute, Swiss Light Source, CH-5232 Villigen, Switzerland
| | - M N Ali
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - G Rossi
- Dipartimento di Fisica, Universitá di Milano, Via Celoria 16, I-20133 Milano, Italy
| | - R Thomale
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland Campus Süd, Würzburg 97074, Germany
| | - C Franchini
- Computational Materials Physics, University of Vienna, Sensengasse 8/8, A-1090 Vienna, Austria
| | - S Picozzi
- Consiglio Nazionale delle Ricerche (CNR-SPIN), Via Vetoio, L'Aquila 67100, Italy
| | - J Fujii
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
| | - V N Strocov
- Paul Scherrer Institute, Swiss Light Source, CH-5232 Villigen, Switzerland
| | - G Sangiovanni
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland Campus Süd, Würzburg 97074, Germany
| | - I Vobornik
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
| | - R J Cava
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - G Panaccione
- Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
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14
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Xu N, Autès G, Matt CE, Lv BQ, Yao MY, Bisti F, Strocov VN, Gawryluk D, Pomjakushina E, Conder K, Plumb NC, Radovic M, Qian T, Yazyev OV, Mesot J, Ding H, Shi M. Distinct Evolutions of Weyl Fermion Quasiparticles and Fermi Arcs with Bulk Band Topology in Weyl Semimetals. Phys Rev Lett 2017; 118:106406. [PMID: 28339253 DOI: 10.1103/physrevlett.118.106406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Indexed: 06/06/2023]
Abstract
The Weyl semimetal phase is a recently discovered topological quantum state of matter characterized by the presence of topologically protected degeneracies near the Fermi level. These degeneracies are the source of exotic phenomena, including the realization of chiral Weyl fermions as quasiparticles in the bulk and the formation of Fermi arc states on the surfaces. Here, we demonstrate that these two key signatures show distinct evolutions with the bulk band topology by performing angle-resolved photoemission spectroscopy, supported by first-principles calculations, on transition-metal monophosphides. While Weyl fermion quasiparticles exist only when the chemical potential is located between two saddle points of the Weyl cone features, the Fermi arc states extend in a larger energy scale and are robust across the bulk Lifshitz transitions associated with the recombination of two nontrivial Fermi surfaces enclosing one Weyl point into a single trivial Fermi surface enclosing two Weyl points of opposite chirality. Therefore, in some systems (e.g., NbP), topological Fermi arc states are preserved even if Weyl fermion quasiparticles are absent in the bulk. Our findings not only provide insight into the relationship between the exotic physical phenomena and the intrinsic bulk band topology in Weyl semimetals, but also resolve the apparent puzzle of the different magnetotransport properties observed in TaAs, TaP, and NbP, where the Fermi arc states are similar.
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Affiliation(s)
- N Xu
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - G Autès
- Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- National Centre for Computational Design and Discovery of Novel Materials MARVEL, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - C E Matt
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - B Q Lv
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - M Y Yao
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - F Bisti
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - V N Strocov
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - D Gawryluk
- Laboratory for Developments and Methods, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - E Pomjakushina
- Laboratory for Developments and Methods, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - K Conder
- Laboratory for Developments and Methods, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - N C Plumb
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - M Radovic
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - T Qian
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - O V Yazyev
- Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- National Centre for Computational Design and Discovery of Novel Materials MARVEL, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - J Mesot
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Laboratory for Solid State Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - H Ding
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100190, China
| | - M Shi
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
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15
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Razzoli E, Jaouen T, Mottas ML, Hildebrand B, Monney G, Pisoni A, Muff S, Fanciulli M, Plumb NC, Rogalev VA, Strocov VN, Mesot J, Shi M, Dil JH, Beck H, Aebi P. Selective Probing of Hidden Spin-Polarized States in Inversion-Symmetric Bulk MoS_{2}. Phys Rev Lett 2017; 118:086402. [PMID: 28282191 DOI: 10.1103/physrevlett.118.086402] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Indexed: 06/06/2023]
Abstract
Spin- and angle-resolved photoemission spectroscopy is used to reveal that a large spin polarization is observable in the bulk centrosymmetric transition metal dichalcogenide MoS_{2}. It is found that the measured spin polarization can be reversed by changing the handedness of incident circularly polarized light. Calculations based on a three-step model of photoemission show that the valley and layer-locked spin-polarized electronic states can be selectively addressed by circularly polarized light, therefore providing a novel route to probe these hidden spin-polarized states in inversion-symmetric systems as predicted by Zhang et al. [Nat. Phys. 10, 387 (2014).NPAHAX1745-247310.1038/nphys2933].
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Affiliation(s)
- E Razzoli
- Département de Physique and Fribourg Center for Nanomaterials, Université de Fribourg, CH-1700 Fribourg, Switzerland
| | - T Jaouen
- Département de Physique and Fribourg Center for Nanomaterials, Université de Fribourg, CH-1700 Fribourg, Switzerland
| | - M-L Mottas
- Département de Physique and Fribourg Center for Nanomaterials, Université de Fribourg, CH-1700 Fribourg, Switzerland
| | - B Hildebrand
- Département de Physique and Fribourg Center for Nanomaterials, Université de Fribourg, CH-1700 Fribourg, Switzerland
| | - G Monney
- Département de Physique and Fribourg Center for Nanomaterials, Université de Fribourg, CH-1700 Fribourg, Switzerland
| | - A Pisoni
- Laboratory of Physics of Complex Matter, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - S Muff
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Institute of Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - M Fanciulli
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Institute of Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - N C Plumb
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - V A Rogalev
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - V N Strocov
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - J Mesot
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Institute of Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
- Laboratory for Solid State Physics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - M Shi
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - J H Dil
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
- Institute of Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - H Beck
- Département de Physique and Fribourg Center for Nanomaterials, Université de Fribourg, CH-1700 Fribourg, Switzerland
| | - P Aebi
- Département de Physique and Fribourg Center for Nanomaterials, Université de Fribourg, CH-1700 Fribourg, Switzerland
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16
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Manzoni G, Gragnaniello L, Autès G, Kuhn T, Sterzi A, Cilento F, Zacchigna M, Enenkel V, Vobornik I, Barba L, Bisti F, Bugnon P, Magrez A, Strocov VN, Berger H, Yazyev OV, Fonin M, Parmigiani F, Crepaldi A. Evidence for a Strong Topological Insulator Phase in ZrTe_{5}. Phys Rev Lett 2016; 117:237601. [PMID: 27982645 DOI: 10.1103/physrevlett.117.237601] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Indexed: 05/05/2023]
Abstract
The complex electronic properties of ZrTe_{5} have recently stimulated in-depth investigations that assigned this material to either a topological insulator or a 3D Dirac semimetal phase. Here we report a comprehensive experimental and theoretical study of both electronic and structural properties of ZrTe_{5}, revealing that the bulk material is a strong topological insulator (STI). By means of angle-resolved photoelectron spectroscopy, we identify at the top of the valence band both a surface and a bulk state. The dispersion of these bands is well captured by ab initio calculations for the STI case, for the specific interlayer distance measured in our x-ray diffraction study. Furthermore, these findings are supported by scanning tunneling spectroscopy revealing the metallic character of the sample surface, thus confirming the strong topological nature of ZrTe_{5}.
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Affiliation(s)
- G Manzoni
- Universitá degli Studi di Trieste, Via Alfonso Valerio 2, Trieste 34127, Italy
| | - L Gragnaniello
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - G Autès
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- National Centre for Computational Design and Discovery of Novel Materials MARVEL, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - T Kuhn
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - A Sterzi
- Universitá degli Studi di Trieste, Via Alfonso Valerio 2, Trieste 34127, Italy
| | - F Cilento
- Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14, km 163.5, Trieste I-34149, Italy
| | - M Zacchigna
- Officina dei Materiali (IOM)-CNR, Laboratorio TASC, Area Science Park - Basovizza, I-34149 Trieste, Italy
| | - V Enenkel
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - I Vobornik
- Officina dei Materiali (IOM)-CNR, Laboratorio TASC, Area Science Park - Basovizza, I-34149 Trieste, Italy
| | - L Barba
- Institute of Crystallography, CNR, Area Science Park, Strada Statale 14, km 163.5 Trieste I-34149, Italy
| | - F Bisti
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Ph Bugnon
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - A Magrez
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - V N Strocov
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - H Berger
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - O V Yazyev
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- National Centre for Computational Design and Discovery of Novel Materials MARVEL, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - M Fonin
- Department of Physics, University of Konstanz, 78457 Konstanz, Germany
| | - F Parmigiani
- Universitá degli Studi di Trieste, Via Alfonso Valerio 2, Trieste 34127, Italy
- Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14, km 163.5, Trieste I-34149, Italy
- International Faculty, University of Köln, 50937 Köln, Germany
| | - A Crepaldi
- Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
- Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14, km 163.5, Trieste I-34149, Italy
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17
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Bouravleuv AD, Lev LL, Piamonteze C, Wang X, Schmitt T, Khrebtov AI, Samsonenko YB, Kanski J, Cirlin GE, Strocov VN. Electronic structure of (In,Mn)As quantum dots buried in GaAs investigated by soft-x-ray ARPES. Nanotechnology 2016; 27:425706. [PMID: 27631689 DOI: 10.1088/0957-4484/27/42/425706] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Electronic structure of a molecular beam epitaxy-grown system of (In,Mn)As quantum dots (QDs) buried in GaAs is explored with soft-x-ray angle-resolved photoelectron spectroscopy (ARPES) using photon energies around 1 keV. This technique, ideally suited for buried systems, extends the momentum-resolving capabilities of conventional ARPES with enhanced probing depth as well as elemental and chemical state specificity achieved with resonant photoexcitation. The experimental results resolve the dispersive energy bands of the GaAs substrate buried in ∼2 nm below the surface, and the impurity states (ISs) derived from the substitutional Mn atoms in the (In,Mn)As QDs and oxidized Mn atoms distributed near the surface. An energy shift of the Mn ISs in the QDs compared to (In,Mn)As DMS is attributed to the band offset and proximity effect at the interface with the surrounding GaAs. The absence of any ISs in the vicinity of the VBM relates the electron transport in (In,Mn)As QDs to the prototype (In,Mn)As diluted magnetic semiconductor. The SX-ARPES results are supported by measurements of the shallow core levels under variation of probing depth through photon energy. X-ray absorption measurements identify significant diffusion of interstitial Mn atoms out of the QDs towards the surface, and the role of magnetic circular dichroism is to block the ferromagnetic response of the (In,Mn)As QDs. Possible routes are drawn to tune the growth procedure aiming at practical applications of the (In,Mn)As based systems.
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Affiliation(s)
- A D Bouravleuv
- St.Petersburg Academic University RAS, 8-3 Khlopina st., 194021 St.Petersburg, Russia. Ioffe Physical Technical Institute RAS, 26 Politekhnicheskaya st., 194021 St.Petersburg, Russia. Institute for Analytical Instrumentation RAS, 31-33 Ivana Chernykh st., 190103 St.Petersburg, Russia. St.Petersburg State University, 7-9 Universitetskaya nab., 199034 St.Petersburg, Russia
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18
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Krempaský J, Muff S, Bisti F, Fanciulli M, Volfová H, Weber AP, Pilet N, Warnicke P, Ebert H, Braun J, Bertran F, Volobuev VV, Minár J, Springholz G, Dil JH, Strocov VN. Entanglement and manipulation of the magnetic and spin-orbit order in multiferroic Rashba semiconductors. Nat Commun 2016; 7:13071. [PMID: 27767052 PMCID: PMC5078730 DOI: 10.1038/ncomms13071] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [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: 05/18/2016] [Accepted: 08/31/2016] [Indexed: 11/17/2022] Open
Abstract
Entanglement of the spin–orbit and magnetic order in multiferroic materials bears a strong potential for engineering novel electronic and spintronic devices. Here, we explore the electron and spin structure of ferroelectric α-GeTe thin films doped with ferromagnetic Mn impurities to achieve its multiferroic functionality. We use bulk-sensitive soft-X-ray angle-resolved photoemission spectroscopy (SX-ARPES) to follow hybridization of the GeTe valence band with the Mn dopants. We observe a gradual opening of the Zeeman gap in the bulk Rashba bands around the Dirac point with increase of the Mn concentration, indicative of the ferromagnetic order, at persistent Rashba splitting. Furthermore, subtle details regarding the spin–orbit and magnetic order entanglement are deduced from spin-resolved ARPES measurements. We identify antiparallel orientation of the ferroelectric and ferromagnetic polarization, and altering of the Rashba-type spin helicity by magnetic switching. Our experimental results are supported by first-principles calculations of the electron and spin structure. In α-GeTe, ferroelectric polarization acts to break inversion symmetry of the lattice and induce a strong Rashba-type spin splitting of the electronic band structure. Here, the authors study how this effect competes with Zeeman splitting due to ferromagnetic exchange coupling in Mn-doped GeTe.
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Affiliation(s)
- J Krempaský
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - S Muff
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.,Institute of Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - F Bisti
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - M Fanciulli
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.,Institute of Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - H Volfová
- Department of Chemistry, Ludwig Maximillian University, 81377 Munich, Germany
| | - A P Weber
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.,Institute of Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - N Pilet
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - P Warnicke
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - H Ebert
- Department of Chemistry, Ludwig Maximillian University, 81377 Munich, Germany
| | - J Braun
- Department of Chemistry, Ludwig Maximillian University, 81377 Munich, Germany
| | - F Bertran
- SOLEIL Synchrotron, L'Orme des Merisiers, F-91192 Gif-sur-Yvette, France
| | - V V Volobuev
- National Technical University, Kharkiv Polytechnic Institute, Frunze Str. 21, 61002 Kharkiv, Ukraine.,Institut für Halbleiter-und Festkörperphysik, Johannes Kepler Universität, A-4040 Linz, Austria
| | - J Minár
- Department of Chemistry, Ludwig Maximillian University, 81377 Munich, Germany.,New Technologies-Research Center University of West Bohemia, Plzeň, Czech Republic
| | - G Springholz
- Institut für Halbleiter-und Festkörperphysik, Johannes Kepler Universität, A-4040 Linz, Austria
| | - J H Dil
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.,Institute of Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - V N Strocov
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
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19
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Dantz M, Pelliciari J, Samal D, Bisogni V, Huang Y, Olalde-Velasco P, Strocov VN, Koster G, Schmitt T. Quenched Magnon excitations by oxygen sublattice reconstruction in (SrCuO2)n/(SrTiO3)2 superlattices. Sci Rep 2016; 6:32896. [PMID: 27616448 PMCID: PMC5018731 DOI: 10.1038/srep32896] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 08/16/2016] [Indexed: 11/14/2022] Open
Abstract
The recently discovered structural reconstruction in the cuprate superlattice (SrCuO2)n/(SrTiO3)2 has been investigated across the critical value of n = 5 using resonant inelastic x-ray scattering (RIXS). We find that at the critical value of n, the cuprate layer remains largely in the bulk-like two-dimensional structure with a minority of Cu plaquettes being reconstructed. The partial reconstruction leads to quenching of the magnons starting at the Γ-point due to the minority plaquettes acting as scattering points. Although comparable in relative abundance, the doped charge impurities in electron-doped cuprate superconductors do not show this quenching of magnetic excitations.
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Affiliation(s)
- M. Dantz
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - J. Pelliciari
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - D. Samal
- MESA+ Institute for Nanotechnology, University of Twente, Post Office Box 217, 7500AE Enschede, The Netherlands
| | - V. Bisogni
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Y. Huang
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - P. Olalde-Velasco
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - V. N. Strocov
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - G. Koster
- MESA+ Institute for Nanotechnology, University of Twente, Post Office Box 217, 7500AE Enschede, The Netherlands
| | - T. Schmitt
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
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20
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Cancellieri C, Mishchenko AS, Aschauer U, Filippetti A, Faber C, Barišić OS, Rogalev VA, Schmitt T, Nagaosa N, Strocov VN. Polaronic metal state at the LaAlO3/SrTiO3 interface. Nat Commun 2016; 7:10386. [PMID: 26813124 PMCID: PMC4737810 DOI: 10.1038/ncomms10386] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [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: 08/11/2015] [Accepted: 12/03/2015] [Indexed: 11/16/2022] Open
Abstract
Interplay of spin, charge, orbital and lattice degrees of freedom in oxide heterostructures results in a plethora of fascinating properties, which can be exploited in new generations of electronic devices with enhanced functionalities. The paradigm example is the interface between the two band insulators LaAlO3 and SrTiO3 that hosts a two-dimensional electron system. Apart from the mobile charge carriers, this system exhibits a range of intriguing properties such as field effect, superconductivity and ferromagnetism, whose fundamental origins are still debated. Here we use soft-X-ray angle-resolved photoelectron spectroscopy to penetrate through the LaAlO3 overlayer and access charge carriers at the buried interface. The experimental spectral function directly identifies the interface charge carriers as large polarons, emerging from coupling of charge and lattice degrees of freedom, and involving two phonons of different energy and thermal activity. This phenomenon fundamentally limits the carrier mobility and explains its puzzling drop at high temperatures.
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Affiliation(s)
- C. Cancellieri
- Swiss Light Source, Paul Scherrer Institute, Villigen CH-5232, Switzerland
- EMPA, Swiss Federal Laboratories for Materials Science & Technology, Ueberlandstrasse 129, Duebendorf 8600, Switzerland
| | - A. S. Mishchenko
- RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - U. Aschauer
- Materials Theory, ETH Zurich, Wolfgang-Pauli-Strasse 27, Zürich CH-8093, Switzerland
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3 3012 Bern, Switzerland
| | - A. Filippetti
- CNR-IOM, Istituto Officina dei Materiali, Cittadella Universitaria, Cagliari, Monserrato 09042-I, Italy
| | - C. Faber
- Materials Theory, ETH Zurich, Wolfgang-Pauli-Strasse 27, Zürich CH-8093, Switzerland
| | - O. S. Barišić
- Institute of Physics, Bijenička 46, 10000 Zagreb, Croatia
| | - V. A. Rogalev
- Swiss Light Source, Paul Scherrer Institute, Villigen CH-5232, Switzerland
| | - T. Schmitt
- Swiss Light Source, Paul Scherrer Institute, Villigen CH-5232, Switzerland
| | - N. Nagaosa
- RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - V. N. Strocov
- Swiss Light Source, Paul Scherrer Institute, Villigen CH-5232, Switzerland
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21
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Rogalev VA, Gröning O, Widmer R, Dil JH, Bisti F, Lev LL, Schmitt T, Strocov VN. Fermi states and anisotropy of Brillouin zone scattering in the decagonal Al-Ni-Co quasicrystal. Nat Commun 2015; 6:8607. [PMID: 26443439 PMCID: PMC4633949 DOI: 10.1038/ncomms9607] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [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: 02/18/2015] [Accepted: 09/10/2015] [Indexed: 11/08/2022] Open
Abstract
Quasicrystals (QCs) are intermetallic alloys that have excellent long-range order but lack translational symmetry in at least one dimension. The valence band electronic structure near the Fermi energy EF in such materials is of special interest since it has a direct relation to their unusual physical properties. However, the Fermi surface (FS) topology as well as the mechanism of QC structure stabilization are still under debate. Here we report the first observation of the three-dimensional FS and valence band dispersions near EF in decagonal Al70Ni20Co10 (d-AlNiCo) QCs using soft X-ray angle-resolved photoemission spectroscopy. We show that the FS, formed by dispersive Al sp-states, has a multicomponent character due to a large contribution from high-order bands. Moreover, we discover that the magnitude of the gap at the FS related to the interaction with Brillouin zone boundary (Hume-Rothery gap) critically differs for the periodic and quasiperiodic directions.
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Affiliation(s)
- V. A. Rogalev
- Department for Synchrotron Radiation and Nanotechnology (SYN), Swiss Light Source, Paul Scherrer Institute, Villigen CH-5232, Switzerland
| | - O. Gröning
- Department of Advanced Materials and Surfaces, EMPA, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, Dübendorf CH-8600, Switzerland
| | - R. Widmer
- Department of Advanced Materials and Surfaces, EMPA, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, Dübendorf CH-8600, Switzerland
| | - J. H. Dil
- Department for Synchrotron Radiation and Nanotechnology (SYN), Swiss Light Source, Paul Scherrer Institute, Villigen CH-5232, Switzerland
- Institute of Condensed Matter Physics, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | - F. Bisti
- Department for Synchrotron Radiation and Nanotechnology (SYN), Swiss Light Source, Paul Scherrer Institute, Villigen CH-5232, Switzerland
| | - L. L. Lev
- Department for Synchrotron Radiation and Nanotechnology (SYN), Swiss Light Source, Paul Scherrer Institute, Villigen CH-5232, Switzerland
- National Research Center Kurchatov Institute, Akademika Kurchatova Square 1, Moscow 123182, Russia
| | - T. Schmitt
- Department for Synchrotron Radiation and Nanotechnology (SYN), Swiss Light Source, Paul Scherrer Institute, Villigen CH-5232, Switzerland
| | - V. N. Strocov
- Department for Synchrotron Radiation and Nanotechnology (SYN), Swiss Light Source, Paul Scherrer Institute, Villigen CH-5232, Switzerland
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22
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Rubensson JE, Söderström J, Binggeli C, Gråsjö J, Andersson J, Såthe C, Hennies F, Bisogni V, Huang Y, Olalde P, Schmitt T, Strocov VN, Föhlisch A, Kennedy B, Pietzsch A. Rydberg-resolved resonant inelastic soft x-ray scattering: dynamics at core ionization thresholds. Phys Rev Lett 2015; 114:133001. [PMID: 25884123 DOI: 10.1103/physrevlett.114.133001] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Indexed: 06/04/2023]
Abstract
Resonant inelastic x-ray scattering spectra excited in the immediate vicinity of the core-level ionization thresholds of N2 have been recorded. Final states of well-resolved symmetry-selected Rydberg series converging to valence-level ionization thresholds with vibrational excitations are observed. The results are well described by a quasi-two-step model which assumes that the excited electron is unaffected by the radiative decay. This threshold dynamics simplifies the interpretation of resonant inelastic x-ray scattering spectra considerably and facilitates characterization of low-energy excited final states in molecular systems.
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Affiliation(s)
- J-E Rubensson
- Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden
| | - J Söderström
- Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden
| | - C Binggeli
- Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden
| | - J Gråsjö
- Department of Pharmacy, Uppsala University, Box 580, SE-751 23 Uppsala, Sweden
| | - J Andersson
- Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden
- Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore
| | - C Såthe
- MAX IV Laboratory, Lund University, Box 118, 221 00 Lund, Sweden
| | - F Hennies
- MAX IV Laboratory, Lund University, Box 118, 221 00 Lund, Sweden
| | - V Bisogni
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Y Huang
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - P Olalde
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - T Schmitt
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - V N Strocov
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - A Föhlisch
- Institute for Methods and Instrumentation in Synchrotron Radiation Research G-ISRR, Helmholtz-Zentrum Berlin für Materialien und Energie Albert-Einstein-Strasse 15, 12489 Berlin, Germany
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany
| | - B Kennedy
- Institute for Methods and Instrumentation in Synchrotron Radiation Research G-ISRR, Helmholtz-Zentrum Berlin für Materialien und Energie Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - A Pietzsch
- Institute for Methods and Instrumentation in Synchrotron Radiation Research G-ISRR, Helmholtz-Zentrum Berlin für Materialien und Energie Albert-Einstein-Strasse 15, 12489 Berlin, Germany
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23
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Pietzsch A, Hennies F, Miedema PS, Kennedy B, Schlappa J, Schmitt T, Strocov VN, Föhlisch A. Snapshots of the fluctuating hydrogen bond network in liquid water on the sub-femtosecond timescale with vibrational resonant inelastic x-ray scattering. Phys Rev Lett 2015; 114:088302. [PMID: 25768783 DOI: 10.1103/physrevlett.114.088302] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Indexed: 05/24/2023]
Abstract
Liquid water molecules interact strongly with each other, forming a fluctuating hydrogen bond network and thereby giving rise to the anomalous phase diagram of liquid water. Consequently, symmetric and asymmetric water molecules have been found in the picosecond time average with IR and optical Raman spectroscopy. With subnatural linewidth resonant inelastic x-ray scattering (RIXS) at vibrational resolution, we take sub-femtosecond snapshots of the electronic and structural properties of water molecules in the hydrogen bond network. We derive a strong dominance of nonsymmetric molecules in liquid water in contrast to the gas phase on the sub-femtosecond timescale of RIXS and determine the fraction of highly asymmetrically distorted molecules.
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Affiliation(s)
- A Pietzsch
- Institute for Methods and Instrumentation in Synchrotron Radiation Research G-ISRR, Helmholtz-Zentrum für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - F Hennies
- MAX IV Laboratory, Box 118, 22100 Lund, Sweden
| | - P S Miedema
- Institute for Methods and Instrumentation in Synchrotron Radiation Research G-ISRR, Helmholtz-Zentrum für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - B Kennedy
- Institute for Methods and Instrumentation in Synchrotron Radiation Research G-ISRR, Helmholtz-Zentrum für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - J Schlappa
- Institute for Methods and Instrumentation in Synchrotron Radiation Research G-ISRR, Helmholtz-Zentrum für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - T Schmitt
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - V N Strocov
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - A Föhlisch
- Institute for Methods and Instrumentation in Synchrotron Radiation Research G-ISRR, Helmholtz-Zentrum für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
- Fakultät für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany
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24
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Magnuson M, Schmitt T, Strocov VN, Schlappa J, Kalabukhov AS, Duda LC. Self-doping processes between planes and chains in the metal-to-superconductor transition of YBa2Cu3O6.9. Sci Rep 2014; 4:7017. [PMID: 25388860 PMCID: PMC4228345 DOI: 10.1038/srep07017] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [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: 07/28/2014] [Accepted: 10/20/2014] [Indexed: 11/08/2022] Open
Abstract
The interplay between the quasi 1-dimensional CuO-chains and the 2-dimensional CuO2 planes of YBa(2)Cu(3)O(6+x) (YBCO) has been in focus for a long time. Although the CuO-chains are known to be important as charge reservoirs that enable superconductivity for a range of oxygen doping levels in YBCO, the understanding of the dynamics of its temperature-driven metal-superconductor transition (MST) remains a challenge. We present a combined study using x-ray absorption spectroscopy and resonant inelastic x-ray scattering (RIXS) revealing how a reconstruction of the apical O(4)-derived interplanar orbitals during the MST of optimally doped YBCO leads to substantial hole-transfer from the chains into the planes, i.e. self-doping. Our ionic model calculations show that localized divalent charge-transfer configurations are expected to be abundant in the chains of YBCO. While these indeed appear in the RIXS spectra from YBCO in the normal, metallic, state, they are largely suppressed in the superconducting state and, instead, signatures of Cu trivalent charge-transfer configurations in the planes become enhanced. In the quest for understanding the fundamental mechanism for high-Tc-superconductivity (HTSC) in perovskite cuprate materials, the observation of such an interplanar self-doping process in YBCO opens a unique novel channel for studying the dynamics of HTSC.
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Affiliation(s)
- M. Magnuson
- Department of Physics, Chemistry and Biology, IFM, Thin Film Physics Division, Linköping University, SE-58183 Linköping, Sweden
| | - T. Schmitt
- Paul Scherrer Institut, Swiss Light Source (SLS), CH-5232 Villigen PSI, Switzerland
| | - V. N. Strocov
- Paul Scherrer Institut, Swiss Light Source (SLS), CH-5232 Villigen PSI, Switzerland
| | - J. Schlappa
- Paul Scherrer Institut, Swiss Light Source (SLS), CH-5232 Villigen PSI, Switzerland
- Institut Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung (G-ISRR), Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, D-12489 Berlin, Germany
| | - A. S. Kalabukhov
- Quantum Devices Physics Group, Department of Microtechnology and Nanoscience-MC2, Chalmers University of Technology, SE412 96 Gothenburg, Sweden
| | - L.-C. Duda
- Department of Physics and Astronomy, Division of Molecular and Condensed Matter Physics, Uppsala University, Box 516, S-751 20 Uppsala, Sweden
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25
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Strocov VN, Wang X, Shi M, Kobayashi M, Krempasky J, Hess C, Schmitt T, Patthey L. Soft-X-ray ARPES facility at the ADRESS beamline of the SLS: concepts, technical realisation and scientific applications. J Synchrotron Radiat 2014; 21:32-44. [PMID: 24365914 DOI: 10.1107/s1600577513019085] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 07/10/2013] [Indexed: 06/03/2023]
Abstract
Soft-X-ray angle-resolved photoelectron spectroscopy (ARPES) with photon energies around 1 keV combines the momentum space resolution with increasing probing depth. The concepts and technical realisation of the new soft-X-ray ARPES endstation at the ADRESS beamline of SLS are described. The experimental geometry of the endstation is characterized by grazing X-ray incidence on the sample to increase the photoyield and vertical orientation of the measurement plane. The vacuum chambers adopt a radial layout allowing most efficient sample transfer. High accuracy of the angular resolution is ensured by alignment strategies focused on precise matching of the X-ray beam and optical axis of the analyzer. The high photon flux of up to 10(13) photons s(-1) (0.01% bandwidth)(-1) delivered by the beamline combined with the optimized experimental geometry break through the dramatic loss of the valence band photoexcitation cross section at soft-X-ray energies. ARPES images with energy resolution up to a few tens of meV are typically acquired on the time scale of minutes. A few application examples illustrate the power of our advanced soft-X-ray ARPES instrumentation to explore the electronic structure of bulk crystals with resolution in three-dimensional momentum, access buried heterostructures and study elemental composition of the valence states using resonant excitation.
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Affiliation(s)
- V N Strocov
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - X Wang
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - M Shi
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - M Kobayashi
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - J Krempasky
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - C Hess
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - T Schmitt
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - L Patthey
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
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26
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Ilakovac V, Guarise M, Grioni M, Schmitt T, Zhou K, Braicovich L, Ghiringhelli G, Strocov VN, Berger H. Opening of a Peierls gap in BaVS3 probed by V L3 edge resonant inelastic x-ray scattering. J Phys Condens Matter 2013; 25:505602. [PMID: 24275702 DOI: 10.1088/0953-8984/25/50/505602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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
V L3 edge resonant inelastic x-ray scattering measurements performed on high quality BaVS3 single crystals reveal that the intra-t2g dd excitations close to the elastic peak are suppressed below the metal-insulator transition induced by the Peierls instability. The depletion of electronic states close to the Fermi level represents a direct observation of the opening of a charge gap inside the t2g manifold.
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Affiliation(s)
- V Ilakovac
- Université Pierre et Marie Curie, CNRS UMR 7614, LCP-MR, F-75231 Paris, France. Université de Cergy-Pontoise, F-95031 Cergy-Pontoise, France
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27
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Höppner M, Seiro S, Chikina A, Fedorov A, Güttler M, Danzenbächer S, Generalov A, Kummer K, Patil S, Molodtsov SL, Kucherenko Y, Geibel C, Strocov VN, Shi M, Radovic M, Schmitt T, Laubschat C, Vyalikh DV. Interplay of Dirac fermions and heavy quasiparticles in solids. Nat Commun 2013; 4:1646. [PMID: 23552061 DOI: 10.1038/ncomms2654] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 02/26/2013] [Indexed: 11/09/2022] Open
Abstract
Many-body interactions in crystalline solids can be conveniently described in terms of quasiparticles with strongly renormalized masses as compared with those of non-interacting particles. Examples of extreme mass renormalization are on the one hand graphene, where the charge carriers obey the linear dispersion relation of massless Dirac fermions, and on the other hand heavy-fermion materials where the effective electron mass approaches the mass of a proton. Here we show that both extremes, Dirac fermions, like they are found in graphene and extremely heavy quasiparticles characteristic for Kondo materials, may not only coexist in a solid but can also undergo strong mutual interactions. Using the example of EuRh₂Si₂, we explicitly demonstrate that these interactions can take place at the surface and in the bulk. The presence of the linear dispersion is imposed solely by the crystal symmetry, whereas the existence of heavy quasiparticles is caused by the localized nature of the 4f states.
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Affiliation(s)
- M Höppner
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
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28
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Sun YP, Miao Q, Pietzsch A, Hennies F, Schmitt T, Strocov VN, Andersson J, Kennedy B, Schlappa J, Föhlisch A, Gel'mukhanov F, Rubensson JE. Interference between resonant and nonresonant inelastic x-ray scattering. Phys Rev Lett 2013; 110:223001. [PMID: 23767717 DOI: 10.1103/physrevlett.110.223001] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Indexed: 06/02/2023]
Abstract
A detailed study of inelastic x-ray scattering from the ground state to the 3Σg(3σ(g)(-1)3s(g)1) state of the O2 molecule is presented. The observed angular anisotropy shows that the vibrational excitations within this final state are strongly dependent on the polarization of the incident radiation. The analysis demonstrates that this is a manifestation of interference between resonant and direct nonresonant inelastic x-ray scattering. This interference provides a new tool to monitor nuclear dynamics by relative rotation of the polarization vectors of the incident and scattered photons.
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Affiliation(s)
- Y-P Sun
- School of Science, Shandong University of Technology, ZiBo, 255049 Shandong, People's Republic of China.
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29
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Dean MPM, James AJA, Springell RS, Liu X, Monney C, Zhou KJ, Konik RM, Wen JS, Xu ZJ, Gu GD, Strocov VN, Schmitt T, Hill JP. High-energy magnetic excitations in the cuprate superconductor Bi(2)Sr(2)CaCu(2)O(8+δ): towards a unified description of its electronic and magnetic degrees of freedom. Phys Rev Lett 2013; 110:147001. [PMID: 25167025 DOI: 10.1103/physrevlett.110.147001] [Citation(s) in RCA: 15] [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: 11/26/2012] [Indexed: 06/03/2023]
Abstract
We investigate the high-energy magnetic excitation spectrum of the high-T(c) cuprate superconductor Bi(2)Sr(2)CaCu(2)O(8+δ) (Bi-2212) using Cu L(3) edge resonant inelastic x-ray scattering. Broad, dispersive magnetic excitations are observed, with a zone boundary energy of ∼ 300 meV and a weak dependence on doping. These excitations are strikingly similar to the bosons proposed to explain the high-energy "kink" observed in photoemission. A phenomenological calculation of the spin response, based on a parametrization of the the angle-resolved photoemission spectroscopy derived electronic structure and Yang-Rice-Zhang quasiparticles, provides a reasonable prediction of the energy dispersion of the observed magnetic excitations. These results indicate a possible unified framework to reconcile the magnetic and electronic properties of the cuprates and we discuss the advantages and disadvantages of such an approach.
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Affiliation(s)
- M P M Dean
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - A J A James
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - R S Springell
- Royal Commission for the Exhibition of 1851 Research Fellow, Interface Analysis Centre, University of Bristol, Bristol BS2 8BS, United Kingdom and London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - X Liu
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - C Monney
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - K J Zhou
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - R M Konik
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - J S Wen
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Z J Xu
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - G D Gu
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - V N Strocov
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - T Schmitt
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - J P Hill
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
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30
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Cancellieri C, Reinle-Schmitt ML, Kobayashi M, Strocov VN, Schmitt T, Willmott PR, Gariglio S, Triscone JM. Interface Fermi states of LaAlO3/SrTiO3 and related heterostructures. Phys Rev Lett 2013; 110:137601. [PMID: 23581372 DOI: 10.1103/physrevlett.110.137601] [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: 07/17/2012] [Indexed: 06/02/2023]
Abstract
The interfaces of LaAlO3/SrTiO3 and (LaAlO3)(x)(SrTiO3)(1-x)/SrTiO3 heterostructures have been investigated by soft x-ray photoelectron spectroscopy for different layer thicknesses across the insulator-to-metal interface transition. The valence band and Fermi edge were probed using resonant photoemission across the Ti L(2,3) absorption edge. The presence of a Fermi-edge signal originating from the partially filled Ti 3d orbitals is only found in the conducting samples. No Fermi-edge signal could be detected for insulating samples below the critical thickness. Furthermore, the angular dependence of the Fermi intensity allows the determination of the spatial extent of the conducting electron density perpendicular to the interface.
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Affiliation(s)
- C Cancellieri
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen, Switzerland.
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31
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Bondino F, Barla A, Schmitt T, Strocov VN, Henry JY, Sanchez JP. Revealing the insulating gap in α'-NaV (2)O(5) with resonant inelastic x-ray scattering. J Phys Condens Matter 2012; 24:325402-5. [PMID: 22809788 DOI: 10.1088/0953-8984/24/32/325402] [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: 06/01/2023]
Abstract
We measured the low energy excitation spectrum of α'-NaV (2)O(5) across its charge ordering and crystallographic phase transition with resonant inelastic x-ray scattering (RIXS) at the V L(3) edge. Exploiting the polarization dependence of the RIXS signal and the high resolution of the data, we reveal the excitation across the insulating gap at 1 eV and identify the excitations from occupied 3d(xy) bonding orbitals to unoccupied bonding 3d(xy) and 3d(yz)/3d(xz) orbitals. Furthermore we observe a progressive change of the electronic structure of α'-NaV (2)O(5) induced by soft x-ray irradiation, with the appearance of features characteristic of sodium deficient Na(x)V (2)O(5) (x < 1).
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Affiliation(s)
- F Bondino
- IOM CNR, Laboratorio TASC, S.S. 14, km 163.5, I-34012 Trieste, Italy.
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32
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Monney C, Zhou KJ, Cercellier H, Vydrova Z, Garnier MG, Monney G, Strocov VN, Berger H, Beck H, Schmitt T, Aebi P. Mapping of electron-hole excitations in the charge-density-wave system 1T-TiSe2 using resonant inelastic x-ray scattering. Phys Rev Lett 2012; 109:047401. [PMID: 23006106 DOI: 10.1103/physrevlett.109.047401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Indexed: 06/01/2023]
Abstract
In high-resolution resonant inelastic x-ray scattering at the Ti L edge of the charge-density-wave system 1T-TiSe(2), we observe sharp low energy loss peaks from electron-hole pair excitations developing at low temperature. These excitations are strongly dispersing as a function of the transferred momentum of light. We show that the unoccupied bands close to the Fermi level can effectively be probed in this broadband material. Furthermore, we extract the order parameter of the charge-density-wave phase from temperature-dependent measurements.
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Affiliation(s)
- C Monney
- Research Department Synchrotron Radiation and Nanotechnology, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
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33
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Razzoli E, Kobayashi M, Strocov VN, Delley B, Bukowski Z, Karpinski J, Plumb NC, Radovic M, Chang J, Schmitt T, Patthey L, Mesot J, Shi M. Bulk electronic structure of superconducting LaRu2P2 single crystals measured by soft-X-ray angle-resolved photoemission spectroscopy. Phys Rev Lett 2012; 108:257005. [PMID: 23004645 DOI: 10.1103/physrevlett.108.257005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Indexed: 06/01/2023]
Abstract
We present a soft x-ray angle-resolved photoemission spectroscopy (SX-ARPES) study of the stoichiometric pnictide superconductor LaRu(2)P(2). The observed electronic structure is in good agreement with density functional theory (DFT) calculations. However, it is significantly different from its counterpart in high-temperature superconducting Fe pnictides. In particular, the bandwidth renormalization present in the Fe pnictides (~2-3) is negligible in LaRu(2)P(2) even though the mass enhancement is similar in both systems. Our results suggest that the superconductivity in LaRu(2) P(2) has a different origin with respect to the iron pnictides. Finally, we demonstrate that the increased probing depth of SX-ARPES, compared to the widely used ultraviolet ARPES, is essential in determining the bulk electronic structure in the experiment.
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Affiliation(s)
- E Razzoli
- Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
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Glawion S, Heidler J, Haverkort MW, Duda LC, Schmitt T, Strocov VN, Monney C, Zhou KJ, Ruff A, Sing M, Claessen R. Two-spinon and orbital excitations of the spin-Peierls system TiOCl. Phys Rev Lett 2011; 107:107402. [PMID: 21981527 DOI: 10.1103/physrevlett.107.107402] [Citation(s) in RCA: 5] [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: 11/08/2010] [Revised: 05/04/2011] [Indexed: 05/31/2023]
Abstract
We combine high-resolution resonant inelastic x-ray scattering with cluster calculations utilizing a recently derived effective magnetic scattering operator to analyze the polarization, excitation energy, and momentum-dependent excitation spectrum of the low-dimensional quantum magnet TiOCl in the range expected for orbital and magnetic excitations (0-2.5 eV). Ti 3d orbital excitations yield complete information on the temperature-dependent crystal-field splitting. In the spin-Peierls phase we observe a dispersive two-spinon excitation and estimate the inter- and intradimer magnetic exchange coupling from a comparison to cluster calculations.
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Affiliation(s)
- S Glawion
- Experimentelle Physik 4, Universität Würzburg, 97074 Würzburg, Germany
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35
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Pietzsch A, Sun YP, Hennies F, Rinkevicius Z, Karlsson HO, Schmitt T, Strocov VN, Andersson J, Kennedy B, Schlappa J, Föhlisch A, Rubensson JE, Gel'mukhanov F. Spatial quantum beats in vibrational resonant inelastic soft x-ray scattering at dissociating states in oxygen. Phys Rev Lett 2011; 106:153004. [PMID: 21568552 DOI: 10.1103/physrevlett.106.153004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Indexed: 05/24/2023]
Abstract
Resonant inelastic soft x-ray scattering (RIXS) spectra excited at the 1σ(g) → 3σ(u) resonance in gas-phase O2 show excitations due to the nuclear degrees of freedom with up to 35 well-resolved discrete vibronic states and a continuum due to the kinetic energy distribution of the separated atoms. The RIXS profile demonstrates spatial quantum beats caused by two interfering wave packets with different momenta as the atoms separate. Thomson scattering strongly affects both the spectral profile and the scattering anisotropy.
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Affiliation(s)
- A Pietzsch
- MAX-lab, Lund University, Box 118, S-221 00 Lund, Sweden
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36
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Strocov VN, Schmitt T, Flechsig U, Patthey L, Chiuzbăian GS. Numerical optimization of spherical variable-line-spacing grating X-ray spectrometers. J Synchrotron Radiat 2011; 18:134-42. [PMID: 21335898 PMCID: PMC3133478 DOI: 10.1107/s0909049510054452] [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] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Accepted: 12/27/2010] [Indexed: 05/09/2023]
Abstract
Operation of an X-ray spectrometer based on a spherical variable-line-spacing (VLS) grating is analyzed using dedicated ray-tracing software allowing fast optimization of the grating parameters and spectrometer geometry. The analysis is illustrated with optical design of a model spectrometer to deliver a resolving power above 20400 at a photon energy of 930 eV (Cu L-edge). With this energy taken as reference, the VLS coefficients are optimized to cancel the lineshape asymmetry (mostly from the coma aberrations) as well as minimize the symmetric aberration broadening at large grating illuminations, dramatically increasing the aberration-limited vertical acceptance of the spectrometer. For any energy away from the reference, corrections to the entrance arm and light incidence angle on the grating are evaluated to maintain the exactly symmetric lineshape. Furthermore, operational modes when these corrections are coordinated are evaluated to maintain either energy-independent focal curve inclination or maximal aberration-limited spectrometer acceptance. The results are supported by analytical evaluation of the coma term of the optical path function. This analysis thus gives a recipe for designing a high-resolution spherical VLS grating spectrometer operating with negligible aberrations at large acceptance and over an extended energy range.
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Affiliation(s)
- V N Strocov
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland.
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37
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Guarise M, Dalla Piazza B, Moretti Sala M, Ghiringhelli G, Braicovich L, Berger H, Hancock JN, van der Marel D, Schmitt T, Strocov VN, Ament LJP, van den Brink J, Lin PH, Xu P, Rønnow HM, Grioni M. Measurement of magnetic excitations in the two-dimensional antiferromagnetic Sr₂CuO₂Cl₂ insulator using resonant x-ray scattering: evidence for extended interactions. Phys Rev Lett 2010; 105:157006. [PMID: 21230933 DOI: 10.1103/physrevlett.105.157006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Indexed: 05/30/2023]
Abstract
We measured the momentum dependence of magnetic excitations in the model spin-1/2 2D antiferromagnetic insulator Sr2CuO2Cl2 (SCOC). We identify a single-spin-wave feature and a multimagnon continuum, with different polarization dependences. The spin waves display a large (70 meV) dispersion between the zone-boundary points (π, 0) and (π/2, π/2). Employing an extended t-t'-t''-U one-band Hubbard model, we find significant electronic hopping beyond nearest-neighbor Cu ions, indicative of extended magnetic interactions. The spectral line shape at (π, 0) indicates sizable quantum effects in SCOC and probably more generally in the cuprates.
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Affiliation(s)
- M Guarise
- Institute of Condensed Matter Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015, Switzerland
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38
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Strocov VN, Schmitt T, Flechsig U, Schmidt T, Imhof A, Chen Q, Raabe J, Betemps R, Zimoch D, Krempasky J, Wang X, Grioni M, Piazzalunga A, Patthey L. High-resolution soft X-ray beamline ADRESS at the Swiss Light Source for resonant inelastic X-ray scattering and angle-resolved photoelectron spectroscopies. J Synchrotron Radiat 2010; 17:631-43. [PMID: 20724785 PMCID: PMC2927903 DOI: 10.1107/s0909049510019862] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Accepted: 05/26/2010] [Indexed: 05/22/2023]
Abstract
The concepts and technical realisation of the high-resolution soft X-ray beamline ADRESS operating in the energy range from 300 to 1600 eV and intended for resonant inelastic X-ray scattering (RIXS) and angle-resolved photoelectron spectroscopy (ARPES) are described. The photon source is an undulator of novel fixed-gap design where longitudinal movement of permanent magnetic arrays controls not only the light polarization (including circular and 0-180 degrees rotatable linear polarizations) but also the energy without changing the gap. The beamline optics is based on the well established scheme of plane-grating monochromator operating in collimated light. The ultimate resolving power E/DeltaE is above 33000 at 1 keV photon energy. The choice of blazed versus lamellar gratings and optimization of their profile parameters is described. Owing to glancing angles on the mirrors as well as optimized groove densities and profiles of the gratings, the beamline is capable of delivering high photon flux up to 1 x 10(13) photons s(-1) (0.01% BW)(-1) at 1 keV. Ellipsoidal refocusing optics used for the RIXS endstation demagnifies the vertical spot size down to 4 microm, which allows slitless operation and thus maximal transmission of the high-resolution RIXS spectrometer delivering E/DeltaE > 11000 at 1 keV photon energy. Apart from the beamline optics, an overview of the control system is given, the diagnostics and software tools are described, and strategies used for the optical alignment are discussed. An introduction to the concepts and instrumental realisation of the ARPES and RIXS endstations is given.
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Affiliation(s)
- V N Strocov
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen-PSI, Switzerland.
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39
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Braicovich L, van den Brink J, Bisogni V, Sala MM, Ament LJP, Brookes NB, De Luca GM, Salluzzo M, Schmitt T, Strocov VN, Ghiringhelli G. Magnetic excitations and phase separation in the underdoped La2-xSrxCuO4 superconductor measured by resonant inelastic X-ray scattering. Phys Rev Lett 2010; 104:077002. [PMID: 20366909 DOI: 10.1103/physrevlett.104.077002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Indexed: 05/23/2023]
Abstract
We probe the collective magnetic modes of La2CuO4 and underdoped La2-xSrxCuO4 (LSCO) by momentum resolved resonant inelastic x-ray scattering (RIXS) at the Cu L3 edge. For the undoped antiferromagnetic sample, we show that the single magnon dispersion measured with RIXS coincides with the one determined by inelastic neutron scattering, thus demonstrating that x rays are an alternative to neutrons in this field. In the spin dynamics of LSCO, we find a branch dispersing up to approximately 400 meV coexisting with one at lower energy. The high-energy branch has never been seen before. It indicates that underdoped LSCO is in a dynamic inhomogeneous spin state.
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Affiliation(s)
- L Braicovich
- CNR-INFM Coherentia and Soft, Dipartimento di Fisica, Politecnico di Milano, I-20133 Milano, Italy
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40
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Strocov VN. Concept of a spectrometer for resonant inelastic X-ray scattering with parallel detection in incoming and outgoing photon energies. J Synchrotron Radiat 2010; 17:103-106. [PMID: 20029118 DOI: 10.1107/s0909049509051097] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Accepted: 11/26/2009] [Indexed: 05/28/2023]
Abstract
A spectrometer for resonant inelastic X-ray scattering (RIXS) is proposed where imaging and dispersion actions in two orthogonal planes are combined to deliver a full two-dimensional map of RIXS intensity in one shot with parallel detection at incoming hv(in) and outgoing hv(out) photon energies. Preliminary ray-tracing simulations with a typical undulator beamline demonstrate a resolving power well above 11000 with both hv(in) and hv(out) near 930 eV, with a vast potential for improvement. Combining this instrument - nicknamed hv(2) spectrometer - with an X-ray free-electron laser source simplifies its technical implementation and enables efficient time-resolved RIXS experiments.
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Affiliation(s)
- V N Strocov
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland.
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41
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Abstract
An experimental and theoretical study of very-low-energy electron diffraction from the (0001) surface of 1T TiS(2) is presented. The normal incidence electron transmission spectrum is measured up to 37 eV above the Fermi level. Ab initio calculations of the spectra are performed with the full-potential extended linear augmented plane wave [Formula: see text] method. The experimental spectrum is interpreted in terms of the unoccupied complex band structure (CBS) of the semi-infinite crystal. Three CBS branches responsible for the electron transmission at normal incidence are determined. The role of inelastic scattering is discussed. The energy dependence of the optical potential V(i) is determined from the shape of the experimental spectral structures. A sharp increase of V(i) at 21.5 eV is detected, which is associated with a plasmon peak in the electron energy-loss function.
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Affiliation(s)
- E E Krasovskii
- Institute of Metal Physics, National Academy of Sciences of Ukraine, Kiev, Ukraine. Departamento de Física de Materiales, Facultad de Químicas, Universidad del País Vasco, Apartado 1072, San Sebastián/Donostia, 20080 Basque Country, Spain. Donostia International Physics Center (DIPC), Paseo de Manuel Lardizibal, 4 San Sebastián/Donostia, 20018 Basque Country, Spain
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Schlappa J, Schmitt T, Vernay F, Strocov VN, Ilakovac V, Thielemann B, Rønnow HM, Vanishri S, Piazzalunga A, Wang X, Braicovich L, Ghiringhelli G, Marin C, Mesot J, Delley B, Patthey L. Collective magnetic excitations in the spin ladder Sr14Cu24O41 measured using high-resolution resonant inelastic x-ray scattering. Phys Rev Lett 2009; 103:047401. [PMID: 19659397 DOI: 10.1103/physrevlett.103.047401] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Indexed: 05/28/2023]
Abstract
We investigate magnetic excitations in the spin-ladder compound Sr_{14}Cu_{24}O_{41} using high-resolution Cu L_{3} edge resonant inelastic x-ray scattering (RIXS). Our findings demonstrate that RIXS couples to two-triplon collective excitations. In contrast to inelastic neutron scattering, the RIXS cross section changes only moderately over the entire Brillouin zone, revealing high sensitivity also at small momentum transfers, allowing determination of the two-triplon energy gap as 100 +/- 30 meV. Our results are backed by calculations within an effective Hubbard model for a finite-size cluster, and confirm that optical selection rules are obeyed for excitations from this spherically symmetric quantum spin-liquid ground state.
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Affiliation(s)
- J Schlappa
- Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
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43
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Ghiringhelli G, Piazzalunga A, Dallera C, Schmitt T, Strocov VN, Schlappa J, Patthey L, Wang X, Berger H, Grioni M. Observation of two nondispersive magnetic excitations in NiO by resonant inelastic soft-X-Ray scattering. Phys Rev Lett 2009; 102:027401. [PMID: 19257316 DOI: 10.1103/physrevlett.102.027401] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Indexed: 05/27/2023]
Abstract
We present high resolution (DeltaE=120 meV) resonant inelastic x-ray scattering data measured at the Ni L3 edge (2p_{3/2}-->3d) on the paradigmatic antiferromagnetic oxide NiO. Spectra reveal clear signatures of magnetic excitations at approximately 95 and approximately 190 meV whose energy seems independent from transferred momentum. These spectral features are well reproduced by a single Ni2+ ion model in an effective exchange field. Within this local model the two magnetic excitations are characterized by a variation of the atomic magnetic moment along the local ordering direction (DeltaS_{alpha}) of one and two units. The DeltaS_{alpha}=2 case has different nature from bimagnons observed in optical Raman spectra, for which DeltaS_{alpha}=0.
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Affiliation(s)
- G Ghiringhelli
- CNR-INFM Coherentia and Soft, Dipartimento di Fisica, Politecnico di Milano, piazza Leonardo da Vinci 32, I-20133 Milano, Italy
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44
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Mans A, Santoso I, Huang Y, Siu WK, Tavaddod S, Arpiainen V, Lindroos M, Berger H, Strocov VN, Shi M, Patthey L, Golden MS. Experimental proof of a structural origin for the shadow fermi surface of Bi2Sr2CaCu2O8+delta. Phys Rev Lett 2006; 96:107007. [PMID: 16605782 DOI: 10.1103/physrevlett.96.107007] [Citation(s) in RCA: 3] [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: 08/03/2005] [Indexed: 05/08/2023]
Abstract
By combining surprising new results from a full polarization analysis of nodal angle-resolved photoemission data from pristine and modulation-free Bi(2)Sr(2)CaCu(2)O(8+delta) with structural information from LEED and ab initio one-step photoemission simulations, we prove that the shadow Fermi surface in these systems is of structural origin, being due to orthorhombic distortions from tetragonal symmetry present both in surface and bulk. Consequently, one of the longest standing open issues in the investigation of the Fermi surface of these widely studied systems finally meets its resolution.
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Affiliation(s)
- A Mans
- van der Waals-Zeeman Institute, University of Amsterdam, NL-1018XE Amsterdam, The Netherlands
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45
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Bovet M, Strocov VN, Clerc F, Koitzsch C, Naumović D, Aebi P. Excited states mapped by secondary photoemission. Phys Rev Lett 2004; 93:107601. [PMID: 15447452 DOI: 10.1103/physrevlett.93.107601] [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: 01/21/2004] [Indexed: 05/24/2023]
Abstract
We report on angle-resolved photoemission (ARPES) experiments on Cu(110) using Mg K(alpha) radiation. The secondary emission (SE) fine structure of electrons below 50 eV is found to map the empty band structure relevant for absolute band mapping in ARPES. The finding is based on a direct comparison of our experiments with very low-energy electron diffraction data [Phys. Rev. Lett. 81, 4943 (1998)]] recently shown to map the unoccupied states representing the photoemission final-state. This suggests a new theoretical approach to the SE process treating the outgoing electron state as the time-reversed diffraction state.
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Affiliation(s)
- M Bovet
- Institut de Physique, Université de Neuchâtel, CH-2000 Neuchâtel, Switzerland
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46
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Strocov VN, Starnberg HI. Absolute band-structure determination by target current spectroscopy: Application to Cu(100). Phys Rev B Condens Matter 1995; 52:8759-8765. [PMID: 9979865 DOI: 10.1103/physrevb.52.8759] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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