1
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Suzuki H, Wang L, Bertinshaw J, Strand HUR, Käser S, Krautloher M, Yang Z, Wentzell N, Parcollet O, Jerzembeck F, Kikugawa N, Mackenzie AP, Georges A, Hansmann P, Gretarsson H, Keimer B. Distinct spin and orbital dynamics in Sr 2RuO 4. Nat Commun 2023; 14:7042. [PMID: 37923750 PMCID: PMC10624926 DOI: 10.1038/s41467-023-42804-3] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 10/20/2023] [Indexed: 11/06/2023] Open
Abstract
The unconventional superconductor Sr2RuO4 has long served as a benchmark for theories of correlated-electron materials. The determination of the superconducting pairing mechanism requires detailed experimental information on collective bosonic excitations as potential mediators of Cooper pairing. We have used Ru L3-edge resonant inelastic x-ray scattering to obtain comprehensive maps of the electronic excitations of Sr2RuO4 over the entire Brillouin zone. We observe multiple branches of dispersive spin and orbital excitations associated with distinctly different energy scales. The spin and orbital dynamical response functions calculated within the dynamical mean-field theory are in excellent agreement with the experimental data. Our results highlight the Hund metal nature of Sr2RuO4 and provide key information for the understanding of its unconventional superconductivity.
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Affiliation(s)
- H Suzuki
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569, Stuttgart, Germany.
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, 980-8578, Japan.
- Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Sendai, 980-8578, Japan.
| | - L Wang
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569, Stuttgart, Germany
| | - J Bertinshaw
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569, Stuttgart, Germany
| | - H U R Strand
- School of Science and Technology, Örebro University, Fakultetsgatan 1, SE-701 82, Örebro, Sweden
- Institute for Molecules and Materials, Radboud University, 6525 AJ, Nijmegen, the Netherlands
| | - S Käser
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569, Stuttgart, Germany
- Department of Physics, Friedrich-Alexander-University (FAU) of Erlangen-Nürnberg, 91058, Erlangen, Germany
| | - M Krautloher
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569, Stuttgart, Germany
| | - Z Yang
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569, Stuttgart, Germany
| | - N Wentzell
- Center for Computational Quantum Physics, Flatiron Institute, Simons Foundation, 162 5th Avenue, New York, 10010, USA
| | - O Parcollet
- Center for Computational Quantum Physics, Flatiron Institute, Simons Foundation, 162 5th Avenue, New York, 10010, USA
- Université Paris-Saclay, CNRS, CEA, Institut de physique théorique, 91191, Gif-sur-Yvette, France
| | - F Jerzembeck
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187, Dresden, Germany
| | - N Kikugawa
- National Institute for Materials Science, Tsukuba, Ibaraki, 305-0003, Japan
| | - A P Mackenzie
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187, Dresden, Germany
| | - A Georges
- Center for Computational Quantum Physics, Flatiron Institute, Simons Foundation, 162 5th Avenue, New York, 10010, USA
- Collége de France, 11 place Marcelin Berthelot, 75005, Paris, France
- Centre de Physique Théorique (CPHT), CNRS, Ecole Polytechnique, IP Paris, 91128, Palaiseau, France
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211, Geneva 4, Switzerland
| | - P Hansmann
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569, Stuttgart, Germany
- Department of Physics, Friedrich-Alexander-University (FAU) of Erlangen-Nürnberg, 91058, Erlangen, Germany
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187, Dresden, Germany
| | - H Gretarsson
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569, Stuttgart, Germany.
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, D-22607, Hamburg, Germany.
| | - B Keimer
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569, Stuttgart, Germany.
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2
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Takahashi H, Suzuki H, Bertinshaw J, Bette S, Mühle C, Nuss J, Dinnebier R, Yaresko A, Khaliullin G, Gretarsson H, Takayama T, Takagi H, Keimer B. Nonmagnetic J=0 State and Spin-Orbit Excitations in K_{2}RuCl_{6}. Phys Rev Lett 2021; 127:227201. [PMID: 34889637 DOI: 10.1103/physrevlett.127.227201] [Citation(s) in RCA: 2] [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: 07/10/2021] [Accepted: 10/18/2021] [Indexed: 06/13/2023]
Abstract
Spin-orbit Mott insulators composed of t_{2g}^{4} transition metal ions may host excitonic magnetism due to the condensation of spin-orbital J=1 triplons. Prior experiments suggest that the 4d antiferromagnet Ca_{2}RuO_{4} embodies this notion, but a J=0 nonmagnetic state as a basis of the excitonic picture remains to be confirmed. We use Ru L_{3}-edge resonant inelastic x-ray scattering to reveal archetypal J multiplets with a J=0 ground state in the cubic compound K_{2}RuCl_{6}, which are well described within the LS-coupling scheme. This result highlights the critical role of unquenched orbital moments in 4d-electron compounds and calls for investigations of quantum criticality and excitonic magnetism on various crystal lattices.
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Affiliation(s)
- H Takahashi
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
- Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - H Suzuki
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - J Bertinshaw
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - S Bette
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - C Mühle
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - J Nuss
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - R Dinnebier
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - A Yaresko
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - G Khaliullin
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
| | - H Gretarsson
- Deutsches Elektronen-Synchrotron DESY, Notkestrstraße 85, D-22607 Hamburg, Germany
| | - T Takayama
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
- Institute for Functional Matter and Quantum Technologies, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - H Takagi
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
- Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
- Institute for Functional Matter and Quantum Technologies, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - B Keimer
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, D-70569 Stuttgart, Germany
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3
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Suzuki H, Liu H, Bertinshaw J, Ueda K, Kim H, Laha S, Weber D, Yang Z, Wang L, Takahashi H, Fürsich K, Minola M, Lotsch BV, Kim BJ, Yavaş H, Daghofer M, Chaloupka J, Khaliullin G, Gretarsson H, Keimer B. Proximate ferromagnetic state in the Kitaev model material α-RuCl 3. Nat Commun 2021; 12:4512. [PMID: 34301938 PMCID: PMC8302668 DOI: 10.1038/s41467-021-24722-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [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: 12/01/2020] [Accepted: 07/01/2021] [Indexed: 11/27/2022] Open
Abstract
α-RuCl3 is a major candidate for the realization of the Kitaev quantum spin liquid, but its zigzag antiferromagnetic order at low temperatures indicates deviations from the Kitaev model. We have quantified the spin Hamiltonian of α-RuCl3 by a resonant inelastic x-ray scattering study at the Ru L3 absorption edge. In the paramagnetic state, the quasi-elastic intensity of magnetic excitations has a broad maximum around the zone center without any local maxima at the zigzag magnetic Bragg wavevectors. This finding implies that the zigzag order is fragile and readily destabilized by competing ferromagnetic correlations. The classical ground state of the experimentally determined Hamiltonian is actually ferromagnetic. The zigzag state is stabilized by quantum fluctuations, leaving ferromagnetism – along with the Kitaev spin liquid – as energetically proximate metastable states. The three closely competing states and their collective excitations hold the key to the theoretical understanding of the unusual properties of α-RuCl3 in magnetic fields. RuCl3 has stood out as a prime candidate in the search for quantum spin liquids; however, its antiferromagnetic ordering at low temperature suggests deviations from typical QSL models. Here, using resonant inelastic x-ray scattering, the authors provide a comprehensive determination of the low energy effective Hamiltonian.
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Affiliation(s)
- H Suzuki
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
| | - H Liu
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
| | - J Bertinshaw
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - K Ueda
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.,Department of Applied Physics, University of Tokyo, Tokyo, Japan
| | - H Kim
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.,Department of Physics, Pohang University of Science and Technology, Pohang, South Korea.,Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, South Korea
| | - S Laha
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - D Weber
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.,Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Z Yang
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - L Wang
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - H Takahashi
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - K Fürsich
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - M Minola
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - B V Lotsch
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.,Department of Chemistry, University of Munich (LMU), München, Germany
| | - B J Kim
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.,Department of Physics, Pohang University of Science and Technology, Pohang, South Korea.,Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, South Korea
| | - H Yavaş
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.,SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - M Daghofer
- Institute for Functional Matter and Quantum Technologies, University of Stuttgart, Stuttgart, Germany.,Center for Integrated Quantum Science and Technology, University of Stuttgart, Stuttgart, Germany
| | - J Chaloupka
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Brno, Czech Republic.,Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - G Khaliullin
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - H Gretarsson
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.,Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - B Keimer
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
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4
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Suzuki H, Gretarsson H, Ishikawa H, Ueda K, Yang Z, Liu H, Kim H, Kukusta D, Yaresko A, Minola M, Sears JA, Francoual S, Wille HC, Nuss J, Takagi H, Kim BJ, Khaliullin G, Yavaş H, Keimer B. Spin waves and spin-state transitions in a ruthenate high-temperature antiferromagnet. Nat Mater 2019; 18:563-567. [PMID: 30911120 DOI: 10.1038/s41563-019-0327-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 02/26/2019] [Indexed: 06/09/2023]
Abstract
Ruthenium compounds serve as a platform for fundamental concepts such as spin-triplet superconductivity1, Kitaev spin liquids2-5 and solid-state analogues of the Higgs mode in particle physics6,7. However, basic questions about the electronic structure of ruthenates remain unanswered, because several key parameters (including Hund's coupling, spin-orbit coupling and exchange interactions) are comparable in magnitude and their interplay is poorly understood, partly due to difficulties in synthesizing large single crystals for spectroscopic experiments. Here we introduce a resonant inelastic X-ray scattering (RIXS)8,9 technique capable of probing collective modes in microcrystals of 4d electron materials. We observe spin waves and spin-state transitions in the honeycomb antiferromagnet SrRu2O6 (ref. 10) and use the extracted exchange interactions and measured magnon gap to explain its high Néel temperature11-16. We expect that the RIXS method presented here will enable momentum-resolved spectroscopy of a large class of 4d transition-metal compounds.
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Affiliation(s)
- H Suzuki
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
| | - H Gretarsson
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - H Ishikawa
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
- Institut für Funktionelle Materie und Quantentechnologien, Universität Stuttgart, Stuttgart, Germany
| | - K Ueda
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
- Department of Applied Physics, University of Tokyo, Tokyo, Japan
| | - Z Yang
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - H Liu
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - H Kim
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
- Department of Physics, Pohang University of Science and Technology, Pohang, South Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, South Korea
| | - D Kukusta
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - A Yaresko
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - M Minola
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - J A Sears
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - S Francoual
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - H-C Wille
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - J Nuss
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - H Takagi
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
- Institut für Funktionelle Materie und Quantentechnologien, Universität Stuttgart, Stuttgart, Germany
- Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - B J Kim
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
- Department of Physics, Pohang University of Science and Technology, Pohang, South Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, South Korea
| | - G Khaliullin
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - H Yavaş
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
- SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - B Keimer
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
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5
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Minola M, Lu Y, Peng YY, Dellea G, Gretarsson H, Haverkort MW, Ding Y, Sun X, Zhou XJ, Peets DC, Chauviere L, Dosanjh P, Bonn DA, Liang R, Damascelli A, Dantz M, Lu X, Schmitt T, Braicovich L, Ghiringhelli G, Keimer B, Le Tacon M. Crossover from Collective to Incoherent Spin Excitations in Superconducting Cuprates Probed by Detuned Resonant Inelastic X-Ray Scattering. Phys Rev Lett 2017; 119:097001. [PMID: 28949586 DOI: 10.1103/physrevlett.119.097001] [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: 10/17/2016] [Indexed: 06/07/2023]
Abstract
Spin excitations in the overdoped high temperature superconductors Tl_{2}Ba_{2}CuO_{6+δ} and (Bi,Pb)_{2}(Sr,La)_{2}CuO_{6+δ} were investigated by resonant inelastic x-ray scattering (RIXS) as functions of doping and detuning of the incoming photon energy above the Cu-L_{3} absorption peak. The RIXS spectra at optimal doping are dominated by a paramagnon feature with peak energy independent of photon energy, similar to prior results on underdoped cuprates. Beyond optimal doping, the RIXS data indicate a sharp crossover to a regime with a strong contribution from incoherent particle-hole excitations whose maximum shows a fluorescencelike shift upon detuning. The spectra of both compound families are closely similar, and their salient features are reproduced by exact-diagonalization calculations of the single-band Hubbard model on a finite cluster. The results are discussed in the light of recent transport experiments indicating a quantum phase transition near optimal doping.
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Affiliation(s)
- M Minola
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - Y Lu
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - Y Y Peng
- CNISM, CNR-SPIN and Dipartimento di Fisica, Politecnico di Milano, 20133 Milano, Italy
| | - G Dellea
- CNISM, CNR-SPIN and Dipartimento di Fisica, Politecnico di Milano, 20133 Milano, Italy
| | - H Gretarsson
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - M W Haverkort
- Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Strasse 40, 01187 Dresden, Germany and Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 19, 69120 Heidelberg, Germany
| | - Y Ding
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - X Sun
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - X J Zhou
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - D C Peets
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - L Chauviere
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - P Dosanjh
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - D A Bonn
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - R Liang
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - A Damascelli
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - M Dantz
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - X Lu
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - T Schmitt
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - L Braicovich
- CNISM, CNR-SPIN and Dipartimento di Fisica, Politecnico di Milano, 20133 Milano, Italy
| | - G Ghiringhelli
- CNISM, CNR-SPIN and Dipartimento di Fisica, Politecnico di Milano, 20133 Milano, Italy
| | - B Keimer
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - M Le Tacon
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
- Institut für Festkörperphysik, Karlsruher Institut für Technologie, Hermann-v.-Helmoltz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
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6
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Gretarsson H, Sung NH, Porras J, Bertinshaw J, Dietl C, Bruin JAN, Bangura AF, Kim YK, Dinnebier R, Kim J, Al-Zein A, Moretti Sala M, Krisch M, Le Tacon M, Keimer B, Kim BJ. Persistent Paramagnons Deep in the Metallic Phase of Sr_{2-x}La_{x}IrO_{4}. Phys Rev Lett 2016; 117:107001. [PMID: 27636488 DOI: 10.1103/physrevlett.117.107001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Indexed: 06/06/2023]
Abstract
We have studied the magnetic excitations of electron-doped Sr_{2-x}La_{x}IrO_{4} (0≤x≤0.10) using resonant inelastic x-ray scattering at the Ir L_{3} edge. The long-range magnetic order is rapidly lost with increasing x, but two-dimensional short-range order (SRO) and dispersive magnon excitations with nearly undiminished spectral weight persist well into the metallic part of the phase diagram. The magnons in the SRO phase are heavily damped and exhibit anisotropic softening. Their dispersions are well described by a pseudospin-1/2 Heisenberg model with exchange interactions whose spatial range increases with doping. We also find a doping-independent high-energy magnetic continuum, which is not described by this model. The spin-orbit excitons arising from the pseudospin-3/2 manifold of the Ir ions broaden substantially in the SRO phase, but remain largely separated from the low-energy magnons. Pseudospin-1/2 models are therefore a good starting point for the theoretical description of the low-energy magnetic dynamics of doped iridates.
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Affiliation(s)
- H Gretarsson
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
| | - N H Sung
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
| | - J Porras
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
| | - J Bertinshaw
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
| | - C Dietl
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
| | - Jan A N Bruin
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
| | - A F Bangura
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
| | - Y K Kim
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul 151-742, South Korea
- Department of Physics and Astronomy, Seoul National University, Seoul 151-747, South Korea
| | - R Dinnebier
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
| | - Jungho Kim
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - A Al-Zein
- European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France
| | - M Moretti Sala
- European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France
| | - M Krisch
- European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France
| | - M Le Tacon
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
- Karlsruher Institut für Technologie, Institut für Festkörperphysik, Hermann-v.-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - B Keimer
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
| | - B J Kim
- Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany
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7
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Gretarsson H, Sung NH, Höppner M, Kim BJ, Keimer B, Le Tacon M. Two-Magnon Raman Scattering and Pseudospin-Lattice Interactions in Sr_{2}IrO_{4} and Sr_{3}Ir_{2}O_{7}. Phys Rev Lett 2016; 116:136401. [PMID: 27081993 DOI: 10.1103/physrevlett.116.136401] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Indexed: 06/05/2023]
Abstract
We have used Raman scattering to investigate the magnetic excitations and lattice dynamics in the prototypical spin-orbit Mott insulators Sr_{2}IrO_{4} and Sr_{3}Ir_{2}O_{7}. Both compounds exhibit pronounced two-magnon Raman scattering features with different energies, line shapes, and temperature dependencies, which in part reflect the different influence of long-range frustrating exchange interactions. Additionally, we find strong Fano asymmetries in the line shapes of low-energy phonon modes in both compounds, which disappear upon cooling below the antiferromagnetic ordering temperatures. These unusual phonon anomalies indicate that the spin-orbit coupling in Mott-insulating iridates is not sufficiently strong to quench the orbital dynamics in the paramagnetic state.
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Affiliation(s)
- H Gretarsson
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - N H Sung
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - M Höppner
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - B J Kim
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - B Keimer
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - M Le Tacon
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
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8
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Minola M, Dellea G, Gretarsson H, Peng YY, Lu Y, Porras J, Loew T, Yakhou F, Brookes NB, Huang YB, Pelliciari J, Schmitt T, Ghiringhelli G, Keimer B, Braicovich L, Le Tacon M. Collective nature of spin excitations in superconducting cuprates probed by resonant inelastic X-ray scattering. Phys Rev Lett 2015; 114:217003. [PMID: 26066453 DOI: 10.1103/physrevlett.114.217003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Indexed: 06/04/2023]
Abstract
We used resonant inelastic x-ray scattering (RIXS) with and without analysis of the scattered photon polarization, to study dispersive spin excitations in the high temperature superconductor YBa_{2}Cu_{3}O_{6+x} over a wide range of doping levels (0.1≤x≤1). The excitation profiles were carefully monitored as the incident photon energy was detuned from the resonant condition, and the spin excitation energy was found to be independent of detuning for all x. These findings demonstrate that the largest fraction of the spin-flip RIXS profiles in doped cuprates arises from magnetic collective modes, rather than from incoherent particle-hole excitations as recently suggested theoretically [Benjamin et al. Phys. Rev. Lett. 112, 247002 (2014)]. Implications for the theoretical description of the electron system in the cuprates are discussed.
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Affiliation(s)
- M Minola
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - G Dellea
- CNISM, CNR-SPIN and Dipartimento di Fisica, Politecnico di Milano, 20133 Milano, Italy
| | - H Gretarsson
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - Y Y Peng
- CNISM, CNR-SPIN and Dipartimento di Fisica, Politecnico di Milano, 20133 Milano, Italy
| | - Y Lu
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - J Porras
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - T Loew
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - F Yakhou
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble F-38043, France
| | - N B Brookes
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble F-38043, France
| | - Y B Huang
- 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
| | - J Pelliciari
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - T Schmitt
- Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - G Ghiringhelli
- CNISM, CNR-SPIN and Dipartimento di Fisica, Politecnico di Milano, 20133 Milano, Italy
| | - B Keimer
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
| | - L Braicovich
- CNISM, CNR-SPIN and Dipartimento di Fisica, Politecnico di Milano, 20133 Milano, Italy
| | - M Le Tacon
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany
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9
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Ortenzi L, Gretarsson H, Kasahara S, Matsuda Y, Shibauchi T, Finkelstein KD, Wu W, Julian SR, Kim YJ, Mazin II, Boeri L. Structural origin of the anomalous temperature dependence of the local magnetic moments in the CaFe2As2 family of materials. Phys Rev Lett 2015; 114:047001. [PMID: 25679903 DOI: 10.1103/physrevlett.114.047001] [Citation(s) in RCA: 4] [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: 08/18/2014] [Indexed: 06/04/2023]
Abstract
We report a combination of Fe Kβ x-ray emission spectroscopy and density functional reduced Stoner theory calculations to investigate the correlation between structural and magnetic degrees of freedom in CaFe2(As1-xPx)2. The puzzling temperature behavior of the local moment found in rare earth-doped CaFe2As2 [H. Gretarsson et al., Phys. Rev. Lett. 110, 047003 (2013)] is also observed in CaFe2(As1-xPx)2. We explain this phenomenon based on first-principles calculations with scaled magnetic interaction. One scaling parameter is sufficient to describe quantitatively the magnetic moments in both CaFe2(As1-xPx)2 (x=0.055) and Ca0.78La0.22Fe2As2 at all temperatures. The anomalous growth of the local moments with increasing temperature can be understood from the observed large thermal expansion of the c-axis lattice parameter combined with strong magnetoelastic coupling. These effects originate from the strong tendency to form As-As dimers across the Ca layer in the CaFe2As2 family of materials. Our results emphasize the dual local-itinerant character of magnetism in Fe pnictides.
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Affiliation(s)
- L Ortenzi
- Institute for Complex Systems (ISC-CNR), c/o Dipartimento di Fisica, Università "La Sapienza", Piazzale Aldo Moro, n. 5, 00185 Rome, Italy and Max-Planck-Institut für Festkörperforschung, Heisenbergstraβe 1, D-70569 Stuttgart, Germany
| | - H Gretarsson
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraβe 1, D-70569 Stuttgart, Germany and Department of Physics, University of Toronto, 60 Saint George Street, Toronto, Ontario M5S 1A7, Canada
| | - S Kasahara
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Y Matsuda
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - T Shibauchi
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan and Department of Advanced Materials Science, University of Tokyo, Kashiwa 277-8561, Japan
| | - K D Finkelstein
- Cornell High Energy Synchrotron Source, Cornell University, Ithaca, New York 14853, USA
| | - W Wu
- Department of Physics, University of Toronto, 60 Saint George Street, Toronto, Ontario M5S 1A7, Canada
| | - S R Julian
- Department of Physics, University of Toronto, 60 Saint George Street, Toronto, Ontario M5S 1A7, Canada
| | - Young-June Kim
- Department of Physics, University of Toronto, 60 Saint George Street, Toronto, Ontario M5S 1A7, Canada
| | - I I Mazin
- Code 6390, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375, USA
| | - L Boeri
- Institute for Theoretical and Computational Physics, TU Graz, Petersgasse 16, 8010 Graz, Austria
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10
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Lupascu A, Clancy JP, Gretarsson H, Nie Z, Nichols J, Terzic J, Cao G, Seo SSA, Islam Z, Upton MH, Kim J, Casa D, Gog T, Said AH, Katukuri VM, Stoll H, Hozoi L, van den Brink J, Kim YJ. Tuning magnetic coupling in Sr2IrO4 thin films with epitaxial strain. Phys Rev Lett 2014; 112:147201. [PMID: 24766006 DOI: 10.1103/physrevlett.112.147201] [Citation(s) in RCA: 10] [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: 12/12/2013] [Indexed: 06/03/2023]
Abstract
We report x-ray resonant magnetic scattering and resonant inelastic x-ray scattering studies of epitaxially strained Sr2IrO4 thin films. The films were grown on SrTiO3 and (LaAlO3)0.3(Sr2AlTaO6)0.7 substrates, under slight tensile and compressive strains, respectively. Although the films develop a magnetic structure reminiscent of bulk Sr2IrO4, the magnetic correlations are extremely anisotropic, with in-plane correlation lengths significantly longer than the out-of-plane correlation lengths. In addition, the compressive (tensile) strain serves to suppress (enhance) the magnetic ordering temperature TN, while raising (lowering) the energy of the zone-boundary magnon. Quantum chemical calculations show that the tuning of magnetic energy scales can be understood in terms of strain-induced changes in bond lengths.
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Affiliation(s)
- A Lupascu
- Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| | - J P Clancy
- Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| | - H Gretarsson
- Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| | - Zixin Nie
- Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| | - J Nichols
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
| | - J Terzic
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
| | - G Cao
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
| | - S S A Seo
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
| | - Z Islam
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - M H Upton
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Jungho Kim
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - D Casa
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - T Gog
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - A H Said
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Vamshi M Katukuri
- Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse. 20, 01069 Dresden, Germany
| | - H Stoll
- Institute for Theoretical Chemistry, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany
| | - L Hozoi
- Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse. 20, 01069 Dresden, Germany
| | - J van den Brink
- Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse. 20, 01069 Dresden, Germany
| | - Young-June Kim
- Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
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11
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Lu X, Gretarsson H, Zhang R, Liu X, Luo H, Tian W, Laver M, Yamani Z, Kim YJ, Nevidomskyy AH, Si Q, Dai P. Avoided quantum criticality and magnetoelastic coupling in BaFe(2-x)Ni(x)As2. Phys Rev Lett 2013; 110:257001. [PMID: 23829752 DOI: 10.1103/physrevlett.110.257001] [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: 03/29/2013] [Indexed: 06/02/2023]
Abstract
We study the structural and magnetic orders in electron-doped BaFe(2-x)Ni(x)As2 by high-resolution synchrotron x-ray and neutron scatterings. Upon Ni doping x, the nearly simultaneous tetragonal-to-orthorhombic structural (T(s)) and antiferromagnetic (T(N)) phase transitions in BaFe2As2 are gradually suppressed and separated, resulting in T(s)>T(N) with increasing x, as was previously observed. However, the temperature separation between T(s) and T(N) decreases with increasing x for x≥0.065, tending toward a quantum bicritical point near optimal superconductivity at x≈0.1. The zero-temperature transition is preempted by the formation of a secondary incommensurate magnetic phase in the region 0.088≲x≲0.104, resulting in a finite value of T(N)≈T(c) + 10 K above the superconducting dome around x≈0.1. Our results imply an avoided quantum critical point, which is expected to strongly influence the properties of both the normal and superconducting states.
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Affiliation(s)
- Xingye Lu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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12
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Gretarsson H, Clancy JP, Liu X, Hill JP, Bozin E, Singh Y, Manni S, Gegenwart P, Kim J, Said AH, Casa D, Gog T, Upton MH, Kim HS, Yu J, Katukuri VM, Hozoi L, van den Brink J, Kim YJ. Crystal-field splitting and correlation effect on the electronic structure of A2IrO3. Phys Rev Lett 2013; 110:076402. [PMID: 25166387 DOI: 10.1103/physrevlett.110.076402] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Indexed: 06/03/2023]
Abstract
The electronic structure of the honeycomb lattice iridates Na(2)IrO(3) and Li(2)IrO(3) has been investigated using resonant inelastic x-ray scattering (RIXS). Crystal-field-split d-d excitations are resolved in the high-resolution RIXS spectra. In particular, the splitting due to noncubic crystal fields, derived from the splitting of j(eff)=3/2 states, is much smaller than the typical spin-orbit energy scale in iridates, validating the applicability of j(eff) physics in A(2)IrO(3). We also find excitonic enhancement of the particle-hole excitation gap around 0.4 eV, indicating that the nearest-neighbor Coulomb interaction could be large. These findings suggest that both Na(2)IrO(3) and Li(2)IrO(3) can be described as spin-orbit Mott insulators, similar to the square lattice iridate Sr(2)IrO(4).
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Affiliation(s)
- H Gretarsson
- Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| | - J P Clancy
- Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| | - X Liu
- CMP&MS Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - J P Hill
- CMP&MS Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Emil Bozin
- CMP&MS Department, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Yogesh Singh
- Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Manauli PO 140 306, Punjab, India
| | - S Manni
- I. Physikalisches Institut, Georg-August-Universität Göttingen, D-37077 Göttingen, Germany
| | - P Gegenwart
- I. Physikalisches Institut, Georg-August-Universität Göttingen, D-37077 Göttingen, Germany
| | - Jungho Kim
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - A H Said
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - D Casa
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - T Gog
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - M H Upton
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Heung-Sik Kim
- Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
| | - J Yu
- Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
| | - Vamshi M Katukuri
- Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - L Hozoi
- Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Jeroen van den Brink
- Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Young-June Kim
- Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
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13
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Gretarsson H, Saha SR, Drye T, Paglione J, Kim J, Casa D, Gog T, Wu W, Julian SR, Kim YJ. Spin-state transition in the Fe pnictides. Phys Rev Lett 2013; 110:047003. [PMID: 25166195 DOI: 10.1103/physrevlett.110.047003] [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: 09/24/2012] [Indexed: 06/03/2023]
Abstract
We report an Fe Kβ x-ray emission spectroscopy study of local magnetic moments in the rare-earth doped iron pnictide Ca(1-x)RE(x)Fe(2)As(2) (RE = La, Pr, and Nd). In all samples studied the size of the Fe local moment is found to decrease significantly with temperature and goes from ∼ 0.9 μ(B) at T = 300 K to ∼ 0.45 μ(B) at T = 70 K. In the collapsed tetragonal phase of Nd- and Pr-doped samples (T<70 K) the local moment is quenched, while the moment remains unchanged for the La-doped sample, which does not show lattice collapse. Our results show that Ca(1-x)RE(x)Fe(2)As(2) (RE = Pr and Nd) exhibits a spin-state transition and provide direct evidence for a nonmagnetic Fe(2+) ion in the collapsed tetragonal phase; spin state as predicted by Yildirim. We argue that the gradual change of the spin state over a wide temperature range reveals the importance of multiorbital physics, in particular the competition between the crystal field split Fe 3d orbitals and the Hund's rule coupling.
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Affiliation(s)
- H Gretarsson
- Department of Physics, University of Toronto, 60 Saint George Street, Toronto, Ontario M5S 1A7, Canada
| | - S R Saha
- Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - T Drye
- Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - J Paglione
- Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Jungho Kim
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - D Casa
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - T Gog
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - W Wu
- Department of Physics, University of Toronto, 60 Saint George Street, Toronto, Ontario M5S 1A7, Canada
| | - S R Julian
- Department of Physics, University of Toronto, 60 Saint George Street, Toronto, Ontario M5S 1A7, Canada
| | - Young-June Kim
- Department of Physics, University of Toronto, 60 Saint George Street, Toronto, Ontario M5S 1A7, Canada
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Jin WT, Gretarsson H, Fujita M, Kim CY, Zhang H, Kim YJ. An x-ray scattering study of the structural phase transition in La(2-x)Sr(x)Cu0.99Fe0.01O4 (x = 0.20). J Phys Condens Matter 2011; 23:365701. [PMID: 21852730 DOI: 10.1088/0953-8984/23/36/365701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report a comprehensive x-ray scattering study of the low-temperature orthorhombic (LTO)-high-temperature tetragonal (HTT) structural phase transition in 1% iron-doped La(2-x)Sr(x)CuO(4) (x = 0.2). The superlattice (032) peak intensity and the width are investigated in detail for a wide temperature range. We found that the structural phase transition is not sharp and the tilt ordering of the CuO(6) octahedra persists above the transition temperature T(S) (≈77 K). Even at room temperature, the superlattice peak is still observable. The structural phase transition is identified as an order-disorder type phase transition. We found that the tilt ordering in our iron-doped material is always short-ranged, and in the HTT phase the correlation between the tilts along the b axis is better preserved than that along the a axis. Moreover, we identify the role of the Fe as the nucleation centers of the LTO domains in the structural phase transition.
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Affiliation(s)
- W T Jin
- Materials Physics Laboratory, State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing, People's Republic of China
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