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Zhang G, Pavarini E. Multiorbital Nature of Doped Sr_{2}IrO_{4}. PHYSICAL REVIEW LETTERS 2023; 131:036504. [PMID: 37540852 DOI: 10.1103/physrevlett.131.036504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 06/27/2023] [Indexed: 08/06/2023]
Abstract
The low-energy j_{eff}=1/2 band of Sr_{2}IrO_{4} bears stark resemblances with the x^{2}-y^{2} band of La_{2}CuO_{4}, and yet no superconductivity has been found so far by doping Sr_{2}IrO_{4}. Behind such a behavior could be inherent failures of the j_{eff}=1/2 picture, in particular when electrons or holes are introduced in the IrO_{2} planes. In view of this, here we reanalyze the j_{eff}=1/2 scenario. By using the local-density approximation plus dynamical mean-field theory approach, we show that the form of the effective j_{eff}=1/2 state is surprisingly stable upon doping. This supports the j_{eff}=1/2 picture. We show that, nevertheless, Sr_{2}IrO_{4} remains in essence a multiorbital system: The hybridization with the j_{eff}=3/2 orbitals sizably reduces the Mott gap by enhancing orbital degeneracy, and part of the holes go into the j_{eff}=3/2 channels. These effects cannot be reproduced by a simple effective screened Coulomb repulsion. In the optical conductivity spectra, multiorbital processes involving the j_{eff}=3/2 states contribute both to the Drude peak and to relatively low-energy features.
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Affiliation(s)
- Guoren Zhang
- School of Sciences, Nantong University, Nantong, 226019, People's Republic of China
- Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - Eva Pavarini
- Institute for Advanced Simulation, Forschungszentrum Jülich, 52425 Jülich, Germany
- JARA High-Performance Computing, Forschungszentrum Jülich, 52425 Jülich, Germany
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2
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Gurung N, Wang C, Bingham NS, Verezhak JAT, Yamaura K, Allodi G, Forino PC, Sanna S, Luetkens H, Scagnoli V. Probing spin fluctuations in NaOsO 3by muon spin rotation and NMR spectroscopy. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:335802. [PMID: 34062527 DOI: 10.1088/1361-648x/ac06eb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 06/01/2021] [Indexed: 06/12/2023]
Abstract
We have used muon spin rotation and relaxation (μSR) and23Na nuclear magnetic resonance (NMR) spectroscopic methods in the NaOsO3antiferromagnetic phase to determine the temperature evolution of the magnetic order parameter and the role of the magnetic fluctuations at the Néel temperature. Additionally, we performed muon spin relaxation measurements in the vicinity ofTA= 30 K, where the appearance of an anomaly in the electrical resistivity was suggested to be due to a progressive reduction of the Os magnetic moment associated with spin fluctuation. Our measurements suggest the absence of prominent change in the spin fluctuations frequency atTA, within the muon probing time scale and the absence of a reduction of the localized Os magnetic moment reflected by the stability within few permille of the local magnetic field strength sensed by the muons below 50 K.
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Affiliation(s)
- Namrata Gurung
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
- Laboratory for Multiscale Materials Experiments, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Chennan Wang
- Laboratory for Muon Spin Spectroscopy (LMU), Paul Scherrer Institute (PSI), CH-5232 Villigen, Switzerland
| | - Nicholas S Bingham
- Department of Applied Physics, Yale University, New Haven, Connecticut 06511, United States of America
| | - Joel A T Verezhak
- Laboratory for Muon Spin Spectroscopy (LMU), Paul Scherrer Institute (PSI), CH-5232 Villigen, Switzerland
| | - Kazunari Yamaura
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Giuseppe Allodi
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, I-43124 Parma, Italy
| | - Paola Caterina Forino
- Department of Physics and Astronomy 'A. Righi', University of Bologna, via Berti-Pichat 6-2, 40127 Bologna, Italy
| | - Samuele Sanna
- Department of Physics and Astronomy 'A. Righi', University of Bologna, via Berti-Pichat 6-2, 40127 Bologna, Italy
| | - Hubertus Luetkens
- Laboratory for Muon Spin Spectroscopy (LMU), Paul Scherrer Institute (PSI), CH-5232 Villigen, Switzerland
| | - V Scagnoli
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
- Laboratory for Multiscale Materials Experiments, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
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3
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Jeong J, Lenz B, Gukasov A, Fabrèges X, Sazonov A, Hutanu V, Louat A, Bounoua D, Martins C, Biermann S, Brouet V, Sidis Y, Bourges P. Magnetization Density Distribution of Sr_{2}IrO_{4}: Deviation from a Local j_{eff}=1/2 Picture. PHYSICAL REVIEW LETTERS 2020; 125:097202. [PMID: 32915616 DOI: 10.1103/physrevlett.125.097202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 04/25/2020] [Accepted: 07/29/2020] [Indexed: 06/11/2023]
Abstract
5d iridium oxides are of huge interest due to the potential for new quantum states driven by strong spin-orbit coupling. The strontium iridate Sr_{2}IrO_{4} is particularly in the spotlight because of the so-called j_{eff}=1/2 state consisting of a quantum superposition of the three local t_{2g} orbitals with, in its simplest version, nearly equal populations, which stabilizes an unconventional Mott insulating state. Here, we report an anisotropic and aspherical magnetization density distribution measured by polarized neutron diffraction in a magnetic field up to 5 T at 4 K, which strongly deviates from a local j_{eff}=1/2 picture even when distortion-induced deviations from the equal weights of the orbital populations are taken into account. Once reconstructed by the maximum entropy method and multipole expansion model refinement, the magnetization density shows four cross-shaped positive lobes along the crystallographic tetragonal axes with a large spatial extent, showing that the xy orbital contribution is dominant. The analogy to the superconducting copper oxide systems might then be weaker than commonly thought.
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Affiliation(s)
- Jaehong Jeong
- Université Paris-Saclay, CNRS, CEA, Laboratoire Léon Brillouin, 91191 Gif-sur-Yvette, France
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul National University, Seoul 08826, Korea
| | - Benjamin Lenz
- Centre de Physique Théorique, Ecole Polytechnique, CNRS UMR7644, Institut Polytechnique de Paris, 91128 Palaiseau Cedex, France
- IMPMC, Sorbonne Université, CNRS, MNHN, IRD, 4 Place Jussieu, 75252 Paris, France
| | - Arsen Gukasov
- Université Paris-Saclay, CNRS, CEA, Laboratoire Léon Brillouin, 91191 Gif-sur-Yvette, France
| | - Xavier Fabrèges
- Université Paris-Saclay, CNRS, CEA, Laboratoire Léon Brillouin, 91191 Gif-sur-Yvette, France
| | - Andrew Sazonov
- Institute of Crystallography, RWTH Aachen University and Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), 85747 Garching, Germany
| | - Vladimir Hutanu
- Institute of Crystallography, RWTH Aachen University and Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), 85747 Garching, Germany
| | - Alex Louat
- Laboratoire de Physique des Solides, Université Paris-Sud, UMR 8502, 91405 Orsay, France
| | - Dalila Bounoua
- Université Paris-Saclay, CNRS, CEA, Laboratoire Léon Brillouin, 91191 Gif-sur-Yvette, France
| | - Cyril Martins
- Laboratoire de Chimie et Physique Quantiques, UMR 5626, Université Paul Sabatier, 118 Route de Narbonne, 31400 Toulouse, France
| | - Silke Biermann
- Centre de Physique Théorique, Ecole Polytechnique, CNRS UMR7644, Institut Polytechnique de Paris, 91128 Palaiseau Cedex, France
- Collège de France, 11 Place Marcelin Berthelot, 75005 Paris, France
- Department of Physics, Division of Mathematical Physics, Lund University, Professorsgatan 1, 22363 Lund, Sweden
- European Theoretical Spectroscopy Facility, 91128 Palaiseau, France
| | - Véronique Brouet
- Laboratoire de Physique des Solides, Université Paris-Sud, UMR 8502, 91405 Orsay, France
| | - Yvan Sidis
- Université Paris-Saclay, CNRS, CEA, Laboratoire Léon Brillouin, 91191 Gif-sur-Yvette, France
| | - Philippe Bourges
- Université Paris-Saclay, CNRS, CEA, Laboratoire Léon Brillouin, 91191 Gif-sur-Yvette, France
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4
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Rossi M, Henriquet C, Jacobs J, Donnerer C, Boseggia S, Al-Zein A, Fumagalli R, Yao Y, Vale JG, Hunter EC, Perry RS, Kantor I, Garbarino G, Crichton W, Monaco G, McMorrow DF, Krisch M, Moretti Sala M. Resonant inelastic X-ray scattering of magnetic excitations under pressure. JOURNAL OF SYNCHROTRON RADIATION 2019; 26:1725-1732. [PMID: 31490164 DOI: 10.1107/s1600577519008877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 06/21/2019] [Indexed: 06/10/2023]
Abstract
Resonant inelastic X-ray scattering (RIXS) is an extremely valuable tool for the study of elementary, including magnetic, excitations in matter. The latest developments of this technique have mostly been aimed at improving the energy resolution and performing polarization analysis of the scattered radiation, with a great impact on the interpretation and applicability of RIXS. Instead, this article focuses on the sample environment and presents a setup for high-pressure low-temperature RIXS measurements of low-energy excitations. The feasibility of these experiments is proved by probing the magnetic excitations of the bilayer iridate Sr3Ir2O7 at pressures up to 12 GPa.
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Affiliation(s)
- Matteo Rossi
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, CS 40220, F-38043 Grenoble, France
| | - Christian Henriquet
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, CS 40220, F-38043 Grenoble, France
| | - Jeroen Jacobs
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, CS 40220, F-38043 Grenoble, France
| | - Christian Donnerer
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
| | - Stefano Boseggia
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
| | - Ali Al-Zein
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, CS 40220, F-38043 Grenoble, France
| | - Roberto Fumagalli
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, CS 40220, F-38043 Grenoble, France
| | - Yi Yao
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, CS 40220, F-38043 Grenoble, France
| | - James G Vale
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
| | - Emily C Hunter
- Centre for Science at Extreme Conditions, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, UK
| | - Robin S Perry
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
| | - Innokenty Kantor
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, CS 40220, F-38043 Grenoble, France
| | - Gaston Garbarino
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, CS 40220, F-38043 Grenoble, France
| | - Wilson Crichton
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, CS 40220, F-38043 Grenoble, France
| | - Giulio Monaco
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, CS 40220, F-38043 Grenoble, France
| | - Desmond F McMorrow
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
| | - Michael Krisch
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, CS 40220, F-38043 Grenoble, France
| | - Marco Moretti Sala
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, CS 40220, F-38043 Grenoble, France
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5
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Moretti Sala M, Martel K, Henriquet C, Al Zein A, Simonelli L, Sahle CJ, Gonzalez H, Lagier MC, Ponchut C, Huotari S, Verbeni R, Krisch M, Monaco G. A high-energy-resolution resonant inelastic X-ray scattering spectrometer at ID20 of the European Synchrotron Radiation Facility. JOURNAL OF SYNCHROTRON RADIATION 2018; 25:580-591. [PMID: 29488940 DOI: 10.1107/s1600577518001200] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Accepted: 01/19/2018] [Indexed: 06/08/2023]
Abstract
An end-station for resonant inelastic X-ray scattering and (resonant) X-ray emission spectroscopy at beamline ID20 of ESRF - The European Synchrotron is presented. The spectrometer hosts five crystal analysers in Rowland geometry for large solid angle collection and is mounted on a rotatable arm for scattering in both the horizontal and vertical planes. The spectrometer is optimized for high-energy-resolution applications, including partial fluorescence yield or high-energy-resolution fluorescence detected X-ray absorption spectroscopy and the study of elementary electronic excitations in solids. In addition, it can be used for non-resonant inelastic X-ray scattering measurements of valence electron excitations.
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Affiliation(s)
- M Moretti Sala
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - K Martel
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - C Henriquet
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - A Al Zein
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - L Simonelli
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - Ch J Sahle
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - H Gonzalez
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - M C Lagier
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - C Ponchut
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - S Huotari
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - R Verbeni
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - M Krisch
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
| | - G Monaco
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France
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6
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Singh V, Pulikkotil JJ. Post-perovskite CaIrO 3: a conventional Slater type antiferromagnetic insulator. Phys Chem Chem Phys 2016; 18:26300-26305. [PMID: 27711536 DOI: 10.1039/c6cp05026c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
To resolve the controversy of whether or not the origin of an electronic gap in antiferromagnetic post-perovskite (pPv) CaIrO3 is due to Coulomb repulsion or spin-orbit coupling, and/or both, we have performed comprehensive full potential density functional theory based calculations. A rather consistent electronic structure, which explains the origin and magnitude of the electronic gap, inter-band d-d transition energies, high thermopower and large magneto-crystalline anisotropy, is obtained with the use of a modified Becke-Johnson (mBJ) exchange potential. Fundamentally, mBJ calculations correctly capture the strong interplay of the crystal field and long range antiferromagnetic ordering of Ir spins as the mechanism that drives pPv-CaIrO3 to an insulating state. Based on our findings, we propose that pPv-CaIrO3 is a conventional Slater type antiferromagnetic insulator.
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Affiliation(s)
- Vijeta Singh
- Academy of Scientific and Innovative Research (AcSIR), CSIR-NPL, New Delhi, India. and Quantum Phenomena & Applications Division, CSIR-National Physical Laboratory, New Delhi, India
| | - J J Pulikkotil
- Academy of Scientific and Innovative Research (AcSIR), CSIR-NPL, New Delhi, India. and Quantum Phenomena & Applications Division, CSIR-National Physical Laboratory, New Delhi, India
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7
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Kim B, Kim BH, Kim K, Min BI. Substrate-tuning of correlated spin-orbit oxides revealed by optical conductivity calculations. Sci Rep 2016; 6:27095. [PMID: 27256281 PMCID: PMC4891771 DOI: 10.1038/srep27095] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 05/11/2016] [Indexed: 11/10/2022] Open
Abstract
We have systematically investigated substrate-strain effects on the electronic structures of two representative Sr-iridates, a correlated-insulator Sr2IrO4 and a metal SrIrO3. Optical conductivities obtained by the ab initio electronic structure calculations reveal that the tensile strain shifts the optical peak positions to higher energy side with altered intensities, suggesting the enhancement of the electronic correlation and spin-orbit coupling (SOC) strength in Sr-iridates. The response of the electronic structure upon tensile strain is found to be highly correlated with the direction of magnetic moment, the octahedral connectivity, and the SOC strength, which cooperatively determine the robustness of Jeff = 1/2 ground states. Optical responses are analyzed also with microscopic model calculation and compared with corresponding experiments. In the case of SrIrO3, the evolution of the electronic structure near the Fermi level shows high tunability of hole bands, as suggested by previous experiments.
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Affiliation(s)
- Bongjae Kim
- Department of Physics, PCTP, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Beom Hyun Kim
- Department of Physics, PCTP, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Kyoo Kim
- Department of Physics, PCTP, Pohang University of Science and Technology, Pohang, 37673, Korea
- MPPC CPM, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - B. I. Min
- Department of Physics, PCTP, Pohang University of Science and Technology, Pohang, 37673, Korea
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8
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Ding Y, Yang L, Chen CC, Kim HS, Han MJ, Luo W, Feng Z, Upton M, Casa D, Kim J, Gog T, Zeng Z, Cao G, Mao HK, van Veenendaal M. Pressure-Induced Confined Metal from the Mott Insulator Sr_{3}Ir_{2}O_{7}. PHYSICAL REVIEW LETTERS 2016; 116:216402. [PMID: 27284666 DOI: 10.1103/physrevlett.116.216402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Indexed: 06/06/2023]
Abstract
The spin-orbit Mott insulator Sr_{3}Ir_{2}O_{7} provides a fascinating playground to explore insulator-metal transition driven by intertwined charge, spin, and lattice degrees of freedom. Here, we report high-pressure electric resistance and resonant inelastic x-ray scattering measurements on single-crystal Sr_{3}Ir_{2}O_{7} up to 63-65 GPa at 300 K. The material becomes a confined metal at 59.5 GPa, showing metallicity in the ab plane but an insulating behavior along the c axis. Such an unusual phenomenon resembles the strange metal phase in cuprate superconductors. Since there is no sign of the collapse of spin-orbit or Coulomb interactions in x-ray measurements, this novel insulator-metal transition is potentially driven by a first-order structural change at nearby pressures. Our discovery points to a new approach for synthesizing functional materials.
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Affiliation(s)
- Yang Ding
- Center for High Pressure Science and Technology Advanced Research, Pudong, Shanghai 201203, China
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
- HPSynC, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, Illinois 60439, USA
| | - Liuxiang Yang
- Center for High Pressure Science and Technology Advanced Research, Pudong, Shanghai 201203, China
- HPSynC, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, Illinois 60439, USA
| | - Cheng-Chien Chen
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Heung-Sik Kim
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea
| | - Myung Joon Han
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea
| | - Wei Luo
- Condensed Matter Theory Group, Department of Physics, Box 530, SE-751 21 Uppsala, Sweden
| | - Zhenxing Feng
- Chemical Sciences and Engineering, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Mary Upton
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Diego Casa
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Jungho Kim
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Thomas Gog
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Zhidan Zeng
- Center for High Pressure Science and Technology Advanced Research, Pudong, Shanghai 201203, China
- HPSynC, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, Illinois 60439, USA
| | - Gang Cao
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
| | - Ho-Kwang Mao
- Center for High Pressure Science and Technology Advanced Research, Pudong, Shanghai 201203, China
- HPSynC, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, Illinois 60439, USA
- Geophysical Laboratory, Carnegie Institution of Washington, Washington, D.C. 20015, USA
| | - Michel van Veenendaal
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
- Department of Physics, Northern Illinois University, De Kalb, Illinois 60115, USA
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9
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Torchinsky DH, Chu H, Zhao L, Perkins NB, Sizyuk Y, Qi T, Cao G, Hsieh D. Structural distortion-induced magnetoelastic locking in Sr(2)IrO(4) revealed through nonlinear optical harmonic generation. PHYSICAL REVIEW LETTERS 2015; 114:096404. [PMID: 25793834 DOI: 10.1103/physrevlett.114.096404] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Indexed: 06/04/2023]
Abstract
We report a global structural distortion in Sr_{2}IrO_{4} using spatially resolved optical second and third harmonic generation rotational anisotropy measurements. A symmetry lowering from an I4_{1}/acd to I4_{1}/a space group is observed both above and below the Néel temperature that arises from a staggered tetragonal distortion of the oxygen octahedra. By studying an effective superexchange Hamiltonian that accounts for this lowered symmetry, we find that perfect locking between the octahedral rotation and magnetic moment canting angles can persist even in the presence of large noncubic local distortions. Our results explain the origin of the forbidden Bragg peaks recently observed in neutron diffraction experiments and reconcile the observations of strong tetragonal distortion and perfect magnetoelastic locking in Sr_{2}IrO_{4}.
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Affiliation(s)
- D H Torchinsky
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
- Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
| | - H Chu
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
- Department of Applied Physics, California Institute of Technology, Pasadena, California 91125, USA
| | - L Zhao
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
- Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
| | - N B Perkins
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55116, USA
| | - Y Sizyuk
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55116, USA
| | - T Qi
- Center for Advanced Materials, Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
| | - G Cao
- Center for Advanced Materials, Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
| | - D Hsieh
- Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA
- Department of Physics, California Institute of Technology, Pasadena, California 91125, USA
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10
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Gunasekera J, Chen Y, Kremenak JW, Miceli PF, Singh DK. Mott insulator-to-metal transition in yttrium-doped CaIrO₃. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:052201. [PMID: 25605689 DOI: 10.1088/0953-8984/27/5/052201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report on the study of insulator-to-metal transition in post-perovskite compound CaIrO3. It is discovered that a gradual chemical substitution of calcium by yttrium leads to the onset of strong metallic behavior in this compound. This observation is in stark contrast to BaIrO3, which preserves its Mott insulating behavior despite excess of the charge carriers due to yttrium doping. Magnetic measurements reveal that both compounds tend to exhibit magnetic character irrespective of the chemical substitution of Ca or Ba. We analyze these unusual observations in light of recent researches that suggest that CaIrO3 does not necessarily possess j = 1/2 ground state due to structural distortion. The insulator-to-metal transition in CaIrO3 will spur new researches to explore more exotic ground state, including superconductivity, in post-perovskite Mott insulators.
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Affiliation(s)
- J Gunasekera
- Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211, USA
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11
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de la Torre A, Hunter EC, Subedi A, McKeown Walker S, Tamai A, Kim TK, Hoesch M, Perry RS, Georges A, Baumberger F. Coherent quasiparticles with a small fermi surface in lightly doped Sr(3)Ir(2)O(7). PHYSICAL REVIEW LETTERS 2014; 113:256402. [PMID: 25554897 DOI: 10.1103/physrevlett.113.256402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Indexed: 06/04/2023]
Abstract
We characterize the electron doping evolution of (Sr_{1-x}La_{x})_{3}Ir_{2}O_{7} by means of angle-resolved photoemission. Concomitant with the metal insulator transition around x≈0.05 we find the emergence of coherent quasiparticle states forming a closed small Fermi surface of volume 3x/2, where x is the independently measured La concentration. The quasiparticle weight Z remains large along the entire Fermi surface, consistent with the moderate renormalization of the low-energy dispersion, and no pseudogap is observed. This indicates a conventional, weakly correlated Fermi liquid state with a momentum independent residue Z≈0.5 in lightly doped Sr_{3}Ir_{2}O_{7}.
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Affiliation(s)
- A de la Torre
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - E C Hunter
- School of Physics and Astronomy, The University of Edinburgh, James Clerk Maxwell Building, Mayfield Road, Edinburgh EH9 2TT, United Kingdom
| | - A Subedi
- Centre de Physique Théorique, École Polytechnique, CNRS, 91128 Palaiseau Cedex, France
| | - S McKeown Walker
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - A Tamai
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - R S Perry
- London Centre for Nanotechnology and UCL Centre for Materials Discovery, University College London, London WC1E 6BT, United Kingdom
| | - A Georges
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland and Centre de Physique Théorique, École Polytechnique, CNRS, 91128 Palaiseau Cedex, France and Collège de France, 11 place Marcelin Berthelot, 75005 Paris, France
| | - F Baumberger
- Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland and Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland and SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife KY16 9SS, United Kingdom
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12
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Lovesey SW, Khalyavin DD. Strange magnetic multipoles and neutron diffraction by an iridate perovskite (Sr2IrO4). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:322201. [PMID: 25055164 DOI: 10.1088/0953-8984/26/32/322201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A theoretical investigation of a plausible construct for electronic structure in iridate perovskites demonstrates the existence of magnetic multipoles hitherto not identified. The strange multipoles, which are parity-even, time-odd and even rank tensors, are absent from the so-called j(eff) = 1/2 model. We prove that the strange multipoles contribute to magnetic neutron diffraction, and we estimate their contribution to intensities of Bragg spots for Sr(2)IrO(4). The construct encompasses the j(eff) = 1/2 model, and it is consistent with the known magnetic structure, ordered magnetic moment, and published resonant x-ray Bragg diffraction data. Over and above time-odd quadrupoles and hexadecapoles, whose contribution changes neutron Bragg intensities by an order of magnitude, according to our estimates, are relatively small triakontadipoles recently proposed as the primary magnetic order-parameter of Sr(2)IrO(4).
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Affiliation(s)
- S W Lovesey
- ISIS Facility, STFC, Didcot, Oxfordshire OX11 0QX, UK. Diamond Light Source Ltd, Didcot, Oxfordshire OX11 0DE, UK
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13
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Sala MM, Ohgushi K, Al-Zein A, Hirata Y, Monaco G, Krisch M. CaIrO3: a spin-orbit Mott insulator beyond the j(eff) ground state. PHYSICAL REVIEW LETTERS 2014; 112:176402. [PMID: 24836260 DOI: 10.1103/physrevlett.112.176402] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Indexed: 06/03/2023]
Abstract
In CaIrO3, electronic correlation, spin-orbit coupling, and tetragonal crystal field splitting are predicted to be of comparable strength. However, the nature of its ground state is still an object of debate, with contradictory experimental and theoretical results. We probe the ground state of CaIrO3 and assess the effective tetragonal crystal field splitting and spin-orbit coupling at play in this system by means of resonant inelastic x-ray scattering. We conclude that insulating CaIrO3 is not a j(eff) = 1/2 iridate and discuss the consequences of our finding to the interpretation of previous experiments. In particular, we clarify how the Mott insulating state in iridates can be readily extended beyond the j(eff) = 1/2 ground state.
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Affiliation(s)
- M Moretti Sala
- European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France
| | - K Ohgushi
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - A Al-Zein
- European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France
| | - Y Hirata
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - G Monaco
- European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France and Dipartimento di Fisica, Università di Trento, via Sommarive 14, 38123 Povo (TN), Italy
| | - M Krisch
- European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France
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14
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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. PHYSICAL REVIEW LETTERS 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] [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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