1
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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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Gong X, Autieri C, Zhou H, Ma J, Tang X, Zheng X, Ming X. In-gap states and strain-tuned band convergence in layered structure trivalent iridate K 0.75Na 0.25IrO 2. Phys Chem Chem Phys 2023; 25:6857-6866. [PMID: 36799367 DOI: 10.1039/d2cp04806j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Iridium oxides (iridates) provide a good platform to study the delicate interplay between spin-orbit coupling (SOC) interactions, electron correlation effects, Hund's coupling and lattice degrees of freedom. An overwhelming number of investigations primarily focus on tetravalent (Ir4+, 5d5) and pentavalent (Ir5+, 5d4) iridates, and far less attention has been paid to iridates with other valence states. Here, we pay our attention to a less-explored trivalent (Ir3+, 5d6) iridate, K0.75Na0.25IrO2, crystallizing in a triangular lattice with edge-sharing IrO6 octahedra and alkali metal ion intercalated [IrO2]- layers, offering a good platform to explore the interplay between different degrees of freedom. We theoretically determine the preferred occupied positions of the alkali metal ions from energetic viewpoints and reproduce the experimentally observed semiconducting behavior and nonmagnetic (NM) properties of K0.75Na0.25IrO2. The SOC interactions play a critical role in the band dispersion, resulting in NM Jeff = 0 states. More intriguingly, our electronic structure not only uncovers the presence of intrinsic in-gap states and nearly free electron character for the conduction band minimum, but also explains the abnormally low activation energy in K0.75Na0.25IrO2. Particularly, the band edge can be effectively modulated by mechanical strain, and the in-gap states feature enhanced band-convergence characteristics by 6% compressive strain, which will greatly enhance the electrical conductivity of K0.75Na0.25IrO2. The present work sheds new light on the unconventional electronic structures of trivalent iridates, indicating their promising application as a nanoelectronic and thermoelectric material, which will attract extensive interest and stimulate experimental works to further understand the unprecedented electronic structures and exploit potential applications of the triangular trivalent iridate.
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Affiliation(s)
- Xujia Gong
- College of Science, Guilin University of Technology, Guilin 541004, People's Republic of China.
| | - Carmine Autieri
- International Research Centre Magtop, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Huanfu Zhou
- Key Lab of New Processing Technology for Nonferrous Metal & Materials, Ministry of Education, School of Materials Science and Engineering, Guilin University of Technology, Guilin 541004, China
| | - Jiafeng Ma
- College of Science, Guilin University of Technology, Guilin 541004, People's Republic of China.
| | - Xin Tang
- Key Lab of New Processing Technology for Nonferrous Metal & Materials, Ministry of Education, School of Materials Science and Engineering, Guilin University of Technology, Guilin 541004, China
| | - Xiaojun Zheng
- College of Science, Guilin University of Technology, Guilin 541004, People's Republic of China.
| | - Xing Ming
- College of Science, Guilin University of Technology, Guilin 541004, People's Republic of China.
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3
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Kim D, Ahn G, Schmehr J, Wilson SD, Moon SJ. Effects of the on-site energy on the electronic response of Sr3(Ir1−xMnx)2O7. Sci Rep 2022; 12:18957. [DOI: 10.1038/s41598-022-23593-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 11/02/2022] [Indexed: 11/10/2022] Open
Abstract
AbstractWe investigated the doping and temperature evolutions of the optical response of Sr3(Ir1−xMnx)2O7 single crystals with 0 ≤ x ≤ 0.36 by utilizing infrared spectroscopy. Substitution of 3d transition metal Mn ions into Sr3Ir2O7 is expected to induce an insulator-to-metal transition via the decrease in the magnitude of the spin–orbit coupling and the hole doping. In sharp contrast, our data reveal the resilience of the spin–orbit coupling and the incoherent character of the charge transport. Upon Mn substitution, an incoherent in-gap excitation at about 0.25 eV appeared with the decrease in the strength of the optical transitions between the effective total angular momentum Jeff bands of the Ir ions. The resonance energies of the optical transitions between the Jeff bands which are directly proportional to the magnitude of the spin–orbit coupling hardly varied. In addition to these evolutions of the low-energy response, Mn substitution led to the emergence of a distinct high-energy optical excitation at about 1.2 eV which is larger than the resonance energies of the optical transitions between the Jeff bands. This observation indicates that the Mn 3d states are located away from the Ir 5d states in energy and that the large difference in the on-site energies of the transition metal ions is responsible for the incoherent charge transport and the robustness of the spin–orbit coupling. The effect of Mn substitution was also registered in the temperature dependence of the electronic response. The anomaly in the optical response of the parent compound observed at the antiferromagnetic transition temperature is notably suppressed in the Mn-doped compounds despite the persistence of the long-range antiferromagnetic ordering. The suppression of the spin-charge coupling could be related to charge disproportionation of the Ir ions.
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4
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Gong D, Yang J, Hao L, Horak L, Xin Y, Karapetrova E, Strempfer J, Choi Y, Kim JW, Ryan PJ, Liu J. Reconciling Monolayer and Bilayer J_{eff}=1/2 Square Lattices in Hybrid Oxide Superlattice. PHYSICAL REVIEW LETTERS 2022; 129:187201. [PMID: 36374692 DOI: 10.1103/physrevlett.129.187201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 08/08/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
The number of atomic layers confined in a two-dimensional structure is crucial for the electronic and magnetic properties. Single-layer and bilayer J_{eff}=1/2 square lattices are well-known examples where the presence of the extra layer turns the XY anisotropy to the c-axis anisotropy. We report on experimental realization of a hybrid SrIrO_{3}/SrTiO_{3} superlattice that integrates monolayer and bilayer square lattices in one layered structure. By synchrotron x-ray diffraction, resonant x-ray magnetic scattering, magnetization, and resistivity measurements, we found that the hybrid superlattice exhibits properties that are distinct from both the single-layer and bilayer systems and cannot be explained by a simple addition of them. In particular, the entire hybrid superlattice orders simultaneously through a single antiferromagnetic transition at temperatures similar to the bilayer system but with all the J_{eff}=1/2 moments mainly pointing in the ab plane similar to the single-layer system. The results show that bringing monolayer and bilayer with orthogonal properties in proximity to each other in a hybrid superlattice structure is a powerful way to stabilize a unique state not obtainable in a uniform structure.
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Affiliation(s)
- Dongliang Gong
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Junyi Yang
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Lin Hao
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei 230031, China
| | - Lukas Horak
- Department of Condensed Matter Physics, Charles University, Ke Karlovu 3, Prague 12116, Czech Republic
| | - Yan Xin
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - Evguenia Karapetrova
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Jörg Strempfer
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Yongseong Choi
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Jong-Woo Kim
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Philip J Ryan
- Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, USA
| | - Jian Liu
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
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5
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Hu Y, Wu X, Yang Y, Gao S, Plumb NC, Schnyder AP, Xie W, Ma J, Shi M. Tunable topological Dirac surface states and van Hove singularities in kagome metal GdV 6Sn 6. SCIENCE ADVANCES 2022; 8:eadd2024. [PMID: 36129982 PMCID: PMC9491707 DOI: 10.1126/sciadv.add2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 08/04/2022] [Indexed: 06/15/2023]
Abstract
Transition-metal-based kagome materials at van Hove filling are a rich frontier for the investigation of novel topological electronic states and correlated phenomena. To date, in the idealized two-dimensional kagome lattice, topologically Dirac surface states (TDSSs) have not been unambiguously observed, and the manipulation of TDSSs and van Hove singularities (VHSs) remains largely unexplored. Here, we reveal TDSSs originating from a ℤ2 bulk topology and identify multiple VHSs near the Fermi level (EF) in magnetic kagome material GdV6Sn6. Using in situ surface potassium deposition, we successfully realize manipulation of the TDSSs and VHSs. The Dirac point of the TDSSs can be tuned from above to below EF, which reverses the chirality of the spin texture at the Fermi surface. These results establish GdV6Sn6 as a fascinating platform for studying the nontrivial topology, magnetism, and correlation effects native to kagome lattices. They also suggest potential application of spintronic devices based on kagome materials.
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Affiliation(s)
- Yong Hu
- Photon Science Division, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Xianxin Wu
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Yongqi Yang
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Shunye Gao
- Photon Science Division, 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
| | - Nicholas C. Plumb
- Photon Science Division, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - Andreas P. Schnyder
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Weiwei Xie
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
| | - Junzhang Ma
- Department of Physics, City University of Hong Kong, Kowloon, Hong Kong, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
- Hong Kong Institute for Advanced Study, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Ming Shi
- Photon Science Division, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
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6
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Pandey S, Zhang H, Yang J, May AF, Sanchez JJ, Liu Z, Chu JH, Kim JW, Ryan PJ, Zhou H, Liu J. Controllable Emergent Spatial Spin Modulation in Sr_{2}IrO_{4} by In Situ Shear Strain. PHYSICAL REVIEW LETTERS 2022; 129:027203. [PMID: 35867461 DOI: 10.1103/physrevlett.129.027203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 05/16/2022] [Accepted: 05/17/2022] [Indexed: 06/15/2023]
Abstract
Symmetric anisotropic interaction can be ferromagnetic and antiferromagnetic at the same time but for different crystallographic axes. We show that the competition of anisotropic interactions of orthogonal irreducible representations can be a general route to obtain new exotic magnetic states. We demonstrate it here by observing the emergence of a continuously tunable 12-layer spatial spin modulation when distorting the square-lattice planes in the quasi-two-dimensional antiferromagnetic Sr_{2}IrO_{4} under in situ shear strain. This translation-symmetry-breaking phase is a result of an unusual strain-activated anisotropic interaction which is at the fourth order and competing with the inherent quadratic anisotropic interaction. Such a mechanism of competing anisotropy is distinct from that among the ferromagnetic, antiferromagnetic, and/or the Dzyaloshinskii-Moriya interactions, and it could be widely applicable and highly controllable in low-dimensional magnets.
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Affiliation(s)
- Shashi Pandey
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Han Zhang
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Junyi Yang
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Andrew F May
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Joshua J Sanchez
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - Zhaoyu Liu
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - Jiun-Haw Chu
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - Jong-Woo Kim
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Philip J Ryan
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
- School of Physical Sciences, Dublin City University, Dublin 11, Ireland
| | - Haidong Zhou
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Jian Liu
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
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7
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Liang A, Chen C, Zheng H, Xia W, Huang K, Wei L, Yang H, Chen Y, Zhang X, Xu X, Wang M, Guo Y, Yang L, Liu Z, Chen Y. Approaching a Minimal Topological Electronic Structure in Antiferromagnetic Topological Insulator MnBi 2Te 4 via Surface Modification. NANO LETTERS 2022; 22:4307-4314. [PMID: 35604392 DOI: 10.1021/acs.nanolett.1c04930] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The topological electronic structure plays a central role in the nontrivial physical properties in topological quantum materials. A minimal, "hydrogen-atom-like" topological electronic structure is desired for research. In this work, we demonstrate an effort toward the realization of such a system in the intrinsic magnetic topological insulator MnBi2Te4, by manipulating the topological surface state (TSS) via surface modification. Using high resolution laser- and synchrotron-based angle-resolved photoemission spectroscopy (ARPES), we found the TSS in MnBi2Te4 is heavily hybridized with a trivial Rashba-type surface state (RSS), which could be efficiently removed by the in situ surface potassium (K) dosing. By employing multiple experimental methods to characterize K dosed surface, we attribute such a modification to the electrochemical reactions of K clusters on the surface. Our work not only gives a clear band assignment in MnBi2Te4 but also provides possible new routes in accentuating the topological behavior in the magnetic topological quantum materials.
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Affiliation(s)
- Aiji Liang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- ShanghaiTech Laboratory for Topological Physics, Shanghai 200031, China
| | - Cheng Chen
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, U.K
| | - Huijun Zheng
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Wei Xia
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- ShanghaiTech Laboratory for Topological Physics, Shanghai 200031, China
| | - Kui Huang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Liyang Wei
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Haifeng Yang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yujie Chen
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Xin Zhang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Xuguang Xu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- ShanghaiTech Laboratory for Topological Physics, Shanghai 200031, China
| | - Meixiao Wang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- ShanghaiTech Laboratory for Topological Physics, Shanghai 200031, China
| | - Yanfeng Guo
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- ShanghaiTech Laboratory for Topological Physics, Shanghai 200031, China
| | - Lexian Yang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Beijing 100084, China
| | - Zhongkai Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- ShanghaiTech Laboratory for Topological Physics, Shanghai 200031, China
| | - Yulin Chen
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
- ShanghaiTech Laboratory for Topological Physics, Shanghai 200031, China
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, U.K
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
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8
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Li Y, Niu R, Xu F, Zhen W, Huang H, Wang J, Zhu W, Zhang C. Enhanced magnetism and persistent insulating state in Mn doped Sr 2IrO 4. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:235602. [PMID: 35290974 DOI: 10.1088/1361-648x/ac5e05] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 03/15/2022] [Indexed: 06/14/2023]
Abstract
The influences of Mn substitution at the Ir site of Sr2IrO4are investigated via a comprehensive study of the variation of structural parameters, the transport and magnetic properties of the Sr2Ir1-xMnxO4samples. The incorporation of Mn leads to an increase of the in-plane Ir-O-Ir bond angle, while it is not sufficient to drive the Mott-insulating state to a metallic state. Interestingly, we find a coexistence of Ir4+-O2--Ir4+super-exchange interaction and Mn3+-O2--Mn4+double exchange interaction inx⩾ 0.06 samples. The Mn3+-O2--Mn4+ferromagnetic domains are isolated by the Ir4+-O2--Ir4+antiferromagnetic areas, leading to a severely localized electronic and magnetic states. The electron hopping between the localized states dominates the conductivity of the Sr2Ir1-xMnxO4samples.
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Affiliation(s)
- Yaodong Li
- High Magnetic Field Laboratory of Anhui Province, HFIPS, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- Science Island Branch of Graduate School, University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Rui Niu
- High Magnetic Field Laboratory of Anhui Province, HFIPS, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - Feng Xu
- High Magnetic Field Laboratory of Anhui Province, HFIPS, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - Weili Zhen
- High Magnetic Field Laboratory of Anhui Province, HFIPS, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - Hui Huang
- High Magnetic Field Laboratory of Anhui Province, HFIPS, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, People's Republic of China
| | - Jingrong Wang
- High Magnetic Field Laboratory of Anhui Province, HFIPS, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - Wenka Zhu
- High Magnetic Field Laboratory of Anhui Province, HFIPS, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - Changjin Zhang
- High Magnetic Field Laboratory of Anhui Province, HFIPS, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
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9
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Gubanov AI, Smolentsev AI, Filatov E, Kuratieva NV, Danilenko AM, Korenev SV. Revisiting Sodium Hexafluoroiridates: Perspective Precursors for Electronic, Quantum, and Related Materials. ACS OMEGA 2021; 6:27697-27701. [PMID: 34722969 PMCID: PMC8552232 DOI: 10.1021/acsomega.1c02722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 10/04/2021] [Indexed: 06/13/2023]
Abstract
The following salts have been synthesized and structurally characterized: Na2[IrF6]·2H2O (C2/m, a = 6.6327(4), b = 10.0740(6), c = 5.9283(5) Å, β = 122.3880(10)°) and Na3[IrF6]·2H2O (R-3, a = 7.5963(3), b = 7.5963(3), c = 9.8056(4) Å) (for the first time) by single-crystal X-ray diffraction; the unit cell parameters of a tetragonal phase (P4 2/mnm, a = 5.005(2), c = 10.074(4) Å) of the stable α-Na2[IrF6] were determined for the first time; and the unit cell parameters of β-Na2[IrF6] (P321, a = 9.332(4), c = 5.136(2) Å) and Na3[IrF6] (P21/n, a = 5.567(4), b = 5.778(4), c = 8.017(2) Å, β = 90.41(2)°) were determined using powder X-ray diffraction (PXRD). The data of the thermal stability was obtained by differential thermal analysis (DTA) for all substances. The presence of Na3[IrF6]·H2O monohydrate is predicted. H2[IrF6] was prepared in a solution and was demonstrated to behave as a strong dibasic acid.
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Affiliation(s)
- Alexander I. Gubanov
- Nikolaev
Institute of Inorganic Chemistry, Siberian
Branch Russian Academy of Science, 3, Acad. Lavrentiev Ave., Novosibirsk 630090, Russian Federation
| | - Anton I. Smolentsev
- Nikolaev
Institute of Inorganic Chemistry, Siberian
Branch Russian Academy of Science, 3, Acad. Lavrentiev Ave., Novosibirsk 630090, Russian Federation
- Novosibirsk
State University, 1,
Pirogova str., Novosibirsk 630090, Russian Federation
| | - Evgeny Filatov
- Nikolaev
Institute of Inorganic Chemistry, Siberian
Branch Russian Academy of Science, 3, Acad. Lavrentiev Ave., Novosibirsk 630090, Russian Federation
| | - Natalia V. Kuratieva
- Nikolaev
Institute of Inorganic Chemistry, Siberian
Branch Russian Academy of Science, 3, Acad. Lavrentiev Ave., Novosibirsk 630090, Russian Federation
| | - Andrey M. Danilenko
- Nikolaev
Institute of Inorganic Chemistry, Siberian
Branch Russian Academy of Science, 3, Acad. Lavrentiev Ave., Novosibirsk 630090, Russian Federation
| | - Sergey Vasilievich Korenev
- Nikolaev
Institute of Inorganic Chemistry, Siberian
Branch Russian Academy of Science, 3, Acad. Lavrentiev Ave., Novosibirsk 630090, Russian Federation
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10
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Sohn B, Kim JR, Kim CH, Lee S, Hahn S, Kim Y, Huh S, Kim D, Kim Y, Kyung W, Kim M, Kim M, Noh TW, Kim C. Observation of metallic electronic structure in a single-atomic-layer oxide. Nat Commun 2021; 12:6171. [PMID: 34702805 PMCID: PMC8548526 DOI: 10.1038/s41467-021-26444-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 10/05/2021] [Indexed: 11/08/2022] Open
Abstract
Correlated electrons in transition metal oxides exhibit a variety of emergent phases. When transition metal oxides are confined to a single-atomic-layer thickness, experiments so far have shown that they usually lose diverse properties and become insulators. In an attempt to extend the range of electronic phases of the single-atomic-layer oxide, we search for a metallic phase in a monolayer-thick epitaxial SrRuO3 film. Combining atomic-scale epitaxy and angle-resolved photoemission measurements, we show that the monolayer SrRuO3 is a strongly correlated metal. Systematic investigation reveals that the interplay between dimensionality and electronic correlation makes the monolayer SrRuO3 an incoherent metal with orbital-selective correlation. Furthermore, the unique electronic phase of the monolayer SrRuO3 is found to be highly tunable, as charge modulation demonstrates an incoherent-to-coherent crossover of the two-dimensional metal. Our work emphasizes the potentially rich phases of single-atomic-layer oxides and provides a guide to the manipulation of their two-dimensional correlated electron systems.
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Affiliation(s)
- Byungmin Sohn
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Jeong Rae Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Choong H Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Sangmin Lee
- Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Korea
| | - Sungsoo Hahn
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Younsik Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Soonsang Huh
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Donghan Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Youngdo Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Wonshik Kyung
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Minsoo Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea
| | - Miyoung Kim
- Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Korea
| | - Tae Won Noh
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea.
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea.
| | - Changyoung Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Korea.
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Korea.
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11
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Dhingra A, Komesu T, Kumar S, Shimada K, Zhang L, Hong X, Dowben PA. Electronic band structure of iridates. MATERIALS HORIZONS 2021; 8:2151-2168. [PMID: 34846422 DOI: 10.1039/d1mh00063b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In this review, an attempt has been made to compare the electronic structures of various 5d iridates (iridium oxides), with an effort to note the common features and differences. Both experimental studies, especially angle-resolved photoemission spectroscopy (ARPES) results, and first-principles band structure calculations have been discussed. This brings to focus the fact that the electronic structures and magnetic properties of the high-Z 5d transition iridates depend on the intricate interplay of strong electron correlation, strong (relativistic) spin-orbit coupling, lattice distortion, and the dimensionality of the system. For example, in the thin film limit, SrIrO3 exhibits a metal-insulator transition that corresponds to the dimensionality crossover, with the band structure resembling that of bulk Sr2IrO4.
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Affiliation(s)
- Archit Dhingra
- Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, Theodore Jorgensen Hall, University of Nebraska, 855 N 16th, P. O. Box 880299, Lincoln, Nebraska 68588-0299, USA.
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12
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Advanced First-Principle Modeling of Relativistic Ruddlesden—Popper Strontium Iridates. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11062527] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this review, we provide a survey of the application of advanced first-principle methods on the theoretical modeling and understanding of novel electronic, optical, and magnetic properties of the spin-orbit coupled Ruddlesden–Popper series of iridates Srn+1IrnO3n+1 (n = 1, 2, and ∞). After a brief description of the basic aspects of the adopted methods (noncollinear local spin density approximation plus an on-site Coulomb interaction (LSDA+U), constrained random phase approximation (cRPA), GW, and Bethe–Salpeter equation (BSE)), we present and discuss select results. We show that a detailed phase diagrams of the metal–insulator transition and magnetic phase transition can be constructed by inspecting the evolution of electronic and magnetic properties as a function of Hubbard U, spin–orbit coupling (SOC) strength, and dimensionality n, which provide clear evidence for the crucial role played by SOC and U in establishing a relativistic (Dirac) Mott–Hubbard insulating state in Sr2IrO4 and Sr3Ir2O7. To characterize the ground-state phases, we quantify the most relevant energy scales fully ab initio—crystal field energy, Hubbard U, and SOC constant of three compounds—and discuss the quasiparticle band structures in detail by comparing GW and LSDA+U data. We examine the different magnetic ground states of structurally similar n = 1 and n = 2 compounds and clarify that the origin of the in-plane canted antiferromagnetic (AFM) state of Sr2IrO4 arises from competition between isotropic exchange and Dzyaloshinskii–Moriya (DM) interactions whereas the collinear AFM state of Sr3Ir2O7 is due to strong interlayer magnetic coupling. Finally, we report the dimensionality controlled metal–insulator transition across the series by computing their optical transitions and conductivity spectra at the GW+BSE level from the the quasi two-dimensional insulating n = 1 and 2 phases to the three-dimensional metallic n=∞ phase.
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13
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Momentum-resolved visualization of electronic evolution in doping a Mott insulator. Nat Commun 2021; 12:1356. [PMID: 33649302 PMCID: PMC7921433 DOI: 10.1038/s41467-021-21605-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 01/29/2021] [Indexed: 11/25/2022] Open
Abstract
High temperature superconductivity in cuprates arises from doping a parent Mott insulator by electrons or holes. A central issue is how the Mott gap evolves and the low-energy states emerge with doping. Here we report angle-resolved photoemission spectroscopy measurements on a cuprate parent compound by sequential in situ electron doping. The chemical potential jumps to the bottom of the upper Hubbard band upon a slight electron doping, making it possible to directly visualize the charge transfer band and the full Mott gap region. With increasing doping, the Mott gap rapidly collapses due to the spectral weight transfer from the charge transfer band to the gapped region and the induced low-energy states emerge in a wide energy range inside the Mott gap. These results provide key information on the electronic evolution in doping a Mott insulator and establish a basis for developing microscopic theories for cuprate superconductivity. How a Mott insulating state evolves into a conducting or superconducting state is a central issue in doping a Mott insulator and important to understand the physics in high temperature cuprate superconductors. Here, the authors visualize the electronic structure evolution of a Mott insulator within the full Mott gap region and address the fundamental issues.
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14
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Abstract
Quasi-2D square planar nickelates exhibit key ingredients of high-Tc superconducting cuprates. Whether bulk samples are superconducting remains an open question, single crystals are ideal platforms for addressing such fundamental questions.
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Affiliation(s)
- Junjie Zhang
- Institute of Crystal Materials
- State Key Laboratory of Crystal Materials
- Shandong University
- Jinan
- China
| | - Xutang Tao
- Institute of Crystal Materials
- State Key Laboratory of Crystal Materials
- Shandong University
- Jinan
- China
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15
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Ahn G, Schmehr JL, Porter Z, Wilson SD, Moon SJ. Doping and temperature evolutions of optical response of Sr 3(Ir 1-xRu x) 2O 7. Sci Rep 2020; 10:22340. [PMID: 33339856 PMCID: PMC7749133 DOI: 10.1038/s41598-020-79263-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 12/01/2020] [Indexed: 11/09/2022] Open
Abstract
We report on optical spectroscopic study of the Sr3(Ir1-xRux)2O7 system over a wide doping regime. We find that the changes in the electronic structure occur in the limited range of the concentration of Ru ions where the insulator-metal transition occurs. In the insulating regime, the electronic structure associated with the effective total angular momentum Jeff = 1/2 Mott state remains robust against Ru doping, indicating the localization of the doped holes. Upon entering the metallic regime, the Mott gap collapses and the Drude-like peak with strange metallic character appears. The evolution of the electronic structure registered in the optical data can be explained in terms of a percolative insulator-metal transition. The phonon spectra display anomalous doping evolution of the lineshapes. While the phonon modes of the compounds deep in the insulating and metallic regimes are almost symmetric, those of the semiconducting compound with x = 0.34 in close proximity to the doping-driven insulator-metal transition show a pronounced asymmetry. The temperature evolution of the phonon modes of the x = 0.34 compound reveals the asymmetry is enhanced in the antiferromagnetic state. We discuss roles of the S = 1 spins of the Ru ions and charge excitations for the conspicuous lineshape asymmetry of the x = 0.34 compound.
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Affiliation(s)
- Gihyeon Ahn
- Department of Physics, Hanyang University, Seoul, 04763, Republic of Korea
| | - J L Schmehr
- Materials Department, University of California, Santa Barbara, CA, 93106, USA
| | - Z Porter
- Materials Department, University of California, Santa Barbara, CA, 93106, USA
| | - S D Wilson
- Materials Department, University of California, Santa Barbara, CA, 93106, USA
| | - S J Moon
- Department of Physics, Hanyang University, Seoul, 04763, Republic of Korea. .,Research Institute of Natural Science, Hanyang University, Seoul, 04763, Republic of Korea.
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16
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Abstract
Understanding the relationship between entangled degrees of freedom (DOF) is a central problem in correlated materials and the possibility to influence their balance is promising toward realizing novel functionalities. In Sr2IrO4, the interaction between spin–orbit coupling and electron correlations induces an exotic ground state with magnetotransport properties promising for antiferromagnetic spintronics applications. Moreover, the coupling between orbital and spin DOF renders the magnetic structure sensitive to the Ir–O bond environment. To date, a detailed understanding of the microscopic spin-lattice and electron–phonon interactions is still lacking. Here, we use strain engineering to perturb the local lattice environment and, by tracking the response of the low-energy elementary excitations, we unveil the response of the microscopic spin and charge interactions. In the high spin–orbit-coupled Sr2IrO4, the high sensitivity of the ground state to the details of the local lattice structure shows a large potential for the manipulation of the functional properties by inducing local lattice distortions. We use epitaxial strain to modify the Ir–O bond geometry in Sr2IrO4 and perform momentum-dependent resonant inelastic X-ray scattering (RIXS) at the metal and at the ligand sites to unveil the response of the low-energy elementary excitations. We observe that the pseudospin-wave dispersion for tensile-strained Sr2IrO4 films displays large softening along the [h,0] direction, while along the [h,h] direction it shows hardening. This evolution reveals a renormalization of the magnetic interactions caused by a strain-driven cross-over from anisotropic to isotropic interactions between the magnetic moments. Moreover, we detect dispersive electron–hole pair excitations which shift to lower (higher) energies upon compressive (tensile) strain, manifesting a reduction (increase) in the size of the charge gap. This behavior shows an intimate coupling between charge excitations and lattice distortions in Sr2IrO4, originating from the modified hopping elements between the t2g orbitals. Our work highlights the central role played by the lattice degrees of freedom in determining both the pseudospin and charge excitations of Sr2IrO4 and provides valuable information toward the control of the ground state of complex oxides in the presence of high spin–orbit coupling.
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17
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Li S, Drueke E, Porter Z, Jin W, Lu Z, Smirnov D, Merlin R, Wilson SD, Sun K, Zhao L. Symmetry-Resolved Two-Magnon Excitations in a Strong Spin-Orbit-Coupled Bilayer Antiferromagnet. PHYSICAL REVIEW LETTERS 2020; 125:087202. [PMID: 32909791 DOI: 10.1103/physrevlett.125.087202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 07/29/2020] [Indexed: 06/11/2023]
Abstract
We used a combination of polarized Raman spectroscopy and spin wave calculations to study magnetic excitations in the strong spin-orbit-coupled bilayer perovskite antiferromagnet Sr_{3}Ir_{2}O_{7}. We observed two broad Raman features at ∼800 and ∼1400 cm^{-1} arising from magnetic excitations. Unconventionally, the ∼800 cm^{-1} feature is fully symmetric (A_{1g}) with respect to the underlying tetragonal (D_{4h}) crystal lattice which, together with its broad line shape, definitively rules out the possibility of a single magnon excitation as its origin. In contrast, the ∼1400 cm^{-1} feature shows up in both the A_{1g} and B_{2g} channels. From spin wave and two-magnon scattering cross-section calculations of a tetragonal bilayer antiferromagnet, we identified the ∼800 cm^{-1} (1400 cm^{-1}) feature as two-magnon excitations with pairs of magnons from the zone-center Γ point (zone-boundary van Hove singularity X point). We further found that this zone-center two-magnon scattering is unique to bilayer perovskite magnets which host an optical branch in addition to the acoustic branch, as compared to their single layer counterparts. This zone-center two-magnon mode is distinct in symmetry from the time-reversal symmetry broken "spin wave gap" and "phase mode" proposed to explain the ∼92 meV (742 cm^{-1}) gap in resonant inelastic x-ray spectroscopy magnetic excitation spectra of Sr_{3}Ir_{2}O_{7}.
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Affiliation(s)
- Siwen Li
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Elizabeth Drueke
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Zach Porter
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - Wencan Jin
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Zhengguang Lu
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA
- Department of Physics, Florida State University, Tallahassee, Florida 32310, USA
| | - Dmitry Smirnov
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA
| | - Roberto Merlin
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Stephen D Wilson
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - Kai Sun
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Liuyan Zhao
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
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18
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Lu C, Liu JM. The J eff = 1/2 Antiferromagnet Sr 2 IrO 4 : A Golden Avenue toward New Physics and Functions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1904508. [PMID: 31667943 DOI: 10.1002/adma.201904508] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Revised: 09/12/2019] [Indexed: 06/10/2023]
Abstract
Iridates have been providing a fertile ground for studying emergent phases of matter that arise from the delicate interplay of various fundamental interactions with approximate energy scale. Among these highly focused quantum materials, the perovskite Sr2 IrO4 , which belongs to the Ruddlesden-Popper series, stands out and has been intensively addressed in the last decade, since it hosts a novel Jeff = 1/2 state that is a profound manifestation of strong spin-orbit coupling. Moreover, the Jeff = 1/2 state represents a rare example of iridates that is better understood both theoretically and experimentally. Here, Sr2 IrO4 is taken as an example to review the recent advances of the Jeff = 1/2 state in two aspects: materials fundamentals and functionality potentials. In the fundamentals part, the basic issues for the layered canted antiferromagnetic order of the Jeff = 1/2 magnetic moments in Sr2 IrO4 are illustrated, and then the progress of the antiferromagnetic order modulation through diverse routes is highlighted. Subsequently, for the functionality potentials, fascinating properties such as atomic-scale giant magnetoresistance, anisotropic magnetoresistance, and nonvolatile memory, are addressed. To conclude, prospective remarks and an outlook are given.
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Affiliation(s)
- Chengliang Lu
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Jun-Ming Liu
- Laboratory of Solid State Microstructures and Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
- Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials and Institute for Advanced Materials, South China Normal University, Guangzhou, 510006, China
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19
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Kuroda K, Arai Y, Rezaei N, Kunisada S, Sakuragi S, Alaei M, Kinoshita Y, Bareille C, Noguchi R, Nakayama M, Akebi S, Sakano M, Kawaguchi K, Arita M, Ideta S, Tanaka K, Kitazawa H, Okazaki K, Tokunaga M, Haga Y, Shin S, Suzuki HS, Arita R, Kondo T. Devil's staircase transition of the electronic structures in CeSb. Nat Commun 2020; 11:2888. [PMID: 32514054 PMCID: PMC7280508 DOI: 10.1038/s41467-020-16707-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 05/15/2020] [Indexed: 12/02/2022] Open
Abstract
Solids with competing interactions often undergo complex phase transitions with a variety of long-periodic modulations. Among such transition, devil's staircase is the most complex phenomenon, and for it, CeSb is the most famous material, where a number of the distinct phases with long-periodic magnetostructures sequentially appear below the Néel temperature. An evolution of the low-energy electronic structure going through the devil's staircase is of special interest, which has, however, been elusive so far despite 40 years of intense research. Here, we use bulk-sensitive angle-resolved photoemission spectroscopy and reveal the devil's staircase transition of the electronic structures. The magnetic reconstruction dramatically alters the band dispersions at each transition. Moreover, we find that the well-defined band picture largely collapses around the Fermi energy under the long-periodic modulation of the transitional phase, while it recovers at the transition into the lowest-temperature ground state. Our data provide the first direct evidence for a significant reorganization of the electronic structures and spectral functions occurring during the devil's staircase.
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Affiliation(s)
- Kenta Kuroda
- ISSP, University of Tokyo, Kashiwa, Chiba, 277-8581, Japan.
| | - Y Arai
- ISSP, University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - N Rezaei
- Department of Physics, Isfahan University of Technology, 84156-83111, Isfahan, Iran
| | - S Kunisada
- ISSP, University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - S Sakuragi
- ISSP, University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - M Alaei
- Department of Physics, Isfahan University of Technology, 84156-83111, Isfahan, Iran
| | - Y Kinoshita
- ISSP, University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - C Bareille
- ISSP, University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - R Noguchi
- ISSP, University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - M Nakayama
- ISSP, University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - S Akebi
- ISSP, University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - M Sakano
- ISSP, University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
- Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - K Kawaguchi
- ISSP, University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - M Arita
- Hiroshima Synchrotron Center, Hiroshima University, Higashi-Hiroshima, 739-0046, Japan
| | - S Ideta
- UVSOR Facility, Institute for Molecular Science, Okazaki, 444-8585, Japan
| | - K Tanaka
- UVSOR Facility, Institute for Molecular Science, Okazaki, 444-8585, Japan
| | - H Kitazawa
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, 305-0047, Japan
| | - K Okazaki
- ISSP, University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - M Tokunaga
- ISSP, University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - Y Haga
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki, 319-1195, Japan
| | - S Shin
- ISSP, University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - H S Suzuki
- ISSP, University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
| | - R Arita
- Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Takeshi Kondo
- ISSP, University of Tokyo, Kashiwa, Chiba, 277-8581, Japan
- Trans-scale Quantum Science Institute, University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
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20
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Nelson JN, Parzyck CT, Faeth BD, Kawasaki JK, Schlom DG, Shen KM. Mott gap collapse in lightly hole-doped Sr 2-xK xIrO 4. Nat Commun 2020; 11:2597. [PMID: 32444617 PMCID: PMC7244596 DOI: 10.1038/s41467-020-16425-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Accepted: 04/23/2020] [Indexed: 11/09/2022] Open
Abstract
The evolution of Sr2IrO4 upon carrier doping has been a subject of intense interest, due to its similarities to the parent cuprates, yet the intrinsic behaviour of Sr2IrO4 upon hole doping remains enigmatic. Here, we synthesize and investigate hole-doped Sr2-xKxIrO4 utilizing a combination of reactive oxide molecular-beam epitaxy, substitutional diffusion and in-situ angle-resolved photoemission spectroscopy. Upon hole doping, we observe the formation of a coherent, two-band Fermi surface, consisting of both hole pockets centred at (π, 0) and electron pockets centred at (π/2, π/2). In particular, the strong similarities between the Fermi surface topology and quasiparticle band structure of hole- and electron-doped Sr2IrO4 are striking given the different internal structure of doped electrons versus holes.
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Affiliation(s)
- J N Nelson
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, New York, 14853, USA
| | - C T Parzyck
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, New York, 14853, USA
| | - B D Faeth
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, New York, 14853, USA
| | - J K Kawasaki
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, New York, 14853, USA.,Department of Materials Science and Engineering, Cornell University, Ithaca, New York, 14853, USA.,Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York, 14853, USA.,Department of Materials Science and Engineering, University of Wisconsin, Madison, Wisconsin, 53706, USA
| | - D G Schlom
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York, 14853, USA.,Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York, 14853, USA
| | - K M Shen
- Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, New York, 14853, USA. .,Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York, 14853, USA.
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21
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Hu Y, Chen X, Peng ST, Lane C, Matzelle M, Sun ZL, Hashimoto M, Lu DH, Schwier EF, Arita M, Wu T, Markiewicz RS, Shimada K, Chen XH, Shen ZX, Bansil A, Wilson SD, He JF. Spectroscopic Evidence for Electron-Boson Coupling in Electron-Doped Sr_{2}IrO_{4}. PHYSICAL REVIEW LETTERS 2019; 123:216402. [PMID: 31809181 DOI: 10.1103/physrevlett.123.216402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Indexed: 06/10/2023]
Abstract
The pseudogap, d-wave superconductivity and electron-boson coupling are three intertwined key ingredients in the phase diagram of the cuprates. Sr_{2}IrO_{4} is a 5d-electron counterpart of the cuprates in which both the pseudogap and a d-wave instability have been observed. Here, we report spectroscopic evidence for the presence of the third key player in electron-doped Sr_{2}IrO_{4}: electron-boson coupling. A kink in nodal dispersion is observed with an energy scale of ∼50 meV. The strength of the kink changes with doping, but the energy scale remains the same. These results provide the first noncuprate platform for exploring the relationship between the pseudogap, d-wave instability, and electron-boson coupling in doped Mott insulators.
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Affiliation(s)
- Yong Hu
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiang Chen
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - S-T Peng
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - C Lane
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA
| | - M Matzelle
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA
| | - Z-L Sun
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - M Hashimoto
- Stanford Synchrotron Radiation Lightsource and Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - D-H Lu
- Stanford Synchrotron Radiation Lightsource and Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - E F Schwier
- Hiroshima Synchrotron Radiation Center, Hiroshima University, Hiroshima 739-0046, Japan
| | - M Arita
- Hiroshima Synchrotron Radiation Center, Hiroshima University, Hiroshima 739-0046, Japan
| | - T Wu
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - R S Markiewicz
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA
| | - K Shimada
- Hiroshima Synchrotron Radiation Center, Hiroshima University, Hiroshima 739-0046, Japan
| | - X-H Chen
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Z-X Shen
- Stanford Synchrotron Radiation Lightsource and Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
- Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, California 94305, USA
| | - A Bansil
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA
| | - S D Wilson
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - J-F He
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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22
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Bhandari C, Satpathy S. Two dimensional electron gas in the [Formula: see text]-doped iridates with strong spin-orbit coupling: La[Formula: see text]Sr 2IrO 4. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:435505. [PMID: 31272089 DOI: 10.1088/1361-648x/ab2f3f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Iridates are of considerable current interest because of the strong spin-orbit coupling that leads to a variety of new phenomena. Using density-functional studies, we predict the formation of a spin-orbital entangled two dimensional electron gas (2DEG) in the [Formula: see text]-doped iridate La[Formula: see text]Sr2IrO4, where a single SrO layer is replaced by a LaO layer. The extra La electron resides close to the [Formula: see text]-doped layer, partially occupying the [Formula: see text] upper Hubbard band and thereby making the interface metallic. The magnetic structure of the bulk is destroyed near the interface, with the Ir0 layer closest to the interface becoming non-magnetic, while the next layer (Ir1) continues to maintain the AFM structure of the bulk, but with a reduced magnetic moment. The Fermi surface consists of a hole pocket and an electron pocket, located in two different Ir layers (Ir0 and Ir1), with both carriers derived from the [Formula: see text] upper Hubbard band. The presence of both electrons and holes at the [Formula: see text]-doped interface suggests unusual transport properties, leading to possible device applications.
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Affiliation(s)
- Churna Bhandari
- Department of Physics & Astronomy, University of Columbia Missouri, Columbia, MO 65211, United States of America
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23
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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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24
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Lenz B, Martins C, Biermann S. Spectral functions of Sr 2IrO 4: theory versus experiment. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:293001. [PMID: 30921786 DOI: 10.1088/1361-648x/ab146a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The spin-orbit Mott insulator Sr2IrO4 has attracted a lot of interest in recent years from theory and experiment due to its close connection to isostructural high-temperature copper oxide superconductors. Despite not being superconductive, its spectral features closely resemble those of the cuprates, including Fermi surface and pseudogap properties. In this article, we review and extend recent work in the theoretical description of the spectral function of pure and electron-doped Sr2IrO4 based on a cluster extension of dynamical mean-field theory ('oriented-cluster DMFT') and compare it to available angle-resolved photoemission data. Current theories provide surprisingly good agreement for pure and electron-doped Sr2IrO4, both in the paramagnetic and antiferromagnetic phases. Most notably, one obtains simple explanations for the experimentally observed steep feature around the M point and the pseudo-gap-like spectral feature in electron-doped Sr2IrO4.
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Affiliation(s)
- B Lenz
- CPHT, Ecole Polytechnique, CNRS, Université Paris-Saclay, Route de Saclay, 91128 Palaiseau, France
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25
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Li J, Wang R, Guo H, Zhu Y, Cao Y, Liu J, Ding H, Wen H, Liu X. Recovery of photoexcited magnetic ordering in Sr 2IrO 4. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:255801. [PMID: 30897558 DOI: 10.1088/1361-648x/ab123d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The recovery of antiferromagnetic and lattice order of Sr2IrO4 upon laser excitation was measured by time-resolved x-ray diffraction on nanosecond time scales. The in situ measurements of both magnetic and lattice order parameters allow direct comparison of their time evolutions without ambiguity. We found that the magnetic order recovers with two time constants. The fast sub-nanosecond recovery is associated with the re-establishment of three dimensional antiferromagnetic order while the slow sub-nanosecond recovery agrees with the lattice cooling on tens of nanoseconds. The strong oscillating behavior of magnetic order during the long time recovery may be related to complicated dynamics of defect-pinned magnetic domains.
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Affiliation(s)
- Jiemin Li
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China. School of Physics, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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26
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Abstract
We discuss a few possibilities of high- T c superconductivity with more than one orbital symmetry contributing to the pairing. First, we show that the high energies of orbital excitations in various cuprates suggest a simplified model with a single orbital of x 2 − y 2 symmetry doped by holes. Next, several routes towards involving both e g orbital symmetries for doped holes are discussed: (i) some give superconductivity in a CuO 2 monolayer on Bi2212 superconductors, Sr 2 CuO 4 − δ , Ba 2 CuO 4 − δ , while (ii) others as nickelate heterostructures or Eu 2 − x Sr x NiO 4 , could in principle realize it as well. At low electron filling of Ru ions, spin-orbital entangled states of t 2 g symmetry contribute in Sr 2 RuO 4 . Finally, electrons with both t 2 g and e g orbital symmetries contribute to the superconducting properties and nematicity of Fe-based superconductors, pnictides or FeSe. Some of them provide examples of orbital-selective Cooper pairing.
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27
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Wang BB, Wang W, Yu SL, Li JX. Particle–hole fluctuations and possible superconductivity in doped α-RuCl 3*. CHINESE PHYSICS B 2019; 28:057402. [DOI: 10.1088/1674-1056/28/5/057402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Abstract
We study various particle–hole excitations and possible superconducting pairings mediated by these fluctuations in doped α-RuCl3 by using multi-band Hubbard model with all t2g orbitals. By performing a random-phase-approximation (RPA) analysis, we find that among all particle–hole excitations, the j
eff = 1/2 pseudospin fluctuations are dominant, suggesting the robustness of j
eff = 1/2 picture even in the doped systems. We also find that the most favorable superconducting state has a d-wave pairing symmetry.
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28
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Nuclear resonant scattering from 193Ir as a probe of the electronic and magnetic properties of iridates. Sci Rep 2019; 9:5097. [PMID: 30911115 PMCID: PMC6433947 DOI: 10.1038/s41598-019-41130-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 02/08/2019] [Indexed: 11/08/2022] Open
Abstract
The high brilliance of modern synchrotron radiation sources facilitates experiments with high-energy x-rays across a range of disciplines, including the study of the electronic and magnetic correlations using elastic and inelastic scattering techniques. Here we report on Nuclear Resonance Scattering at the 73 keV nuclear level in 193Ir. The transitions between the hyperfine split levels show an untypically high E2/M1 multi-polarity mixing ratio combined with an increased sensitivity to certain changes in the hyperfine field direction compared to non-mixing transitions. The method opens a new way for probing local magnetic and electronic properties of correlated materials containing iridium and provides novel insights into anisotropic magnetism in iridates. In particular, unexpected out-of-plane components of magnetic hyperfine fields and non-zero electric field gradients in Sr2IrO4 have been detected and attributed to the strong spin-orbit interaction in this iridate. Due to the high, 62% natural abundance of the 193Ir isotope, no isotopic enrichment of the samples is required, qualifying the method for a broad range of applications.
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29
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Meyers D, Cao Y, Fabbris G, Robinson NJ, Hao L, Frederick C, Traynor N, Yang J, Lin J, Upton MH, Casa D, Kim JW, Gog T, Karapetrova E, Choi Y, Haskel D, Ryan PJ, Horak L, Liu X, Liu J, Dean MPM. Magnetism in iridate heterostructures leveraged by structural distortions. Sci Rep 2019; 9:4263. [PMID: 30862782 PMCID: PMC6414659 DOI: 10.1038/s41598-019-39422-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/18/2019] [Indexed: 11/09/2022] Open
Abstract
Fundamental control of magnetic coupling through heterostructure morphology is a prerequisite for rational engineering of magnetic ground states. We report the tuning of magnetic interactions in superlattices composed of single and bilayers of SrIrO3 inter-spaced with SrTiO3 in analogy to the Ruddlesden-Popper series iridates. Magnetic scattering shows predominately c-axis antiferromagnetic orientation of the magnetic moments for the bilayer, as in Sr3Ir2O7. However, the magnetic excitation gap, measured by resonant inelastic x-ray scattering, is quite different between the two structures, evidencing a significant change in the stability of the competing magnetic phases. In contrast, the single layer iridate hosts a more bulk-like gap. We find these changes are driven by bending of the c-axis Ir-O-Ir bond, which is much weaker in the single layer, and subsequent local environment changes, evidenced through x-ray diffraction and magnetic excitation modeling. Our findings demonstrate how large changes in the magnetic interactions can be tailored and probed in spin-orbit coupled heterostructures by engineering subtle structural modulations.
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Affiliation(s)
- D Meyers
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York, 11973, USA.
| | - Yue Cao
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York, 11973, USA
| | - G Fabbris
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York, 11973, USA
| | - Neil J Robinson
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York, 11973, USA
| | - Lin Hao
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - C Frederick
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - N Traynor
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - J Yang
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Jiaqi Lin
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - M H Upton
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, 60439, USA
| | - D Casa
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, 60439, USA
| | - Jong-Woo Kim
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, 60439, USA
| | - T Gog
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, 60439, USA
| | - E Karapetrova
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, 60439, USA
| | - Yongseong Choi
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, 60439, USA
| | - D Haskel
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, 60439, USA
| | - P J Ryan
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, 60439, USA.,School of Physical Sciences, Dublin City University, Dublin 9, Ireland
| | - Lukas Horak
- Department of Condensed Matter Physics, Charles University, Ke Karlovu 3, Prague, 12116, Czech Republic
| | - X Liu
- 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, China
| | - Jian Liu
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee, 37996, USA.
| | - M P M Dean
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York, 11973, USA.
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30
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Wang Z, Okada Y, O'Neal J, Zhou W, Walkup D, Dhital C, Hogan T, Clancy P, Kim YJ, Hu YF, Santos LH, Wilson SD, Trivedi N, Madhavan V. Disorder induced power-law gaps in an insulator-metal Mott transition. Proc Natl Acad Sci U S A 2018; 115:11198-11202. [PMID: 30322914 PMCID: PMC6217382 DOI: 10.1073/pnas.1808056115] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A correlated material in the vicinity of an insulator-metal transition (IMT) exhibits rich phenomenology and a variety of interesting phases. A common avenue to induce IMTs in Mott insulators is doping, which inevitably leads to disorder. While disorder is well known to create electronic inhomogeneity, recent theoretical studies have indicated that it may play an unexpected and much more profound role in controlling the properties of Mott systems. Theory predicts that disorder might play a role in driving a Mott insulator across an IMT, with the emergent metallic state hosting a power-law suppression of the density of states (with exponent close to 1; V-shaped gap) centered at the Fermi energy. Such V-shaped gaps have been observed in Mott systems, but their origins are as-yet unknown. To investigate this, we use scanning tunneling microscopy and spectroscopy to study isovalent Ru substitutions in Sr3(Ir1-xRux)2O7 (0 ≤ x ≤ 0.5) which drive the system into an antiferromagnetic, metallic state. Our experiments reveal that many core features of the IMT, such as power-law density of states, pinning of the Fermi energy with increasing disorder, and persistence of antiferromagnetism, can be understood as universal features of a disordered Mott system near an IMT and suggest that V-shaped gaps may be an inevitable consequence of disorder in doped Mott insulators.
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Affiliation(s)
- Zhenyu Wang
- Department of Physics, University of Illinois Urbana-Champaign, Urbana, IL 61801
- Frederick Seitz Materials Research Laboratory, University of Illinois Urbana-Champaign, Urbana, IL 61801
| | - Yoshinori Okada
- Quantum Materials Science Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa 904-0495, Japan
| | - Jared O'Neal
- Mathematics Department, The Ohio State University, Columbus, OH 43210
| | - Wenwen Zhou
- Department of Physics, Boston College, Chestnut Hill, MA 02467
| | - Daniel Walkup
- Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - Chetan Dhital
- Department of Physics, Kennesaw State University, Marietta, GA 30060
| | - Tom Hogan
- Materials Department, University of California, Santa Barbara, CA 93106
| | - Patrick Clancy
- Department of Physics, University of Toronto, Toronto, ON M5S 1A7, Canada
| | - Young-June Kim
- Department of Physics, University of Toronto, Toronto, ON M5S 1A7, Canada
| | - Y F Hu
- Canadian Light Source, Saskatoon, SK S7N 2V3, Canada
| | - Luiz H Santos
- Department of Physics, University of Illinois Urbana-Champaign, Urbana, IL 61801
- Institute for Condensed Matter Theory, University of Illinois Urbana-Champaign, Urbana, IL 61801
| | - Stephen D Wilson
- Materials Department, University of California, Santa Barbara, CA 93106
| | - Nandini Trivedi
- Department of Physics, The Ohio State University, Columbus, Ohio 43210
| | - Vidya Madhavan
- Department of Physics, University of Illinois Urbana-Champaign, Urbana, IL 61801;
- Frederick Seitz Materials Research Laboratory, University of Illinois Urbana-Champaign, Urbana, IL 61801
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31
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Kawasaki JK, Kim CH, Nelson JN, Crisp S, Zollner CJ, Biegenwald E, Heron JT, Fennie CJ, Schlom DG, Shen KM. Engineering Carrier Effective Masses in Ultrathin Quantum Wells of IrO_{2}. PHYSICAL REVIEW LETTERS 2018; 121:176802. [PMID: 30411938 DOI: 10.1103/physrevlett.121.176802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 05/09/2018] [Indexed: 06/08/2023]
Abstract
The carrier effective mass plays a crucial role in modern electronic, optical, and catalytic devices and is fundamentally related to key properties of solids such as the mobility and density of states. Here we demonstrate a method to deterministically engineer the effective mass using spatial confinement in metallic quantum wells of the transition metal oxide IrO_{2}. Using a combination of in situ angle-resolved photoemission spectroscopy measurements in conjunction with precise synthesis by oxide molecular-beam epitaxy, we show that the low-energy electronic subbands in ultrathin films of rutile IrO_{2} have their effective masses enhanced by up to a factor of 6 with respect to the bulk. The origin of this strikingly large mass enhancement is the confinement-induced quantization of the highly nonparabolic, three-dimensional electronic structure of IrO_{2} in the ultrathin limit. This mechanism lies in contrast to that observed in other transition metal oxides, in which mass enhancement tends to result from complex electron-electron interactions and is difficult to control. Our results demonstrate a general route towards the deterministic enhancement and engineering of carrier effective masses in spatially confined systems, based on an understanding of the three-dimensional bulk electronic structure.
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Affiliation(s)
- Jason K Kawasaki
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853, USA
- Laboratory for Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
- Department of Materials Science and Engineering, University of Wisconsin, Madison, Wisconsin 53706, USA
| | - Choong H Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, Korea
| | - Jocienne N Nelson
- Laboratory for Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA
| | - Sophie Crisp
- Laboratory for Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA
| | - Christian J Zollner
- Department of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Eric Biegenwald
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
| | - John T Heron
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
| | - Craig J Fennie
- Department of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Darrell G Schlom
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853, USA
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA
| | - Kyle M Shen
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853, USA
- Laboratory for Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA
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32
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Kim SY, Lee MC, Han G, Kratochvilova M, Yun S, Moon SJ, Sohn C, Park JG, Kim C, Noh TW. Spectroscopic Studies on the Metal-Insulator Transition Mechanism in Correlated Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1704777. [PMID: 29761925 DOI: 10.1002/adma.201704777] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 12/18/2017] [Indexed: 06/08/2023]
Abstract
The metal-insulator transition (MIT) in correlated materials is a novel phenomenon that accompanies a large change in resistivity, often many orders of magnitude. It is important in its own right but its switching behavior in resistivity can be useful for device applications. From the material physics point of view, the starting point of the research on the MIT should be to understand the microscopic mechanism. Here, an overview of recent efforts to unravel the microscopic mechanisms for various types of MITs in correlated materials is provided. Research has focused on transition metal oxides (TMOs), but transition metal chalcogenides have also been studied. Along the way, a new class of MIT materials is discovered, the so-called relativistic Mott insulators in 5d TMOs. Distortions in the MO6 (M = transition metal) octahedron are found to have a large and peculiar effect on the band structure in an orbital dependent way, possibly paving a way to the orbital selective Mott transition. In the final section, the character of the materials suitable for applications is summarized, followed by a brief discussion of some of the efforts to control MITs in correlated materials, including a dynamical approach using light.
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Affiliation(s)
- So Yeun Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Min-Cheol Lee
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Garam Han
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Marie Kratochvilova
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Seokhwan Yun
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Soon Jae Moon
- Department of Physics, Hanyang University, Seoul, Republic of Korea
| | - Changhee Sohn
- Materials Science and Technology Division, Oak Ridge National Laboratory, TN, 37831, USA
| | - Je-Geun Park
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Changyoung Kim
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Tae Won Noh
- Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, Republic of Korea
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33
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Chun SH, Yuan B, Casa D, Kim J, Kim CY, Tian Z, Qiu Y, Nakatsuji S, Kim YJ. Magnetic Excitations across the Metal-Insulator Transition in the Pyrochlore Iridate Eu_{2}Ir_{2}O_{7}. PHYSICAL REVIEW LETTERS 2018; 120:177203. [PMID: 29756838 DOI: 10.1103/physrevlett.120.177203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 01/04/2018] [Indexed: 06/08/2023]
Abstract
We report a resonant inelastic x-ray scattering study of the magnetic excitation spectrum in a highly insulating Eu_{2}Ir_{2}O_{7} single crystal that exhibits a metal-insulator transition at T_{MI}=111(7) K. A propagating magnon mode with a 20 meV bandwidth and a 28 meV magnon gap is found in the excitation spectrum at 7 K, which is expected in the all-in-all-out magnetically ordered state. This magnetic excitation exhibits substantial softening as the temperature is raised towards T_{MI} and turns into a highly damped excitation in the paramagnetic phase. Remarkably, the softening occurs throughout the whole Brillouin zone including the zone boundary. This observation is inconsistent with the magnon renormalization expected in a local moment system and indicates that the strength of the electron correlation in Eu_{2}Ir_{2}O_{7} is only moderate, so that electron itinerancy should be taken into account in describing its magnetism.
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Affiliation(s)
- Sae Hwan Chun
- Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| | - Bo Yuan
- Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| | - Diego Casa
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Jungho Kim
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Chang-Yong Kim
- Canadian Light Source, 44 Innovation Boulevard, Saskatoon, Saskatchewan S7N 2V3, Canada
| | - Zhaoming Tian
- Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan
| | - Yang Qiu
- Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan
| | - Satoru Nakatsuji
- Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan
| | - Young-June Kim
- Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
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34
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Malvestuto M, Ciprian R, Caretta A, Casarin B, Parmigiani F. Ultrafast magnetodynamics with free-electron lasers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:053002. [PMID: 29315080 DOI: 10.1088/1361-648x/aaa211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The study of ultrafast magnetodynamics has entered a new era thanks to the groundbreaking technological advances in free-electron laser (FEL) light sources. The advent of these light sources has made possible unprecedented experimental schemes for time-resolved x-ray magneto-optic spectroscopies, which are now paving the road for exploring the ultimate limits of out-of-equilibrium magnetic phenomena. In particular, these studies will provide insights into elementary mechanisms governing spin and orbital dynamics, therefore contributing to the development of ultrafast devices for relevant magnetic technologies. This topical review focuses on recent advancement in the study of non-equilibrium magnetic phenomena from the perspective of time-resolved extreme ultra violet (EUV) and soft x-ray spectroscopies at FELs with highlights of some important experimental results.
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Affiliation(s)
- Marco Malvestuto
- Elettra-Sincrotrone Trieste S.C.p.A. Strada Statale 14-km 163.5 in AREA Science Park 34149 Basovizza, Trieste, Italy
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35
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Unidirectional spin density wave state in metallic (Sr 1-xLa x ) 2IrO 4. Nat Commun 2018; 9:103. [PMID: 29317642 PMCID: PMC5760634 DOI: 10.1038/s41467-017-02647-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Accepted: 12/14/2017] [Indexed: 12/03/2022] Open
Abstract
Materials that exhibit both strong spin–orbit coupling and electron correlation effects are predicted to host numerous new electronic states. One prominent example is the Jeff = 1/2 Mott state in Sr2IrO4, where introducing carriers is predicted to manifest high temperature superconductivity analogous to the S = 1/2 Mott state of La2CuO4. While bulk superconductivity currently remains elusive, anomalous quasiparticle behaviors paralleling those in the cuprates such as pseudogap formation and the formation of a d-wave gap are observed upon electron-doping Sr2IrO4. Here we establish a magnetic parallel between electron-doped Sr2IrO4 and hole-doped La2CuO4 by unveiling a spin density wave state in electron-doped Sr2IrO4. Our magnetic resonant X-ray scattering data reveal the presence of an incommensurate magnetic state reminiscent of the diagonal spin density wave state observed in the monolayer cuprate (La1−xSrx)2CuO4. This link supports the conjecture that the quenched Mott phases in electron-doped Sr2IrO4 and hole-doped La2CuO4 support common competing electronic phases. Electron-doped Sr2IrO4 is an intriguing material for searching for an unconventional superconducting state. Here the authors demonstrate that a spin density wave state exists in the metallic phase of electron-doped Sr2IrO4 which provides a link between the electronic phase diagrams of the hole-doped cuprates and the electron-doped iridates.
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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}. PHYSICAL REVIEW LETTERS 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] [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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Direct experimental observation of the molecular J eff = 3/2 ground state in the lacunar spinel GaTa 4Se 8. Nat Commun 2017; 8:782. [PMID: 28978909 PMCID: PMC5627251 DOI: 10.1038/s41467-017-00841-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 07/28/2017] [Indexed: 11/08/2022] Open
Abstract
Strong spin–orbit coupling lifts the degeneracy of t2g orbitals in 5d transition-metal systems, leaving a Kramers doublet and quartet with effective angular momentum of Jeff = 1/2 and 3/2, respectively. These spin–orbit entangled states can host exotic quantum phases such as topological Mott state, unconventional superconductivity, and quantum spin liquid. The lacunar spinel GaTa4Se8 was theoretically predicted to form the molecular Jeff = 3/2 ground state. Experimental verification of its existence is an important first step to exploring the consequences of the Jeff = 3/2 state. Here, we report direct experimental evidence of the Jeff = 3/2 state in GaTa4Se8 by means of excitation spectra of resonant inelastic X-ray scattering at the Ta L3 and L2 edges. We find that the excitations involving the Jeff = 1/2 molecular orbital are absent only at the Ta L2 edge, manifesting the realization of the molecular Jeff = 3/2 ground state in GaTa4Se8. The strong interaction between electron spin and orbital degrees of freedom in 5d oxides can lead to exotic electronic ground states. Here the authors use resonant inelastic X-ray scattering to demonstrate that the theoretically proposed Jeff = 3/2 state is realised in GaTa4Se8.
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38
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Pärschke EM, Wohlfeld K, Foyevtsova K, van den Brink J. Correlation induced electron-hole asymmetry in quasi- two-dimensional iridates. Nat Commun 2017; 8:686. [PMID: 28947738 PMCID: PMC5612937 DOI: 10.1038/s41467-017-00818-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 07/25/2017] [Indexed: 11/09/2022] Open
Abstract
The resemblance of crystallographic and magnetic structures of the quasi-two-dimensional iridates Ba2IrO4 and Sr2IrO4 to La2CuO4 points at an analogy to cuprate high-Tc superconductors, even if spin-orbit coupling is very strong in iridates. Here we examine this analogy for the motion of a charge (hole or electron) added to the antiferromagnetic ground state. We show that correlation effects render the hole and electron case in iridates very different. An added electron forms a spin polaron, similar to the cuprates, but the situation of a removed electron is far more complex. Many-body 5d 4 configurations form which can be singlet and triplet states of total angular momentum that strongly affect the hole motion. This not only has ramifications for the interpretation of (inverse-)photoemission experiments but also demonstrates that correlation physics renders electron- and hole-doped iridates fundamentally different.Some iridate compounds such as Sr2IrO4 have electronic and atomic structures similar to quasi-2D copper oxides, raising the prospect of high temperature superconductivity. Here, the authors show that there is significant electron-hole asymmetry in iridates, contrary to expectations from the cuprates.
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Affiliation(s)
| | - Krzysztof Wohlfeld
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Pasteura 5, PL-02093, Warsaw, Poland
| | - Kateryna Foyevtsova
- University of British Columbia, 6224 Agricultural Road, Vancouver, BC, Canada, V6T 1Z1
| | - Jeroen van den Brink
- IFW Dresden, Helmholtzstr. 20, 01069, Dresden, Germany.,Institute for Theoretical Physics, TU Dresden, 01069, Dresden, Germany
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39
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Abstract
We report on infrared spectroscopy experiments on the electronic response in (Sr1-x La x )2IrO4 (x = 0, 0.021, and 0.067). Our data show that electron doping induced by La substitution leads to an insulator-to-metal transition. The evolution of the electronic structure across the transition reveals the robustness of the strong electronic correlations against the electron doping. The conductivity data of the metallic compound show the signature of the pseudogap that bears close similarity to the analogous studies of the pseudogap in the underdoped cuprates. While the low energy conductivity of the metallic compound is barely frequency dependent, the formation of the pseudogap is revealed by the gradual suppression of the featureless conductivity below a threshold frequency of about 17 meV. The threshold structure develops below about 100 K which is in the vicinity of the onset of the short-range antiferromagnetic order. Our results demonstrate that the electronic correlations play a crucial role in the anomalous charge dynamics in the (Sr1-x La x )2IrO4 system.
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40
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[OsF6
]
x
−
: Molecular Models for Spin-Orbit Entangled Phenomena. Chemistry 2017; 23:11244-11248. [DOI: 10.1002/chem.201702894] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Indexed: 11/07/2022]
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41
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Sumita S, Nomoto T, Yanase Y. Multipole Superconductivity in Nonsymmorphic Sr_{2}IrO_{4}. PHYSICAL REVIEW LETTERS 2017; 119:027001. [PMID: 28753338 DOI: 10.1103/physrevlett.119.027001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Indexed: 06/07/2023]
Abstract
Discoveries of marked similarities to high-T_{c} cuprate superconductors point to the realization of superconductivity in the doped J_{eff}=1/2 Mott insulator Sr_{2}IrO_{4}. Contrary to the mother compound of cuprate superconductors, several stacking patterns of in-plane canted antiferromagnetic moments have been reported, which are distinguished by the ferromagnetic components as -++-, ++++, and -+-+. In this paper, we clarify unconventional features of the superconductivity coexisting with -++- and -+-+ structures. Combining the group theoretical analysis and numerical calculations for an effective J_{eff}=1/2 model, we show unusual superconducting gap structures in the -++- state protected by nonsymmorphic magnetic space group symmetry. Furthermore, our calculation shows that the Fulde-Ferrell-Larkin-Ovchinnikov superconductivity is inevitably stabilized in the -+-+ state since the odd-parity magnetic -+-+ order makes the band structure asymmetric by cooperating with spin-orbit coupling. These unusual superconducting properties are signatures of magnetic multipole order in nonsymmorphic crystal.
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Affiliation(s)
- Shuntaro Sumita
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Takuya Nomoto
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Youichi Yanase
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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42
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Hao L, Meyers D, Frederick C, Fabbris G, Yang J, Traynor N, Horak L, Kriegner D, Choi Y, Kim JW, Haskel D, Ryan PJ, Dean MPM, Liu J. Two-Dimensional J_{eff}=1/2 Antiferromagnetic Insulator Unraveled from Interlayer Exchange Coupling in Artificial Perovskite Iridate Superlattices. PHYSICAL REVIEW LETTERS 2017; 119:027204. [PMID: 28753323 DOI: 10.1103/physrevlett.119.027204] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Indexed: 06/07/2023]
Abstract
We report an experimental investigation of the two-dimensional J_{eff}=1/2 antiferromagnetic Mott insulator by varying the interlayer exchange coupling in [(SrIrO_{3})_{1}, (SrTiO_{3})_{m}] (m=1, 2 and 3) superlattices. Although all samples exhibited an insulating ground state with long-range magnetic order, temperature-dependent resistivity measurements showed a stronger insulating behavior in the m=2 and m=3 samples than the m=1 sample which displayed a clear kink at the magnetic transition. This difference indicates that the blocking effect of the excessive SrTiO_{3} layer enhances the effective electron-electron correlation and strengthens the Mott phase. The significant reduction of the Néel temperature from 150 K for m=1 to 40 K for m=2 demonstrates that the long-range order stability in the former is boosted by a substantial interlayer exchange coupling. Resonant x-ray magnetic scattering revealed that the interlayer exchange coupling has a switchable sign, depending on the SrTiO_{3} layer number m, for maintaining canting-induced weak ferromagnetism. The nearly unaltered transition temperature between the m=2 and the m=3 demonstrated that we have realized a two-dimensional antiferromagnet at finite temperatures with diminishing interlayer exchange coupling.
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Affiliation(s)
- Lin Hao
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - D Meyers
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Clayton Frederick
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Gilberto Fabbris
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Junyi Yang
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Nathan Traynor
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Lukas Horak
- Department of Condensed Matter Physics, Charles University, Ke Karlovu 3, Prague 12116, Czech Republic
| | - Dominik Kriegner
- Department of Condensed Matter Physics, Charles University, Ke Karlovu 3, Prague 12116, Czech Republic
- Institute of Physics, Academy of Sciences of the Czech Republic, v.v.i., Cukrovarnická 10, 16253 Praha 6, Czech Republic
| | - Yongseong Choi
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Jong-Woo Kim
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Daniel Haskel
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Phil J Ryan
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
- School of Physical Sciences, Dublin City University, Dublin 9, Ireland
| | - M P M Dean
- Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Jian Liu
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
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Gao B, Weng Y, Zhang JJ, Zhang H, Zhang Y, Dong S. Magnetic and electronic properties of La 3 MO 7 and possible polaron formation in hole-doped La 3 MO 7 (M = Ru and Os). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:095803. [PMID: 28114120 DOI: 10.1088/1361-648x/aa552c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Oxides with 4d/5d transition metal ions are physically interesting for their particular crystalline structures as well as the spin-orbit coupled electronic structures. Recent experiments revealed a series of 4d/5d transition metal oxides R 3 MO7 (R: rare earth; M: 4d/5d transition metal) with unique quasi-one-dimensional M chains. Here first-principles calculations have been performed to study the electronic structures of La3OsO7 and La3RuO7. Our study confirm both of them to be Mott insulating antiferromagnets with identical magnetic order. The reduced magnetic moments, which are much smaller than the expected value for ideal high-spin state (3 t 2g orbitals occupied), are attributed to the strong p - d hybridization with oxygen ions, instead of the spin-orbit coupling. The Ca-doping to La3OsO7 and La3RuO7 can not only modulate the nominal carrier density but also affect the orbital order as well as the local distortions. The Coulombic attraction and particular orbital order would prefer to form polarons, which might explain the puzzling insulating behavior of doped 5d transition metal oxides. In addition, our calculations predict that the Ca-doping can trigger ferromagnetism in La3RuO7 but not in La3OsO7.
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Affiliation(s)
- Bin Gao
- Department of Physics, Southeast University, Nanjing 211189, People's Republic of China
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Chu H, Zhao L, de la Torre A, Hogan T, Wilson SD, Hsieh D. A charge density wave-like instability in a doped spin-orbit-assisted weak Mott insulator. NATURE MATERIALS 2017; 16:200-203. [PMID: 28092687 DOI: 10.1038/nmat4836] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 11/21/2016] [Indexed: 06/06/2023]
Abstract
Layered perovskite iridates realize a rare class of Mott insulators that are predicted to be strongly spin-orbit coupled analogues of the parent state of cuprate high-temperature superconductors. Recent discoveries of pseudogap, magnetic multipolar ordered and possible d-wave superconducting phases in doped Sr2IrO4 have reinforced this analogy among the single layer variants. However, unlike the bilayer cuprates, no electronic instabilities have been reported in the doped bilayer iridate Sr3Ir2O7. Here we show that Sr3Ir2O7 realizes a weak Mott state with no cuprate analogue by using ultrafast time-resolved optical reflectivity to uncover an intimate connection between its insulating gap and antiferromagnetism. However, we detect a subtle charge density wave-like Fermi surface instability in metallic electron doped Sr3Ir2O7 at temperatures (TDW) close to 200 K via the coherent oscillations of its collective modes, which is reminiscent of that observed in cuprates. The absence of any signatures of a new spatial periodicity below TDW from diffraction, scanning tunnelling and photoemission based probes suggests an unconventional and possibly short-ranged nature of this density wave order.
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Affiliation(s)
- H Chu
- Department of Applied Physics, California Institute of Technology, Pasadena, California 91125, USA
- Institute for Quantum Information and Matter, 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
| | - A de la Torre
- 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
| | - T Hogan
- Materials Department, University of California, Santa Barbara, California 93106, USA
| | - S D Wilson
- Materials Department, University of California, Santa Barbara, California 93106, 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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45
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Lu X, McNally DE, Moretti Sala M, Terzic J, Upton MH, Casa D, Ingold G, Cao G, Schmitt T. Doping Evolution of Magnetic Order and Magnetic Excitations in (Sr_{1-x}La_{x})_{3}Ir_{2}O_{7}. PHYSICAL REVIEW LETTERS 2017; 118:027202. [PMID: 28128620 DOI: 10.1103/physrevlett.118.027202] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Indexed: 06/06/2023]
Abstract
We use resonant elastic and inelastic x-ray scattering at the Ir-L_{3} edge to study the doping-dependent magnetic order, magnetic excitations, and spin-orbit excitons in the electron-doped bilayer iridate (Sr_{1-x}La_{x})_{3}Ir_{2}O_{7} (0≤x≤0.065). With increasing doping x, the three-dimensional long range antiferromagnetic order is gradually suppressed and evolves into a three-dimensional short range order across the insulator-to-metal transition from x=0 to 0.05, followed by a transition to two-dimensional short range order between x=0.05 and 0.065. Because of the interactions between the J_{eff}=1/2 pseudospins and the emergent itinerant electrons, magnetic excitations undergo damping, anisotropic softening, and gap collapse, accompanied by weakly doping-dependent spin-orbit excitons. Therefore, we conclude that electron doping suppresses the magnetic anisotropy and interlayer couplings and drives (Sr_{1-x}La_{x})_{3}Ir_{2}O_{7} into a correlated metallic state with two-dimensional short range antiferromagnetic order. Strong antiferromagnetic fluctuations of the J_{eff}=1/2 moments persist deep in this correlated metallic state, with the magnon gap strongly suppressed.
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Affiliation(s)
- Xingye Lu
- Research Department Synchrotron Radiation and Nanotechnology, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - D E McNally
- Research Department Synchrotron Radiation and Nanotechnology, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - M Moretti Sala
- European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France
| | - J Terzic
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
- Department of Physics, University of Colorado at Boulder, Boulder, Colorado 80309, USA
| | - M H Upton
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - D Casa
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - G Ingold
- Research Department Synchrotron Radiation and Nanotechnology, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
- SwissFEL, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | - G Cao
- Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
- Department of Physics, University of Colorado at Boulder, Boulder, Colorado 80309, USA
| | - T Schmitt
- Research Department Synchrotron Radiation and Nanotechnology, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
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Kondo T, Ochi M, Nakayama M, Taniguchi H, Akebi S, Kuroda K, Arita M, Sakai S, Namatame H, Taniguchi M, Maeno Y, Arita R, Shin S. Orbital-Dependent Band Narrowing Revealed in an Extremely Correlated Hund's Metal Emerging on the Topmost Layer of Sr_{2}RuO_{4}. PHYSICAL REVIEW LETTERS 2016; 117:247001. [PMID: 28009182 DOI: 10.1103/physrevlett.117.247001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Indexed: 06/06/2023]
Abstract
We use a surface-selective angle-resolved photoemission spectroscopy and unveil the electronic nature on the topmost layer of Sr_{2}RuO_{4} crystal, consisting of slightly rotated RuO_{6} octahedrons. The γ band derived from the 4d_{xy} orbital is found to be about three times narrower than that for the bulk. This strongly contrasts with a subtle variation seen in the α and β bands derived from the one-dimensional 4d_{xz/yz}. This anomaly is reproduced by the dynamical mean-field theory calculations, introducing not only the on-site Hubbard interaction but also the significant Hund's coupling. We detect a coherence-to-incoherence crossover theoretically predicted for Hund's metals, which has been recognized only recently. The crossover temperature in the surface is about half that of the bulk, indicating that the naturally generated monolayer of reconstructed Sr_{2}RuO_{4} is extremely correlated and well isolated from the underlying crystal.
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Affiliation(s)
- Takeshi Kondo
- ISSP, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - M Ochi
- Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, Japan
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - M Nakayama
- ISSP, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - H Taniguchi
- Department of Materials Science and Engineering, Iwate University, Morioka 020-8551, Japan
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - S Akebi
- ISSP, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - K Kuroda
- ISSP, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - M Arita
- Hiroshima Synchrotron Center, Hiroshima University, Higashi-Hiroshima 739-0046, Japan
| | - S Sakai
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - H Namatame
- Hiroshima Synchrotron Center, Hiroshima University, Higashi-Hiroshima 739-0046, Japan
| | - M Taniguchi
- Hiroshima Synchrotron Center, Hiroshima University, Higashi-Hiroshima 739-0046, Japan
- Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Y Maeno
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - R Arita
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
| | - S Shin
- ISSP, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
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47
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Ahn G, Song SJ, Hogan T, Wilson SD, Moon SJ. Infrared Spectroscopic Evidences of Strong Electronic Correlations in (Sr1-xLax)3Ir2O7. Sci Rep 2016; 6:32632. [PMID: 27599573 PMCID: PMC5013521 DOI: 10.1038/srep32632] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 08/11/2016] [Indexed: 11/09/2022] Open
Abstract
We report on infrared spectroscopic studies of the electronic response of the (Sr1-xLax)3Ir2O7 system. Our experiments revealed hallmarks of strong electronic correlations in the evolution of the electronic response across the filling-controlled insulator-metal transition. We observed a collapse of the Jeff = 1/2 Mott gap accompanying the transfer of the spectral weight from the high-energy region to the gap region with electron doping. The intraband conductivity at the metallic side of the transition was found to consist of coherent Drude-like and incoherent responses. The sum rule and the extended Drude model analyses further indicated a large mass enhancement. Our results demonstrate a critical role of the electronic correlations in the charge dynamics of the (Sr1-xLax)3Ir2O7 system.
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Affiliation(s)
- Gihyeon Ahn
- Department of Physics, Hanyang University, Seoul 04763, Korea
| | - S. J. Song
- Department of Physics, Hanyang University, Seoul 04763, Korea
| | - T. Hogan
- Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA
- Department of Materials, University of California, Santa Barbara, California 93106, USA
| | - S. D. Wilson
- Department of Materials, University of California, Santa Barbara, California 93106, USA
| | - S. J. Moon
- Department of Physics, Hanyang University, Seoul 04763, Korea
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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}. PHYSICAL REVIEW LETTERS 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] [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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49
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Krupin O, Dakovski GL, Kim BJ, Kim JW, Kim J, Mishra S, Chuang YD, Serrao CR, Lee WS, Schlotter WF, Minitti MP, Zhu D, Fritz D, Chollet M, Ramesh R, Molodtsov SL, Turner JJ. Ultrafast dynamics of localized magnetic moments in the unconventional Mott insulator Sr2IrO4. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:32LT01. [PMID: 27310659 DOI: 10.1088/0953-8984/28/32/32lt01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report a time-resolved study of the ultrafast dynamics of the magnetic moments formed by the [Formula: see text] states in Sr2IrO4 by directly probing the localized iridium 5d magnetic state through resonant x-ray diffraction. Using optical pump-hard x-ray probe measurements, two relaxation time scales were determined: a fast fluence-independent relaxation is found to take place on a time scale of 1.5 ps, followed by a slower relaxation on a time scale of 500 ps-1.5 ns.
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Affiliation(s)
- O Krupin
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94720, USA. European XFEL, Hamburg 22761, Germany
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50
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Zhong Y, Wang Y, Han S, Lv YF, Wang WL, Zhang D, Ding H, Zhang YM, Wang L, He K, Zhong R, Schneeloch JA, Gu GD, Song CL, Ma XC, Xue QK. Nodeless pairing in superconducting copper-oxide monolayer films on Bi2Sr2CaCu2O8+. Sci Bull (Beijing) 2016. [DOI: 10.1007/s11434-016-1145-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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