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Zhang H, Sanchez JJ, Chu JH, Liu J. Perspective: probing elasto-quantum materials with x-ray techniques and in situanisotropic strain. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:333002. [PMID: 38722324 DOI: 10.1088/1361-648x/ad493e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 05/09/2024] [Indexed: 05/22/2024]
Abstract
Anisotropic lattice deformation plays an important role in the quantum mechanics of solid state physics. The possibility of mediating the competition and cooperation among different order parameters by applyingin situstrain/stress on quantum materials has led to discoveries of a variety of elasto-quantum effects on emergent phenomena. It has become increasingly critical to have the capability of combining thein situstrain tuning with x-ray techniques, especially those based on synchrotrons, to probe the microscopic elasto-responses of the lattice, spin, charge, and orbital degrees of freedom. Herein, we briefly review the recent studies that embarked on utilizing elasto-x-ray characterizations on representative material systems and demonstrated the emerging opportunities enabled by this method. With that, we further discuss the promising prospect in this rising area of quantum materials research and the bright future of elasto-x-ray techniques.
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Affiliation(s)
- Han Zhang
- Changzhou University, Changzhou, Jiangsu 213001, People's Republic of China
| | - Joshua J Sanchez
- Massachusetts Institute of Technology, Cambridge, MA 02139, United States of America
| | - Jiun-Haw Chu
- Department of Physics, University of Washington, Seattle, WA 98195, United States of America
| | - Jian Liu
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, United States of America
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2
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Giant stress response of terahertz magnons in a spin-orbit Mott insulator. Nat Commun 2022; 13:6674. [DOI: 10.1038/s41467-022-34375-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 10/21/2022] [Indexed: 11/06/2022] Open
Abstract
AbstractMagnonic devices operating at terahertz frequencies offer intriguing prospects for high-speed electronics with minimal energy dissipation However, guiding and manipulating terahertz magnons via external parameters present formidable challenges. Here we report the results of magnetic Raman scattering experiments on the antiferromagnetic spin-orbit Mott insulator Sr2IrO4 under uniaxial stress. We find that the energies of zone-center magnons are extremely stress sensitive: lattice strain of 0.1% increases the magnon energy by 40%. The magnon response is symmetric with respect to the sign of the applied stress (tensile or compressive), but depends strongly on its direction in the IrO2 planes. A theory based on coupling of the spin-orbit-entangled iridium magnetic moments to lattice distortions provides a quantitative explanation of the Raman data and a comprehensive framework for the description of magnon-lattice interactions in magnets with strong spin-orbit coupling. The possibility to efficiently manipulate the propagation of terahertz magnons via external stress opens up multifold design options for reconfigurable magnonic devices.
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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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4
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Sarychev MN, Hosseny WAL, Zhevstovskikh IV, Ulanov VA, Shakurov GS, Egranov AV, Surikov VT, Averkiev NS, Gudkov VV. Manifestation of the Jahn-Teller effect subject to quadraticT⊗e+t2problem in ultrasonic attenuation. Case study of CaF 2:Cr crystal with isovalent and aliovalent substitution. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:225401. [PMID: 35139497 DOI: 10.1088/1361-648x/ac533c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 02/09/2022] [Indexed: 06/14/2023]
Abstract
A new approach is introduced to obtain information about the adiabatic potential energy surface of the Jahn-Teller (JT) complexes subject to theT⊗e+t2problem in doped crystals. It employs simulation of the contribution of the JT sub-system to ultrasonic attenuation with account of three mechanisms of relaxation and subsequent comparison with the experimental data on temperature dependence of the attenuation obtained with the use of doped crystal and nominally pure one. The approach has been applied to the CaF2crystal doped with chromium. The experiment has been carried out at the frequencies of (13-158) × 106Hz at low temperatures (4-170 K). Peak for all the ultrasonic normal modes propagating along the [110] axis has been observed at about 8 K. It has been considered as the JT effect manifestation by the sub-system of Cr2+F8-complexes. Symmetry properties of the global minima and saddle points have been identified, the JT stabilization energies and coordinates of the extrema points in the five-dimensional space of symmetrized displacements have been evaluated. Besides, a broad shoulder has been found at 15-40 K and attributed to contribution of the Cr3+F8-sub-system.
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Affiliation(s)
| | - Wessam A L Hosseny
- Ural Federal University, Ekaterinburg 620002, Russia
- Department of Physics, Faculty of Science, Benha University, Benha, 13511, Egypt
| | - Irina V Zhevstovskikh
- Ural Federal University, Ekaterinburg 620002, Russia
- M.N. Miheev Institute of Metal Physics, Ural Branch of Russian Academy of Sciences, Ekaterinburg 620108, Russia
| | - Vladimir A Ulanov
- Kazan State Power Engineering University, Kazan, 420066, Russia
- E.K. Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center of Russian Academy of Sciences, Kazan, 420029, Russia
| | - Gilman S Shakurov
- E.K. Zavoisky Physical-Technical Institute, FRC Kazan Scientific Center of Russian Academy of Sciences, Kazan, 420029, Russia
| | - Aleksandr V Egranov
- A.P. Vinogradov Institute of Geochemistry, Siberian Branch of Russian Academy of Sciences, Irkutsk, 664033, Russia
- Irkutsk State University, Irkutsk, 664003, Russia
| | - Vladimir T Surikov
- Institute of Solid State Chemistry, Ural Branch of Russian Academy of Sciences, Ekaterinburg 620990, Russia
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Suzuki H, Liu H, Bertinshaw J, Ueda K, Kim H, Laha S, Weber D, Yang Z, Wang L, Takahashi H, Fürsich K, Minola M, Lotsch BV, Kim BJ, Yavaş H, Daghofer M, Chaloupka J, Khaliullin G, Gretarsson H, Keimer B. Proximate ferromagnetic state in the Kitaev model material α-RuCl 3. Nat Commun 2021; 12:4512. [PMID: 34301938 PMCID: PMC8302668 DOI: 10.1038/s41467-021-24722-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 07/01/2021] [Indexed: 11/27/2022] Open
Abstract
α-RuCl3 is a major candidate for the realization of the Kitaev quantum spin liquid, but its zigzag antiferromagnetic order at low temperatures indicates deviations from the Kitaev model. We have quantified the spin Hamiltonian of α-RuCl3 by a resonant inelastic x-ray scattering study at the Ru L3 absorption edge. In the paramagnetic state, the quasi-elastic intensity of magnetic excitations has a broad maximum around the zone center without any local maxima at the zigzag magnetic Bragg wavevectors. This finding implies that the zigzag order is fragile and readily destabilized by competing ferromagnetic correlations. The classical ground state of the experimentally determined Hamiltonian is actually ferromagnetic. The zigzag state is stabilized by quantum fluctuations, leaving ferromagnetism – along with the Kitaev spin liquid – as energetically proximate metastable states. The three closely competing states and their collective excitations hold the key to the theoretical understanding of the unusual properties of α-RuCl3 in magnetic fields. RuCl3 has stood out as a prime candidate in the search for quantum spin liquids; however, its antiferromagnetic ordering at low temperature suggests deviations from typical QSL models. Here, using resonant inelastic x-ray scattering, the authors provide a comprehensive determination of the low energy effective Hamiltonian.
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Affiliation(s)
- H Suzuki
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
| | - H Liu
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
| | - J Bertinshaw
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - K Ueda
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.,Department of Applied Physics, University of Tokyo, Tokyo, Japan
| | - H Kim
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.,Department of Physics, Pohang University of Science and Technology, Pohang, South Korea.,Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, South Korea
| | - S Laha
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - D Weber
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.,Institute of Nanotechnology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Z Yang
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - L Wang
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - H Takahashi
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - K Fürsich
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - M Minola
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - B V Lotsch
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.,Department of Chemistry, University of Munich (LMU), München, Germany
| | - B J Kim
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.,Department of Physics, Pohang University of Science and Technology, Pohang, South Korea.,Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, South Korea
| | - H Yavaş
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.,SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - M Daghofer
- Institute for Functional Matter and Quantum Technologies, University of Stuttgart, Stuttgart, Germany.,Center for Integrated Quantum Science and Technology, University of Stuttgart, Stuttgart, Germany
| | - J Chaloupka
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Brno, Czech Republic.,Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - G Khaliullin
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany
| | - H Gretarsson
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.,Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - B Keimer
- Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany.
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6
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Croshaw J, Huff T, Rashidi M, Wood J, Lloyd E, Pitters J, Wolkow RA. Ionic charge distributions in silicon atomic surface wires. NANOSCALE 2021; 13:3237-3245. [PMID: 33533379 DOI: 10.1039/d0nr08295c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Using a non-contact atomic force microscope (nc-AFM), we examine continuous dangling bond (DB) wire structures patterned on the hydrogen terminated silicon (100)-2 × 1 surface. By probing the DB structures at varying energies, we identify the formation of previously unobserved ionic charge distributions which are correlated to the net charge of DB wires and their predicted degrees of freedom in lattice distortions. Performing spectroscopic analysis, we identify higher energy configurations corresponding to alternative lattice distortions as well as tip-induced charging effects. By varying the length and orientation of these DB structures, we further highlight key features in the formation of these ionic surface phases.
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Affiliation(s)
- Jeremiah Croshaw
- Department of Physics, University of Alberta, Edmonton, Alberta T6G 2J1, Canada. and Quantum Silicon Inc., Edmonton, Alberta T6G 2M9, Canada
| | - Taleana Huff
- Nanotechnology Research Centre, National Research Council Canada, Edmonton, Alberta T6G 2M9, Canada
| | - Mohammad Rashidi
- Department of Physics, University of Alberta, Edmonton, Alberta T6G 2J1, Canada.
| | - John Wood
- Department of Physics, University of Alberta, Edmonton, Alberta T6G 2J1, Canada.
| | - Erika Lloyd
- Department of Physics, University of Alberta, Edmonton, Alberta T6G 2J1, Canada.
| | - Jason Pitters
- Nanotechnology Research Centre, National Research Council Canada, Edmonton, Alberta T6G 2M9, Canada
| | - Robert A Wolkow
- Department of Physics, University of Alberta, Edmonton, Alberta T6G 2J1, Canada. and Quantum Silicon Inc., Edmonton, Alberta T6G 2M9, Canada and Nanotechnology Research Centre, National Research Council Canada, Edmonton, Alberta T6G 2M9, Canada
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7
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Ishikawa H, Yajima T, Matsuo A, Kindo K. Ligand dependent magnetism of theJeff= 3/2 Mott insulator Cs 2MX6( M= Ta, Nb, X= Br, Cl). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:125802. [PMID: 33463529 DOI: 10.1088/1361-648x/abd7b5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Accepted: 12/31/2020] [Indexed: 06/12/2023]
Abstract
Magnetic and structural properties of double perovskite type bromides Cs2MBr6(M= Ta, Nb), where Ta4+(5d1) and Nb4+(4d1) ions form the face centered cubic lattice, are investigated and compared with chlorides Cs2MCl6. Cs2TaBr6exhibits the effective magnetic moment of 0.24μB, which is much smaller than the spin only value of ad1ion, 1.73μB, and comparable to 0.25μBin Cs2TaCl6. On the other hand, the effective magnetic moment of Cs2NbBr6is 0.7μBand is substantially smaller than 1.0μBin Cs2NbCl6. On cooling, successive structural and magnetic phase transitions accompanying the release of electronic entropy approximatelyRln 4 in total as expected for theJeff= 3/2 state are observed. The type of the ligand changes the temperature dependence of magnetic susceptibility at low temperature as well as its magnitude. The role of the ligands on the magnetism ofJeff= 3/2 Mott insulators are discussed in the light of metal-ligand hybridization and the electron-lattice coupling.
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Affiliation(s)
- Hajime Ishikawa
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, Japan
| | - Takeshi Yajima
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, Japan
| | - Akira Matsuo
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, Japan
| | - Koichi Kindo
- Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, Japan
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8
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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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9
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Wei M, Song K, Yang Y, Huang Q, Tian Y, Hao X, Qin W. Organic Multiferroic Magnetoelastic Complexes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2003293. [PMID: 32875629 DOI: 10.1002/adma.202003293] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/31/2020] [Indexed: 06/11/2023]
Abstract
The design of crystal structures aids the discovery of interesting physical phenomena in organic crystals. In this work, the optimization of the coronene-tetracyanoquinodimethane (TCNQ) structure generates non-degenerate energy levels of spin-up and spin-down electrons after charge transfer, producing spontaneous spin polarization, leading to pronounced ferromagnetism. The deformed crystal lattice can significantly affect the saturation magnetization of organic ferromagnets to present a remarkable magnetoelastic coupling. Furthermore, the magnetic-field-induced lattice shrinkage of the ferromagnetic crystals supports a spin-lattice-interaction-dependent magnetoelastic coupling. This concept of organic magnetoelastic coupling will pave the way for the rapid mechanical control of spin polarization in organic multiferroic magnetoelastic materials.
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Affiliation(s)
- Mengmeng Wei
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
| | - Kepeng Song
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, China
| | - Yuying Yang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
| | - Qikun Huang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
| | - Yufeng Tian
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
| | - Xiaotao Hao
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
- ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Wei Qin
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, 250100, China
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10
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Zhang H, Hao L, Yang J, Mutch J, Liu Z, Huang Q, Noordhoek K, May AF, Chu JH, Kim JW, Ryan PJ, Zhou H, Liu J. Comprehensive Electrical Control of Metamagnetic Transition of a Quasi-2D Antiferromagnet by In Situ Anisotropic Strain. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2002451. [PMID: 32697370 DOI: 10.1002/adma.202002451] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 06/12/2020] [Indexed: 06/11/2023]
Abstract
Effective nonmagnetic control of the spin structure is at the forefront of the study for functional quantum materials. This study demonstrates that, by applying an anisotropic strain up to only 0.05%, the metamagnetic transition field of spin-orbit-coupled Mott insulator Sr2 IrO4 can be in situ modulated by almost 300%. Simultaneous measurements of resonant X-ray scattering and transport reveal that this drastic response originates from the complete strain-tuning of the transition between the spin-flop and spin-flip limits, and is always accompanied by large elastoconductance and magnetoconductance. This enables electrically controllable and electronically detectable metamagnetic switching, despite the antiferromagnetic insulating state. The obtained strain-magnetic field phase diagram reveals that C4 -symmetry-breaking anisotropy is introduced by strain via pseudospin-lattice coupling, directly demonstrating the pseudo-Jahn-Teller effect of spin-orbit-coupled complex oxides. The extracted coupling strength is much weaker than the superexchange interactions, yet crucial for the spontaneous symmetry-breaking, affording the remarkably efficient strain-control.
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Affiliation(s)
- Han Zhang
- Department of Physics and Astronomy, The University of Tennessee, 217A A. H. Nielsen Physics Building, Knoxville, TN, 37996, USA
| | - Lin Hao
- Department of Physics and Astronomy, The University of Tennessee, 217A A. H. Nielsen Physics Building, Knoxville, TN, 37996, USA
| | - Junyi Yang
- Department of Physics and Astronomy, The University of Tennessee, 217A A. H. Nielsen Physics Building, Knoxville, TN, 37996, USA
| | - Josh Mutch
- Department of Physics, University of Washington, Seattle, WA, 98195, USA
| | - Zhaoyu Liu
- Department of Physics, University of Washington, Seattle, WA, 98195, USA
| | - Qing Huang
- Department of Physics and Astronomy, The University of Tennessee, 217A A. H. Nielsen Physics Building, Knoxville, TN, 37996, USA
| | - Kyle Noordhoek
- Department of Physics and Astronomy, The University of Tennessee, 217A A. H. Nielsen Physics Building, Knoxville, TN, 37996, USA
| | - Andrew F May
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Jiun-Haw Chu
- Department of Physics, University of Washington, Seattle, WA, 98195, USA
| | - Jong-Woo Kim
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Philip J Ryan
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL, 60439, USA
- School of Physical Sciences, Dublin City University, Dublin 11, Ireland
| | - Haidong Zhou
- Department of Physics and Astronomy, The University of Tennessee, 217A A. H. Nielsen Physics Building, Knoxville, TN, 37996, USA
| | - Jian Liu
- Department of Physics and Astronomy, The University of Tennessee, 217A A. H. Nielsen Physics Building, Knoxville, TN, 37996, USA
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11
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Liu H, Chaloupka J, Khaliullin G. Kitaev Spin Liquid in 3d Transition Metal Compounds. PHYSICAL REVIEW LETTERS 2020; 125:047201. [PMID: 32794780 DOI: 10.1103/physrevlett.125.047201] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 07/02/2020] [Indexed: 06/11/2023]
Abstract
We study the exchange interactions and resulting magnetic phases in the honeycomb cobaltates. For a broad range of trigonal crystal fields acting on Co^{2+} ions, the low-energy pseudospin-1/2 Hamiltonian is dominated by bond-dependent Ising couplings that constitute the Kitaev model. The non-Kitaev terms nearly vanish at small values of trigonal field Δ, resulting in spin liquid ground state. Considering Na_{3}Co_{2}SbO_{6} as an example, we find that this compound is proximate to a Kitaev spin liquid phase, and can be driven into it by slightly reducing Δ by ∼20 meV, e.g., via strain or pressure control. We argue that, due to the more localized nature of the magnetic electrons in 3d compounds, cobaltates offer the most promising search area for Kitaev model physics.
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Affiliation(s)
- Huimei Liu
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Jiří Chaloupka
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 2, Brno 61137, Czech Republic
- Central European Institute of Technology, Masaryk University, Kamenice 753/5, Brno 62500, Czech Republic
| | - Giniyat Khaliullin
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
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12
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Lim ZS, Li C, Chi X, Omar GJ, Ma HH, Huang Z, Zeng S, Yang P, Venkatesan T, Rusydi A, Pennycook SJ, Ariando A. Magnetic Anisotropy of a Quasi Two-Dimensional Canted Antiferromagnet. NANO LETTERS 2020; 20:1890-1895. [PMID: 32004008 DOI: 10.1021/acs.nanolett.9b05120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We report the control of the interplane magnetic exchange coupling in CaIrO3 perovskite thin films and superlattices with SrTiO3. By analyzing the anisotropic magneto-transport data, we demonstrate that a semimetallic paramagnetic CaIrO3 turns into a canted antiferromagnetic Mott insulator at reduced dimensions. The emergence of a biaxial magneto-crystalline anisotropy indicates the canted moment responding to the cubic symmetry. Extending to superlattices and probing oxygen octahedral rotation by half-integer X-ray Braggs diffraction, a more complete picture about the canted moment evolution with interplane coupling can be understood. Remarkably, a rotation of the canted moments' easy axes by 45° is also observed by a sign reversal of the in-plane strain. These results demonstrate the robustness of anisotropic magnetoresistance in revealing quasi two-dimensional canted antiferromagnets, as well as valuable insights about quadrupolar magnetoelastic coupling, relevant for designing future antiferromagnetic spintronic devices.
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Affiliation(s)
- Zhi Shiuh Lim
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411
- Department of Physics, National University of Singapore, Singapore 117542
| | - Changjian Li
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411
- Department of Materials Science and Engineering, National University of Singapore, Singapore 119077
| | - Xiao Chi
- Department of Physics, National University of Singapore, Singapore 117542
- Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, Singapore 117603
| | - Ganesh Ji Omar
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411
- Department of Physics, National University of Singapore, Singapore 117542
| | - Haijiao Harsan Ma
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411
- Department of Physics, National University of Singapore, Singapore 117542
| | - Zhen Huang
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411
| | - Shengwei Zeng
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411
- Department of Physics, National University of Singapore, Singapore 117542
| | - Ping Yang
- Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, Singapore 117603
| | - Thirumalai Venkatesan
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411
- Department of Physics, National University of Singapore, Singapore 117542
- Department of Materials Science and Engineering, National University of Singapore, Singapore 119077
| | - Andrivo Rusydi
- Department of Physics, National University of Singapore, Singapore 117542
- Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, Singapore 117603
| | - Stephen John Pennycook
- Department of Materials Science and Engineering, National University of Singapore, Singapore 119077
| | - Ariando Ariando
- NUSNNI-NanoCore, National University of Singapore, Singapore 117411
- Department of Physics, National University of Singapore, Singapore 117542
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13
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Huang C, Wu F, Yu S, Jena P, Kan E. Discovery of twin orbital-order phases in ferromagnetic semiconducting VI3 monolayer. Phys Chem Chem Phys 2020; 22:512-517. [DOI: 10.1039/c9cp05643b] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Discovery of twin orbital-order ferromagnetic semiconducting phases in VI3-like 2D systems.
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Affiliation(s)
- Chengxi Huang
- Physics Department
- Virginia Commonwealth University
- Richmond
- USA
- Department of Applied Physics and Institution of Energy and Microstructure
| | - Fang Wu
- College of Information Science and Technology
- Nanjing Forestry University
- Nanjing
- P. R. China
| | - Shunli Yu
- National Laboratory of Solid State Microstructures and School of Physics
- Nanjing University
- Nanjing 210093
- P. R. China
| | - Puru Jena
- Physics Department
- Virginia Commonwealth University
- Richmond
- USA
| | - Erjun Kan
- Department of Applied Physics and Institution of Energy and Microstructure
- Nanjing University of Science and Technology
- Nanjing
- P. R. China
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14
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Giant anisotropic magnetoresistance and nonvolatile memory in canted antiferromagnet Sr 2IrO 4. Nat Commun 2019; 10:2280. [PMID: 31123257 PMCID: PMC6533248 DOI: 10.1038/s41467-019-10299-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Accepted: 05/02/2019] [Indexed: 11/09/2022] Open
Abstract
Antiferromagnets have been generating intense interest in the spintronics community, owing to their intrinsic appealing properties like zero stray field and ultrafast spin dynamics. While the control of antiferromagnetic (AFM) orders has been realized by various means, applicably appreciated functionalities on the readout side of AFM-based devices are urgently desired. Here, we report the remarkably enhanced anisotropic magnetoresistance (AMR) as giant as ~160% in a simple resistor structure made of AFM Sr2IrO4 without auxiliary reference layer. The underlying mechanism for the giant AMR is an indispensable combination of atomic scale giant-MR-like effect and magnetocrystalline anisotropy energy, which was not accessed earlier. Furthermore, we demonstrate the bistable nonvolatile memory states that can be switched in-situ without the inconvenient heat-assisted procedure, and robustly preserved even at zero magnetic field, due to the modified interlayer coupling by 1% Ga-doping in Sr2IrO4. These findings represent a straightforward step toward the AFM spintronic devices.
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15
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Vale JG, Boseggia S, Walker HC, Springell RS, Hunter EC, Perry RS, Collins SP, McMorrow DF. Critical fluctuations in the spin-orbit Mott insulator Sr 3Ir 2O 7. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:185803. [PMID: 30721882 DOI: 10.1088/1361-648x/ab0471] [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
X-ray magnetic critical scattering measurements and specific heat measurements were performed on the perovskite iridate [Formula: see text]. We find that the magnetic interactions close to the Néel temperature [Formula: see text] are three-dimensional. This contrasts with previous studies which suggest two-dimensional behaviour like Sr2IrO4. Violation of the Harris criterion ([Formula: see text]) means that weak disorder becomes relevant. This leads a rounding of the antiferromagnetic phase transition at [Formula: see text], and modifies the critical exponents relative to the clean system. Specifically, we determine that the critical behaviour of [Formula: see text] is representative of the diluted 3D Ising universality class.
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Affiliation(s)
- J G Vale
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London (UCL), Gower Street, London, WC1E 6BT, United Kingdom. Laboratory for Quantum Magnetism, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, CH-1015, Switzerland
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16
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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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