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Sano R, Ominato Y, Matsuo M. Acoustomagnonic Spin Hall Effect in Honeycomb Antiferromagnets. PHYSICAL REVIEW LETTERS 2024; 132:236302. [PMID: 38905670 DOI: 10.1103/physrevlett.132.236302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 05/03/2024] [Indexed: 06/23/2024]
Abstract
The recently discovered Van der Waals antiferromagnets have suffered from the lack of a comprehensive method to study their magnetic properties. Here, we propose an ac intrinsic magnon spin Hall current driven by surface acoustic waves as a novel probe for such antiferromagnets. Our results pave the way towards mechanical detection and manipulation of the magnetic order in two-dimensional antiferromagnets. Furthermore, they will overcome the difficulties with weak magnetic responses inherent in the use of antiferromagnets and hence provide a building block for future antiferromagnetic spintronics.
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Affiliation(s)
| | | | - Mamoru Matsuo
- Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan
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2
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Pacholski MJ, Lemut G, Ovdat O, Adagideli I, Beenakker CWJ. Deconfinement of Majorana Vortex Modes Produces a Superconducting Landau Level. PHYSICAL REVIEW LETTERS 2021; 126:226801. [PMID: 34152183 DOI: 10.1103/physrevlett.126.226801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/26/2021] [Indexed: 06/13/2023]
Abstract
A spatially oscillating pair potential Δ(r)=Δ_{0}e^{2iK·r} with momentum K>Δ_{0}/ℏv drives a deconfinement transition of the Majorana bound states in the vortex cores of a Fu-Kane heterostructure (a 3D topological insulator with Fermi velocity v, on a superconducting substrate with gap Δ_{0}, in a perpendicular magnetic field). In the deconfined phase at zero chemical potential the Majorana fermions form a dispersionless Landau level, protected by chiral symmetry against broadening due to vortex scattering. The coherent superposition of electrons and holes in the Majorana Landau level is detectable as a local density of states oscillation with wave vector sqrt[K^{2}-(Δ_{0}/ℏv)^{2}]. The striped pattern also provides a means to measure the chirality of the Majorana fermions.
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Affiliation(s)
- M J Pacholski
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, Netherlands
| | - G Lemut
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, Netherlands
| | - O Ovdat
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, Netherlands
| | - I Adagideli
- Faculty of Engineering and Natural Sciences, Sabanci University, 34956 Orhanli-Tuzla, Istanbul, Turkey
- MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, Netherlands
| | - C W J Beenakker
- Instituut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, Netherlands
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Qi Y, Qiu C, Xiao M, He H, Ke M, Liu Z. Acoustic Realization of Quadrupole Topological Insulators. PHYSICAL REVIEW LETTERS 2020; 124:206601. [PMID: 32501055 DOI: 10.1103/physrevlett.124.206601] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 04/29/2020] [Indexed: 06/11/2023]
Abstract
A quadrupole topological insulator, being one higher-order topological insulator with nontrivial quadrupole quantization, has been intensely investigated very recently. However, the tight-binding model proposed for such emergent topological insulators demands both positive and negative hopping coefficients, which imposes an obstacle in practical realizations. Here, we introduce a feasible approach to design the sign of hopping in acoustics, and construct the first acoustic quadrupole topological insulator that stringently emulates the tight-binding model. The inherent hierarchy quadrupole topology has been experimentally confirmed by detecting the acoustic responses at the bulk, edge, and corner of the sample. Potential applications can be anticipated for the topologically robust in-gap states, such as acoustic sensing and energy trapping.
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Affiliation(s)
- Yajuan Qi
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Chunyin Qiu
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Meng Xiao
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Hailong He
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, China
- Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Manzhu Ke
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, China
- Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Zhengyou Liu
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, China
- Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
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4
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Nayga MM, Rachel S, Vojta M. Magnon Landau Levels and Emergent Supersymmetry in Strained Antiferromagnets. PHYSICAL REVIEW LETTERS 2019; 123:207204. [PMID: 31809086 DOI: 10.1103/physrevlett.123.207204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Indexed: 06/10/2023]
Abstract
Inhomogeneous strain applied to lattice systems can induce artificial gauge fields for particles moving on this lattice. Here we demonstrate how to engineer a novel state of matter, namely an antiferromagnet with a Landau-level excitation spectrum of magnons. We consider a honeycomb-lattice Heisenberg model and show that triaxial strain leads to equally spaced pseudo-Landau levels at the upper end of the magnon spectrum, with degeneracies characteristic of emergent supersymmetry. We also present a particular strain protocol which induces perfectly quantized magnon Landau levels over the whole bandwidth. We discuss experimental realizations and generalizations.
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Affiliation(s)
- Mary Madelynn Nayga
- Institut für Theoretische Physik and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
- Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany
| | - Stephan Rachel
- School of Physics, University of Melbourne, Parkville, VIC 3010, Australia
| | - Matthias Vojta
- Institut für Theoretische Physik and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
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Ziatdinov M, Banerjee A, Maksov A, Berlijn T, Zhou W, Cao HB, Yan JQ, Bridges CA, Mandrus DG, Nagler SE, Baddorf AP, Kalinin SV. Atomic-scale observation of structural and electronic orders in the layered compound α-RuCl 3. Nat Commun 2016; 7:13774. [PMID: 27941761 PMCID: PMC5159869 DOI: 10.1038/ncomms13774] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 11/01/2016] [Indexed: 01/24/2023] Open
Abstract
A pseudospin-1/2 Mott phase on a honeycomb lattice is proposed to host the celebrated two-dimensional Kitaev model which has an elusive quantum spin liquid ground state, and fascinating physics relevant to the development of future templates towards topological quantum bits. Here we report a comprehensive, atomically resolved real-space study by scanning transmission electron and scanning tunnelling microscopies on a novel layered material displaying Kitaev physics, α-RuCl3. Our local crystallography analysis reveals considerable variations in the geometry of the ligand sublattice in thin films of α-RuCl3 that opens a way to realization of a spatially inhomogeneous magnetic ground state at the nanometre length scale. Using scanning tunnelling techniques, we observe the electronic energy gap of ≈0.25 eV and intra-unit cell symmetry breaking of charge distribution in individual α-RuCl3 surface layer. The corresponding charge-ordered pattern has a fine structure associated with two different types of charge disproportionation at Cl-terminated surface.
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Affiliation(s)
- M Ziatdinov
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - A Banerjee
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - A Maksov
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Bredesen Center for Interdisciplinary Research, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - T Berlijn
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - W Zhou
- Material Science &Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - H B Cao
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - J-Q Yan
- Material Science &Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Department of Material Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - C A Bridges
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - D G Mandrus
- Material Science &Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Department of Material Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - S E Nagler
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Bredesen Center for Interdisciplinary Research, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - A P Baddorf
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - S V Kalinin
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Institute for Functional Imaging of Materials, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.,Bredesen Center for Interdisciplinary Research, University of Tennessee, Knoxville, Tennessee 37996, USA
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Keil R, Poli C, Heinrich M, Arkinstall J, Weihs G, Schomerus H, Szameit A. Universal Sign Control of Coupling in Tight-Binding Lattices. PHYSICAL REVIEW LETTERS 2016; 116:213901. [PMID: 27284657 DOI: 10.1103/physrevlett.116.213901] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Indexed: 06/06/2023]
Abstract
We present a method of locally inverting the sign of the coupling term in tight-binding systems, by means of inserting a judiciously designed ancillary site and eigenmode matching of the resulting vertex triplet. Our technique can be universally applied to all lattice configurations, as long as the individual sites can be detuned. We experimentally verify this method in laser-written photonic lattices and confirm both the magnitude and the sign of the coupling by interferometric measurements. Based on these findings, we demonstrate how such universal sign-flipped coupling links can be embedded into extended lattice structures to impose a Z_{2}-gauge transformation. This opens a new avenue for investigations on topological effects arising from magnetic fields with aperiodic flux patterns or in disordered systems.
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Affiliation(s)
- Robert Keil
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - Charles Poli
- Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom
| | - Matthias Heinrich
- Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany
| | - Jake Arkinstall
- Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom
| | - Gregor Weihs
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - Henning Schomerus
- Department of Physics, Lancaster University, Lancaster LA1 4YB, United Kingdom
| | - Alexander Szameit
- Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany
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