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Feng J, Zhou X, Xu M, Shi J, Li Y. Layer Control of Magneto-Optical Effects and Their Quantization in Spin-Valley Splitting Antiferromagnets. NANO LETTERS 2024; 24:3898-3905. [PMID: 38525906 DOI: 10.1021/acs.nanolett.3c05052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/26/2024]
Abstract
Magneto-optical effects (MOE), interfacing the fundamental interplay between magnetism and light, have served as a powerful probe for magnetic order, band topology, and valley index. Here, based on multiferroic and topological bilayer antiferromagnets (AFMs), we propose a layer control of MOE (L-MOE), which is created and annihilated by layer-stacking or an electric field effect. The key character of L-MOE is the sign-reversible response controlled by ferroelectric polarization, the Néel vector, or the electric field direction. Moreover, the sign-reversible L-MOE can be quantized in topologically insulating AFMs. We reveal that the switchable L-MOE originates from the combined contributions of spin-conserving and spin-flip interband transitions in spin-valley splitting AFMs, a phenomenon not observed in conventional AFMs. Our findings bridge the ancient MOE to the emergent realms of layertronics, valleytronics, and multiferroics and may hold immense potential in these fields.
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Affiliation(s)
- Jiaqi Feng
- Laboratory of Quantum Functional Materials Design and Application, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, China
| | - Xiaodong Zhou
- Laboratory of Quantum Functional Materials Design and Application, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, China
| | - Meiling Xu
- Laboratory of Quantum Functional Materials Design and Application, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, China
| | - Jingming Shi
- Laboratory of Quantum Functional Materials Design and Application, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, China
| | - Yinwei Li
- Laboratory of Quantum Functional Materials Design and Application, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, China
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Zhou X, Feng W, Zhang RW, Šmejkal L, Sinova J, Mokrousov Y, Yao Y. Crystal Thermal Transport in Altermagnetic RuO_{2}. PHYSICAL REVIEW LETTERS 2024; 132:056701. [PMID: 38364129 DOI: 10.1103/physrevlett.132.056701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 11/10/2023] [Accepted: 12/20/2023] [Indexed: 02/18/2024]
Abstract
We demonstrate the emergence of a pronounced thermal transport in the recently discovered class of magnetic materials-altermagnets. From symmetry arguments and first-principles calculations performed for the showcase altermagnet, RuO_{2}, we uncover that crystal Nernst and crystal thermal Hall effects in this material are very large and strongly anisotropic with respect to the Néel vector. We find the large crystal thermal transport to originate from three sources of Berry's curvature in momentum space: the Weyl fermions due to crossings between well-separated bands, the strong spin-flip pseudonodal surfaces, and the weak spin-flip ladder transitions, defined by transitions among very weakly spin-split states of similar dispersion crossing the Fermi surface. Moreover, we reveal that the anomalous thermal and electrical transport coefficients in RuO_{2} are linked by an extended Wiedemann-Franz law in a temperature range much wider than expected for conventional magnets. Our results suggest that altermagnets may assume a leading role in realizing concepts in spin caloritronics not achievable with ferromagnets or antiferromagnets.
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Affiliation(s)
- Xiaodong Zhou
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Laboratory of Quantum Functional Materials Design and Application, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, China
| | - Wanxiang Feng
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Run-Wu Zhang
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Libor Šmejkal
- Institute of Physics, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00 Praha 6, Czech Republic
| | - Jairo Sinova
- Institute of Physics, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00 Praha 6, Czech Republic
| | - Yuriy Mokrousov
- Institute of Physics, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
| | - Yugui Yao
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, School of Physics, Beijing Institute of Technology, Beijing 100081, China
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3d Transition Metal Adsorption Induced the valley-polarized Anomalous Hall Effect in Germanene. Sci Rep 2016; 6:27830. [PMID: 27312176 PMCID: PMC4911552 DOI: 10.1038/srep27830] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 05/25/2016] [Indexed: 01/29/2023] Open
Abstract
Based on DFT + U and Berry curvature calculations, we study the electronic structures and topological properties of 3d transition metal (TM) atom (from Ti to Co) adsorbed germanene (TM-germanene). We find that valley-polarized anomalous Hall effect (VAHE) can be realized in germanene by adsorbing Cr, Mn, or Co atoms on its surface. A finite valley Hall voltage can be easily detected in their nanoribbon, which is important for valleytronics devices. Moreover, different valley-polarized current and even reversible valley Hall voltage can be archived by shifting the Fermi energy of the systems. Such versatile features of the systems show potential in next generation electronics devices.
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Vedyayev A, Ryzhanova N, Strelkov N, Dieny B. Spontaneous anomalous and spin Hall effects due to spin-orbit scattering of evanescent wave functions in magnetic tunnel junctions. PHYSICAL REVIEW LETTERS 2013; 110:247204. [PMID: 25165958 DOI: 10.1103/physrevlett.110.247204] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Indexed: 06/03/2023]
Abstract
We theoretically investigated the anomalous Hall effect (AHE) and spin Hall effect (SHE) transversal to the insulating spacer I, in magnetic tunnel junctions of the form F/I/F where the F's are ferromagnetic layers and I represents a tunnel barrier. We considered the case of purely ballistic (quantum mechanical) transport. These effects arise because of the asymmetric scattering of evanescent wave functions due to the spin-orbit interaction in the tunnel barrier. The AHE and SHE we investigated have a surface nature due to the proximity effect. Their amplitude is of first order in the scattering potential. This contrasts with ferromagnetic metals wherein these effects are of second (side-jump scattering) and third (skew scattering) order in these potentials. The value of the AHE current in the insulating spacer may be much larger than that in metallic ferromagnetic electrodes. For the antiparallel orientation of the magnetizations in the two F electrodes, a spontaneous Hall current exists even at zero applied voltage.
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Affiliation(s)
- A Vedyayev
- Department of Physics, Moscow Lomonosov State University, Moscow 119991, Russia and SPINTEC, UMR 8191 CEA-INAC/CNRS/UJF-Grenoble 1/Grenoble-INP, 38054 Grenoble, France
| | - N Ryzhanova
- Department of Physics, Moscow Lomonosov State University, Moscow 119991, Russia and SPINTEC, UMR 8191 CEA-INAC/CNRS/UJF-Grenoble 1/Grenoble-INP, 38054 Grenoble, France
| | - N Strelkov
- Department of Physics, Moscow Lomonosov State University, Moscow 119991, Russia and SPINTEC, UMR 8191 CEA-INAC/CNRS/UJF-Grenoble 1/Grenoble-INP, 38054 Grenoble, France
| | - B Dieny
- SPINTEC, UMR 8191 CEA-INAC/CNRS/UJF-Grenoble 1/Grenoble-INP, 38054 Grenoble, France
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Mokrousov Y, Zhang H, Freimuth F, Zimmermann B, Long NH, Weischenberg J, Souza I, Mavropoulos P, Blügel S. Anisotropy of spin relaxation and transverse transport in metals. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:163201. [PMID: 23511040 DOI: 10.1088/0953-8984/25/16/163201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Using first-principles methods we explore the anisotropy of the spin relaxation and transverse transport properties in bulk metals with respect to the real-space direction of the spin-quantization axis in paramagnets or of the spontaneous magnetization in ferromagnets. Owing to the presence of the spin-orbit coupling the orbital and spin character of the Bloch states depends sensitively on the orientation of the spins relative to the crystal axes. This leads to drastic changes in quantities which rely on interband mixing induced by the spin-orbit interaction. The anisotropy is particularly striking for quantities which exhibit spiky and irregular distributions in the Brillouin zone, such as the spin-mixing parameter or the Berry curvature of the electronic states. We demonstrate this for three cases: (i) the Elliott-Yafet spin-relaxation mechanism in paramagnets with structural inversion symmetry; (ii) the intrinsic anomalous Hall effect in ferromagnets; and (iii) the spin Hall effect in paramagnets. We discuss the consequences of the pronounced anisotropic behavior displayed by these properties for spin-polarized transport applications.
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Affiliation(s)
- Yuriy Mokrousov
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, Jülich, Germany.
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Gradhand M, Fedorov DV, Pientka F, Zahn P, Mertig I, Györffy BL. First-principle calculations of the Berry curvature of Bloch states for charge and spin transport of electrons. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:213202. [PMID: 22575767 DOI: 10.1088/0953-8984/24/21/213202] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Recent progress in wave packet dynamics based on the insight of Berry pertaining to adiabatic evolution of quantum systems has led to the need for a new property of a Bloch state, the Berry curvature, to be calculated from first principles. We report here on the response to this challenge by the ab initio community during the past decade. First we give a tutorial introduction of the conceptual developments we mentioned above. Then we describe four methodologies which have been developed for first-principle calculations of the Berry curvature. Finally, to illustrate the significance of the new developments, we report some results of calculations of interesting physical properties such as the anomalous and spin Hall conductivity as well as the anomalous Nernst conductivity and discuss the influence of the Berry curvature on the de Haas-van Alphen oscillation.
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Affiliation(s)
- M Gradhand
- Max Planck Institute of Microstructure Physics, Halle, Germany.
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Zhang H, Lazo C, Blügel S, Heinze S, Mokrousov Y. Electrically tunable quantum anomalous Hall effect in graphene decorated by 5d transition-metal adatoms. PHYSICAL REVIEW LETTERS 2012; 108:056802. [PMID: 22400951 DOI: 10.1103/physrevlett.108.056802] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2011] [Indexed: 05/31/2023]
Abstract
Based on first-principles calculations, we predict that 5d transition metals on graphene present a unique class of hybrid systems exhibiting topological transport effects that can be manipulated effectively by external electric fields. The origin of this phenomenon lies in the exceptional magnetic properties and the large spin-orbit interaction of the 5d metals leading to significant magnetic moments accompanied with colossal magnetocrystalline anisotropy energies. A strong magnetoelectric response is predicted that offers the possibility to switch the spontaneous magnetization direction by moderate electric fields, enabling an electrically tunable quantum anomalous Hall effect.
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Affiliation(s)
- Hongbin Zhang
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, D-52425 Jülich, Germany.
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Weischenberg J, Freimuth F, Sinova J, Blügel S, Mokrousov Y. Ab initio theory of the scattering-independent anomalous Hall effect. PHYSICAL REVIEW LETTERS 2011; 107:106601. [PMID: 21981517 DOI: 10.1103/physrevlett.107.106601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Indexed: 05/31/2023]
Abstract
We report on first-principles calculations of the side-jump contribution to the anomalous Hall conductivity (AHC) directly from the electronic structure of a perfect crystal. We implemented our approach for a short-range scattering disorder model within the density functional theory and computed the full scattering-independent AHC in elemental bcc Fe, hcp Co, fcc Ni, and L1(0) FePd and FePt alloys. The full AHC thus calculated agrees systematically with experiment to a degree unattainable so far, correctly capturing the previously missing elements of side-jump contributions, hence paving the way to a truly predictive theory of the anomalous Hall effect and turning it from a characterization tool to a probing tool of multiband complex electronic band structures.
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Affiliation(s)
- Jürgen Weischenberg
- Peter Grünberg Institut, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany
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