1
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Zhang H, Wang WW, Qiao C, Zhang L, Liang MC, Wu R, Wang XJ, Liu XJ, Zhang X. Topological spin-orbit-coupled fermions beyond rotating wave approximation. Sci Bull (Beijing) 2024; 69:747-755. [PMID: 38331706 DOI: 10.1016/j.scib.2024.01.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 12/24/2023] [Accepted: 01/15/2024] [Indexed: 02/10/2024]
Abstract
The realization of spin-orbit-coupled ultracold gases has driven a wide range of research and is typically based on the rotating wave approximation (RWA). By neglecting the counter-rotating terms, RWA characterizes a single near-resonant spin-orbit (SO) coupling in a two-level system. Here, we propose and experimentally realize a new scheme for achieving a pair of two-dimensional (2D) SO couplings for ultracold fermions beyond RWA. This work not only realizes the first anomalous Floquet topological Fermi gas beyond RWA, but also significantly improves the lifetime of the 2D-SO-coupled Fermi gas. Based on pump-probe quench measurements, we observe a deterministic phase relation between two sets of SO couplings, which is characteristic of our beyond-RWA scheme and enables the two SO couplings to be simultaneously tuned to the optimum 2D configurations. We observe intriguing band topology by measuring two-ring band-inversion surfaces, quantitatively consistent with a Floquet topological Fermi gas in the regime of high Chern numbers. Our study can open an avenue to explore exotic SO physics and anomalous topological states based on long-lived SO-coupled ultracold fermions.
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Affiliation(s)
- Han Zhang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China; Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Wen-Wei Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China; Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Chang Qiao
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China; Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
| | - Long Zhang
- School of Physics and Institute for Quantum Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; Hefei National Laboratory, Hefei 230088, China
| | - Ming-Cheng Liang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China; Collaborative Innovation Center of Quantum Matter, Beijing 100871, China; Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Rui Wu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China; Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Xu-Jie Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China; Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Xiong-Jun Liu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China; Collaborative Innovation Center of Quantum Matter, Beijing 100871, China; Hefei National Laboratory, Hefei 230088, China; International Quantum Academy, Shenzhen 518048, China.
| | - Xibo Zhang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China; Collaborative Innovation Center of Quantum Matter, Beijing 100871, China; Hefei National Laboratory, Hefei 230088, China; Beijing Academy of Quantum Information Sciences, Beijing 100193, China.
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2
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Zhang B, Tang C, Yang P, Chen J. Tuning Rashba-Dresselhaus effect with ferroelectric polarization at asymmetric heterostructural interface. MATERIALS HORIZONS 2024; 11:262-270. [PMID: 37934455 DOI: 10.1039/d3mh00635b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
The spin-orbit interaction (SOI) plays an essential role in materials properties, and controlling its intensity has great potential in the design of materials. In this work, asymmetric [(La0.7Sr0.3MnO3)8/(BaTiO3)t/(SrTiO3)2]8 superlattices were fabricated on (001) SrTiO3 substrate with SrO or TiO2 termination, labelled as SrO-SL and TiO2-SL, respectively. The in-plane angular magnetoresistance of the superlattices shows a combination of two- and four-fold symmetry components. The coefficient of two-fold symmetry component has opposite sign with current I along [100] and [110] directions for TiO2-SL, while it has the same sign for SrO-SL. Detailed study shows that the asymmetric cation inter-mixing and ferroelectricity-modulated electronic charge transfer induce asymmetric electronic potential for SrO-SL with dominating Rashba SOI, and symmetric electronic potential for TiO2-SL with dominating Dresselhaus SOI induced by BaTiO3. This work shows that the Rashba and Dresselhaus SOIs are sensitive to the ferroelectric polarization in the asymmetric structure.
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Affiliation(s)
- Bangmin Zhang
- Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, Centre for Physical Mechanics and Biophysics, School of Physics, Sun Yat-sen University, Guangzhou 510275, China.
| | - Chunhua Tang
- Department of Materials Science & Engineering, National University of, Singapore, 9 Engineering Drive 1, 117576, Singapore.
| | - Ping Yang
- Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, 117603, Singapore
| | - Jingsheng Chen
- Department of Materials Science & Engineering, National University of, Singapore, 9 Engineering Drive 1, 117576, Singapore.
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3
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Xu J, Li K, Huynh UN, Fadel M, Huang J, Sundararaman R, Vardeny V, Ping Y. How spin relaxes and dephases in bulk halide perovskites. Nat Commun 2024; 15:188. [PMID: 38168025 PMCID: PMC10761878 DOI: 10.1038/s41467-023-42835-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 10/23/2023] [Indexed: 01/05/2024] Open
Abstract
Spintronics in halide perovskites has drawn significant attention in recent years, due to their highly tunable spin-orbit fields and intriguing interplay with lattice symmetry. Here, we perform first-principles calculations to determine the spin relaxation time (T1) and ensemble spin dephasing time ([Formula: see text]) in a prototype halide perovskite, CsPbBr3. To accurately capture spin dephasing in external magnetic fields we determine the Landé g-factor from first principles and take it into account in our calculations. These allow us to predict intrinsic spin lifetimes as an upper bound for experiments, identify the dominant spin relaxation pathways, and evaluate the dependence on temperature, external fields, carrier density, and impurities. We find that the Fröhlich interaction that dominates carrier relaxation contributes negligibly to spin relaxation, consistent with the spin-conserving nature of this interaction. Our theoretical approach may lead to new strategies to optimize spin and carrier transport properties.
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Affiliation(s)
- Junqing Xu
- Department of Physics, Hefei University of Technology, Hefei, Anhui, China
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA
| | - Kejun Li
- Department of Physics, University of California, Santa Cruz, California, USA
| | - Uyen N Huynh
- Department of Physics and Astronomy, University of Utah, Salt Lake City, UT, USA
| | - Mayada Fadel
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Jinsong Huang
- Department of Applied Physical Sciences, University of North Carolina, Chapel Hill, NC, USA
| | - Ravishankar Sundararaman
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA.
| | - Valy Vardeny
- Department of Physics and Astronomy, University of Utah, Salt Lake City, UT, USA.
| | - Yuan Ping
- Department of Physics, University of California, Santa Cruz, California, USA.
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, USA.
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4
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Stephanovich VA, Kirichenko EV, Engel G, Sinner A. Spin-orbit-coupled fractional oscillators and trapped Bose-Einstein condensates. Phys Rev E 2024; 109:014222. [PMID: 38366503 DOI: 10.1103/physreve.109.014222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 01/04/2024] [Indexed: 02/18/2024]
Abstract
We study the ensemble of pseudo-spin 1/2 ultracold bosons, performing Lévy flights, confined in a parabolic potential. The (pseudo-) spin-orbit coupling (SOC) is additionally imposed on these particles. We consider the structure and dynamics of macroscopic pseudospin qubits based on Bose-Einstein condensates, obtained from the above "fractional" bosons. Under "fractional" we understand the substitution of the ordinary second derivative (kinetic energy term) in the Gross-Pitaevskii equation by a so-called fractional Laplacian, characterized by the Lévy index μ. We show that the joint action of interparticle interaction, SOC, and Zeeman splitting in a synthetic magnetic field makes the dynamics of corresponding qubit highly nontrivial with evident chaotic features at both strong interactions and Lévy indices μ→1 when the Lévy trajectories of bosons with long jumps dominated over those derived from ordinary Gaussian distribution, corresponding to μ=2. Using analytical and numerical arguments, we discuss the possibilities to control the above qubit using the synergy of SOC, interaction strength, and "fractionality," characterized by the Lévy index μ.
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Affiliation(s)
- V A Stephanovich
- Institute of Physics, University of Opole, Oleska 48, 45-052, Opole, Poland
| | - E V Kirichenko
- Institute of Physics, University of Opole, Oleska 48, 45-052, Opole, Poland
| | - G Engel
- Institute of Physics, University of Opole, Oleska 48, 45-052, Opole, Poland
| | - A Sinner
- Institute of Physics, University of Opole, Oleska 48, 45-052, Opole, Poland
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5
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Kashikar R, Popoola A, Lisenkov S, Stroppa A, Ponomareva I. Persistent and Quasipersistent Spin Textures in Halide Perovskites Induced by Uniaxial Stress. J Phys Chem Lett 2023; 14:8541-8547. [PMID: 37724873 DOI: 10.1021/acs.jpclett.3c02248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
Persistent spin textures are highly desirable for applications in spintronics, as they allow for long carrier spin lifetimes. However, they are also rare, as they require a delicate balance between spin-momentum coupling parameters. We used density functional theory simulations to predict the possibility of achieving these desirable spin textures through the application of uniaxial stress. Hybrid organic-inorganic perovskite MPSnBr3 (MP = CH3PH3) is a ferroelectric semiconductor which exhibits persistent spin textures near its conduction band minimum and mostly Rashba type spin textures in the vicinity of its valence band maximum. Application of uniaxial stress leads to the gradual evolution of the valence band spin textures from mostly Rashba type to quasipersistent ones under a tensile load and to pure Rashba or quasipersistent ones under a compressive load. The material exhibits flexibility, a rubber-like response, and both positive and negative piezoelectric constants. A combination of such properties may create opportunities for flexible and rubbery spintronic devices.
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Affiliation(s)
- Ravi Kashikar
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Abduljelili Popoola
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Sergey Lisenkov
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - A Stroppa
- Consiglio Nazionale delle Ricerche, Institute for Superconducting and Innovative Materials and Devices (CNR-SPIN), c/o Department of Physical and Chemical Sciences, University of L'Aquila, Via Vetoio I-67100 Coppito L'Aquila, Italy
| | - I Ponomareva
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
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6
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Jin KH, Jiang W, Sethi G, Liu F. Topological quantum devices: a review. NANOSCALE 2023; 15:12787-12817. [PMID: 37490310 DOI: 10.1039/d3nr01288c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
The introduction of the concept of topology into condensed matter physics has greatly deepened our fundamental understanding of transport properties of electrons as well as all other forms of quasi particles in solid materials. It has also fostered a paradigm shift from conventional electronic/optoelectronic devices to novel quantum devices based on topology-enabled quantum device functionalities that transfer energy and information with unprecedented precision, robustness, and efficiency. In this article, the recent research progress in topological quantum devices is reviewed. We first outline the topological spintronic devices underlined by the spin-momentum locking property of topology. We then highlight the topological electronic devices based on quantized electron and dissipationless spin conductivity protected by topology. Finally, we discuss quantum optoelectronic devices with topology-redefined photoexcitation and emission. The field of topological quantum devices is only in its infancy, we envision many significant advances in the near future.
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Affiliation(s)
- Kyung-Hwan Jin
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang 37673, Republic of Korea
| | - Wei Jiang
- School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Gurjyot Sethi
- Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112, USA.
| | - Feng Liu
- Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112, USA.
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7
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Zhang Y, Hang C, Huang G. Matter-wave solitons in an array of spin-orbit-coupled Bose-Einstein condensates. Phys Rev E 2023; 108:014208. [PMID: 37583229 DOI: 10.1103/physreve.108.014208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Accepted: 06/29/2023] [Indexed: 08/17/2023]
Abstract
We investigate matter-wave solitons in a binary Bose-Einstein condensate (BEC) with spin-orbit (SO) coupling, loaded in a one-dimensional (1D) deep optical lattice and a three-dimensional anisotropic magnetic trap, which creates an array of elongated sub-BECs with transverse tunneling. We show that the system supports 1D continuous and discrete solitons localized in the longitudinal (along the array) and the transverse (across the array) directions, respectively. In addition, such solitons are always unpolarized in the zero-momentum state but polarized in finite-momentum states. We also show that the system supports stable two-dimensional semidiscrete solitons, including single- and multiple-peaked ones, localized in both the longitudinal and transverse directions. Stability diagrams for single-peaked semidiscrete solitons in different parameter spaces are identified. The results reported here are beneficial not only for understanding the physical property of SO-coupled BECs but also for generating new types of matter-wave solitons.
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Affiliation(s)
- Yanchao Zhang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
| | - Chao Hang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
- NYU-ECNU Institute of Physics, New York University at Shanghai, Shanghai 200062, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Guoxiang Huang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China
- NYU-ECNU Institute of Physics, New York University at Shanghai, Shanghai 200062, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
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8
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Zhang Z, Qin S, Zang J, Fang C, Hu J, Zhang FC. Controlling Dzyaloshinskii-Moriya interaction in a centrosymmetric nonsymmorphic crystal. Sci Bull (Beijing) 2023:S2095-9273(23)00287-6. [PMID: 37208269 DOI: 10.1016/j.scib.2023.04.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 04/04/2023] [Accepted: 04/25/2023] [Indexed: 05/21/2023]
Abstract
Presence of the Dzyaloshinskii-Moriya (DM) interaction in limited noncentrosymmetric materials leads to novel spin textures and exotic chiral physics. The emergence of DM interaction in centrosymmetric crystals could greatly enrich material realization. Here we show that an itinerant centrosymmetric crystal respecting a nonsymmorphic space group is a new platform for the DM interaction. Taking P4/nmm space group as an example, we demonstrate that the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction induces the DM interactions, in addition to the Heisenberg exchange and the Kaplan-Shekhtman-Entin-wohlman-Aharony (KSEA) interaction. The direction of DM vector depends on the positions of magnetic atoms in the real space, and the amplitude depends on the location of the Fermi surface in the reciprocal space. The diversity stems from the position-dependent site groups and the momentum-dependent electronic structures guaranteed by the nonsymmorphic symmetries. Our study unveils the role of the nonsymmorphic symmetries in affecting magnetism, and suggests that the nonsymmorphic crystals can be promising platforms to design magnetic interactions.
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Affiliation(s)
- Zhongyi Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shengshan Qin
- University of Chinese Academy of Sciences, Beijing 100049, China; School of Physics, Beijing Institute of Technology, Beijing 100081, China; Kavli Institute for Theoretical Sciences, CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China.
| | - Jiadong Zang
- Department of Physics and Astronomy, University of New Hampshire, Durham 03824, USA; Materials Science Program, University of New Hampshire, Durham 03824, USA
| | - Chen Fang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Kavli Institute for Theoretical Sciences, CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Jiangping Hu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Kavli Institute for Theoretical Sciences, CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China; South Bay Interdisciplinary Science Center, Dongguan 523808, China
| | - Fu-Chun Zhang
- Kavli Institute for Theoretical Sciences, CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China; Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
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9
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Zhang L, Pan D, Zhu S, Li S. Polaron induced local spin texture and anomalous Hall effect in the quadrilateral prism-shaped nanotube with Rashba and Dresselhaus spin-orbit coupling. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:255401. [PMID: 36972620 DOI: 10.1088/1361-648x/acc7ea] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 03/27/2023] [Indexed: 06/18/2023]
Abstract
We theoretically study the spin-texture dynamics and the transverse asymmetric charge deflection induced by the polaron in a quadrilateral prism-shaped nanotube with the Rashba and Dresselhaus spin-orbit coupling (SOC). We reveal the polaron gives rise to the nontrivial local spin textures in the nanotube within the cross section plane. The spins demonstrate oscillations and the oscillating patterns are dependent on the SOC type. For the nanotube containing a segment of the ferromagnetic domain, the sizable asymmetric charge deflections could additionally take place, namely, the anomalous Hall effect. The amount of the deflected charges is determined by the strength and orientations of the ferromagnetic magnetization as well as the SOC type. The work provides a valuable insight of the coherent transport of polaron through a quasi-one-dimensional nanotube with Rashba and Dresselhaus SOC and open avenues for the potential device applications.
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Affiliation(s)
- Longlong Zhang
- National Space Science Center, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Deng Pan
- College of Optoelectronics, Taiyuan University of Technology, Taiyuan 030024, People's Republic of China
| | - Shilei Zhu
- College of Physics, Taiyuan University of Technology, Taiyuan 030024, People's Republic of China
| | - Shiqi Li
- College of Optoelectronics, Taiyuan University of Technology, Taiyuan 030024, People's Republic of China
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10
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Ishihara J, Mori T, Suzuki T, Sato S, Morita K, Kohda M, Ohno Y, Miyajima K. Imprinting Spatial Helicity Structure of Vector Vortex Beam on Spin Texture in Semiconductors. PHYSICAL REVIEW LETTERS 2023; 130:126701. [PMID: 37027869 DOI: 10.1103/physrevlett.130.126701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 01/17/2023] [Accepted: 02/13/2023] [Indexed: 06/19/2023]
Abstract
We present the transfer of the spatially variant polarization of topologically structured light to the spatial spin texture in a semiconductor quantum well. The electron spin texture, which is a circular pattern with repeating spin-up and spin-down states whose repetition rate is determined by the topological charge, is directly excited by a vector vortex beam with a spatial helicity structure. The generated spin texture efficiently evolves into a helical spin wave pattern owing to the spin-orbit effective magnetic fields in the persistent spin helix state by controlling the spatial wave number of the excited spin mode. By tuning the repetition length and azimuthal angle, we simultaneously generate helical spin waves with opposite phases by a single beam.
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Affiliation(s)
- Jun Ishihara
- Department of Applied Physics, Tokyo University of Science, Tokyo 125-8585, Japan
| | - Takachika Mori
- Department of Applied Physics, Tokyo University of Science, Tokyo 125-8585, Japan
| | - Takuya Suzuki
- Department of Applied Physics, Tokyo University of Science, Tokyo 125-8585, Japan
| | - Sota Sato
- Graduate School of Electrical and Electronic Engineering, Chiba University, Chiba 263-8522, Japan
| | - Ken Morita
- Graduate School of Electrical and Electronic Engineering, Chiba University, Chiba 263-8522, Japan
| | - Makoto Kohda
- Department of Materials Science, Tohoku University, Sendai 980-8579, Japan
| | - Yuzo Ohno
- Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8573, Japan
| | - Kensuke Miyajima
- Department of Applied Physics, Tokyo University of Science, Tokyo 125-8585, Japan
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11
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Kokhanchik P, Solnyshkov D, Stöferle T, Piętka B, Szczytko J, Malpuech G. Modulated Rashba-Dresselhaus Spin-Orbit Coupling for Topology Control and Analog Simulations. PHYSICAL REVIEW LETTERS 2022; 129:246801. [PMID: 36563269 DOI: 10.1103/physrevlett.129.246801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 10/28/2022] [Indexed: 06/17/2023]
Abstract
We show theoretically that Rashba-Dresselhaus spin-orbit coupling (RDSOC) in lattices acts as a synthetic gauge field. This allows us to control both the phase and the magnitude of tunneling coefficients between sites, which is the key ingredient to implement topological Hamitonians and spin lattices useful for simulation perpectives. We use liquid crystal based microcavities in which RDSOC can be switched on and off as a model platform. We propose a realistic scheme for implementation of a Su-Schrieffer-Heeger chain in which the edge states existence can be tuned, and a Harper-Hofstadter model with a tunable contrasted flux for each (pseudo)spin component. We further show that a transverse-field Ising model and classical XY Hamiltonian with tunable parameters can be implemented, opening up prospects for analog physics, simulations, and optimization.
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Affiliation(s)
- Pavel Kokhanchik
- Institut Pascal, Université Clermont Auvergne, CNRS, Clermont INP, F-63000 Clermont-Ferrand, France
| | - Dmitry Solnyshkov
- Institut Pascal, Université Clermont Auvergne, CNRS, Clermont INP, F-63000 Clermont-Ferrand, France
- Institut Universitaire de France (IUF), 75231 Paris, France
| | - Thilo Stöferle
- IBM Research Europe-Zurich, CH-8803 Rüschlikon, Switzerland
| | - Barbara Piętka
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Jacek Szczytko
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Guillaume Malpuech
- Institut Pascal, Université Clermont Auvergne, CNRS, Clermont INP, F-63000 Clermont-Ferrand, France
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12
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Zribi J, Pierucci D, Bisti F, Zheng B, Avila J, Khalil L, Ernandes C, Chaste J, Oehler F, Pala M, Maroutian T, Hermes I, Lhuillier E, Pan A, Ouerghi A. Unidirectional Rashba spin splitting in single layer WS 2(1-x)Se 2xalloy. NANOTECHNOLOGY 2022; 34:075705. [PMID: 36347029 DOI: 10.1088/1361-6528/aca0f6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 11/08/2022] [Indexed: 06/16/2023]
Abstract
Atomically thin two-dimensional (2D) layered semiconductors such as transition metal dichalcogenides have attracted considerable attention due to their tunable band gap, intriguing spin-valley physics, piezoelectric effects and potential device applications. Here we study the electronic properties of a single layer WS1.4Se0.6alloys. The electronic structure of this alloy, explored using angle resolved photoemission spectroscopy, shows a clear valence band structure anisotropy characterized by two paraboloids shifted in one direction of thek-space by a constant in-plane vector. This band splitting is a signature of a unidirectional Rashba spin splitting with a related giant Rashba parameter of 2.8 ± 0.7 eV Å. The combination of angle resolved photoemission spectroscopy with piezo force microscopy highlights the link between this giant unidirectional Rashba spin splitting and an in-plane polarization present in the alloy. These peculiar anisotropic properties of the WS1.4Se0.6alloy can be related to local atomic orders induced during the growth process due the different size and electronegativity between S and Se atoms. This distorted crystal structure combined to the observed macroscopic tensile strain, as evidenced by photoluminescence, displays electric dipoles with a strong in-plane component, as shown by piezoelectric microscopy. The interplay between semiconducting properties, in-plane spontaneous polarization and giant out-of-plane Rashba spin-splitting in this 2D material has potential for a wide range of applications in next-generation electronics, piezotronics and spintronics devices.
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Affiliation(s)
- Jihene Zribi
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, F-91120, Palaiseau, France
| | - Debora Pierucci
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, F-91120, Palaiseau, France
| | - Federico Bisti
- Dipartimento di Scienze Fisiche e Chimiche, Università dell'Aquila, Via Vetoio 10, I-67100 L'Aquila, Italy
| | - Biyuan Zheng
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Materials Science and Engineering, Hunan University, Changsha, Hunan 410082, People's Republic of China
| | - José Avila
- Synchrotron-SOLEIL, Saint-Aubin, BP48, F-91192 Gif sur Yvette Cedex, France
| | - Lama Khalil
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, F-91120, Palaiseau, France
| | - Cyrine Ernandes
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, F-91120, Palaiseau, France
| | - Julien Chaste
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, F-91120, Palaiseau, France
| | - Fabrice Oehler
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, F-91120, Palaiseau, France
| | - Marco Pala
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, F-91120, Palaiseau, France
| | - Thomas Maroutian
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, F-91120, Palaiseau, France
| | - Ilka Hermes
- Park Systems Europe GmbH. Schildkroetstrasse 15, D-68199 Mannheim, Germany
| | - Emmanuel Lhuillier
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP, F-75005 Paris, France
| | - Anlian Pan
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Materials Science and Engineering, Hunan University, Changsha, Hunan 410082, People's Republic of China
| | - Abdelkarim Ouerghi
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, F-91120, Palaiseau, France
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13
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Helgers PLJ, Stotz JAH, Sanada H, Kunihashi Y, Biermann K, Santos PV. Flying electron spin control gates. Nat Commun 2022; 13:5384. [PMID: 36104320 PMCID: PMC9475040 DOI: 10.1038/s41467-022-32807-x] [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: 10/31/2021] [Accepted: 08/18/2022] [Indexed: 11/17/2022] Open
Abstract
The control of "flying” (or moving) spin qubits is an important functionality for the manipulation and exchange of quantum information between remote locations on a chip. Typically, gates based on electric or magnetic fields provide the necessary perturbation for their control either globally or at well-defined locations. Here, we demonstrate the dynamic control of moving electron spins via contactless gates that move together with the spins. The concept is realized using electron spins trapped and transported by moving potential dots defined by a surface acoustic wave (SAW). The SAW strain at the electron trapping site, which is set by the SAW amplitude, acts as a contactless, tunable gate that controls the precession frequency of the flying spins via the spin-orbit interaction. We show that the degree of precession control in moving dots exceeds previously reported results for unconstrained transport by an order of magnitude and is well accounted for by a theoretical model for the strain contribution to the spin-orbit interaction. This flying spin gate permits the realization of an acoustically driven optical polarization modulator based on electron spin transport, a key element for on-chip spin information processing with a photonic interface. Spin qubits are a platform for quantum computing. There are many advantages for quantum information processing if the spin qubit can move. Here, Helgers et al. use a surface acoustic wave to define a moving quantum dot and demonstrate the magneticfield-free control of the spin precession, bringing “flying” spin qubits a step closer.
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14
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Absor MAU, Lukmantoro A, Santoso I. Full-zone persistent spin textures with giant spin splitting in two-dimensional group IV-V compounds. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:445501. [PMID: 35998620 DOI: 10.1088/1361-648x/ac8c14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 08/23/2022] [Indexed: 06/15/2023]
Abstract
Persistent spin texture (PST), a property of solid-state materials maintaining unidirectional spin polarization in the momentumk-space, offers a route to deliver the necessary long carrier spin lifetimes through the persistent spin helix (PSH) mechanism. However, most of the discovered PST locally occurred in the small part around certain high symmetryk-points or lines in the first Brillouin zone (FBZ), thus limiting the stability of the PSH state. Herein, by symmetry analysis and first-principles calculations, we report the emergence of full-zone PST (FZPST), a phenomenon displaying the PST in the whole FBZ, in the two-dimensional group IV-VA2B2(A= Si, Sn, Ge;B= Bi, Sb) compounds. Due to the existence of the in-plane mirror symmetry operation in the wave vector point group symmetry for the arbitraryk⃗in the whole FBZ, fully out-of-plane spin polarization is observed in thek-space, thus maintaining the FZPST. Importantly, we observed giant spin splitting in which the PST sustains, supporting large spin-orbit coupling parameters and small wavelengths of the PSH states. Ourk⃗⋅p⃗analysis demonstrated that the FZPST is robust for the non-degenerate bands, which can be effectively controlled by the application of an external electric field, thus offering a promising platform for future spintronic applications.
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Affiliation(s)
- Moh Adhib Ulil Absor
- Department of Physics, Universitas Gadjah Mada, Sekip Utara BLS 21, Yogyakarta 55281, Indonesia
| | - Arif Lukmantoro
- Department of Physics, Universitas Gadjah Mada, Sekip Utara BLS 21, Yogyakarta 55281, Indonesia
| | - Iman Santoso
- Department of Physics, Universitas Gadjah Mada, Sekip Utara BLS 21, Yogyakarta 55281, Indonesia
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15
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Du BH, Chen MN, Hu LB. Influence of Rashba spin-orbit coupling on Josephson effect in triplet superconductor/two-dimensional semiconductor/triplet superconductor junctions. CHINESE PHYSICS B 2022; 31:077201. [DOI: 10.1088/1674-1056/ac587e] [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
We study theoretically Josephson effect in a planar ballistic junction between two triplet superconductors with p-wave orbital symmetries and separated by a two-dimensional (2D) semiconductor channel with strong Rashba spin–orbit coupling. In triplet superconductors, three types of orbital symmetries are considered. We use Bogoliubov–de Gennes formalism to describe quasiparticle propagations through the junction and the supercurrents are calculated in terms of Andreev reflection coefficients. The features of the variation of the supercurrents with the change of the strength of Rashba spin–orbit coupling are investigated in some detail. It is found that for the three types of orbital symmetries considered, both the magnitudes of supercurrent and the current-phase relations can be manipulated effectively by tuning the strength of Rashba spin–orbit coupling. The interplay of Rashba spin–orbit coupling and Zeeman magnetic field on supercurrent is also investigated in some detail.
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16
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Fernandez A, Acharya M, Lee HG, Schimpf J, Jiang Y, Lou D, Tian Z, Martin LW. Thin-Film Ferroelectrics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2108841. [PMID: 35353395 DOI: 10.1002/adma.202108841] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 03/03/2022] [Indexed: 06/14/2023]
Abstract
Over the last 30 years, the study of ferroelectric oxides has been revolutionized by the implementation of epitaxial-thin-film-based studies, which have driven many advances in the understanding of ferroelectric physics and the realization of novel polar structures and functionalities. New questions have motivated the development of advanced synthesis, characterization, and simulations of epitaxial thin films and, in turn, have provided new insights and applications across the micro-, meso-, and macroscopic length scales. This review traces the evolution of ferroelectric thin-film research through the early days developing understanding of the roles of size and strain on ferroelectrics to the present day, where such understanding is used to create complex hierarchical domain structures, novel polar topologies, and controlled chemical and defect profiles. The extension of epitaxial techniques, coupled with advances in high-throughput simulations, now stands to accelerate the discovery and study of new ferroelectric materials. Coming hand-in-hand with these new materials is new understanding and control of ferroelectric functionalities. Today, researchers are actively working to apply these lessons in a number of applications, including novel memory and logic architectures, as well as a host of energy conversion devices.
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Affiliation(s)
- Abel Fernandez
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Megha Acharya
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Han-Gyeol Lee
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Jesse Schimpf
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Yizhe Jiang
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Djamila Lou
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Zishen Tian
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Lane W Martin
- Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
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17
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Sino PAL, Feng LY, Villaos RAB, Cruzado HN, Huang ZQ, Hsu CH, Chuang FC. Anisotropic Rashba splitting in Pt-based Janus monolayers PtXY (X,Y = S, Se, or Te). NANOSCALE ADVANCES 2021; 3:6608-6616. [PMID: 36132660 PMCID: PMC9419079 DOI: 10.1039/d1na00334h] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 09/13/2021] [Indexed: 06/14/2023]
Abstract
Recent studies have demonstrated the feasibility of synthesizing two-dimensional (2D) Janus materials which possess intrinsic structural asymmetry. Hence, we performed a systematic first-principles study of 2D Janus transition metal dichalcogenide (TMD) monolayers based on PtXY (X,Y = S, Se, or Te). Our calculated formation energies show that these monolayer Janus structures retain the 1T phase. Furthermore, phonon spectral calculations confirm that these Janus TMD monolayers are thermodynamically stable. We found that PtSSe, PtSTe, and PtSeTe exhibit an insulating phase with indirect band gaps of 2.108, 1.335, and 1.221 eV, respectively, from hybrid functional calculations. Due to the breaking of centrosymmetry in the crystal structure, the spin-orbit coupling (SOC)-induced anisotropic Rashba splitting is observed around the M point. The calculated Rashba strengths from M to Γ (α M-Γ R) are 1.654, 1.103, and 0.435 eV Å-1, while the calculated values from M to K (α M-K R) are 1.333, 1.244, and 0.746 eV Å-1, respectively, for PtSSe, PtSTe, and PtSeTe. Interestingly, the spin textures reveal that the spin-splitting is mainly attributed to the Rashba effect. However, a Dresselhaus-like contribution also plays a secondary role. Finally, we found that the band gaps and the strength of the Rashba effect can be further tuned through biaxial strain. Our findings indeed show that Pt-based Janus TMDs demonstrate the potential for spintronics applications.
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Affiliation(s)
- Paul Albert L Sino
- Department of Physics, National Sun Yat-sen University 70 Lienhai Rd. Kaohsiung 80424 Taiwan +886-7-5253733
| | - Liang-Ying Feng
- Department of Physics, National Sun Yat-sen University 70 Lienhai Rd. Kaohsiung 80424 Taiwan +886-7-5253733
| | - Rovi Angelo B Villaos
- Department of Physics, National Sun Yat-sen University 70 Lienhai Rd. Kaohsiung 80424 Taiwan +886-7-5253733
| | - Harvey N Cruzado
- Department of Physics, National Sun Yat-sen University 70 Lienhai Rd. Kaohsiung 80424 Taiwan +886-7-5253733
- Institute of Mathematical Sciences and Physics, College of Arts and Sciences, University of the Philippines Los Baños, College Laguna 4031 Philippines
| | - Zhi-Quan Huang
- Department of Physics, National Sun Yat-sen University 70 Lienhai Rd. Kaohsiung 80424 Taiwan +886-7-5253733
| | - Chia-Hsiu Hsu
- Department of Physics, National Sun Yat-sen University 70 Lienhai Rd. Kaohsiung 80424 Taiwan +886-7-5253733
- Department of Physics, National Tsing Hua University Hsinchu 30013 Taiwan
| | - Feng-Chuan Chuang
- Department of Physics, National Sun Yat-sen University 70 Lienhai Rd. Kaohsiung 80424 Taiwan +886-7-5253733
- Physics Division, National Center for Theoretical Sciences Taipei 10617 Taiwan
- Department of Physics, National Tsing Hua University Hsinchu 30013 Taiwan
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18
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Król M, Rechcińska K, Sigurdsson H, Oliwa P, Mazur R, Morawiak P, Piecek W, Kula P, Lagoudakis PG, Matuszewski M, Bardyszewski W, Piętka B, Szczytko J. Realizing Optical Persistent Spin Helix and Stern-Gerlach Deflection in an Anisotropic Liquid Crystal Microcavity. PHYSICAL REVIEW LETTERS 2021; 127:190401. [PMID: 34797125 DOI: 10.1103/physrevlett.127.190401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 08/24/2021] [Indexed: 06/13/2023]
Abstract
Spin-orbit interactions which couple the spin of a particle with its momentum degrees of freedom lie at the center of spintronic applications. Of special interest in semiconductor physics are Rashba and Dresselhaus spin-orbit coupling. When equal in strength, the Rashba and Dresselhaus fields result in SU(2) spin rotation symmetry and emergence of the persistent spin helix only investigated for charge carriers in semiconductor quantum wells. Recently, a synthetic Rashba-Dresselhaus Hamiltonian was shown to describe cavity photons confined in a microcavity filled with optically anisotropic liquid crystal. In this Letter, we present a purely optical realization of two types of spin patterns corresponding to the persistent spin helix and the Stern-Gerlach experiment in such a cavity. We show how the symmetry of the Hamiltonian results in spatial oscillations of the spin orientation of photons traveling in the plane of the cavity.
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Affiliation(s)
- Mateusz Król
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, PL-02-093 Warsaw, Poland
| | - Katarzyna Rechcińska
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, PL-02-093 Warsaw, Poland
| | - Helgi Sigurdsson
- Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, building 1, Moscow 121205, Russia
- Department of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, United Kingdom
- Science Institute, University of Iceland, Dunhagi 3, IS-107 Reykjavik, Iceland
| | - Przemysław Oliwa
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, PL-02-093 Warsaw, Poland
| | - Rafał Mazur
- Institute of Applied Physics, Military University of Technology, Kaliskiego 2, PL-00-908 Warsaw, Poland
| | - Przemysław Morawiak
- Institute of Applied Physics, Military University of Technology, Kaliskiego 2, PL-00-908 Warsaw, Poland
| | - Wiktor Piecek
- Institute of Applied Physics, Military University of Technology, Kaliskiego 2, PL-00-908 Warsaw, Poland
| | - Przemysław Kula
- Institute of Chemistry, Military University of Technology, Kaliskiego 2, PL-00-908 Warsaw, Poland
| | - Pavlos G Lagoudakis
- Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, building 1, Moscow 121205, Russia
- Department of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Michał Matuszewski
- Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, PL-02-668 Warsaw, Poland
| | - Witold Bardyszewski
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Pasteura 5, PL-02-093 Warsaw, Poland
| | - Barbara Piętka
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, PL-02-093 Warsaw, Poland
| | - Jacek Szczytko
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, PL-02-093 Warsaw, Poland
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19
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Ukpong AM. Emergence of Nontrivial Spin Textures in Frustrated Van Der Waals Ferromagnets. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:1770. [PMID: 34361155 PMCID: PMC8308132 DOI: 10.3390/nano11071770] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 06/11/2021] [Accepted: 06/12/2021] [Indexed: 11/16/2022]
Abstract
In this work, first principles ground state calculations are combined with the dynamic evolution of a classical spin Hamiltonian to study the metamagnetic transitions associated with the field dependence of magnetic properties in frustrated van der Waals ferromagnets. Dynamically stabilized spin textures are obtained relative to the direction of spin quantization as stochastic solutions of the Landau-Lifshitz-Gilbert-Slonczewski equation under the flow of the spin current. By explicitly considering the spin signatures that arise from geometrical frustrations at interfaces, we may observe the emergence of a magnetic skyrmion spin texture and characterize the formation under competing internal fields. The analysis of coercivity and magnetic hysteresis reveals a dynamic switch from a soft to hard magnetic configuration when considering the spin Hall effect on the skyrmion. It is found that heavy metals in capped multilayer heterostructure stacks host field-tunable spiral skyrmions that could serve as unique channels for carrier transport. The results are discussed to show the possibility of using dynamically switchable magnetic bits to read and write data without the need for a spin transfer torque. These results offer insight to the spin transport signatures that dynamically arise from metamagnetic transitions in spintronic devices.
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Affiliation(s)
- Aniekan Magnus Ukpong
- Theoretical and Computational Condensed Matter and Materials Physics Group, School of Chemistry and Physics, University of KwaZulu-Natal, Pietermaritzburg 3201, South Africa
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20
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Maryenko D, Kawamura M, Ernst A, Dugaev VK, Sherman EY, Kriener M, Bahramy MS, Kozuka Y, Kawasaki M. Interplay of spin-orbit coupling and Coulomb interaction in ZnO-based electron system. Nat Commun 2021; 12:3180. [PMID: 34039969 PMCID: PMC8155003 DOI: 10.1038/s41467-021-23483-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 04/30/2021] [Indexed: 11/09/2022] Open
Abstract
Spin-orbit coupling (SOC) is pivotal for various fundamental spin-dependent phenomena in solids and their technological applications. In semiconductors, these phenomena have been so far studied in relatively weak electron-electron interaction regimes, where the single electron picture holds. However, SOC can profoundly compete against Coulomb interaction, which could lead to the emergence of unconventional electronic phases. Since SOC depends on the electric field in the crystal including contributions of itinerant electrons, electron-electron interactions can modify this coupling. Here we demonstrate the emergence of the SOC effect in a high-mobility two-dimensional electron system in a simple band structure MgZnO/ZnO semiconductor. This electron system also features strong electron-electron interaction effects. By changing the carrier density with Mg-content, we tune the SOC strength and achieve its interplay with electron-electron interaction. These systems pave a way to emergent spintronic phenomena in strong electron correlation regimes and to the formation of quasiparticles with the electron spin strongly coupled to the density.
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Affiliation(s)
- D Maryenko
- RIKEN Center for Emergent Matter Science(CEMS), Wako, Japan.
| | - M Kawamura
- RIKEN Center for Emergent Matter Science(CEMS), Wako, Japan
| | - A Ernst
- Institute for Theoretical Physics, Johannes Kepler University, Linz, Austria.,Max Planck Institute of Microstructure Physics, Halle, Germany
| | - V K Dugaev
- Department of Physics and Medical Engineering, Rzeszów University of Technology, Rzeszów, Poland
| | - E Ya Sherman
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Bilbao, Spain.,Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - M Kriener
- RIKEN Center for Emergent Matter Science(CEMS), Wako, Japan
| | - M S Bahramy
- Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Tokyo, Japan.,Department of Physics and Astronomy, The University of Manchester, Manchester, UK
| | - Y Kozuka
- Research Center for Magnetic and Spintronic Materials, National Institute for Materials Science (NIMS), Tsukuba, Japan.,JST, PRESTO, Kawaguchi, Saitama, Japan
| | - M Kawasaki
- RIKEN Center for Emergent Matter Science(CEMS), Wako, Japan.,Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), The University of Tokyo, Tokyo, Japan
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21
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Absor MAU, Faishol Y, Anshory M, Santoso I, Sholihun S, Sabarman H, Ishii F. Highly persistent spin textures with giant tunable spin splitting in the two-dimensional germanium monochalcogenides. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:305501. [PMID: 34015779 DOI: 10.1088/1361-648x/ac0383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The ability to control the spin textures in semiconductors is a fundamental step toward novel spintronic devices, while seeking desirable materials exhibiting persistent spin texture (PST) remains a key challenge. The PST is the property of materials preserving a unidirectional spin orientation in the momentum space, which has been predicted to support an extraordinarily long spin lifetime of carriers. Herein, by using first-principles density functional theory calculations, we report the emergence of the PST in the two-dimensional (2D) germanium monochalcogenides (GeMC). By considering two stable formation of the 2D GeMC, namely the pure GeX and Janus Ge2XY monolayers (X, Y = S, Se, and Te), we observed the PST around the valence band maximum where the spin orientation is enforced by the lower point group symmetry of the crystal. In the case of the pure GeX monolayers, we found that the PST is characterized by fully out-of-plane spin orientation protected by C2v point group, while the canted PST in the y - z plane is observed in the case of the Janus Ge2XY monolayers due to the lowering symmetry into Cs point group. More importantly, we find large spin-orbit coupling (SOC) parameter in which the PST sustains, which could be effectively tuned by in-plane strain. The large SOC parameter observed in the present systems leads to the small wavelength of the spatially periodic mode of the spin polarization, which is promising for realization of the short spin channel in the spin Hall transistor devices.
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Affiliation(s)
- Moh Adhib Ulil Absor
- Physics, Universitas Gadjah Mada, BLS 21 Sekip Utara Yogyakarta, Yogyakarta, 55281, INDONESIA
| | - Yusuf Faishol
- Physics, Universitas Gadjah Mada, BLS 21 Sekip Utara Yogyakarta, Yogyakarta, 55281, INDONESIA
| | - Muhammad Anshory
- Physics, Universitas Gadjah Mada, BLS 21 Sekip Utara Yogyakarta, Yogyakarta, 55281, INDONESIA
| | - Iman Santoso
- Physics, Universitas Gadjah Mada , Fakultas MIPA, Sekip Utara, BLS 21, Yogyakarta, 55281, INDONESIA
| | - Sholihun Sholihun
- Physics, Universitas Gadjah Mada, BLS 21 Sekip Utara Yogyakarta, Yogyakarta, 55281, INDONESIA
| | - Harsojo Sabarman
- Department of Physics, Gadjah Mada University, Sekip Utara Yogyakarta 55281, Bulaksumur, Yogyakarta, Yogyakarta, 55281, INDONESIA
| | - Fumiyuki Ishii
- Kanazawa University, Nanomaterials Research Institute, Kanazawa University, 920-1192, Kanazawa, Japan., Kanazawa, Ishikawa, 920-1192, JAPAN
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22
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Zhao HJ, Nakamura H, Arras R, Paillard C, Chen P, Gosteau J, Li X, Yang Y, Bellaiche L. Purely Cubic Spin Splittings with Persistent Spin Textures. PHYSICAL REVIEW LETTERS 2020; 125:216405. [PMID: 33275000 DOI: 10.1103/physrevlett.125.216405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/10/2020] [Accepted: 10/09/2020] [Indexed: 06/12/2023]
Abstract
Purely cubic spin splittings in the band structure of bulk insulators have not been extensively investigated yet despite the fact that they may pave the way for novel spin-orbitronic applications and can also result in a variety of promising spin phenomena. By symmetry analysis and first-principles simulations, we report symmetry-enforced purely cubic spin splittings (SEPCSS) that can even lead to persistent spin textures. In particular, these SEPCSS can be thought to be complementary to the cubic Rashba and cubic Dresselhaus types of spin splittings. Strikingly, the presently discovered SEPCSS are expected to exist in the large family of materials crystallizing in the 6[over ¯]m2 and 6[over ¯] point groups, including the Ge_{3}Pb_{5}O_{11}, Pb_{7}Br_{2}F_{12}, and Pb_{7}Cl_{2}F_{12} compounds.
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Affiliation(s)
- Hong Jian Zhao
- Physics Department, University of Arkansas, Fayetteville, Arkansas 72701, USA
- Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Hiro Nakamura
- Physics Department, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Rémi Arras
- CEMES, Université de Toulouse, CNRS, UPS, 29 Rue Jeanne Marvig, F-31055 Toulouse, France
| | - Charles Paillard
- Physics Department, University of Arkansas, Fayetteville, Arkansas 72701, USA
- Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
- Laboratoire SPMS, CentraleSuplec/CNRS UMR8580, Université Paris-Saclay, 8-10 Rue Joliot-Curie, 91190 Gif-sur-Yvette, France
| | - Peng Chen
- Physics Department, University of Arkansas, Fayetteville, Arkansas 72701, USA
- Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Julien Gosteau
- CEMES, Université de Toulouse, CNRS, UPS, 29 Rue Jeanne Marvig, F-31055 Toulouse, France
| | - Xu Li
- Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210093, China
| | - Yurong Yang
- Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210093, China
| | - Laurent Bellaiche
- Physics Department, University of Arkansas, Fayetteville, Arkansas 72701, USA
- Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA
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23
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Zhang YC, Jian Y, Yu ZF, Zhang AX, Xue JK. Stability and quantum escape dynamics of spin-orbit-coupled Bose-Einstein condensates in the shallow trap. Phys Rev E 2020; 102:032220. [PMID: 33076041 DOI: 10.1103/physreve.102.032220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 09/04/2020] [Indexed: 11/07/2022]
Abstract
The Bose-Einstein condensates in a finite depth potential well provide an ideal platform to study the quantum escape dynamics. In this paper, the ground state, tunneling, and diffusion dynamics of the spin-orbit coupling (SOC) of Bose-Einstein condensates with two pseudospin components in a shallow trap are studied analytically and numerically. The phase transition between the plane-wave phase and zero-momentum phase of the ground state is obtained. Furthermore, the stability of the ground state is discussed, and the stability diagram in the parameter space is provided. The bound state (in which condensates are stably trapped in the potential well), the quasibound state (in which condensates tunnel through the well), and the unstable state (in which diffusion occurs) are revealed. We find that the finite depth potential well has an important effect on the phase transition of the ground state, and, interestingly, SOC can stabilize the system against the diffusion and manipulate the tunneling and diffusion dynamics. In particular, spatial anisotropic tunneling and diffusion dynamics of the two pseudospin components induced by SOC in quasibound and unstable states are observed. We provide an effective model and method to study and control the quantum tunneling and diffusion dynamics.
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Affiliation(s)
- Yan-Chao Zhang
- College of Physics and Electronics Engineering, Northwest Normal University, Lanzhou 730070, China
| | - Yue Jian
- College of Physics and Electronics Engineering, Northwest Normal University, Lanzhou 730070, China
| | - Zi-Fa Yu
- College of Physics and Electronics Engineering, Northwest Normal University, Lanzhou 730070, China
| | - Ai-Xia Zhang
- College of Physics and Electronics Engineering, Northwest Normal University, Lanzhou 730070, China
| | - Ju-Kui Xue
- College of Physics and Electronics Engineering, Northwest Normal University, Lanzhou 730070, China
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24
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Lu X, Liu H. The topological properties of D +p-wave superconductors in the mixed Rashba/Dresselhaus systems. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:455601. [PMID: 32717734 DOI: 10.1088/1361-648x/aba980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 07/27/2020] [Indexed: 02/28/2024]
Abstract
We investigate the effect of mixing Rashba/Dresselhaus spin-orbit couplings (SOCs) on the topological properties of D + p-wave superconductors. It is known that the nodal D + p-wave Rashba superconductors become gapful under a Zeeman magnetic field. We extend this gap-generation mechanism to mixed Rashba/Dresselhaus systems and find that the induced energy gaps are strongly modified by the Dresselhaus component in the second quadrant of the Brillion zone (BZ). We further calculate the Chern number numerically and obtain the topological phase diagram. It is shown that the Dresselhaus SOCs have a negative effect on the topological properties; the topological nontrivial region withC= -4 in the phase diagram shrinks as the amplitude of the Dresselhaus component increases. In the Dresselhaus-dominated regime, the contributions of gapped nodes from different quadrants of the BZ cancel each other, resulting in zero Chern number in most of the phase diagram. The numerical results are well explained by an approximate analytical formula for Chern number.
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Affiliation(s)
- Xiancong Lu
- Department of Physics, Xiamen University, Xiamen 361005, People's Republic of China
| | - Hongxu Liu
- Department of Physics, Xiamen University, Xiamen 361005, People's Republic of China
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25
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Liu X, Tang N, Zhang S, Zhang X, Guan H, Zhang Y, Qian X, Ji Y, Ge W, Shen B. Effective Manipulation of Spin Dynamics by Polarization Electric Field in InGaN/GaN Quantum Wells at Room Temperature. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:1903400. [PMID: 32670748 PMCID: PMC7341096 DOI: 10.1002/advs.201903400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 05/07/2020] [Indexed: 06/11/2023]
Abstract
III-nitride wide bandgap semiconductors are favorable materials for developing room temperature spintronic devices. The effective manipulation of spin dynamics is a critical request to realize spin field-effect transistor (FET). In this work, the dependence of the spin relaxation time on external strain-induced polarization electric field is investigated in InGaN/GaN multiple quantum wells (MQWs) by time-resolved Kerr rotation spectroscopy. Owing to the almost canceled two different spin-orbit coupling (SOC), the spin relaxation time as long as 311 ps in the MQWs is obtained at room temperature, being much longer than that in bulk GaN. Furthermore, upon applying an external uniaxial strain, the spin relaxation time decreases sensitively, which originates from the breaking of the SU(2) symmetry. The extracted ratio of the SOC coefficients shows a linear dependence on the external strain, confirming the essential role of the polarization electric field. This effective manipulation of the spin relaxation time sheds light on GaN-based nonballistic spin FET working at room temperature.
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Affiliation(s)
- Xingchen Liu
- State Key Laboratory of Artificial Microstructure and Mesoscopic PhysicsSchool of PhysicsPeking UniversityBeijing100871China
| | - Ning Tang
- State Key Laboratory of Artificial Microstructure and Mesoscopic PhysicsSchool of PhysicsPeking UniversityBeijing100871China
- Frontiers Science Center for Nano‐optoelectronics & Collaborative Innovation Center of Quantum MatterPeking UniversityBeijing100871China
| | - Shixiong Zhang
- State Key Laboratory of Artificial Microstructure and Mesoscopic PhysicsSchool of PhysicsPeking UniversityBeijing100871China
| | - Xiaoyue Zhang
- State Key Laboratory of Artificial Microstructure and Mesoscopic PhysicsSchool of PhysicsPeking UniversityBeijing100871China
| | - Hongming Guan
- State Key Laboratory of Artificial Microstructure and Mesoscopic PhysicsSchool of PhysicsPeking UniversityBeijing100871China
| | - Yunfan Zhang
- State Key Laboratory of Artificial Microstructure and Mesoscopic PhysicsSchool of PhysicsPeking UniversityBeijing100871China
| | - Xuan Qian
- State Key Laboratory for Superlattices and MicrostructuresInstitute of SemiconductorsChinese Academy of SciencesBeijing100083China
- College of Materials Science and Opto‐Electronic TechnologyCollege of Physical SciencesUniversity of Chinese Academy of SciencesBeijing100049China
| | - Yang Ji
- State Key Laboratory for Superlattices and MicrostructuresInstitute of SemiconductorsChinese Academy of SciencesBeijing100083China
- College of Materials Science and Opto‐Electronic TechnologyCollege of Physical SciencesUniversity of Chinese Academy of SciencesBeijing100049China
| | - Weikun Ge
- State Key Laboratory of Artificial Microstructure and Mesoscopic PhysicsSchool of PhysicsPeking UniversityBeijing100871China
| | - Bo Shen
- State Key Laboratory of Artificial Microstructure and Mesoscopic PhysicsSchool of PhysicsPeking UniversityBeijing100871China
- Frontiers Science Center for Nano‐optoelectronics & Collaborative Innovation Center of Quantum MatterPeking UniversityBeijing100871China
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26
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Liu K, Luo W, Ji J, Barone P, Picozzi S, Xiang H. Band splitting with vanishing spin polarizations in noncentrosymmetric crystals. Nat Commun 2019; 10:5144. [PMID: 31723139 PMCID: PMC6854082 DOI: 10.1038/s41467-019-13197-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 10/25/2019] [Indexed: 11/10/2022] Open
Abstract
The Dresselhaus and Rashba effects are well-known phenomena in solid-state physics, in which spin–orbit coupling splits spin-up and spin-down energy bands of nonmagnetic non-centrosymmetric crystals. Here, we discuss a phenomenon we dub band splitting with vanishing spin polarizations (BSVSP), in which, as usual, spin-orbit coupling splits the energy bands in nonmagnetic non-centrosymmetric systems. Surprisingly, however, both split bands show no net spin polarization along certain high-symmetry lines in the Brillouin zone. In order to rationalize this phenomenon, we propose a classification of point groups into pseudo-polar and non-pseudo-polar groups. By means of first-principles simulations, we demonstrate that BSVSP can take place in both symmorphic (e.g., bulk GaAs) and non-symmorphic systems (e.g., two dimensional ferroelectric SnTe). Furthermore, we identify a linear magnetoelectric coupling in reciprocal space, which could be employed to tune the spin polarization with an external electric field. The BSVSP effect and its manipulation could therefore form the basis for future spintronic devices. Spin-orbit couplings enable the electrical manipulation of spin degrees of freedom and so have a central role in spintronic devices. Here, the authors identify an unconventional spin-orbit effect in high-symmetry situations that leads to a linear magnetoelectric coupling in reciprocal space.
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Affiliation(s)
- Kai Liu
- Key Laboratory of Computational Physical Sciences (Ministry of Education), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai, 200433, China.,Collaborative Innovation Center of Advanced Microstructures, Nanjing, 210093, China
| | - Wei Luo
- Key Laboratory of Computational Physical Sciences (Ministry of Education), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai, 200433, China.,Collaborative Innovation Center of Advanced Microstructures, Nanjing, 210093, China
| | - Junyi Ji
- Key Laboratory of Computational Physical Sciences (Ministry of Education), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai, 200433, China.,Collaborative Innovation Center of Advanced Microstructures, Nanjing, 210093, China
| | - Paolo Barone
- Consiglio Nazionale delle Ricerche CNR-SPIN Via dei Vestini 31, 66100, Chieti, Italy
| | - Silvia Picozzi
- Consiglio Nazionale delle Ricerche CNR-SPIN Via dei Vestini 31, 66100, Chieti, Italy.
| | - Hongjun Xiang
- Key Laboratory of Computational Physical Sciences (Ministry of Education), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai, 200433, China. .,Collaborative Innovation Center of Advanced Microstructures, Nanjing, 210093, China.
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27
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Rechcińska K, Król M, Mazur R, Morawiak P, Mirek R, Łempicka K, Bardyszewski W, Matuszewski M, Kula P, Piecek W, Lagoudakis PG, Piętka B, Szczytko J. Engineering spin-orbit synthetic Hamiltonians in liquid-crystal optical cavities. Science 2019; 366:727-730. [DOI: 10.1126/science.aay4182] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 10/15/2019] [Indexed: 11/02/2022]
Abstract
Spin-orbit interactions lead to distinctive functionalities in photonic systems. They exploit the analogy between the quantum mechanical description of a complex electronic spin-orbit system and synthetic Hamiltonians derived for the propagation of electromagnetic waves in dedicated spatial structures. We realize an artificial Rashba-Dresselhaus spin-orbit interaction in a liquid crystal–filled optical cavity. Three-dimensional tomography in energy-momentum space enabled us to directly evidence the spin-split photon mode in the presence of an artificial spin-orbit coupling. The effect is observed when two orthogonal linear polarized modes of opposite parity are brought near resonance. Engineering of spin-orbit synthetic Hamiltonians in optical cavities opens the door to photonic emulators of quantum Hamiltonians with internal degrees of freedom.
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Affiliation(s)
- Katarzyna Rechcińska
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Mateusz Król
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Rafał Mazur
- Institute of Applied Physics, Military University of Technology, ul. gen. S. Kaliskiego 2, 00-908 Warsaw, Poland
| | - Przemysław Morawiak
- Institute of Applied Physics, Military University of Technology, ul. gen. S. Kaliskiego 2, 00-908 Warsaw, Poland
| | - Rafał Mirek
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Karolina Łempicka
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Witold Bardyszewski
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Michał Matuszewski
- Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw, Poland
| | - Przemysław Kula
- Institute of Chemistry, Military University of Technology, ul. gen. S. Kaliskiego 2, 00-908 Warsaw, Poland
| | - Wiktor Piecek
- Institute of Applied Physics, Military University of Technology, ul. gen. S. Kaliskiego 2, 00-908 Warsaw, Poland
| | - Pavlos G. Lagoudakis
- Skolkovo Institute of Science and Technology, Skolkovo 143025, Russian Federation
- Department of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, UK
| | - Barbara Piętka
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Jacek Szczytko
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
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28
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Kroeze RM, Guo Y, Lev BL. Dynamical Spin-Orbit Coupling of a Quantum Gas. PHYSICAL REVIEW LETTERS 2019; 123:160404. [PMID: 31702345 DOI: 10.1103/physrevlett.123.160404] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Indexed: 06/10/2023]
Abstract
We realize the dynamical 1D spin-orbit coupling (SOC) of a Bose-Einstein condensate confined within an optical cavity. The SOC emerges through spin-correlated momentum impulses delivered to the atoms via Raman transitions. These are effected by classical pump fields acting in concert with the quantum dynamical cavity field. Above a critical pump power, the Raman coupling emerges as the atoms superradiantly populate the cavity mode with photons. Concomitantly, these photons cause a backaction onto the atoms, forcing them to order their spin-spatial state. This SOC-inducing superradiant Dicke phase transition results in a spinor-helix polariton condensate. We observe emergent SOC through spin-resolved atomic momentum imaging and temporal heterodyne measurement of the cavity-field emission. Dynamical SOC in quantum gas cavity QED, and the extension to dynamical gauge fields, may enable the creation of Meissner-like effects, topological superfluids, and exotic quantum Hall states in coupled light-matter systems.
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Affiliation(s)
- Ronen M Kroeze
- Department of Physics, Stanford University, Stanford, California 94305, USA
- E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305, USA
| | - Yudan Guo
- Department of Physics, Stanford University, Stanford, California 94305, USA
- E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305, USA
| | - Benjamin L Lev
- Department of Physics, Stanford University, Stanford, California 94305, USA
- E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
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29
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Rashba-like spin splitting along three momentum directions in trigonal layered PtBi 2. Nat Commun 2019; 10:4765. [PMID: 31628366 PMCID: PMC6802102 DOI: 10.1038/s41467-019-12805-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 09/27/2019] [Indexed: 11/08/2022] Open
Abstract
Spin-orbit coupling (SOC) has gained much attention for its rich physical phenomena and highly promising applications in spintronic devices. The Rashba-type SOC in systems with inversion symmetry breaking is particularly attractive for spintronics applications since it allows for flexible manipulation of spin current by external electric fields. Here, we report the discovery of a giant anisotropic Rashba-like spin splitting along three momentum directions (3D Rashba-like spin splitting) with a helical spin polarization around the M points in the Brillouin zone of trigonal layered PtBi2. Due to its inversion asymmetry and reduced symmetry at the M point, Rashba-type as well as Dresselhaus-type SOC cooperatively yield a 3D spin splitting with αR ≈ 4.36 eV Å in PtBi2. The experimental realization of 3D Rashba-like spin splitting not only has fundamental interests but also paves the way to the future exploration of a new class of material with unprecedented functionalities for spintronics applications. Rashba type spin splitting – relevant for spintronics applications - is driven by inversion symmetry breaking but could so far not be realized in all momentum directions in a crystal. Here, the authors report on PtBi2 that exhibits Rashba spin splitting in all three momentum directions.
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30
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Li X, Zhang S, Huang H, Hu L, Liu F, Wang Q. Unidirectional Spin-Orbit Interaction Induced by the Line Defect in Monolayer Transition Metal Dichalcogenides for High-Performance Devices. NANO LETTERS 2019; 19:6005-6012. [PMID: 31386373 DOI: 10.1021/acs.nanolett.9b01812] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Spin-orbit (SO) interaction is an indispensable element in the field of spintronics for effectively manipulating the spin of carriers. However, in crystalline solids, the momentum-dependent SO effective magnetic field generally results in spin randomization by a process known as the Dyakonov-Perel spin relaxation, leading to the loss of spin information. To overcome this obstacle, the persistent spin helix (PSH) state with a unidirectional SO field was proposed but difficult to achieve in real materials. Here, on the basis of first-principles calculations and tight-binding model analysis, we report for the first time a unidirectional SO field in monolayer transition metal dichalcogenides (TMDs, MX2, M = Mo, W; and X = S, Se) induced by two parallel chalcogen vacancy lines. By changing the relative positions of the two vacancy lines, the direction of the SO field can be tuned from x to y. Moreover, using k·p perturbation theory and group theory analysis, we demonstrate that the emerging unidirectional SO field is subject to both the structural symmetry and 1D nature of such defects engineered in 2D TMDs. In particular, through transport calculations, we confirm that the predicted SO states carry highly coherent spin current. Our findings shed new light on creating PSH states for high-performance spintronic devices.
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Affiliation(s)
- Xiaoyin Li
- Center for Applied Physics and Technology, Department of Materials Science and Engineering, HEDPS, College of Engineering , Peking University , Beijing 100871 , China
- Department of Materials Science and Engineering , University of Utah , Salt Lake City , Utah 84112 , United States
| | - Shunhong Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at Microscale , University of Science and Technology of China , Hefei , Anhui 230026 , China
- Department of Materials Science and Engineering , University of Utah , Salt Lake City , Utah 84112 , United States
| | - Huaqing Huang
- Department of Materials Science and Engineering , University of Utah , Salt Lake City , Utah 84112 , United States
| | - Lin Hu
- Department of Materials Science and Engineering , University of Utah , Salt Lake City , Utah 84112 , United States
- Beijing Computational Science Research Center , Beijing 100193 , China
| | - Feng Liu
- Department of Materials Science and Engineering , University of Utah , Salt Lake City , Utah 84112 , United States
| | - Qian Wang
- Center for Applied Physics and Technology, Department of Materials Science and Engineering, HEDPS, College of Engineering , Peking University , Beijing 100871 , China
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31
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Fujita T, Morimoto K, Kiyama H, Allison G, Larsson M, Ludwig A, Valentin SR, Wieck AD, Oiwa A, Tarucha S. Angular momentum transfer from photon polarization to an electron spin in a gate-defined quantum dot. Nat Commun 2019; 10:2991. [PMID: 31311919 PMCID: PMC6635371 DOI: 10.1038/s41467-019-10939-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 06/03/2019] [Indexed: 11/18/2022] Open
Abstract
Gate-defined quantum dots (QDs) are such a highly-tunable quantum system in which single spins can be electrically coupled, manipulated, and measured. However, the spins in gate-defined QDs are lacking its interface to free-space photons. Here, we verify that a circularly-polarized single photon can excite a single electron spin via the transfer of angular momentum, measured using Pauli spin blockade (PSB) in a double QD. We monitor the inter-dot charge tunneling which only occur when the photo-electron spin in one QD is anti-parallel to the electron spin in the other. This allows us to detect single photo-electrons in the spin-up/down basis using PSB. The photon polarization dependence of the excited spin state was finally confirmed for the heavy-hole exciton excitation. The angular momentum transfer observed here is a fundamental step providing a route to instant injection of spins, distributing single spin information, and possibly towards extending quantum communication. Gate-defined quantum dots offer a way to engineer electrically controllable quantum systems with potential for information processing. Here, the authors transfer angular momentum from the polarization of a single photon to the spin of a single electron in a gate-defined double quantum dot.
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Affiliation(s)
- Takafumi Fujita
- Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan. .,The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan.
| | - Kazuhiro Morimoto
- Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Haruki Kiyama
- Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.,The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan
| | - Giles Allison
- Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.,Center for Emergent Matter Science (CEMS), RIKEN, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan
| | - Marcus Larsson
- Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Arne Ludwig
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, Gebäude NB, D-44780, Bochum, Germany
| | - Sascha R Valentin
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, Gebäude NB, D-44780, Bochum, Germany
| | - Andreas D Wieck
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, Gebäude NB, D-44780, Bochum, Germany
| | - Akira Oiwa
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan.,Center for Spintronics Research Network (CSRN), Graduate School of Engineering Science, Osaka University, Osaka, 565-0871, Japan.,Quantum Information and Quantum Biology Division, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Osaka, 565-0871, Japan
| | - Seigo Tarucha
- Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.,Center for Emergent Matter Science (CEMS), RIKEN, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan
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32
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Silva JF, Vernek E. Modified exchange interaction between magnetic impurities in spin-orbit coupled quantum wires. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:135802. [PMID: 30665202 DOI: 10.1088/1361-648x/ab0076] [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
Indirect exchange interaction between magnetic impurities in one dimensional systems is a matter of long discussions since Kittel has established that in the asymptotic limit it decays as the inverse of distance x between the impurities. In this work we investigate this problem in a quantum wire with Rashba spin-orbit coupling (SOC). By employing a second order perturbation theory we find that one additional oscillatory term appears in each of the Ruderman-Kittel-Kasuya-Yosida (RKKY), the Dzaloshinkii-Moryia and the Ising couplings. Remarkably, these extra terms resulting from the spin precession of the conduction electrons induced by the SOC do not decay as in the usual RKKY interaction. We show that these extra oscillations arise from the finite momenta band splitting induced by the spin-orbit coupling that modifies the spin-flip scatterings occurring at the Fermi energy. Our findings open up a new perspective in the long-distance magnetic interactions in solid state systems.
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Affiliation(s)
- Joelson F Silva
- Instituto de Física, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais 38400-902, Brazil
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33
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Tang WH, Zhang S. Quantum Spin Dynamics in a Normal Bose Gas with Spin-Orbit Coupling. PHYSICAL REVIEW LETTERS 2018; 121:120403. [PMID: 30296115 DOI: 10.1103/physrevlett.121.120403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Indexed: 06/08/2023]
Abstract
In this Letter, we investigate spin dynamics of a two-component Bose gas with spin-orbit coupling realized in cold atom experiments. We derive coupled hydrodynamic equations for number and spin densities as well as their associated currents. Specializing to the quasi-one-dimensional situation, we obtain analytic solutions of the spin helix structure and its dynamics in both adiabatic and diabatic regimes. In the adiabatic regime, the transverse spin decays parabolically in the short-time limit and exponentially in the long-time limit, depending on initial polarization. In contrast, in the diabatic regime, transverse spin density and current oscillate in a way similar to the charge-current oscillation in an undamped LC circuit. The effects of Rabi coupling on the short-time spin dynamics is also discussed. Finally, using realistic experimental parameters for ^{87}Rb, we show that the timescales for spin dynamics is of the order of milliseconds to a few seconds and can be observed experimentally.
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Affiliation(s)
- Wai Ho Tang
- Department of Physics and Center of Theoretical and Computational Physics, The University of Hong Kong, Hong Kong, China
| | - Shizhong Zhang
- Department of Physics and Center of Theoretical and Computational Physics, The University of Hong Kong, Hong Kong, China
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34
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Bencivenga F, Calvi A, Capotondi F, Cucini R, Mincigrucci R, Simoncig A, Manfredda M, Pedersoli E, Principi E, Dallari F, Duncan RA, Izzo MG, Knopp G, Maznev AA, Monaco G, Di Mitri S, Gessini A, Giannessi L, Mahne N, Nikolov IP, Passuello R, Raimondi L, Zangrando M, Masciovecchio C. Four-wave-mixing experiments with seeded free electron lasers. Faraday Discuss 2018; 194:283-303. [PMID: 27711831 DOI: 10.1039/c6fd00089d] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The development of free electron laser (FEL) sources has provided an unprecedented bridge between the scientific communities working with ultrafast lasers and extreme ultraviolet (XUV) and X-ray radiation. Indeed, in recent years an increasing number of FEL-based applications have exploited methods and concepts typical of advanced optical approaches. In this context, we recently used a seeded FEL to demonstrate a four-wave-mixing (FWM) process stimulated by coherent XUV radiation, namely the XUV transient grating (X-TG). We hereby report on X-TG measurements carried out on a sample of silicon nitride (Si3N4). The recorded data bears evidence for two distinct signal decay mechanisms: one occurring on a sub-ps timescale and one following slower dynamics extending throughout and beyond the probed timescale range (100 ps). The latter is compatible with a slower relaxation (time decay > ns), that may be interpreted as the signature of thermal diffusion modes. From the peak intensity of the X-TG signal we could estimate a value of the effective third-order susceptibility which is substantially larger than that found in SiO2, so far the only sample with available X-TG data. Furthermore, the intensity of the time-coincidence peak shows a linear dependence on the intensity of the three input beams, indicating that the measurements were performed in the weak field regime. However, the timescale of the ultrafast relaxation exhibits a dependence on the intensity of the XUV radiation. We interpreted the observed behaviour as the generation of a population grating of free-electrons and holes that, on the sub-ps timescale, relaxes to generate lattice excitations. The background free detection inherent to the X-TG approach allowed the determination of FEL-induced electron dynamics with a sensitivity largely exceeding that of transient reflectivity and transmissivity measurements, usually employed for this purpose.
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Affiliation(s)
- F Bencivenga
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in AREA Science Park, 34149 Basovizza, Italy.
| | - A Calvi
- Department of Physics, University of Trieste, Via A.Valerio 2, 34127 Trieste, Italy
| | - F Capotondi
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in AREA Science Park, 34149 Basovizza, Italy.
| | - R Cucini
- IOM-CNR, Strada Statale 14-km 163.5, 34149 Basovizza, Trieste, Italy
| | - R Mincigrucci
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in AREA Science Park, 34149 Basovizza, Italy.
| | - A Simoncig
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in AREA Science Park, 34149 Basovizza, Italy.
| | - M Manfredda
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in AREA Science Park, 34149 Basovizza, Italy.
| | - E Pedersoli
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in AREA Science Park, 34149 Basovizza, Italy.
| | - E Principi
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in AREA Science Park, 34149 Basovizza, Italy.
| | - F Dallari
- Department of Physics, University of Trento, Via Sommarive 14, Povo, TN, Italy
| | - R A Duncan
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, USA
| | - M G Izzo
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in AREA Science Park, 34149 Basovizza, Italy.
| | - G Knopp
- Paul Scherrer Institute, Villigen 5232, Switzerland
| | - A A Maznev
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, USA
| | - G Monaco
- Department of Physics, University of Trento, Via Sommarive 14, Povo, TN, Italy
| | - S Di Mitri
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in AREA Science Park, 34149 Basovizza, Italy.
| | - A Gessini
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in AREA Science Park, 34149 Basovizza, Italy.
| | - L Giannessi
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in AREA Science Park, 34149 Basovizza, Italy. and ENEA CR Frascati, Via E. Fermi 45, 00044 Frascati, Rome, Italy
| | - N Mahne
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in AREA Science Park, 34149 Basovizza, Italy.
| | - I P Nikolov
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in AREA Science Park, 34149 Basovizza, Italy.
| | - R Passuello
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in AREA Science Park, 34149 Basovizza, Italy.
| | - L Raimondi
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in AREA Science Park, 34149 Basovizza, Italy.
| | - M Zangrando
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in AREA Science Park, 34149 Basovizza, Italy. and IOM-CNR, Strada Statale 14-km 163.5, 34149 Basovizza, Trieste, Italy
| | - C Masciovecchio
- Elettra-Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in AREA Science Park, 34149 Basovizza, Italy.
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35
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Tao LL, Tsymbal EY. Persistent spin texture enforced by symmetry. Nat Commun 2018; 9:2763. [PMID: 30018283 PMCID: PMC6050308 DOI: 10.1038/s41467-018-05137-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 06/14/2018] [Indexed: 12/03/2022] Open
Abstract
Persistent spin texture (PST) is the property of some materials to maintain a uniform spin configuration in the momentum space. This property has been predicted to support an extraordinarily long spin lifetime of carriers promising for spintronics applications. Here, we predict that there exists a class of noncentrosymmetric bulk materials, where the PST is enforced by the nonsymmorphic space group symmetry of the crystal. Around certain high symmetry points in the Brillouin zone, the sublattice degrees of freedom impose a constraint on the effective spin-orbit field, which orientation remains independent of the momentum and thus maintains the PST. We illustrate this behavior using density-functional theory calculations for a handful of promising candidates accessible experimentally. Among them is the ferroelectric oxide BiInO3-a wide band gap semiconductor which sustains a PST around the conduction band minimum. Our results broaden the range of materials that can be employed in spintronics.
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Affiliation(s)
- L L Tao
- Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE, 68588, USA
| | - Evgeny Y Tsymbal
- Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE, 68588, USA.
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36
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Karimi S, Ullrich CA, D'Amico I, Perez F. Spin-helix Larmor mode. Sci Rep 2018; 8:3470. [PMID: 29472630 PMCID: PMC5823951 DOI: 10.1038/s41598-018-21818-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 02/01/2018] [Indexed: 11/29/2022] Open
Abstract
A two-dimensional electron gas (2DEG) with equal-strength Rashba and Dresselhaus spin-orbit coupling sustains persistent helical spin-wave states, which have remarkably long lifetimes. In the presence of an in-plane magnetic field, there exist single-particle excitations that have the character of propagating helical spin waves. For magnon-like collective excitations, the spin-helix texture reemerges as a robust feature, giving rise to a decoupling of spin-orbit and electronic many-body effects. We prove that the resulting spin-flip wave dispersion is the same as in a magnetized 2DEG without spin-orbit coupling, apart from a shift by the spin-helix wave vector. The precessional mode about the persistent spin-helix state is shown to have an energy given by the bare Zeeman splitting, in analogy with Larmor’s theorem. We also discuss ways to observe the spin-helix Larmor mode experimentally.
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Affiliation(s)
- Shahrzad Karimi
- Department of Physics and Astronomy, University of Missouri, Columbia, MO, 65211, USA
| | - Carsten A Ullrich
- Department of Physics and Astronomy, University of Missouri, Columbia, MO, 65211, USA.
| | - Irene D'Amico
- Department of Physics, University of York, York, YO10 5DD, United Kingdom
| | - Florent Perez
- Institut des Nanosciences de Paris, CNRS/Université Paris VI, Paris, 75005, France
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37
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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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38
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Mahmood F, Alpichshev Z, Lee YH, Kong J, Gedik N. Observation of Exciton-Exciton Interaction Mediated Valley Depolarization in Monolayer MoSe 2. NANO LETTERS 2018; 18:223-228. [PMID: 29239177 DOI: 10.1021/acs.nanolett.7b03953] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The valley pseudospin in monolayer transition metal dichalcogenides (TMDs) has been proposed as a new way to manipulate information in various optoelectronic devices. This relies on a large valley polarization that remains stable over long time scales (hundreds of nanoseconds). However, time-resolved measurements report valley lifetimes of only a few picoseconds. This has been attributed to mechanisms such as phonon-mediated intervalley scattering and a precession of the valley pseudospin through electron-hole exchange. Here we use transient spin grating to directly measure the valley depolarization lifetime in monolayer MoSe2. We find a fast valley decay rate that scales linearly with the excitation density at different temperatures. This establishes the presence of strong exciton-exciton Coulomb exchange interactions enhancing the valley depolarization. Our work highlights the microscopic processes inhibiting the efficient use of the exciton valley pseudospin in monolayer TMDs.
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Affiliation(s)
- Fahad Mahmood
- Department of Physics, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Zhanybek Alpichshev
- Department of Physics, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Yi-Hsien Lee
- Materials Science and Engineering, National Tsing-Hua University , Hsinchu 30013, Taiwan
| | - Jing Kong
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Nuh Gedik
- Department of Physics, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
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39
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Kunihashi Y, Sanada H, Tanaka Y, Gotoh H, Onomitsu K, Nakagawara K, Kohda M, Nitta J, Sogawa T. Drift-Induced Enhancement of Cubic Dresselhaus Spin-Orbit Interaction in a Two-Dimensional Electron Gas. PHYSICAL REVIEW LETTERS 2017; 119:187703. [PMID: 29219564 DOI: 10.1103/physrevlett.119.187703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Indexed: 06/07/2023]
Abstract
We investigated the effect of an in-plane electric field on drifting spins in a GaAs quantum well. Kerr rotation images of the drifting spins revealed that the spin precession wavelength increases with increasing drift velocity regardless of the transport direction. A model developed for drifting spins with a heated electron distribution suggests that the in-plane electric field enhances the effective magnetic field component originating from the cubic Dresselhaus spin-orbit interaction.
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Affiliation(s)
- Yoji Kunihashi
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - Haruki Sanada
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - Yusuke Tanaka
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - Hideki Gotoh
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - Koji Onomitsu
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
| | - Keita Nakagawara
- Department of Materials Science, Tohoku University, 6-6-02 Aramaki-Aza, Aoba-ku, Sendai 980-8579, Japan
| | - Makoto Kohda
- Department of Materials Science, Tohoku University, 6-6-02 Aramaki-Aza, Aoba-ku, Sendai 980-8579, Japan
| | - Junsaku Nitta
- Department of Materials Science, Tohoku University, 6-6-02 Aramaki-Aza, Aoba-ku, Sendai 980-8579, Japan
| | - Tetsuomi Sogawa
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
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40
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Kolasiński K, Sellier H, Szafran B. Extraction of the Rashba spin-orbit coupling constant from scanning gate microscopy conductance maps for quantum point contacts. Sci Rep 2017; 7:14935. [PMID: 29097691 PMCID: PMC5668439 DOI: 10.1038/s41598-017-14380-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 10/09/2017] [Indexed: 11/09/2022] Open
Abstract
We study the possibility for the extraction of the Rashba spin-orbit coupling constant for a two-dimensional electron gas with the conductance microscopy technique. Due to the interplay between the effective magnetic field due to the Rashba spin-orbit coupling and the external magnetic field applied within the plane of confinement, the electron backscattering induced by a charged tip of an atomic force microscope located above the sample leads to the spin precession and spin mixing of the incident and reflected electron waves between the QPC and the tip-induced 2DEG depletion region. This mixing leads to a characteristic angle-dependent beating pattern visible in the conductance maps. We show that the structure of the Fermi level, bearing signatures of the spin-orbit coupling, can be extracted from the Fourier transform of the interference fringes in the conductance maps as a function of the magnetic field direction. We propose a simple analytical model which can be used to fit the experimental data in order to obtain the spin-orbit coupling constant.
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Affiliation(s)
- K Kolasiński
- AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059, Kraków, Poland
| | - H Sellier
- Université Grenoble Alpes, CNRS, Institut Néel, 38000, Grenoble, France
| | - B Szafran
- AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059, Kraków, Poland.
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41
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Hofmann A, Maisi VF, Krähenmann T, Reichl C, Wegscheider W, Ensslin K, Ihn T. Anisotropy and Suppression of Spin-Orbit Interaction in a GaAs Double Quantum Dot. PHYSICAL REVIEW LETTERS 2017; 119:176807. [PMID: 29219432 DOI: 10.1103/physrevlett.119.176807] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Indexed: 06/07/2023]
Abstract
The spin-flip tunneling rates are measured in GaAs-based double quantum dots by time-resolved charge detection. Such processes occur in the Pauli spin blockade regime with two electrons occupying the double quantum dot. Ways are presented for tuning the spin-flip tunneling rate, which on the one hand gives access to measuring the Rashba and Dresselhaus spin-orbit coefficients. On the other hand, they make it possible to turn on and off the effect of spin-orbit interaction with a high on/off ratio. The tuning is accomplished by choosing the alignment of the tunneling direction with respect to the crystallographic axes, as well as by choosing the orientation of the external magnetic field with respect to the spin-orbit magnetic field. Spin lifetimes of 10 s are achieved at a tunneling rate close to 1 kHz.
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Affiliation(s)
- A Hofmann
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - V F Maisi
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - T Krähenmann
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - C Reichl
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - W Wegscheider
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - K Ensslin
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - T Ihn
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
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42
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Srinivasan A, Miserev DS, Hudson KL, Klochan O, Muraki K, Hirayama Y, Reuter D, Wieck AD, Sushkov OP, Hamilton AR. Detection and Control of Spin-Orbit Interactions in a GaAs Hole Quantum Point Contact. PHYSICAL REVIEW LETTERS 2017; 118:146801. [PMID: 28430471 DOI: 10.1103/physrevlett.118.146801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Indexed: 06/07/2023]
Abstract
We investigate the relationship between the Zeeman interaction and the inversion-asymmetry-induced spin-orbit interactions (Rashba and Dresselhaus SOIs) in GaAs hole quantum point contacts. The presence of a strong SOI results in the crossing and anticrossing of adjacent spin-split hole subbands in a magnetic field. We demonstrate theoretically and experimentally that the anticrossing energy gap depends on the interplay between the SOI terms and the highly anisotropic hole g tensor and that this interplay can be tuned by selecting the crystal axis along which the current and magnetic field are aligned. Our results constitute the independent detection and control of the Dresselhaus and Rashba SOIs in hole systems, which could be of importance for spintronics and quantum information applications.
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Affiliation(s)
- A Srinivasan
- School of Physics, University of New South Wales, Sydney New South Wales 2052, Australia
| | - D S Miserev
- School of Physics, University of New South Wales, Sydney New South Wales 2052, Australia
| | - K L Hudson
- School of Physics, University of New South Wales, Sydney New South Wales 2052, Australia
| | - O Klochan
- School of Physics, University of New South Wales, Sydney New South Wales 2052, Australia
| | - K Muraki
- NTT Basic Research Laboratories, NTT corporation, Atsugi-shi, Kanagawa 243-0198, Japan
| | - Y Hirayama
- Graduate School of Science, Tohoku University, Sendai-shi, Miyagi 980-8578, Japan
| | - D Reuter
- Fachbereich Physik, University of Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
| | - A D Wieck
- Angewandte Festkorperphysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany
| | - O P Sushkov
- School of Physics, University of New South Wales, Sydney New South Wales 2052, Australia
| | - A R Hamilton
- School of Physics, University of New South Wales, Sydney New South Wales 2052, Australia
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43
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Popkov V, Schütz GM. Solution of the Lindblad equation for spin helix states. Phys Rev E 2017; 95:042128. [PMID: 28505738 DOI: 10.1103/physreve.95.042128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Indexed: 06/07/2023]
Abstract
Using Lindblad dynamics we study quantum spin systems with dissipative boundary dynamics that generate a stationary nonequilibrium state with a nonvanishing spin current that is locally conserved except at the boundaries. We demonstrate that with suitably chosen boundary target states one can solve the many-body Lindblad equation exactly in any dimension. As solution we obtain pure states at any finite value of the dissipation strength and any system size. They are characterized by a helical stationary magnetization profile and a ballistic spin current which is independent of system size, even when the quantum spin system is not integrable. These results are derived in explicit form for the one-dimensional spin-1/2 Heisenberg chain and its higher-spin generalizations, which include the integrable spin-1 Zamolodchikov-Fateev model and the biquadratic Heisenberg chain.
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Affiliation(s)
- V Popkov
- Helmholtz-Institut für Strahlen-und Kernphysik, Universität Bonn, Nussallee 14-16, 53119 Bonn, Germany
| | - G M Schütz
- Institute of Complex Systems II, Forschungszentrum Jülich, 52425 Jülich, Germany
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44
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Orso G. Anderson Transition of Cold Atoms with Synthetic Spin-Orbit Coupling in Two-Dimensional Speckle Potentials. PHYSICAL REVIEW LETTERS 2017; 118:105301. [PMID: 28339248 DOI: 10.1103/physrevlett.118.105301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Indexed: 06/06/2023]
Abstract
We investigate the metal-insulator transition occurring in two-dimensional (2D) systems of noninteracting atoms in the presence of artificial spin-orbit interactions and a spatially correlated disorder generated by laser speckles. Based on a high order discretization scheme, we calculate the precise position of the mobility edge and verify that the transition belongs to the symplectic universality class. We show that the mobility edge depends strongly on the mixing angle between Rashba and Dresselhaus spin-orbit couplings. For equal couplings a non-power-law divergence is found, signaling the crossing to the orthogonal class, where such a 2D transition is forbidden.
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Affiliation(s)
- Giuliano Orso
- Université Paris Diderot, Sorbonne Paris Cité, Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162, 75013 Paris, France
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45
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Strong confinement-induced engineering of the g factor and lifetime of conduction electron spins in Ge quantum wells. Nat Commun 2016; 7:13886. [PMID: 28000670 PMCID: PMC5187588 DOI: 10.1038/ncomms13886] [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: 03/11/2016] [Accepted: 11/09/2016] [Indexed: 11/08/2022] Open
Abstract
Control of electron spin coherence via external fields is fundamental in spintronics. Its implementation demands a host material that accommodates the desirable but contrasting requirements of spin robustness against relaxation mechanisms and sizeable coupling between spin and orbital motion of the carriers. Here, we focus on Ge, which is a prominent candidate for shuttling spin quantum bits into the mainstream Si electronics. So far, however, the intrinsic spin-dependent phenomena of free electrons in conventional Ge/Si heterojunctions have proved to be elusive because of epitaxy constraints and an unfavourable band alignment. We overcome these fundamental limitations by investigating a two-dimensional electron gas in quantum wells of pure Ge grown on Si. These epitaxial systems demonstrate exceptionally long spin lifetimes. In particular, by fine-tuning quantum confinement we demonstrate that the electron Landé g factor can be engineered in our CMOS-compatible architecture over a range previously inaccessible for Si spintronics.
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46
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Kammermeier M, Wenk P, Schliemann J. Control of Spin Helix Symmetry in Semiconductor Quantum Wells by Crystal Orientation. PHYSICAL REVIEW LETTERS 2016; 117:236801. [PMID: 27982661 DOI: 10.1103/physrevlett.117.236801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Indexed: 06/06/2023]
Abstract
We investigate the possibility of spin-preserving symmetries due to the interplay of Rashba and Dresselhaus spin-orbit coupling in n-doped zinc-blende semiconductor quantum wells of general crystal orientation. It is shown that a conserved spin operator can be realized if and only if at least two growth direction Miller indices agree in modulus. The according spin-orbit field has in general both in-plane and out-of-plane components and is always perpendicular to the shift vector of the corresponding persistent spin helix. We also analyze higher-order effects arising from the Dresselhaus term, and the impact of our results on weak (anti)localization corrections.
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Affiliation(s)
- Michael Kammermeier
- Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
| | - Paul Wenk
- Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
| | - John Schliemann
- Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
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47
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Fu J, Penteado PH, Hachiya MO, Loss D, Egues JC. Persistent Skyrmion Lattice of Noninteracting Electrons with Spin-Orbit Coupling. PHYSICAL REVIEW LETTERS 2016; 117:226401. [PMID: 27925749 DOI: 10.1103/physrevlett.117.226401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Indexed: 06/06/2023]
Abstract
A persistent spin helix (PSH) is a robust helical spin-density pattern arising in disordered 2D electron gases with Rashba α and Dresselhaus β spin-orbit (SO) tuned couplings, i.e., α=±β. Here, we investigate the emergence of a persistent Skyrmion lattice (PSL) resulting from the coherent superposition of PSHs along orthogonal directions-crossed PSHs-in wells with two occupied subbands ν=1, 2. For realistic GaAs wells, we show that the Rashba α_{ν} and Dresselhaus β_{ν} couplings can be simultaneously tuned to equal strengths but opposite signs, e.g., α_{1}=β_{1} and α_{2}=-β_{2}. In this regime, and away from band anticrossings, our noninteracting electron gas sustains a topologically nontrivial Skyrmion-lattice spin-density excitation, which inherits the robustness against spin-independent disorder and interactions from its underlying crossed PSHs. We find that the spin relaxation rate due to the interband SO coupling is comparable to that of the cubic Dresselhaus term as a mechanism of the PSL decay. Near anticrossings, the interband-induced spin mixing leads to unusual spin textures along the energy contours beyond those of the Rahsba-Dresselhaus bands. Our PSL opens up the unique possibility of observing topological phenomena, e.g., topological and Skyrmion Hall effects, in ordinary GaAs wells with noninteracting electrons.
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Affiliation(s)
- Jiyong Fu
- Instituto de Física de São Carlos, Universidade de São Paulo, 13560-970 São Carlos, São Paulo, Brazil
| | - Poliana H Penteado
- Instituto de Física de São Carlos, Universidade de São Paulo, 13560-970 São Carlos, São Paulo, Brazil
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - Marco O Hachiya
- Instituto de Física de São Carlos, Universidade de São Paulo, 13560-970 São Carlos, São Paulo, Brazil
| | - Daniel Loss
- Department of Physics, University of Basel, CH-4056 Basel, Switzerland
| | - J Carlos Egues
- Instituto de Física de São Carlos, Universidade de São Paulo, 13560-970 São Carlos, São Paulo, Brazil
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48
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Ciorga M. Electrical spin injection and detection in high mobility 2DEG systems. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:453003. [PMID: 27619530 DOI: 10.1088/0953-8984/28/45/453003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this review paper we present the current status of research related to the topic of electrical spin injection and detection in two-dimensional electron gas (2DEG) systems, formed typically at the interface between two III-V semiconductor compounds. We discuss both theoretical aspects of spin injection in case of ballistic transport as well as give an overview of available reports on spin injection experiments performed on 2DEG structures. In the experimental part we focus particularly on our recent work on all-semiconductor structures with a 2DEG confined at an inverted GaAs/(Al,Ga)As interface and with a ferromagnetic semiconductor (Ga,Mn)As employed as a source of spin-polarized electrons.
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Affiliation(s)
- M Ciorga
- Institute for Experimental and Applied Physics, University of Regensburg, 93040 Regensburg, Germany
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49
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Enhanced spin-orbit coupling in core/shell nanowires. Nat Commun 2016; 7:12413. [PMID: 27491871 PMCID: PMC4980452 DOI: 10.1038/ncomms12413] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 06/30/2016] [Indexed: 12/02/2022] Open
Abstract
The spin–orbit coupling (SOC) in semiconductors is strongly influenced by structural asymmetries, as prominently observed in bulk crystal structures that lack inversion symmetry. Here we study an additional effect on the SOC: the asymmetry induced by the large interface area between a nanowire core and its surrounding shell. Our experiments on purely wurtzite GaAs/AlGaAs core/shell nanowires demonstrate optical spin injection into a single free-standing nanowire and determine the effective electron g-factor of the hexagonal GaAs wurtzite phase. The spin relaxation is highly anisotropic in time-resolved micro-photoluminescence measurements on single nanowires, showing a significant increase of spin relaxation in external magnetic fields. This behaviour is counterintuitive compared with bulk wurtzite crystals. We present a model for the observed electron spin dynamics highlighting the dominant role of the interface-induced SOC in these core/shell nanowires. This enhanced SOC may represent an interesting tuning parameter for the implementation of spin–orbitronic concepts in semiconductor-based structures. Spin-orbit coupling underlies many important spintronic concepts, and is strongly influenced by crystal symmetry. Here, the authors demonstrate a strong enhancement of spin-orbit coupling in core/shell semiconductor nanowires induced by the large interfacial surface areas
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50
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Transient Grating Spectroscopy in Magnetic Thin Films: Simultaneous Detection of Elastic and Magnetic Dynamics. Sci Rep 2016; 6:29143. [PMID: 27377262 PMCID: PMC4932598 DOI: 10.1038/srep29143] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 06/13/2016] [Indexed: 11/24/2022] Open
Abstract
Surface magnetoelastic waves are coupled elastic and magnetic excitations that propagate along the surface of a magnetic material. Ultrafast optical techniques allow for a non-contact excitation and detection scheme while providing the ability to measure both elastic and magnetic components individually. Here we describe a simple setup suitable for excitation and time resolved measurements of high frequency magnetoelastic waves, which is based on the transient grating technique. The elastic dynamics are measured by diffracting a probe laser pulse from the long-wavelength spatially periodic structural deformation. Simultaneously, a magnetooptical measurement, either Faraday or Kerr effect, is sensitive to the out-of-plane magnetization component. The correspondence in the response of the two channels probes the resonant interaction between the two degrees of freedom and reveals their intimate coupling. Unraveling the observed dynamics requires a detailed understanding of the spatio-temporal evolution of temperature, magnetization and thermo-elastic strain in the ferromagnet. Numerical solution of thermal diffusion in two dimensions provides the basis on which to understand the sensitivity in the magnetooptic detection.
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