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Milivojević M. Symmetric spin-orbit interaction in triple quantum dot and minimisation of spin-orbit leakage in CNOT gate. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:085302. [PMID: 29328053 DOI: 10.1088/1361-648x/aaa736] [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
We analyse spin-orbit interaction in triple quantum dots and show that a symmetric spin-orbit Hamiltonian does not follow the standard form used in double quantum dots, as a consequence of the presence of the third dot in the setup. Furthermore, CNOT implementation schemes based on the exchange interaction were studied. It was shown that an antisymmetric Dzyaloshinsky-Moriya term is the dominant source of spin-orbit leakage from the computational space. We present a simple scheme for the minimisation of leakage that can be implemented in cases where interacting spins enclose parallelogram or equilateral triangle loops.
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Affiliation(s)
- Marko Milivojević
- Department of Physics, University of Belgrade, Studentski trg 12-16, 11000 Belgrade, Serbia
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2
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Kepenekian M, Even J. Rashba and Dresselhaus Couplings in Halide Perovskites: Accomplishments and Opportunities for Spintronics and Spin-Orbitronics. J Phys Chem Lett 2017; 8:3362-3370. [PMID: 28661150 DOI: 10.1021/acs.jpclett.7b01015] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
In halide hybrid organic-inorganic perovskites (HOPs), spin-orbit coupling (SOC) presents a well-documented large influence on band structure. However, SOC may also present more exotic effects, such as Rashba and Dresselhaus couplings. In this Perspective, we start by recalling the main features of this effect and what makes HOP materials ideal candidates for the generation and tuning of spin-states. Then, we detail the main spectroscopy techniques able to characterize these effects and their application to HOPs. Finally, we discuss potential applications in spintronics and in spin-orbitronics in those nonmagnetic systems, which would complete the skill set of HOPs and perpetuate their ride on the crest of the wave of popularity started with optoelectronics and photovoltaics.
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Affiliation(s)
- Mikaël Kepenekian
- Institut des Sciences Chimiques de Rennes, UMR 6226, CNRS - Université de Rennes 1, 35700 Rennes, France
| | - Jacky Even
- Fonctions Optiques pour les Technologies de l'Information (FOTON), INSA de Rennes, CNRS, UMR 6082, 35708 Rennes, France
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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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Wang G, Liu BL, Balocchi A, Renucci P, Zhu CR, Amand T, Fontaine C, Marie X. Gate control of the electron spin-diffusion length in semiconductor quantum wells. Nat Commun 2014; 4:2372. [PMID: 24052071 PMCID: PMC3791469 DOI: 10.1038/ncomms3372] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 07/29/2013] [Indexed: 11/10/2022] Open
Abstract
The spin diffusion length is a key parameter to describe the transport properties of spin polarized electrons in solids. Electrical spin injection in semiconductor structures, a major issue in spintronics, critically depends on this spin diffusion length. Gate control of the spin diffusion length could be of great importance for the operation of devices based on the electric field manipulation and transport of electron spin. Here we demonstrate that the spin diffusion length in a GaAs quantum well can be electrically controlled. Through the measurement of the spin diffusion coefficient by spin grating spectroscopy and of the spin relaxation time by time-resolved optical orientation experiments, we show that the diffusion length can be increased by more than 200% with an applied gate voltage of 5 V. These experiments allow at the same time the direct simultaneous measurements of both the Rashba and Dresselhaus spin-orbit splittings.
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Affiliation(s)
- G Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China
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Chen TW. Maximum intrinsic spin-Hall conductivity in two-dimensional systems with k-linear spin-orbit interaction. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:155801. [PMID: 23507831 DOI: 10.1088/0953-8984/25/15/155801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We analytically calculate the intrinsic spin-Hall conductivities (ISHCs) (σ(z)(xy) and σ(z)(yx)) in a clean, two-dimensional system with generic k-linear spin-orbit interaction. The coefficients of the product of the momentum and spin components form a spin-orbit matrix β̃. We find that the determinant of the spin-orbit matrix detβ̃ describes the effective coupling of the spin sz and orbital motion Lz. The decoupling of spin and orbital motion results in a sign change of the ISHC and the band-overlapping phenomenon. Furthermore, we show that the ISHC is in general unsymmetrical (σ(z)(xy) ≠ -σ(z)(yx)), and it is governed by the asymmetric response function Δβ̃, which is the difference in band-splitting along two directions: those of the applied electric field and the spin-Hall current. The obtained non-vanishing asymmetric response function also implies that the ISHC can be larger than e/8π, but has an upper bound value of e/4π. We will show that the unsymmetrical properties of the ISHC can also be deduced from the manifestation of the Berry curvature in the nearly degenerate area. On the other hand, by investigating the equilibrium spin current, we find that detβ̃ determines the field strength of the SU(2) non-Abelian gauge field.
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Affiliation(s)
- Tsung-Wei Chen
- Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan.
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6
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Intronati GA, Tamborenea PI, Weinmann D, Jalabert RA. Spin relaxation near the metal-insulator transition: dominance of the Dresselhaus spin-orbit coupling. PHYSICAL REVIEW LETTERS 2012; 108:016601. [PMID: 22304276 DOI: 10.1103/physrevlett.108.016601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Indexed: 05/31/2023]
Abstract
We identify the Dresselhaus spin-orbit coupling as the source of the dominant spin-relaxation mechanism in the impurity band of a wide class of n-doped zinc blende semiconductors. The Dresselhaus hopping terms are derived and incorporated into a tight-binding model of impurity sites, and they are shown to unexpectedly dominate the spin relaxation, leading to spin-relaxation times in good agreement with experimental values. This conclusion is drawn from two complementary approaches: an analytical diffusive-evolution calculation and a numerical finite-size scaling study of the spin-relaxation time.
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Affiliation(s)
- Guido A Intronati
- Departamento de Física, FCEN, Universidad de Buenos Aires, Ciudad Universitaria, Pab. I, C1428EHA Buenos Aires, Argentina
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7
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Balocchi A, Duong QH, Renucci P, Liu BL, Fontaine C, Amand T, Lagarde D, Marie X. Full electrical control of the electron spin relaxation in GaAs quantum wells. PHYSICAL REVIEW LETTERS 2011; 107:136604. [PMID: 22026883 DOI: 10.1103/physrevlett.107.136604] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Indexed: 05/31/2023]
Abstract
The electron spin dynamics in (111)-oriented GaAs/AlGaAs quantum wells is studied by time-resolved photoluminescence spectroscopy. By applying an external electric field of 50 kV/cm a two-order of magnitude increase of the spin relaxation time can be observed reaching values larger than 30 ns; this is a consequence of the electric field tuning of the spin-orbit conduction band splitting which can almost vanish when the Rashba term compensates exactly the Dresselhaus one. The measurements under a transverse magnetic field demonstrate that the electron spin relaxation time for the three space directions can be tuned simultaneously with the applied electric field.
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Affiliation(s)
- A Balocchi
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, France
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8
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Abstract
Semiconductor spintronicsSpintronics refers commonly to phenomena in which the spin of electrons in a solid state environment plays the determining role. In a more narrow sense spintronics is an emerging research field of electronics: spintronics devices are based on a spin control of electronics, or on an electrical and optical control of spin or magnetism. While metal spintronics has already found its niche in the computer industry—giant magnetoresistance systems are used as hard disk read heads—semiconductor spintronics is yet to demonstrate its full potential. This review presents selected themes of semiconductor spintronics, introducing important concepts in spin transport, spin injection, Silsbee-Johnson spin-charge coupling, and spin-dependent tunneling, as well as spin relaxation and spin dynamics. The most fundamental spin-dependent interaction in nonmagnetic semiconductors is spin-orbit coupling. Depending on the crystal symmetries of the material, as well as on the structural properties of semiconductor based heterostructures, the spin-orbit coupling takes on different functional forms, giving a nice playground of effective spin-orbit Hamiltonians. The effective Hamiltonians for the most relevant classes of materials and heterostructures are derived here from realistic electronic band structure descriptions. Most semiconductor device systems are still theoretical concepts, waiting for experimental demonstrations. A review of selected proposed, and a few demonstrated devices is presented, with detailed description of two important classes: magnetic resonant tunnel structures and bipolar magnetic diodes and transistors. In view of the importance of ferromagnetic semiconductor materials, a brief discussion of diluted magnetic semiconductors is included. In most cases the presentation is of tutorial style, introducing the essential theoretical formalism at an accessible level, with case-study-like illustrations of actual experimental results, as well as with brief reviews of relevant recent achievements in the field.
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Krich JJ, Halperin BI. Cubic Dresselhaus spin-orbit coupling in 2D electron quantum dots. PHYSICAL REVIEW LETTERS 2007; 98:226802. [PMID: 17677870 DOI: 10.1103/physrevlett.98.226802] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2007] [Indexed: 05/16/2023]
Abstract
We study effects of the oft-neglected cubic Dresselhaus spin-orbit coupling (i.e., directly proportional p3) in GaAs/AlGaAs quantum dots. Using a semiclassical billiard model, we estimate the magnitude of the spin-orbit induced avoided crossings in a closed quantum dot in a Zeeman field. Using previous analyses based on random matrix theory, we calculate corresponding effects on the conductance through an open quantum dot. Combining our results with an experiment on an 8 microm2 quantum dot [D. M. Zumbühl, Phys. Rev. B 72, 081305 (2005)10.1103/PhysRevB.72.081305] suggests that (1) the GaAs Dresselhaus coupling constant gamma is approximately 9 eV A3, significantly less than the commonly cited value of 27.5 eV A3, and (2) the majority of the spin-flip effects can come from the cubic Dresselhaus term.
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Affiliation(s)
- Jacob J Krich
- Physics Department, Harvard University, Cambridge, Massachusetts 02138, USA
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10
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Chantis AN, van Schilfgaarde M, Kotani T. Ab initio prediction of conduction band spin splitting in zinc blende semiconductors. PHYSICAL REVIEW LETTERS 2006; 96:086405. [PMID: 16606206 DOI: 10.1103/physrevlett.96.086405] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2005] [Indexed: 05/08/2023]
Abstract
We use a recently developed self-consistent GW approximation to present systematic ab initio calculations of the conduction band spin splitting in III-V and II-VI zinc blende semiconductors. The spin-orbit interaction is taken into account as a perturbation to the scalar relativistic Hamiltonian. These are the first calculations of conduction band spin splittings based on a quasiparticle approach; and because the self-consistent GW scheme accurately reproduces the relevant band parameters, it is expected to be a reliable predictor of spin splittings. The results are compared to the few available experimental data and a previous calculation based on a model one-particle potential. We also briefly address the widely used k x p parametrization in the context of these results.
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11
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Fal'ko VI, Altshuler BL, Tsyplyatyev O. Anisotropy of spin splitting and spin relaxation in lateral quantum dots. PHYSICAL REVIEW LETTERS 2005; 95:076603. [PMID: 16196808 DOI: 10.1103/physrevlett.95.076603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2005] [Indexed: 05/04/2023]
Abstract
Inelastic spin relaxation and spin splitting epsilon(s) in lateral quantum dots are studied in the regime of strong in-plane magnetic field. Because of both the g-factor energy dependence and spin-orbit coupling, epsilon(s) demonstrates a substantial nonlinear magnetic field dependence similar to that observed by Hanson et al. [Phys. Rev. Lett. 91, 196802 (2003)]. It also varies with the in-plane orientation of the magnetic field due to crystalline anisotropy of the spin-orbit coupling. The spin relaxation rate is also anisotropic, the anisotropy increasing with the field. When the magnetic length is less than the "thickness" of the GaAs dot, the relaxation can be an order of magnitude faster for B ||[100] than for B || [110].
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Könemann J, Haug RJ, Maude DK, Fal'ko VI, Altshuler BL. Spin-orbit coupling and anisotropy of spin splitting in quantum dots. PHYSICAL REVIEW LETTERS 2005; 94:226404. [PMID: 16090418 DOI: 10.1103/physrevlett.94.226404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2004] [Indexed: 05/03/2023]
Abstract
In lateral quantum dots, the combined effect of both Dresselhaus and Bychkov-Rashba spin-orbit coupling is equivalent to an effective magnetic field +/- B(SO) which has the opposite sign for s(z)= +/- 1/2 spin electrons. When the external magnetic field is perpendicular to the planar structure, the field B(SO) generates an additional splitting for electron states as compared to the spin splitting in the in-plane field orientation. The anisotropy of spin splitting has been measured and then analyzed in terms of spin-orbit coupling in several AlGaAs/GaAs quantum dots by means of resonant tunneling spectroscopy. From the measured values and sign of the anisotropy we are able to determine the dominating spin-orbit coupling mechanism.
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Affiliation(s)
- J Könemann
- Institut für Festkörperphysik, Universität Hannover, Appelstrasse 2, D-30167 Hannover, Germany
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Hashimoto K, Muraki K, Kumada N, Saku T, Hirayama Y. Effects of inversion asymmetry on electron-nuclear spin coupling in semiconductor heterostructures: possible role of spin-orbit interactions. PHYSICAL REVIEW LETTERS 2005; 94:146601. [PMID: 15904087 DOI: 10.1103/physrevlett.94.146601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2004] [Indexed: 05/02/2023]
Abstract
We show that electron-nuclear spin coupling in semiconductor heterostructures is strongly modified by their potential inversion asymmetry. This is demonstrated in a GaAs quantum well, where we observe that the current-induced nuclear spin polarization at Landau-level filling factor nu=2/3 is completely suppressed when the quantum well is made largely asymmetric with gate voltages. Furthermore, we find that the nuclear spin relaxation rate is also modified by the potential asymmetry. These findings strongly suggest that even a very weak Rashba spin-orbit interaction can play a dominant role in determining the electron-nuclear spin coupling.
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Affiliation(s)
- Katsushi Hashimoto
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, Kanagawa 243-0198, Japan
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14
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Ganichev SD, Bel'kov VV, Golub LE, Ivchenko EL, Schneider P, Giglberger S, Eroms J, De Boeck J, Borghs G, Wegscheider W, Weiss D, Prettl W. Experimental separation of Rashba and Dresselhaus spin splittings in semiconductor quantum wells. PHYSICAL REVIEW LETTERS 2004; 92:256601. [PMID: 15245041 DOI: 10.1103/physrevlett.92.256601] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2003] [Indexed: 05/24/2023]
Abstract
The relative strengths of Rashba and Dresselhaus terms describing the spin-orbit coupling in semiconductor quantum well (QW) structures are extracted from photocurrent measurements on n-type InAs QWs containing a two-dimensional electron gas (2DEG). This novel technique makes use of the angular distribution of the spin-galvanic effect at certain directions of spin orientation in the plane of a QW. The ratio of the relevant Rashba and Dresselhaus coefficients can be deduced directly from experiment and does not relay on theoretically obtained quantities. Thus our experiments open a new way to determine the different contributions to spin-orbit coupling.
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Affiliation(s)
- S D Ganichev
- Fakultät Physik, University of Regensburg, 93040 Regensburg, Germany
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15
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Karimov OZ, John GH, Harley RT, Lau WH, Flatté ME, Henini M, Airey R. High temperature gate control of quantum well spin memory. PHYSICAL REVIEW LETTERS 2003; 91:246601. [PMID: 14683140 DOI: 10.1103/physrevlett.91.246601] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2003] [Indexed: 05/24/2023]
Abstract
Time-resolved optical measurements in (110)-oriented GaAs/AlGaAs quantum wells show a tenfold increase of the spin-relaxation rate as a function of applied electric field from 20 to 80 kV cm(-1) at 170 K and indicate a similar variation at 300 K, in agreement with calculations based on the Rashba effect. Spin relaxation is almost field independent below 20 kV cm(-1) reflecting quantum well interface asymmetry. The results indicate the achievability of a voltage-gateable spin-memory time longer than 3 ns simultaneously with a high electron mobility.
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Affiliation(s)
- O Z Karimov
- School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ, United Kingdom
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Rashba EI, Efros AL. Orbital mechanisms of electron-spin manipulation by an electric field. PHYSICAL REVIEW LETTERS 2003; 91:126405. [PMID: 14525382 DOI: 10.1103/physrevlett.91.126405] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2003] [Indexed: 05/24/2023]
Abstract
A theory of spin manipulation of quasi-two-dimensional (2D) electrons by a time-dependent gate voltage applied to a quantum well is developed. The Dresselhaus and Rashba spin-orbit coupling mechanisms are shown to be rather efficient for this purpose. The spin response to a perpendicular-to-plane electric field is due to a deviation from the strict 2D limit and is controlled by the ratios of the spin, cyclotron, and confinement frequencies. The dependence of this response on the magnetic field direction is indicative of the strengths of the competing spin-orbit coupling mechanisms.
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Affiliation(s)
- E I Rashba
- Department of Physics, SUNY at Buffalo, Buffalo, New York 14260, USA.
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Schliemann J, Egues JC, Loss D. Nonballistic spin-field-effect transistor. PHYSICAL REVIEW LETTERS 2003; 90:146801. [PMID: 12731937 DOI: 10.1103/physrevlett.90.146801] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2002] [Indexed: 05/24/2023]
Abstract
We propose a spin-field-effect transistor based on spin-orbit coupling of both the Rashba and the Dresselhaus types. Different from earlier proposals, spin transport through our device is tolerant against spin-independent scattering processes. Hence the requirement of strictly ballistic transport can be relaxed. This follows from a unique interplay between the Dresselhaus and the Rashba coupling; these can be tuned to have equal strengths, leading to k-independent eigenspinors even in two dimensions. We discuss two-dimensional devices as well as quantum wires. In the latter, our setup presents strictly parabolic dispersions which avoids complications from anticrossings of different bands.
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Affiliation(s)
- John Schliemann
- Department of Physics and Astronomy, University of Basel, CH-4056 Basel, Switzerland
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18
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Miller JB, Zumbühl DM, Marcus CM, Lyanda-Geller YB, Goldhaber-Gordon D, Campman K, Gossard AC. Gate-controlled spin-orbit quantum interference effects in lateral transport. PHYSICAL REVIEW LETTERS 2003; 90:076807. [PMID: 12633263 DOI: 10.1103/physrevlett.90.076807] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2002] [Indexed: 05/24/2023]
Abstract
In situ control of spin-orbit coupling in coherent transport using a clean GaAs/AlGaAs two-dimensional electron gas is realized, leading to a gate-tunable crossover from weak localization to antilocalization. The necessary theory of 2D magnetotransport in the presence of spin-orbit coupling beyond the diffusive approximation is developed and used to analyze experimental data. With this theory the Rashba contribution and linear and cubic Dresselhaus contributions to spin-orbit coupling are separately estimated, allowing the angular dependence of spin-orbit precession to be extracted at various gate voltages.
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Affiliation(s)
- J B Miller
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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Zumbühl DM, Miller JB, Marcus CM, Campman K, Gossard AC. Spin-orbit coupling, antilocalization, and parallel magnetic fields in quantum dots. PHYSICAL REVIEW LETTERS 2002; 89:276803. [PMID: 12513231 DOI: 10.1103/physrevlett.89.276803] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2002] [Indexed: 05/24/2023]
Abstract
We investigate antilocalization due to spin-orbit coupling in ballistic GaAs quantum dots. Antilocalization that is prominent in large dots is suppressed in small dots, as anticipated theoretically. Parallel magnetic fields suppress both antilocalization and also, at larger fields, weak localization, consistent with random matrix theory results once orbital coupling of the parallel field is included. In situ control of spin-orbit coupling in dots is demonstrated as a gate-controlled crossover from weak localization to antilocalization.
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Affiliation(s)
- D M Zumbühl
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
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20
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Brand MA, Malinowski A, Karimov OZ, Marsden PA, Harley RT, Shields AJ, Sanvitto D, Ritchie DA, Simmons MY. Precession and motional slowing of spin evolution in a high mobility two-dimensional electron gas. PHYSICAL REVIEW LETTERS 2002; 89:236601. [PMID: 12485026 DOI: 10.1103/physrevlett.89.236601] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2002] [Indexed: 05/24/2023]
Abstract
Optical spin-dynamic measurements in a high-mobility n-doped GaAs/AlGaAs quantum well show oscillatory evolution at 1.8 K consistent with a quasi-collision-free D'yakonov-Perel'-Kachorovskii regime. Above 5 K evolution becomes exponential as expected for collision-dominated spin dynamics. Momentum scattering times extracted from Hall mobility and Monte Carlo simulation of spin polarization agree at 1.8 K but diverge at higher temperatures, indicating the importance of electron-electron scattering and an intrinsic upper limit for the spin-relaxation rate.
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Affiliation(s)
- M A Brand
- Department of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, United Kingdom
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21
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Halperin BI, Stern A, Oreg Y, Cremers JN, Folk JA, Marcus CM. Spin-orbit effects in a GaAs quantum dot in a parallel magnetic field. PHYSICAL REVIEW LETTERS 2001; 86:2106-2109. [PMID: 11289866 DOI: 10.1103/physrevlett.86.2106] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2000] [Indexed: 05/23/2023]
Abstract
We analyze the effects of spin-orbit coupling on fluctuations of the conductance of a quantum dot fabricated in a GaAs heterostructure. Counterintuitively we argue that spin-orbit effects may become important in the presence of a large parallel magnetic field B( parallel), even if they are negligible for B( parallel) = 0. This should be manifest in the level repulsion of a closed dot, and in reduced conductance fluctuations in dots with a small number of open channels in each lead, for large B( parallel). Our picture is consistent with the experimental observations of Folk et al.
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Affiliation(s)
- B I Halperin
- Lyman Laboratory of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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22
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Grundler D. Large Rashba splitting in InAs quantum wells due to electron wave function penetration into the barrier layers. PHYSICAL REVIEW LETTERS 2000; 84:6074-6077. [PMID: 10991127 DOI: 10.1103/physrevlett.84.6074] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/1999] [Indexed: 05/23/2023]
Abstract
We report on zero-field spin splitting of two-dimensional electron systems. Though absent in the unbiased InAs square asymmetric quantum well (SAQW), the Rashba splitting becomes pronounced by applying a positive back-gate voltage. In our SAQW, the Rashba parameter alpha increases with electron density and is tuned by a factor of about 2 using an additional front gate without charging the well. We argue that the band-edge profile provides the important contribution for spin-orbit interaction due to barrier penetration of the envelope wave function. This mechanism can provide the potential for high speed implementation in spintronics.
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Affiliation(s)
- D Grundler
- Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstrasse 11, D-20355 Hamburg, Germany
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23
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Papadakis SJ, Manoharan HC, Shayegan M, Winkler R. The effect of spin splitting on the metallic behavior of a two-dimensional system. Science 1999; 283:2056-8. [PMID: 10092222 DOI: 10.1126/science.283.5410.2056] [Citation(s) in RCA: 138] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Experiments on a constant-density two-dimensional hole system in a gallium arsenide quantum well revealed that the metallic behavior observed in the zero-magnetic-field temperature dependence of the resistivity depends on the symmetry of the confinement potential and the resulting spin splitting of the valence band.
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Affiliation(s)
- SJ Papadakis
- Department of Electrical Engineering, Princeton University, Princeton, NJ 08544, USA. Institut fur Technische Physik III, Universitat Erlangen-Nurnberg, Staudtstrasse 7, D-91058 Erlangen, Germany
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Willatzen M, Cardona M, Christensen NE. Terms linear in k in the band structure of wurtzite-type semiconductors. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:10703-10714. [PMID: 9982637 DOI: 10.1103/physrevb.53.10703] [Citation(s) in RCA: 125] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Gammon D, Snow ES, Shanabrook BV, Katzer DS, Park D. Fine structure splitting in the optical spectra of single GaAs quantum dots. PHYSICAL REVIEW LETTERS 1996; 76:3005-3008. [PMID: 10060846 DOI: 10.1103/physrevlett.76.3005] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
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26
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Knap W, Skierbiszewski C, Zduniak A, Litwin-Staszewska E, Bertho D, Kobbi F, Robert JL, Pikus GE, Pikus FG, Iordanskii SV, Mosser V, Zekentes K, Lyanda-Geller YB. Weak antilocalization and spin precession in quantum wells. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:3912-3924. [PMID: 9983944 DOI: 10.1103/physrevb.53.3912] [Citation(s) in RCA: 372] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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