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1.
First‐principles calculations are employed to demonstrate a giant Rashba spin splitting in Bi2Se3:Tl. Biaxial tensile and compressive strain is used to tune the splitting by modifying the potential gradient. The band gap is found to increase under compression and decreases under tension, whereas the dependence of the Rashba spin splitting on the strain is the opposite. Large values of αR = 1.57 eV Å at the bottom of the conduction band (electrons) and αR = 3.34 eV Å at the top of the valence band (holes) are obtained without strain. These values can be further enhanced to αR = 1.83 eV Å and αR = 3.64 eV Å, respectively, by 2% tensile strain. (© 2014 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
2.
Using the time-dependent Schrödinger equation, we present the analytical result of the expectation value of spin injected into a two-dimensional electron gas with respect to an arbitrarily spin-polarized electron state and monitor the spin time-evolution. We demonstrate that the expectation value of spin operator Sx is the time-independent, and only the expectation values in the Sy-Sz plane are time-dependent. A detailed study of spin precession in the spin-valve and spin-transistor geometry is presented, in which the initial spin-polarized electron state point perpendicular and parallel to the current direction, respectively. We put forward the possible reason that the resistance change is independent of gate voltage in the spin-valve geometry. Furthermore, it has been shown that the effective magnetic field generated by the spin-orbit interaction is not same with the truly magnetic field. The main effect of the truly magnetic field is to align the spin along the field direction, but the effective magnetic field generated by the spin-orbit interaction does not. 相似文献
3.
R. Gammag C. Villagonzalo 《The European Physical Journal B - Condensed Matter and Complex Systems》2012,85(1):22
The effect of atomic disorder on the electron transport and the magnetoresistance (MR) of Co2CrAl Heusler alloy (HA) films has been investigated. We show that Co2CrAl films with L21 order exhibit a negative value for the temperature coefficient of resistivity (TCR) in a temperature range of 10 < T < 290 K, and the temperature dependence of electric conductivity varies as T
3/2 similarly to that of the zero-gap semiconductors. The atomic or the site disorder on the way of L21 → B2 → A2 → amorphous state in Co2CrAl HA films causes the deviation from this dependence: reduction in the absolute value of TCR as well as decrease in the
resistivity down to ϱ(T = 293 K) ∼ 200 μΩ cm in comparison to ϱ(T = 293 K) ∼ 230 μΩ cm typical for the Co2CrAl films with L21 order. The magnetic-field dependence of MR of the Co2CrAl films with L21 order is determined by two competing contributions: a positive Lorentz scattering and a negative s-d scattering. The atomic disorder in Co2CrAl films drastically changes MR behavior due to its strong influence on the magnetic properties. 相似文献
4.
We consider a two-dimensional electron gas (2DEG) with the Rashba spin-orbit interaction (SOI) in the presence of a perpendicular magnetic field. We derive analytical expressions of the density of states (DOS) of a 2DEG with the Rashba SOI in the presence of a magnetic field by using the Green's function technique. The DOS allows us to obtain the analytical expressions of the magnetoconductivities for spin-up and spin-down electrons. The conductivities for spin-up and spin-down electrons oscillate with different frequencies and give rise to the beating patterns in the amplitude of the Shubnikov-de Haas (SdH) oscillations. We find a simple equation which determines the zero-field spin splitting energy if the magnetic field corresponding to any beat node is known from the experiment. Our analytical results reproduce well the experimentally observed non-periodic beating patterns, number of oscillations between two successive nodes and the measured zero-field spin splitting energy. 相似文献
5.
Weber CP Orenstein J Bernevig BA Zhang SC Stephens J Awschalom DD 《Physical review letters》2007,98(7):076604
We describe measurements of spin dynamics in the two-dimensional electron gas in GaAs/GaAlAs quantum wells. Optical techniques, including transient spin-grating spectroscopy, are used to probe the relaxation rates of spin polarization waves in the wave vector range from zero to 6x10(4) cm-1. We find that the spin polarization lifetime is maximal at a nonzero wave vector, in contrast with expectations based on ordinary spin diffusion, but in quantitative agreement with recent theories that treat diffusion in the presence of spin-orbit coupling. 相似文献
6.
H. B. Wang Y. K. Li Z. H. Yang J. Wang 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,78(3):405-409
We report a theoretical study on the interfacial electron transport
in the ferromagnet/two-dimensional electron gas (FM/2DEG) hybrid
junction at zero bias, where the Rashba spin-orbit interaction
(RSOI) is considered in 2DEG region. It is shown that a nonzero
charge current can spontaneously flow in the interface of the
junction due to broken time reversal symmetry and spin-dependent
scattering of electron at interface. This interfacial charge current
can be modulated by system parameters such as the magnetization of
FM, RSOI strength, and interface barrier, moreover, it can be
optimized as the magnetization of FM in 2DEG plane is perpendicular
to interface whereas it can vanish as the FM magnetization is
parallel to interface. 相似文献
7.
《Physics letters. A》2006,352(3):250-255
Based on a self-consistent semiclassical approach, in this Letter we try to contribute to the basic physical understanding of some controversial issues about the intrinsic spin Hall effect in a Rashba two-dimensional electron gas. We show that for a Rashba two-dimensional electron gas in the diffusive transport thermodynamic limit, there exist some simple but much clear physical reasons which explain naturally why the intrinsic spin Hall effect in such a system cannot survive in the dc limit. The physical pictures established in this Letter resolve some puzzles existed in some previous theoretical treatments about this extraordinary effect. 相似文献
8.
The phenomenon of low-temperature spin Coulomb drag in a two-dimensional electron gas is investigated. The spin transresistivity coefficient is essentially enhanced in the diffusive regime, as compared to conventional predictions. The origin of this enhancement is the quantum coherence of spin-up and spin-down electrons propagating in the same random impurity potential and coupled via the Coulomb interaction. A comprehensive analysis of spin and interlayer Coulomb drag effects is presented. 相似文献
9.
K. V. Ivanin A. V. Leont’ev V. S. Lobkov V. V. Samartsev 《Bulletin of the Russian Academy of Sciences: Physics》2011,75(2):172-174
The results from femtosecond four-wave-mixing experiments carried out in two-dimensional gas at the GaAs/AlGaAs heterojunction
boundary under room temperature conditionsare presented. The obtained values of the spin and electron diffusion coefficients
are 163.2 and 200 cm2/s respectively. The spin and electron relaxation times are found to be 50.7 ps and 3 ns respectively. 相似文献
10.
Zhu ZH Levy G Ludbrook B Veenstra CN Rosen JA Comin R Wong D Dosanjh P Ubaldini A Syers P Butch NP Paglione J Elfimov IS Damascelli A 《Physical review letters》2011,107(18):186405
The electronic structure of Bi(2)Se(3) is studied by angle-resolved photoemission and density functional theory. We show that the instability of the surface electronic properties, observed even in ultrahigh-vacuum conditions, can be overcome via in situ potassium deposition. In addition to accurately setting the carrier concentration, new Rashba-like spin-polarized states are induced, with a tunable, reversible, and highly stable spin splitting. Ab initio slab calculations reveal that these Rashba states are derived from 5-quintuple-layer quantum-well states. While the K-induced potential gradient enhances the spin splitting, this may be present on pristine surfaces due to the symmetry breaking of the vacuum-solid interface. 相似文献
11.
Salis G Fuchs DT Kikkawa JM Awschalom DD Ohno Y Ohno H 《Physical review letters》2001,86(12):2677-2680
Conduction electrons are used to optically polarize, detect, and manipulate nuclear spin in a (110) GaAs quantum well. Using optical Larmor magnetometry, we find that nuclear spin can be polarized along or against the applied magnetic field, depending on field polarity and tilting of the sample with respect to the optical pump beam. Periodic optical excitation of the quantum-confined electron spin reveals a complete spectrum of optically induced and quadrupolar-split nuclear resonances, as well as evidence for Deltam = 2 transitions. 相似文献
12.
We discuss the mechanism of the anomalous Hall effect in a Rashba-Dresselhaus two-dimensional electron gas subjected to a homogeneous out-of-plane magnetization. On the basis of a systematic treatment of the kinetic equations for the spin-density matrix, results are derived for the dynamic Hall conductivity in a closed form. Its nonanalytic dependence on both the scattering time and the frequency of the applied electric field is discussed. Except for in a special Rashba-Dresselhaus model, there is a finite intrinsic anomalous Hall effect, which is extremely sensitive to short-range elastic scattering. 相似文献
13.
W. Xu Z. Zeng F. Lu C. Zhang 《Physica E: Low-dimensional Systems and Nanostructures》2006,34(1-2):272
We examine how the Rashba spin-orbit interaction (SOI) affects the fast-electron optical spectrum of a two-dimensional electron gas (2DEG). It is found that for a spin-split 2DEG, the spectrum of optical absorption is mainly induced by plasmon excitation via inter-SO electronic transition. From the width and position of the spectrum, the Rashba spin-splitting can be identified optically and, therefore, important spintronic properties can be measured though optical experiments. 相似文献
14.
15.
Influence of spin-orbit coupling induced by in-plane external electric field on the intrinsic spin-Hall effect in a Rashba two-dimensional electron gas 下载免费PDF全文
We study theoretically the influence of spin--orbit
coupling induced by in-plane external electric field on the
intrinsic spin-Hall effect in a two-dimensional electron gas with
Rashba spin--orbit coupling. We show that, after such an influence is
taken into account, the static intrinsic spin-Hall effect can be
stabilized in a disordered Rashba two-dimensional electron gas, and
the static intrinsic spin-Hall conductivity shall exhibit some
interesting characteristics as conceived in some original
theoretical proposals. 相似文献
16.
主要研究具有倒置能带结构的n-HgTe/HgCdTe第三类量子阱Shubnikov-de Haas(SdH)振荡中的拍频现象.发现在量子阱中电子存在强烈的Rashba自旋分裂,通过对SdH振荡进行三种不同方法的分析:SdH振荡对1/B关系的快速傅里叶变换、SdH振荡中拍频节点分析和对SdH振荡拍频数值拟合,得到了完全一致的电子Rashba自旋分裂能量(28—36 meV).
关键词:
n-HgTe/HgCdTe
Shubnikov-de Haas振荡
Rashba自旋分裂 相似文献
17.
Perez F Aku-leh C Richards D Jusserand B Smith LC Wolverson D Karczewski G 《Physical review letters》2007,99(2):026403
The g-factor enhancement of the spin-polarized two-dimensional electron gas was measured directly over a wide range of spin polarizations, using spin flip resonant Raman scattering spectroscopy on two-dimensional electron gases embedded in Cd(1-x)Mn(x)Te semimagnetic quantum wells. At zero Raman transferred momentum, the single-particle spin flip excitation, energy Z*, coexists in the Raman spectrum with the spin flip wave of energy Z, the bare giant Zeeman splitting. We compare the measured g-factor enhancement with recent spin-susceptibility enhancement theories and deduce the spin-polarization dependence of the mass renormalization. 相似文献
18.
YT Wang GH Kim CF Huang ST Lo WJ Chen JT Nicholls LH Lin DA Ritchie YH Chang CT Liang BP Dolan 《J Phys Condens Matter》2012,24(40):405801
We study the temperature flow of conductivities in a gated GaAs two-dimensional electron gas (2DEG) containing self-assembled InAs dots and compare the results with recent theoretical predictions. By changing the gate voltage, we are able to tune the 2DEG density and thus vary disorder and spin-splitting. Data for both the spin-resolved and spin-degenerate phase transitions are presented, the former collapsing to the latter with decreasing gate voltage and/or decreasing spin-splitting. The experimental results support a recent theory, based on modular symmetry, which predicts how the critical Hall conductivity varies with spin-splitting. 相似文献
19.
The current-induced spin polarization (CISP) is investigated in a combined Rashba-Dresselhaus spin-orbit-coupled two-dimensional electron gas, subjected to a homogeneous out-of-plane magnetization. It is found that, in addition to the usual collision-related in-plane parts of CISP, there are two impurity-density-free contributions, arising from intrinsic and disorder-mediated mechanisms. The intrinsic parts of spin polarization are related to the Berry curvature, analogous with the anomalous and spin Hall effects. For short-range collision, the disorder-mediated spin polarizations completely cancel the intrinsic ones and the total in-plane components of CISP equal those for systems without magnetization. However, for remote disorders, this cancellation does not occur and the total in-plane components of CISP strongly depend on the spin-orbit interaction coefficients and magnetization for both pure Rashba and combined Rashba-Dresselhaus models. 相似文献
20.
A. Phirouznia F. Ghamari 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,74(3):357-362
Non-equilibrium spin accumulation in two-dimensional domain wall (DW) in the presence of external electric field and Rashba
type spin-orbit coupling within the Boltzmann semi-classical
model is investigated. Transport and relaxation of spin polarized current in the DW is governed by spin-flip rates which are
determined by the Rashba interaction and magnetic impurities. Numerical results show that at low impurity densities and nonadiabatic
transport regimes, the Rashba interaction significantly enhances spin polarization of conduction electrons inside the DW. 相似文献