Spin-orbit splitting and weak antilocalization in an asymmetric /InP quantum well

Abstract

Low-magnetic-field magnetoresistance of a two-dimensional electron gas (2DEG) in a triangular quantum well at a single In 0.53 Ga 0.47 As-InP heterointerface has been studied. It was shown that the spin-orbit relaxation plays a significant role in the low-field magnetoresistivity in a wide range of 2DEG densities (1.8-5.5) × 10 11 cm −2 . Analysis shows that both cubic and linear terms in the wavevector must be taken into account in spin splitting to describe experimental results. The linear term is mainly related to the asymmetry of the quantum well (Rashba term). Analysis of the density dependence of the spin-orbit interaction rate permits separation of the spin splittings related to the lack of inversion of the crystal and to the asymmetry of quantum well and determination of the spin splitting parameters for 2D electrons in asymmetric In 0.53 Ga 0.47 As quantum wells.

Spin dynamics in semiconductors

“…Experimental methods to determine the spin-orbit coupling coefficients consist of magnetotransport (including both the Shubnikov-de Haas oscillation [158][159][160][161][162][163][164][165][166][167][168] and weak (anti-)localization [137,[169][170][171][172][173][174][175][176]), optically probed spin dynamics (spin relaxation [177][178][179] and spin precession [60]), electron spin resonance [180] and spin-flip Raman scattering [133,181], etc. Recently, it was proposed that the radiation-induced oscillatory magnetoresistance can be used as a sensitive probe of the zero-field spin-splitting [182].…”

Spin dynamics in semiconductors

“…Specifically, it was found that even in symmetric quantum wells, the built-in electric field contributes an intersubband Rashba spin-orbit coupling, though it does not contribute to the intrasubband spinorbit coupling [120,121]. Experimental methods to determine the spin-orbit coupling coefficients consist of magnetotransport (including both the Shubnikov-de Haas oscillation [158][159][160][161][162][163][164][165][166][167][168] and weak (anti-)localization [137,[169][170][171][172][173][174][175][176]), optically probed spin dynamics (spin relaxation [177][178][179] and spin precession [60]), electron spin resonance [180] and spin-flip Raman scattering [133,181], etc. Recently, it was proposed that the radiation-induced oscillatory magnetoresistance can be used as a sensitive probe of the zero-field spin-splitting [182].…”

“…7. The effects of structure inversion asymmetry, heterointerface and gate-voltage on the Dresselhaus and Rashba spin-orbit couplings in quantum wells were studied experimentally in Refs [37,55,137,162,175,178,179,183,192,193]…”

Electron phase and spin decoherence in the vicinity of the second subband edge in an asymmetrical quantum well

“…Therefore, a so-called antilocalization maximum in the magnetoresistance or a minimum in the magnetoconductivity with increasing magnetic fields was predicted [9]. For a 2D electron gas (2DEG) an antilocalization maximum in the magnetoresistance was experimentally observed in GaAs-based heterostructures [6,10] but subsequent experiments demonstrated that the influence of the SO scattering is much more pronounced in In 0.53 Ga 0.47 As/InP heterostructures [7,11]. These latter studies on asymmetric quantum wells in In 0.53 Ga 0.47 As/InP heterostructures enabled the main physical mechanisms for SO relaxation in the 2DEG to be studied [7,11,12].…”

“…For a 2D electron gas (2DEG) an antilocalization maximum in the magnetoresistance was experimentally observed in GaAs-based heterostructures [6,10] but subsequent experiments demonstrated that the influence of the SO scattering is much more pronounced in In 0.53 Ga 0.47 As/InP heterostructures [7,11]. These latter studies on asymmetric quantum wells in In 0.53 Ga 0.47 As/InP heterostructures enabled the main physical mechanisms for SO relaxation in the 2DEG to be studied [7,11,12]. The goal of this paper is to clarify the contribution of electrons in the second subband to the spin and phase decoherence of electrons in an asymmetric quantum well.…”