Rashba spin splitting in biased semiconductor quantum wells

TL;DR

This paper presents a theoretical study of Rashba spin splitting in biased semiconductor quantum wells, revealing nonmonotonic and anisotropic behavior at large wave vectors, with analytical and numerical insights into parameter dependencies.

Contribution

It introduces an analytical model capturing the nonmonotonic and anisotropic Rashba spin splitting behavior at large wave vectors in biased quantum wells.

Findings

RSS is nonmonotonic and anisotropic at large wave vectors.

RSS increases with decreasing band gap, subband index, and other parameters.

The analytical model accurately explains the observed behaviors.

Abstract

Rashba spin splitting (RSS) in biased semiconductor quantum wells is investigated theoretically based on the eight-band envelope function model. We find that at large wave vectors, RSS is both nonmonotonic and anisotropic as a function of in-plane wave vector, in contrast to the widely used linear and isotropic model. We derive an analytical expression for RSS, which can correctly reproduce such nonmonotonic behavior at large wave vectors. We also investigate numerically the dependence of RSS on the various band parameters and find that RSS increases with decreasing band gap and subband index, increasing valence band offset, external electric field, and well width. Our analytical expression for RSS provides a satisfactory explanation to all these features.