Current-induced spin polarization for a general two-dimensional electron system

TL;DR

This paper investigates how current-induced spin polarization in a two-dimensional electron gas depends on electron density and spin-orbit interactions, revealing density-dependent behaviors and the influence of disorder types.

Contribution

It provides a comprehensive analysis of current-induced spin polarization considering general spin-orbit interactions and different disorder models in 2D electron systems.

Findings

Spin polarization depends on electron density for non-linear spin-orbit interactions.

Cubic spin-orbit couplings enhance spin polarization at higher densities.

Remote disorders cause rapid spin polarization increase at high densities.

Abstract

In this paper, current-induced spin polarization for two-dimensional electron gas with a general spin-orbit interaction is investigated. For isotropic energy spectrum, the in-plane current-induced spin polarization is found to be dependent on the electron density for non-linear spin-orbit interaction and increases with the increment of sheet density, in contrast to the case for $\bm k$-linear spin-orbit coupling model. The numerical evaluation is performed for InAs/InSb heterojunction with spin-orbit coupling of both linear and cubic spin-orbit coupling types. For $\delta$-type short-range electron-impurity scattering, it is found that the current-induced spin polarization increases with increasing the density when cubic spin-orbit couplings are considered. However, for remote disorders, a rapid enhancement of current-induced spin polarization is always observed at high electron density, even in the case without cubic spin-orbit coupling. This result demonstrates the collision-related feature of current-induced spin polarization. The effects of different high order spin-orbit couplings on spin polarization can be comparable.