Role of linear and cubic terms for the drift-induced Dresselhaus spin-orbit splitting in a two-dimensional electron gas

TL;DR

This study investigates the Dresselhaus spin-orbit interaction in 2DEGs within quantum wells, revealing that the spin-splitting remains linear with drift velocity even when cubic terms are significant, and quantifies the coupling parameter.

Contribution

It provides a quantitative analysis of the Dresselhaus coupling parameter, including the effects of cubic terms, strain, and quantum well confinement in 2DEGs.

Findings

Spin-splitting is linear in drift velocity despite cubic SOI importance.

Quantitative determination of the Dresselhaus coupling parameter, including its sign.

Relation of spin-splitting to quantum well properties and strain effects.

Abstract

The Dresselhaus spin-orbit interaction (SOI) of a series of two-dimensional electron gases (2DEGs) hosted in GaAs/AlGaAs and InGaAs/GaAs (001) quantum wells (QWs) is measured by monitoring the precession frequency of the spins as a function of an in-plane electric field. The measured spin-orbit-induced spin-splitting is linear in the drift velocity, even in the regime where the cubic Dresselhaus SOI is important. We relate the measured splitting to the Dresselhaus coupling parameter, the QW confinement, the Fermi wavenumber and to strain effects. From this, the coupling parameter is determined quantitatively, including its sign.