Nonlinear spin Hall effect in GaAs (110) quantum wells

TL;DR

This paper investigates how a nonlinear external electric field induces a stationary pure spin current in GaAs (110) quantum wells through spin-orbit interactions, revealing a quadratic dependence on the field amplitude.

Contribution

It introduces a model combining Dresselhaus and random Rashba spin-orbit couplings to explain nonlinear spin current generation in GaAs quantum wells.

Findings

Spin current is proportional to the square of the electric field amplitude.

Virtual spin-flip transitions are responsible for the stationary spin current.

The model accounts for both uniform Dresselhaus and random Rashba interactions.

Abstract

We consider stationary spin current in a (110)-oriented GaAs-based symmetric quantum well due to a nonlinear response to an external periodic electric field. The model assumed includes the Dresselhaus spin-orbit interaction and the random Rashba spin-orbit coupling. The Dresselhaus term is uniform in the quantum well plane and gives rise to spin splitting of the electron band. The external electric field of frequency $\omega$ - in the presence of random Rashba coupling -- leads to virtual spin-flip transitions between spin subbands, generating stationary pure spin current proportional to the square of the field amplitude.