Spin current generation from Coulomb-Rashba interaction in semiconductor bilayers

TL;DR

This paper demonstrates that Coulomb-induced spin-orbit interactions in semiconductor bilayers can generate spin currents in one layer driven by charge currents in the other, revealing a novel spin transport mechanism.

Contribution

It introduces a new spin current generation mechanism based on Coulomb-Rashba interaction in double-layer structures, distinct from known effects like spin Hall drag.

Findings

Spin current can be generated via Coulomb-Rashba interaction.

The effect is distinct from spin Hall drag and not necessarily perpendicular to the charge current.

The mechanism relies on electron density fluctuations in coupled layers.

Abstract

Electrons in double-layer semiconductor heterostructures experience a special type of spin-orbit interaction which arises in each layer from the perpendicular component of the Coulomb electric field created by electron density fluctuations in the other layer. We show that this interaction, acting in combination with the usual spin-orbit interaction, can generate a spin current in one layer when a charge current is driven in the other. This effect is symmetry-wise distinct from the spin Hall drag. The spin current is not, in general, perpendicular to the drive current.