Spin Hall Drag

TL;DR

This paper predicts a novel Spin Hall Drag effect in electronic bilayers, where an electric current in one layer induces spin accumulation in the other, driven by spin-orbit and Coulomb interactions, with measurable optical signals.

Contribution

Theoretical prediction of Spin Hall Drag effect in bilayers, detailing its mechanisms and temperature dependence, which has not been previously described.

Findings

Spin Hall Drag causes detectable spin accumulation.

Dominant side-jump contribution at low temperatures, scaling as T^2.

Skew-scattering contribution scales as T^3.

Abstract

We predict a new effect in electronic bilayers: the {\it Spin Hall Drag}. The effect consists in the generation of spin accumulation across one layer by an electric current along the other layer. It arises from the combined action of spin-orbit and Coulomb interactions. Our theoretical analysis, based on the Boltzmann equation formalism, identifies two main contributions to the spin Hall drag resistivity: the side-jump contribution, which dominates at low temperature, going as $T^2$, and the skew-scattering contribution, which is proportional to $T^3$. The induced spin accumulation is large enough to be detected in optical rotation experiments.