`Spin-Spin' Hall Effect in Two-Dimensional Electron Systems with Spin-Orbit Interaction

TL;DR

This paper predicts a novel 'spin-spin' Hall effect in two-dimensional electron systems with Rashba spin-orbit interaction, where an in-plane spin current induces a transverse spin-polarized current without magnetic fields.

Contribution

It introduces the concept of a 'spin-spin' Hall effect, a new spin transport phenomenon in 2D electron systems with spin-orbit coupling, expanding understanding of spin Hall effects.

Findings

Identification of a new transverse spin current induced by in-plane spin-polarized current

Prediction of a 'spin-spin' Hall effect without magnetic field

Calculation of spin Hall conductivities in Rashba systems

Abstract

We calculate spin Hall conductivities in the two dimensional electron systems with Rashba spin-orbit interaction. The salient feature is that, apart from the usual spin-Hall conductivity \sigma^z_{xy} which corresponds to the induction of out-of-plane spin-current due to the application of transverse charge current, there is a novel spin-Hall conductivity \sigma^\perp_{xy} which arises due to the induction of transverse spin-polarized current in the transverse direction by the application of in-plane spin-polarized current. This phenomenon which we call as `spin-spin' Hall effect is a spin analog of conventional Hall effect, but with no magnetic field. This contribution may be understood through the spin-diffusive equation.