Spin current and polarization in impure 2D electron systems with spin-orbit coupling

TL;DR

This paper derives transport equations for 2D electron systems with spin-orbit coupling and disorder, analyzing spin accumulation and the spin-Hall effect, revealing that the spin-Hall conductivity vanishes in infinite systems regardless of parameters.

Contribution

It provides a theoretical framework for understanding spin transport and accumulation in disordered 2D systems with spin-orbit interaction, including the conditions for the spin-Hall effect.

Findings

Spin accumulation can be induced by electric fields in finite samples.

Spin-Hall conductivity vanishes in infinite systems regardless of spin-orbit strength.

Coupled diffusion equations describe spin and charge transport in disordered 2D systems.

Abstract

We derive the transport equations for two-dimensional electron systems with spin-orbit interaction and short-range spin-independent disorder. In the limit of slow spatial variations of the electron distribution we obtain coupled diffusion equations for the electron density and spin. Using these equations we calculate electric-field induced spin accumulation in a finite-size sample for arbitrary ratio between spin-orbit energy splitting and elastic scattering rate. We demonstrate that the spin-Hall conductivity vanishes in an infinite system independent of this ratio.