Spin Accumulation and Equilibrium Currents at the Edge of 2DEGs with Spin-Orbit Coupling

TL;DR

This paper investigates how spin-orbit coupling and potential barriers in 2DEGs lead to spin accumulation and currents at edges, revealing boundary-induced spin and charge phenomena without external bias.

Contribution

It demonstrates that boundary effects in 2DEGs with Rashba spin-orbit coupling produce equilibrium and non-equilibrium spin and charge currents localized at edges.

Findings

Spin accumulation occurs near the barrier under external current.

Equilibrium inhomogeneous spin currents flow parallel to the boundary.

In-plane magnetic fields induce inhomogeneous charge currents at the edge.

Abstract

We show that in a two dimensional electron gas (2DEG) the interplay between the Rashba spin-orbit coupling and a potential barrier (eg., the sample edge) generates interesting spin effects. In the presence of an external charge current, a spin accumulation is built up near the barrier while in equilibrium there is an inhomogeneous spin current which is localized at the barrier and flows parallel to it. When an in-plane magnetic field perpendicular to the barrier is applied, the system also develops an inhomogeneous charge current density. These effects originate purely from the structure of the eigenstates near the boundary.