Pure spin current generated by reflection at a normal metal/two-dimensional electron gas interface

Abstract

The concept of a spin current is a useful tool in understanding spin transport in hybrid systems but its very definition is problematic in systems where spin-orbit coupling effects are strong. In the absence of spin-dependent scattering, the spin current remains well defined. We here propose a method for generating pure spin currents in a normal metal where the spin current consequently does not suffer from the aforementioned problems pertaining to its very definition or spin-relaxation processes. More specifically, we show how an unpolarized incident charge current can induce a pure transverse spin current by means of scattering at a normal metal/two-dimensional electron gas interface. This occurs for both Rashba and Dresselhaus spin-orbit coupling. An experimental setup for observation of this effect is proposed.