Coupled spin-charge drift-diffusion equations for the Rashba model

Coupled spin-charge drift-diffusion equations are derived for a biased two-dimensional electron gas with weak Rashba spin-orbit interaction. The basic equations formally agree with recent results obtained for spin-orbit coupled small polarons. It is shown that effects of an in-plane electric field on a homogeneous spin system can completely be described by an associated in-plane magnetic field. Exploiting this analogy, we predict among other things the electric-field equivalent of the Hanle effect.