We provide a precise microscopic definition of the recently observed inverse Edelstein effect
in which a nonequilibrium spin accumulation in the plane of a two-dimensional (interfacial)
electron gas drives an electric current perpendicular to its own direction. The drift-diffusion
equations that govern the effect are presented and applied to the interpretation of the
experiments.

The spin Hall effect (SHE) and the inverse spin Hall effect (ISHE) are well established
phenomena in current spintronics research. A third important effect is the current-induced
spin polarization, which, within the Rashba model for a spin-orbit coupled two-dimensional
disordered electron gas, has been predicted by Edelstein in 1990 and it is referred to as the
Edelstein effect (EE). This effect is deeply connected to the above two effects thanks to a
constraint dictated by the equation of motion. Less known is the inverse Edelstein effect …