Semiconductor quantum wells, inter-metallic interfaces, layered oxides, and monolayer materials are all promising platforms for the observation of spincharge conversion due to strong spin-orbit interaction in the quasi two dimensional electron liquid they host. In this talk I focus on two closely related effects that can occur in these materials, namely the conversion of charge current to spin current (spin Hall effect) and the generation of spin polarization from an electric current (Edelstein effect). Together with their inverses (in the sense of Onsager reciprocity relations), these effects constitute a useful set of tools for spintronic applications. The theoretical challenge is to provide a unified treatment of the different mechanisms at work, including spin precession, spin relaxation, electron-impurity scattering and electron-electron scattering. I show how the SU(2) drift-diffusion theory allows such a unified treatment, and I describe its application to the interpretation of recent experiments on spin-charge conversion at the interface between two non-magnetic metals (Ag/Bi)† .
† J. C. Rojas-Sanchez et al., Nature Commun. 4, 2944 (2013).