Irreversible thermodynamics at surfaces: inverse Edelstein effect for topological insulator

Abstract

We employ Onsager’s irreversible thermodynamics to study the inverse Edelstein effect (IEE) for a non-magnetic material (NM) adjacent to a topological insulator (TI) with a strong spin–orbit interaction. The TI surface state region is treated as quasi two-dimensional (2D). For the IEE, the source is a 3D spin flux incident from the NM that converts, at the NM–TI interface, to a quasi-2D charge current in the TI. For the Edelstein effect (EE), the source is a quasi-2D charge flux incident from the TI that converts, at the interface, to a three-dimensional (3D) spin flux in the NM. For strong spin–orbit coupling, as considered here, when the 3D spin flux crosses to the 2D TI, the quasi-2D charge current is produced along with a quasi-2D spin accumulation. (For weak spin–orbit coupling, production of charge current and of spin accumulation are distinct processes.) We compute the associated rates of heating.