Manifestation of extrinsic spin Hall effect in superconducting structures: Non-dissipative magnetoelectric effects

TL;DR

This paper develops a quasiclassical framework to describe non-dissipative magnetoelectric effects, like spin-galvanic and inverse effects, in superconducting hybrid structures with extrinsic spin-orbit coupling, revealing new avenues for superconducting magnetoelectronics.

Contribution

It introduces a generalized Usadel equation capturing extrinsic spin-orbit effects in superconductors, linking spin Hall phenomena to superconducting transport properties.

Findings

Prediction of non-dissipative spin-galvanic effects in superconductors.

Derivation of boundary conditions reducing to drift-diffusion in normal state.

Identification of superconducting counterparts to spin-Hall and anomalous Hall effects.

Abstract

We present a comprehensive quasiclassical approach for studying transport properties of superconducting diffusive hybrid structures in the presence of extrinsic spin-orbit coupling. We derive a generalized Usadel equation and boundary conditions that in the normal state reduce to the drift-diffusion theory governing the spin-Hall effect in inversion symmetric materials. These equations predict the non-dissipative spin-galvanic effect, that is the generation of supercurrents by a spin-splitting field, and its inverse -- the creation of magnetic moment by a supercurrent. These effects can be seen as counterparts of the spin-Hall, anomalous Hall and their inverse effects in the superconducting state. Our theory opens numerous possibilities for using superconducting structures in magnetoelectronics.