Quasiclassical boundary conditions for spin-orbit coupled interfaces with spin-charge conversion

TL;DR

This paper develops a boundary condition for quasiclassical Green functions at spin-orbit coupled interfaces, enabling the study of spin-charge conversion phenomena like spin-Hall effects in superconductor hybrid structures.

Contribution

It introduces a new boundary condition incorporating gradient terms for spin-orbit interfaces, advancing the theoretical modeling of spin-charge conversion in superconducting hybrids.

Findings

Predicts supercurrent-induced non-local magnetization in normal metals via spin-orbit interfaces.

Enables modeling of spin-Hall effects in superconductor-normal metal structures.

Provides a foundation for exploring spintronics phenomena in superconducting systems.

Abstract

The quasiclassical theory of superconductivity provides a methodology to study emergent phenomena in hybrid structures comprised of superconductors interfaced with other materials. A key component in this theory is the boundary condition that the Green functions describing the materials must satisfy. Recently, progress has been made toward formulating such a boundary condition for interfaces with spin-orbit coupling, the latter playing an important role for several phenomena in spintronics. Here, we derive a boundary condition for spin-orbit coupled interfaces that includes gradient terms which enables the description of spin-Hall like effects with superconductors due to such interfaces. As an example, we show that the boundary conditions predict that a supercurrent flowing through a superconductor that is coupled to a normal metal via a spin-orbit interface can induce a non-local magnetization in the normal metal.