Ballistic Josephson junctions in the presence of generic spin dependent fields

TL;DR

This paper develops a theoretical framework for ballistic Josephson junctions with spin-dependent fields, revealing phenomena like zero-energy peaks, spin currents, and magnetization effects due to spin-orbit coupling and spin textures.

Contribution

It provides a generic quasi-classical Green's function expression and analyzes the interplay of spin textures and superconductivity in heterostructures, predicting new spin-related effects.

Findings

Density of states may show zero-energy peaks due to spin-dependent couplings.

Spin currents and magnetic moments are induced in SNS structures.

Spin accumulation occurs at S/N interfaces, enabling potential control of magnetization.

Abstract

Ballistic Josephson junctions are studied in the presence of a spin-splitting field and spin-orbit coupling. A generic expression for the quasi-classical Green's function is obtained and with its help we analyze several aspects of the proximity effect between a spin-textured normal metal (N) and singlet superconductors (S). In particular, we show that the density of states may show a zero-energy peak which is a generic consequence of the spin-dependent couplings in heterostructures. In addition we also obtain the spin current and the induced magnetic moment in a SNS structure and discuss possible coherent manipulation of the magnetization which results from the coupling between the superconducting phase and the spin degree of freedom. Our theory predicts a spin accumulation at the S/N interfaces, and transverse spin currents flowing perpendicular to the junction interfaces. Some of these findings can be understood in the light of a non-Abelian electrostatics.