Non-equilibrium quantum transport and analytical conductance formula in spin-textured diffusive superconducting heterostructures

TL;DR

This paper derives an analytical formula for charge conductance in non-equilibrium spin-textured superconducting heterostructures, revealing significant deviations from local density of states that aid in identifying unconventional superconductivity.

Contribution

It introduces a general analytical conductance formula for non-equilibrium superconducting heterostructures with spin textures, validated against numerical results.

Findings

Analytical conductance formula matches numerical results at finite temperatures.

Strong deviations between conductance spectra and local density of states are predicted.

The results help identify spectroscopic signatures of unconventional superconductivity.

Abstract

We study non-equilibrium quantum transport of spin, heat, and charge in diffusive heterostructures including both superconductors and materials with spin-dependent fields, such as textured ferromagnets and spin-orbit coupled materials. Using the quasiclassical theory of superconductivity, we derive a general analytical formula for the zero-temperature charge conductance valid in the non-linear regime. The analytical results are in excellent agreement with previous numerical calculations at small but finite temperatures. We predict a strong deviation between the conductance spectra and local density of states in certain junctions, which is important to correctly identify spectroscopic fingerprints of unconventional superconductivity.