Proximity effect with noncentrosymmetric superconductors

TL;DR

This paper investigates the superconducting proximity effect in noncentrosymmetric superconductors interfaced with diffusive metals, revealing how local density of states analysis can uncover exotic pairing symmetries and gap relations.

Contribution

It introduces a numerical approach using the Usadel equation to analyze proximity effects, enabling identification of triplet and singlet pairing signatures in noncentrosymmetric superconductors.

Findings

Identification of triplet pairing signatures in local density of states

Discrimination between triplet and singlet gap orderings

Estimation of specific gap ratios based on spin polarization effects

Abstract

We describe the superconducting proximity effect taking place in a contact between a noncentrosymmetric superconductor and a diffusive normal/ferromagnetic metal within the quasiclassical theory of superconductivity. By solving numerically the Usadel equation with boundary conditions valid for arbitrary interface transparency, we show that the analysis of the proximity-modified local density of states in the normal side can be used to obtain information about the exotic superconductivity of noncentrosymmetric materials. We point out the signatures of triplet pairing, the coexistence of triplet and singlet pairing, and particular orbital symmetries of the pair potential. Exploiting the directional dependence of the spin polarization pair breaking effect on the triplet correlations, we show how the order relation between triplet and singlet gaps can be discriminated and that an estimation of the specific gap ratio is possible in some cases.