Anomalous proximity effect in d-wave superconductors

TL;DR

This paper theoretically investigates the anomalous proximity effect in d-wave superconductors, revealing how disorder induces a gapless superconducting state at the surface, with detailed spatial and angular analysis.

Contribution

It provides a self-consistent theoretical analysis of the proximity effect in disordered d-wave superconductors using Eilenberger equations, highlighting the emergence of a gapless state.

Findings

Disorder induces a gapless superconducting state at the surface.

The spatial variation of the quasiparticle density of states is characterized.

The pair potential and propagators are calculated self-consistently.

Abstract

The anomalous proximity effect between a d-wave superconductor and a surface layer with small electronic mean free path is studied theoretically in the framework of the Eilenberger equations. The angular and spatial structure of the pair potential and the quasiclassical propagators in the interface region is calculated selfconsistently. The variation of the spatially-resolved quasiparticle density of states from the bulk to the surface is studied. It is shown that the isotropic gapless superconducting state is induced in the disordered layer.