Conductance suppression in normal metal-superconductor mesoscopic strucutres

TL;DR

This paper investigates how conductance in normal metal-superconductor mesoscopic structures varies with interface resistance, revealing a sign change in conductance difference and comparing theoretical predictions with experimental data.

Contribution

It introduces a combined scattering matrix and Green's function approach to analyze conductance behavior in S/N systems, highlighting the sign change with interface resistance.

Findings

Conductance difference becomes negative at high interface resistances.

The sign of conductance difference changes as interface resistance decreases.

Theoretical results align with experimental observations.

Abstract

Using a scattering matrix approach and quasiclassical Green's function technique, we calculate the conductance of the S/N system (see Fig.1). We establish that the difference between the superconducting and normal state conductance $(\delta G = G_s - G_n)$ is negative for large S/N interface resistances $(R_{S/N})$ and changes sign with decreasing $R_{S/N}$. The comparision of the result obtained with experimental data is carried out.