The effect of nonmagnetic impurities on the local density of states in s-wave superconductors

TL;DR

This paper investigates how nonmagnetic impurities influence the local density of states in s-wave superconductors, revealing a linear relationship with magnetic induction and providing data to estimate mean free paths.

Contribution

It presents a self-consistent solution of quasiclassical equations showing impurity effects on LDOS and offers numerical data useful for experimental estimation of mean free paths.

Findings

LDOS at zero energy varies linearly with magnetic induction

The proportionality constant weakly depends on electron mean free path

Numerical profiles of LDOS aid in experimental analysis

Abstract

We study the effect of nonmagnetic impurities on the local density of states (LDOS) in s-wave superconductors. The quasiclassical equations of superconductivity are solved selfconsistently to show how LDOS evolves with impurity concentration. The spatially averaged zero-energy LDOS is a linear function of magnetic induction in low fields, N(E=0)=cB/H_{c2}, for all impurity concentration. The constant of proportionality "c" depends weakly on the electron mean free path. We present numerical data for differential conductance and spatial profile of zero-energy LDOS which can help in estimating the mean free path through the LDOS measurement.