Effects of magnetic impurities on two-band superconductor

TL;DR

This paper investigates how magnetic impurities influence the properties of a two-band superconductor by solving Eliashberg equations, revealing unusual behaviors in gaps and penetration lengths and exploring the impact on critical temperature.

Contribution

It provides a detailed analysis of magnetic impurity effects on multiband superconductors using a direct solution of Eliashberg equations, highlighting novel behaviors.

Findings

Unusual temperature dependence of gaps and penetration lengths.

Magnetic impurities affect the critical temperature and density of states.

Negative induced gaps may raise the critical temperature.

Abstract

I calculated the effect of magnetic impurities on the normal and superconductive properties of a multiband s-wave superconductor by direct solution of the two-band Eliashberg equations. In this way I determined the critical temperature, the values of the superconductive gaps, the shape of the superconductive density of states and other physical quantities that depend on the concentration of magnetic impurities. I found that the gaps and the penetration lengths display an unusual behaviour as a function of temperature. I examine the possibility that the presence of a negative induced gap raises the critical temperature.