Role of anisotropic impurity scattering in anisotropic superconductors

TL;DR

This paper develops a theory for how anisotropic impurity scattering affects superconductivity, showing that strong anisotropic scattering can make superconductivity more resistant to impurities, especially relevant for high-temperature superconductors like YBCO.

Contribution

It introduces a comprehensive model incorporating anisotropic impurity scattering effects in anisotropic superconductors, highlighting conditions that enhance superconductivity robustness.

Findings

Strong anisotropic scattering reduces impurity pair-breaking effects.

Overlap of anisotropy functions enhances superconductivity resilience.

Implications for high-temperature superconductor YBCO discussed.

Abstract

A theory of nonmagnetic impurities in an anisotropic superconductor including the effect of anisotropic (momentum-dependent) impurity scattering is given. It is shown that for a strongly anisotropic scattering the reduction of the pair-breaking effect of the impurities is large. For a significant overlap between the anisotropy functions of the scattering potential and that of the pair potential and for a large amount of anisotropic scattering rate in impurity potential the superconductivity becomes robust vis a vis impurity concentration. The implications of our result for YBCO high-temperature superconductor are discussed.