Full orbital decomposition of Yu-Shiba-Rusinov states based on first principles

TL;DR

This paper presents a first-principles method to analyze Yu-Shiba-Rusinov states in superconductors with magnetic impurities, decomposing these states into orbital contributions and examining their spatial characteristics.

Contribution

The work extends the Bogoliubov-de Gennes framework within a KKR method to include collinear magnetism and orbital decomposition of YSR states in 3d impurities in superconducting Pb.

Findings

YSR states decompose into orbital contributions

Impurity states' spatial extent varies with orbital character

First-principles approach enables quantitative comparison with experiments

Abstract

We have implemented the Bogoliubov-de Gennes (BdG) equation in a screened Korringa-Kohn- Rostoker (KKR) method for solving, self-consistently, the superconducting state for 3d crystals including substitutional impurities. In this report we extend this theoretical framework to allow for collinear magnetism and apply it to fcc Pb with 3d magnetic impurities. In the presence of magnetic impurities, there is a pair-breaking effect that results in sup-gap Yu-Shiba-Rusinov (YSR) states which we decompose into contributions from the individual orbital character. We determine the spatial extent of these impurity states, showing how the different orbital character affects the details of the YSR states within the superconducting gap. Our work highlights the importance of the first principles based description which captures the quantitative details making direct comparisons possible with experimental findings.