Yu-Shiba-Rusinov bands in superconductors in contact with a magnetic insulator

TL;DR

This paper investigates how magnetic insulators influence the electronic states of superconductors, revealing that their effects mimic magnetic impurities and can lead to the formation of Yu-Shiba-Rusinov bands.

Contribution

It introduces a boundary condition approach for strongly spin-dependent interfaces, linking magnetic insulator effects to impurity-induced Shiba bands in superconductors.

Findings

Magnetic insulators affect superconductor density of states similarly to magnetic impurities.

Boundary conditions can model the formation of Yu-Shiba-Rusinov bands.

Impurity effects of localized spins are mapped onto boundary problems.

Abstract

Superconductor-Ferromagnet (SF) heterostructures are of interest due to numerous phenomena related to the spin-dependent interaction of Cooper pairs with the magnetization. Here we address the effects of a magnetic insulator on the density of states of a superconductor based on a recently developed boundary condition for strongly spin-dependent interfaces. We show that the boundary to a magnetic insulator has a similar effect like the presence of magnetic impurities. In particular we find that the impurity effects of strongly scattering localized spins leading to the formation of Shiba bands can be mapped onto the boundary problem.