Impurity scattering effect on the zero-energy peak of the local density of states in a multi-quantum vortex core

TL;DR

This paper investigates how non-magnetic impurities influence the zero-energy peak in the local density of states within multi-quantum vortex cores, revealing impurity-induced peak movement that aligns theory with experiments.

Contribution

It provides a theoretical analysis of impurity effects on vortex bound states in multi-quantum vortices, clarifying the behavior of zero-energy peaks.

Findings

Zero-energy peaks move towards vortex centers with increased impurity scattering

Impurity effects reconcile previous theoretical predictions with experimental observations

The study focuses on vortex cores with winding numbers 2 and 4

Abstract

We theoretically study a non-magnetic impurity effect on the vortex bound states of a multi-quantum vortex. The zero-energy peak of the local density of states is investigated for vortex cores with the winding numbers 2 and 4 within the framework of the quasiclassical theory of superconductivity. We find that the zero-energy peaks, which appear away from the vortex center in the clean limit, move towards the vortex center with increasing the impurity scattering rate, resolving a contradiction between an experimental result and previous theoretical predictions.