Vortex core shrinkage in a two gap superconductor: application to MgB2

TL;DR

This paper investigates vortex core size reduction in MgB2 using a two-band model, revealing Kramer-Pesch effects in both bands despite differing impurity levels, and explores how diffusivities influence core size.

Contribution

It introduces a two-band model for MgB2 vortex cores, demonstrating Kramer-Pesch effects in both bands and analyzing the impact of band diffusivities on core size.

Findings

Kramer-Pesch effect occurs in both bands despite one being dirty.

Vortex core size varies with temperature and band diffusivities.

The model explains vortex behavior in MgB2 considering two distinct bands.

Abstract

As a model for the vortex core in MgB2 we study a two band model with a clean sigma band and a dirty pi band. We present calculations of the vortex core size in both bands as a function of temperature and show that there exists a Kramer-Pesch effect in both bands even though only one of the bands is in the clean limit. We present calculations for different pi band diffusivities and coherence lengths.