# Field dependence of the vortex-core sizes in dirty two-band superconductors

## TL;DR

This study investigates how vortex core sizes in dirty two-band superconductors vary with magnetic field and band parameters, revealing distinct behaviors depending on the measurement method and band diffusion disparities.

## Contribution

It provides a detailed analysis of vortex core size dependence on magnetic field and band parameters, highlighting differences between coherence length and quasiparticle density of states measurements.

## Key findings

- Vortex core sizes from coherence lengths and quasiparticle density vary differently with magnetic field.
- Near the upper critical field, both core size measures converge.
- Disparities in diffusion constants lead to different vortex core regimes.

## Abstract

We study the structure of Abrikosov vortices in two-band superconductors for different external magnetic fields and different parameters of the bands. The vortex core size determined by the coherence lengths are found to have qualitatively different behaviour from that determined by the quasiparticle density of states spatial variation. These different vortex core length scales coincide near the upper critical field, while the discrepancy between them becomes quite significant at lower fields. Within the diffusive approximation we demonstrate several generic regimes in the field dependence of the vortex core sizes determined by the disparity of diffusion constants in the two bands.