Distinct magnetic signatures of fractional vortex configurations in multiband superconductors

TL;DR

This paper investigates fractional vortex configurations in multiband superconductors using a two-component Ginzburg-Landau model, revealing unique magnetic signatures that can be detected experimentally.

Contribution

It demonstrates how fractional vortices form and stabilize in multiband superconductors and identifies their distinct magnetic signatures for experimental detection.

Findings

Fractional vortices appear due to band-specific vortex entry thresholds.

These vortices stabilize near the sample edges.

Distinct magnetic signatures can be observed in magnetization and susceptibility measurements.

Abstract

Vortices carrying fractions of a flux quantum are predicted to exist in multiband superconductors, where vortex core can split between multiple band-specific components of the superconducting condensate. Using the two-component Ginzburg-Landau model, we examine such vortex configurations in a two-band superconducting slab in parallel magnetic field. The fractional vortices appear due to the band-selective vortex penetration caused by different thresholds for vortex entry within each band-condensate, and stabilize near the edges of the sample. We show that the resulting fractional vortex configurations leave distinct fingerprints in the static measurements of the magnetization, as well as in ac dynamic measurements of the magnetic susceptibility, both of which can be readily used for the detection of these fascinating vortex states in several existing multiband superconductors.