Vortices with Fractional Flux Quanta in Multi-Band Superconductors

TL;DR

This paper explores the formation and behavior of vortices with fractional flux quanta in multi-band superconductors, revealing how broken time-reversal symmetry and domain walls influence vortex configurations under magnetic fields.

Contribution

It introduces the concept of fractional flux vortices in multi-component superconductors with broken time-reversal symmetry, highlighting their unique magnetic field distributions and stability conditions.

Findings

Vortices dissociate into fractional flux quanta in multi-band superconductors.

Domain walls connect states with opposite chiralities, affecting vortex arrangements.

Magnetic field distribution becomes ribbon-shaped at domain walls under external fields.

Abstract

In superconductors with three or more components, time-reversal symmetry may be broken when the inter-component couplings are repulsive, leading to a superconducting state with two-fold degeneracy. When prepared carefully there is a stable domain wall on a constriction which connects two bulks in states with opposite chiralities. Applying on external magnetic field, vortices in different components dissociate with each other, resulting in a ribbon shape distribution of magnetic field at the position of domain wall.