Magnetic field delocalization and flux inversion in fractional vortices in two-component superconductors

TL;DR

This paper explores magnetic field behavior in two-component superconductors, revealing delocalized fields and flux inversion phenomena in fractional vortices, which differ significantly from single-component vortex characteristics.

Contribution

It uncovers conditions for magnetic field localization and introduces flux inversion in fractional vortices, a novel effect in two-component superconductors.

Findings

Localized magnetic fields only for integer flux vortices and specific half-quantum vortices.

Most fractional vortices exhibit delocalized magnetic fields with slow decay.

Magnetic field inversion occurs in half of the parameter space for fractional vortices.

Abstract

We demonstrate that, in contrast to the single-component Abrikosov vortex, in two-component superconductors vortex solutions with exponentially screened magnetic field exist only in exceptional cases: in the case of vortices carrying an integer number of flux quanta, and in a special parameter limit for half-quantum vortices. For all other parameters the vortex solutions have delocalized magnetic field with a slowly decaying tail. Furthermore, we demonstrate a new effect which is generic in two-component systems but has no counterpart in single-component systems: on exactly half of the parameter space of the $U(1)\times U(1)$ Ginzburg-Landau model, the magnetic field of a generic fractional vortex inverts its direction at a certain distance from the vortex core.