Skyrmionic state and stable half-quantum vortices in chiral p-wave superconductors

TL;DR

This paper demonstrates that in chiral p-wave superconductors, skyrmions composed of half-quantum vortices can be thermodynamically stable, unlike fractional flux vortices which are usually unstable in bulk samples.

Contribution

The study reveals a regime where skyrmions, formed by separated half-quantum vortices, are stable topological defects in chiral p-wave superconductors, contrasting with prior instability of fractional vortices.

Findings

Skyrmions are stable in certain regimes of chiral p-wave superconductors.

Half-quantum vortices can form stable skyrmions under external fields.

Integer flux vortex lattices are not thermodynamically favored in these conditions.

Abstract

Observability of half-quantum vortices and skyrmions in p-wave superconductors is an outstanding open question. Under the most common conditions, fractional flux vortices are not thermodynamically stable in bulk samples. Here we show that in chiral p-wave superconductors, there is a regime where, in contrast lattices of integer flux vortices are not thermodynamically stable. Instead skyrmions made of spatially separated half-quantum vortices are the topological defects produced by an applied external field.