One-dimensional fermi liquid and symmetry breaking in the vortex core

TL;DR

This paper investigates how localized fermions in vortex cores can cause symmetry breaking, leading to asymmetric vortex shapes through a spontaneous admixture of p-wave components in s-wave superconductors.

Contribution

It introduces a mechanism for symmetry breaking in vortex cores caused by fermion-induced instability and spontaneous p-wave admixture in conventional s-wave vortices.

Findings

Fermions in vortex cores can destabilize symmetric structures.

Spontaneous p-wave component leads to asymmetric vortex shapes.

The phenomenon parallels symmetry breaking in electroweak Z-strings.

Abstract

Fermions localized within vortex cores can form one-dimensional Fermi liquids. The nonzero density of states in these Fermi-liquids can lead to instability of the symmetric structure of the vortex core. We consider a symmetry breaking which is obtained due to spontaneous admixture of the spin-triplet p-wave component of the order parameter in conventional s-wave vortex in the presence of magnetic field. This occurs at low enough temperature and leads to an asymmetric shape of the vortex core. Similar phenomenon of the symmetry breaking induced by the core fermions occurs in electroweak $Z$-strings (S.G. Naculich, Phys. Rev. Lett., 75 (1995), 998).