Fractional vortex array realized at twin boundary in a nematic superconductor

TL;DR

This paper models vortex structures in a nematic superconductor with twin boundaries, revealing fractional vortices and their topological nature, which could be observed through vortex flow dynamics.

Contribution

It introduces a two-component Ginzburg-Landau model to describe fractional vortex states at twin boundaries in nematic superconductors.

Findings

Nematic vortex cores rotate 90 degrees across twin boundary.

At the twin boundary, vortices split into two fractional merons.

Vortex flow evolution can confirm the exotic vortex states.

Abstract

Within a framework of two-component Ginzburg-Landau theory as a model of superconducting FeSe, we study the spatial structure of vortex states in the presence of nematic twin boundary in an s + d wave nematic superconductor. The result shows that the orientation of the nematic vortex core is rotated 90 degrees across the twin boundary, and just at the twin boundary the nematic vortex becomes two fractional vortices with the topological nature of core-down and core-up merons. The exotic vortex states may be confirmed by observing the time evolution of vortex flow when the vortices are trapped in and escape from the nematic twin boundary.