Berry phase in Magnetic Superconductors

TL;DR

This paper develops a theory of superconductivity in magnetic systems with nontrivial topological band structures, revealing that gauge flux leads to nodes in the superconducting gap where the Fermi surface intersects gauge strings.

Contribution

It introduces a novel theoretical framework for understanding superconductivity in magnetic materials with topologically nontrivial electronic bands.

Findings

Superconducting gap exhibits nodes at gauge string intersections.

Gauge flux affects the phase structure of wavefunctions in superconductors.

The theory applies to both 2D and 3D magnetic systems.

Abstract

In magnetic systems, electronic bands often acquire nontrivial topological structure characterized by gauge flux distribution in momentum (k)-space. It sometimes follows that the phase of the wavefunctions cannot be defined uniquely over the whole Brillouin zone. In this Letter we develop a theory of superconductivity in the presence of this gauge flux both in two- and three-dimensional systems. It is found that the superconducting gap has "nodes" as a function of k where the Fermi surface is penetrated by a gauge string.