Pairing state in multicomponent superconductors

TL;DR

This paper uses microscopic weak coupling theory to predict the pairing states in multicomponent superconductors with various crystal symmetries, highlighting the typical breaking of time-reversal symmetry in singlet cases.

Contribution

It provides a theoretical prediction of pairing states and symmetry-breaking phenomena in multicomponent superconductors based on their crystal symmetry.

Findings

Superconducting phases often break time-reversal symmetry in singlet cases.

Triplet superconductors generally have non-magnetic order parameters.

Predictions apply to cubic, hexagonal, and tetragonal crystal symmetries.

Abstract

We use the microscopic weak coupling theory to predict the pairing state in superconductors of cubic, hexagonal, or tetragonal symmetry, where the order parameter is multicomponent, i.e., transforms according to either a 2-dimensional or a 3-dimensional representation of the crystal point group. We show that the superconducting phase usually breaks the time-reversal symmetry for singlet multicomponent superconductors. The superconducting order parameter for triplet superconductors in most cases turns out to be non-magnetic.