Symmetry and Gap Classification of the non-symmorphic SrPtAs

TL;DR

This paper classifies the possible superconducting gap structures in SrPtAs based on its symmetry properties, providing insights into its unconventional pairing and topological features.

Contribution

It offers a comprehensive symmetry-based classification of gap functions and constructs a tight-binding model for SrPtAs, clarifying its symmetry and topological characteristics.

Findings

Symmetry classification of gap functions in SrPtAs

Construction of a tight-binding model for the material

Clarification of symmetry and topology in non-symmorphic systems

Abstract

The hexagonal superconductor SrPtAs exhibits time-reversal-symmetry breaking below $T_c$, hinting at an unconventional pairing state. Therefore, the symmetry of the underlying crystal is important for the classification of possible gap structures and their mixing. Here, we use the generating point group D$_{6h}$ of SrPtAs for a comprehensive classification of the gap functions and to construct a tight-binding model. Our work clarifies questions of symmetry and topology in this non-symmorphic material and allows for better comparison with other hexagonal systems.