# Symmetry of superconducting pairing in non-pseudospin electron bands

## TL;DR

This paper develops a symmetry classification for superconducting gaps in non-pseudospin electron bands, revealing unique cases where triplet gaps do not follow traditional transformation rules, affecting nodal structures.

## Contribution

It introduces a symmetry classification framework for non-pseudospin bands and identifies exceptional cases impacting triplet gap transformations and nodal structures.

## Key findings

- Four exceptional cases where triplet gaps do not transform as pseudovectors.
- Construction of symmetry-compliant multiband pairing Hamiltonians.
- Implications for the nodal structure in superconductors.

## Abstract

We develop the symmetry classification of superconducting gap functions in electron bands that do not transform under the crystal point group operations like the pure spin-1/2 states. The Bloch state bases in twofold degenerate bands with spin-orbit coupling are defined across the Brillouin zone in the way which satisfies the symmetry and continuity requirements. These bases are used to construct general multiband pairing Hamiltonians in centrosymmetric crystals. Focusing on single-band pairing, four exceptional cases are identified in which the triplet gap function does not transform under the point group operations as a pseudovector, with a significant impact on the nodal structure.