Odd Parity and Line Nodes in Non-Symmorphic Superconductors

TL;DR

This paper challenges previous group theory-based claims by showing that non-symmorphic superconductors with twofold screw axes can host line nodes in odd parity order parameters, impacting the understanding of unconventional superconductors.

Contribution

It demonstrates that certain non-symmorphic symmetries allow odd parity superconducting states to have line nodes, contrary to prior assumptions based on symmorphic symmetry arguments.

Findings

Half of the odd parity representations vanish on specific Brillouin zone faces.

Implications for superconductors like UPt3, UBe13, Li2Pt3B, and Na4Ir3O8.

Revises understanding of symmetry constraints in non-symmorphic superconductors.

Abstract

Group theory arguments have been invoked to argue that odd parity order parameters cannot have line nodes in the presence of spin-orbit coupling. In this paper we show that these arguments do not hold for certain non-symmorphic superconductors. Specifically, we demonstrate that when the underlying crystal has a twofold screw axis, half of the odd parity representations vanish on the Brillouin zone face perpendicular to this axis. Many unconventional superconductors have non-symmorphic space groups, and we discuss implications for several materials, including UPt3, UBe13, Li2Pt3B and Na4Ir3O8.