Odd parity and line nodes in nonsymmorphic 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 Rapid Communication we show that these arguments do not hold for certain nonsymmorphic 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 nonsymmorphic space groups, and we discuss implications for several materials, including ${\text{UPt}}_{3}$, ${\text{UBe}}_{13}$, ${\text{Li}}_{2}{\text{Pt}}_{3}\text{B}$, and ${\text{Na}}_{4}{\text{Ir}}_{3}{\text{O}}_{8}$.