Parity Violation in a Single Domain of Spin-Triplet Sr2RuO4 Superconductors

TL;DR

This paper reports the observation of an unconventional parity-violating vortex in single-domain Sr2RuO4 superconductors, suggesting a helical vortex structure with topological properties, revealed through transport measurements.

Contribution

It introduces the first experimental evidence of parity violation in a single domain of Sr2RuO4, indicating a helical vortex with topological characteristics.

Findings

Anomalous voltage components even in bias current

Evidence of a helical vortex structure with Hopf invariant

Parity violation linked to vortex topology

Abstract

We observed an unconventional parity-violating vortex in single domain Sr2RuO4 single crystals using a transport measurement. The current-voltage characteristics of submicron Sr2RuO4 shows that the induced voltage has anomalous components which are even function of the bias current. The results may suggest that the vortex itself has a helical internal structure characterized by a Hopf invariant (a topological invariant). We also discuss that the hydrodynamics of such a helical vortex causes the parity violation to retain the topological invariant.