Gap structure of the non-symmorphic superconductor LaNiGa2 probed by muSR

TL;DR

This study uses muSR measurements to investigate the gap structure of LaNiGa2, revealing a two-band superconductor with strong interband coupling and supporting its classification as a fully-gapped, nonunitary spin-triplet superconductor.

Contribution

It provides the first muSR-based evidence for the two-band nature and strong interband coupling in LaNiGa2, supporting its unconventional superconductivity.

Findings

Superfluid density fits a two-band model with strong interband coupling.

Vortex core size dependence suggests single-band-like behavior.

Supports LaNiGa2 as a fully-gapped, nonunitary spin-triplet superconductor.

Abstract

We report muon spin rotation (muSR) measurements of the temperature dependence of the absolute value of the magnetic penetration depth and the magnetic field dependence of the vortex core size in the mixed state of the non-symmorphic superconductor LaNiGa2. The temperature dependence of the normalized superfluid density is shown to be well described by a two-band model with strong interband coupling. Consistent with a strong coupling of the superconducting condensates in two different bands, we show that the field dependence of the vortex core size resembles that of a single-band superconductor. Our results lend support to the proposal that LaNiGa2 is a fully-gapped, internally antisymmetric nonunitary spin-triplet superconductor.