The ThIrSi superconductor, with Tc=6.5 K, is expected to show unusual features in view of its noncentrosymmetric structure and the presence of heavy elements featuring a sizable spin-orbit coupling. Here, we report a comprehensive study of its electronic properties by means of local-probe techniques: muon-spin rotation and relaxation ({\textmu}SR) and nuclear magnetic resonance (NMR). Both the superfluid density ρsc(T) (determined via transverse-field {\textmu}SR) and the spin-lattice relaxation rate T1−1(T) (determined via NMR) suggest a nodeless superconductivity. Furthermore, the absence of spontaneous magnetic fields below Tc, as evinced from zero-field {\textmu}SR measurements, indicates a preserved time-reversal symmetry in the superconducting state of ThIrSi. Temperature-dependent upper critical fields as well as field-dependent superconducting muon-spin relaxations suggest the presence of multiple superconducting gaps in ThIrSi.
@article{arxiv.2302.08075,
title = {Nodeless superconductivity in the noncentrosymmetric ThIrSi compound},
author = {D. Tay and T. Shang and Priscila F. S. Rosa and F. B. Santos and J. D. Thompson and Z. Fisk and H. -R. Ott and T. Shiroka},
journal= {arXiv preprint arXiv:2302.08075},
year = {2023}
}