Superconductivity in noncentrosymmetric NbReSi investigated by muon spin rotation and relaxation

Noncentrosymmetric materials are a promising paradigm to explore unconventional superconductivity. In particular, several Re-containing noncentrosymmetric materials have attracted considerable attention due to a superconducting state with broken time-reversal symmetry. A comprehensive study on the superconducting ground state of NbReSi was performed using magnetization, resistivity, and muon spin rotation/relaxation measurements. Zero-field muon spectroscopy results showed the absence of spontaneous magnetic field below the superconducting transition temperature, ${T}_c$ = 6.29(3) K, indicating the preserved time-reversal symmetry. Transverse field muon spin rotation measurements confirms an $s$-wave nature of the sample with $\mathrm{\ensuremath{\Delta}}(0)/{k}_B{T}_c$ = 1.73(2).