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 $\mathrm{\Delta }\left(0\right)/k_B{T}_c$ = 1.73(2).

• Received 14 November 2021
• Revised 3 February 2022
• Accepted 21 March 2022

DOI:https://doi.org/10.1103/PhysRevB.105.094523