Evidence for non-unitary triplet-pairing superconductivity in noncentrosymmetric TaRuSi and comparison with isostructural TaReSi
The study investigated superconducting properties in noncentrosymmetric ternary superconductors TaXSi (TaReSi and TaRuSi) using muon spin rotation ($μ$SR) and density functional theory. While TaReSi shows isotropic s-wave superconductivity, TaRuSi exhibits multi-gap superconductivity and broken time-reversal symmetry (TRS). DFT suggests this TRS breaking in TaRuSi arises from a non-unitary triplet pairing state, which is consistent with the relatively weak spin-orbit coupling in that material.