Multigap superconductivity in chiral noncentrosymmetric TaRh2 B2

Abstract

We report the observation of multigap superconductivity in TaRh2B2. We show TaRh2B2 is a bulk type-II superconductor with a transition temperature Tc=6.00(5) K. We present transverse-field muon spin relaxation data where the superconducting gap can be fit using a two-gap s+s-wave model. We also report the zero-field electronic specific heat in the superconducting state that is best described by the same s+s model, providing further evidence of multiband behavior in this superconductor. Zero-field muon spin relaxation measurements show time-reversal symmetry is preserved in the superconducting state. We demonstrate that TaRh2B2 has an upper critical field of 15.2(1) T, which is significantly higher than previously reported and exceeds the Pauli limit.