Nodeless superconductivity in the noncentrosymmetric superconductor BiPd

Abstract

We report low-temperature thermal conductivity measurements on high-quality single crystalline α-BiPd, a noncentrosymmetric superconductor with T c ≃ 3.8 K. In zero magnetic field, the residual linear term κ 0/T is absent, indicating a full gap and suggesting dominant singlet pairing. Consistent with this picture, κ 0(H)/T shows weak field dependence in low field, but grows relatively fast in fields above 0.03 T (≃1/5H c2). Implications for the material's disputed high-field behavior are discussed, and constraints are placed on the previously proposed scenarios. © 2016 IOP Publishing Ltd