Evidence of double-gap superconductivity in noncentrosymmetric Nb0.18Re0.82 single crystals

Abstract

We combine point contact spectroscopy with specific heat measurements to probe the superconducting state in noncentrosymmetric Nb0.18Re0.82 single crystals. The conductance spectra clearly exhibit a two-peak structure that is well reproduced within a two-band model with isotropic gaps in the spectrum. Such an observation is confirmed by distinct features of the specific heat both at low temperatures and in the range approaching the transition to the normal state. The analyses provide convincing evidence that the two-gap superconducting pairing is a robust feature of Nb0.18Re0.82