Fully gapped superconductivity without sign reversal in the topological superconductor PbTaSe2
Abstract
We investigate the superconducting gap function of topological superconductor PbTaSe2. Temperature, magnetic field, and three-dimensional (3D) field-angle dependences of the specific heat prove that the superconductivity of PbTaSe2 is fully-gapped, with two isotropic s-wave gaps. The pair-breaking effect is probed by systematically increasing non-magnetic disorders through H+-irradiations. The superconducting transition temperature, Tc, is found to be robust against disorders, which suggests that the pairing should be sign-preserved rather than sign-reversed.
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