Nonreciprocal transport in a non-centrosymmetric bulk superconductor

Non-centrosymmetric superconductors have attracted considerable interest in view of rich exotic properties. Recently discovered nonlinear electric transport in superconducting states created the renewed interest in non-centrosymmetric superconductors, offering opportunities of investigating new properties and functionalities. Nonlinear superconducting transport has been investigated in superconducting chiral nanotubes [1] and 2D non-centrosymmetric superconductors [2] so far, but there has been no report of 3D non-centrosymmetric superconductors. In this presentation, we report the observation of the nonlinear superconducting transport in bulk superconductor PbTaSe₂ with three-fold rotational symmetry. Observed nonlinear resistance was enhanced in superconducting states and characteristic selection rule corresponding to trigonal crystal symmetry has been confirmed. [1] F. Qin et al., Nat. Comm. 8, 14465 (2017). [2] R. Wakatsuki et al., Sci. Adv. 3, e1602390 (2017).