Superconductivity in Noncentrosymmetric LaNiZn Single Crystal

In this study, we observed bulk superconductivity in LaNiZn below Tc = 1.5 K, as confirmed by its electrical transport and specific heat capacity (Delta Cel/gamma Tc = 1.41). The upper critical fields along the hexagonal crystallographic c-axis and in the basal plane at 30 mK were found to be 0.36 and 0.24 T, respectively, suggesting mainly an orbital mechanism for field-induced depairing and a negligible spin triplet component in the superconducting order parameter. The angular dependence of Hc2 is explained by an effective mass model with an oblate-shaped effective Fermi surface. Our experimental and band calculation under local density approximation results suggested that LaNiZn is a Bardeen- Cooper-Schrieffer s-wave-type superconductor in the dirty limit, possibly involving multiple bands.