Superconductivity and Signatures of Nontrivial Topology in the Layered Compound Ca₂Pd₃Sb₄

Superconductivity in low-dimensional compounds has attracted considerable interest. In this study, we report a new layered Pd-based type-II superconductor, Ca2Pd3Sb4, which contains CaPd2Sb3 of CaBe2Ge2 blocks and CaPdSb of CeMg2Si2 blocks that are stacked alternately along the crystallographic c axis. The measured electrical resistivity, magnetic susceptibility, and specific heat of the Ca2Pd3Sb4 crystals, which are grown via a self-flux method, consistently demonstrate bulk superconductivity at about 1.30 K. Further analyses of the data indicate strong anisotropic behavior with the parameter gamma similar to 3.8 along the ab plane and c axis. Longitudinal magnetotransport measurements up to similar to 18 T reveal notable Shubnikov-de Haas oscillations with a single frequency (F = 462 T), demonstrating the existence of an electron pocket in the Brillouin zone. First-principles calculation reveals that the metallicity of the compound with a quasi-two-dimensional Fermi surface and the d orbitals of Pd and p orbitals of Sb are the main contributors to the total density of states at the Fermi level in Ca2Pd3Sb4. [GRAPHICS] .