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 γ ∼ 3.8 along the ab plane and c axis. Longitudinal magnetotransport measurements up 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.