Fermi Surface Topology and Magneto-transport Properties of Superconducting Pd₃Bi₂Se₂

Pd₃Bi₂Se₂ is a rare realization of a superconducting metal with a non-zero Z₂ topological invariant. We report the growth of high-quality single crystals of layered Pd₃Bi₂Se₂ with a superconducting transition at Tc ~ 0.80 K and upper critical fields of ~10 mT and ~5 mT for the in-plane and out-of-plane directions, respectively. Our density functional theory (DFT) calculations reveal three pairs of doubly degenerate bands crossing the Fermi level, all displaying clear three-dimensional dispersion consistent with the overall low electronic anisotropy (<2). The multiband electronic nature of Pd₃Bi₂Se₂ is evident in magneto-transport measurements, yielding a sign-changing Hall resistivity at low temperatures. The magnetoresistance is non-saturating and follows Kohler's scaling rule. We interpret the magneto-transport data in terms of open orbits that are revealed in the DFT-calculated Fermi surface. de Haas-van Alphen (dHvA) oscillation measurements using torque magnetometry on single crystals yield four frequencies for out-of-plane fields: F_α = (150 ± 26)T, F_β = (293 ± 10)T, F_γ = (375 ± 20)T, and F_η = (1017 ± 12)T, with the low frequency dominating the spectrum. Through the measurement of angular dependent dHvA oscillations and DFT calculations, we identify the F_α frequency with an approximately ellipsoidal electron pocket centered on the L₂ point of the Brillouin zone. Lifshitz-Kosevich analysis of the dHvA oscillations reveals a small cyclotron effective mass: m^* = (0.11 ± 0.02) m₀ and a nontrivial Berry phase for the dominant orbit. The presence of nontrivial topology in a bulk superconductor positions Pd₃Bi₂Se₂ as a potential candidate for exploring topological superconductivity.