Fermi Surface Topology and Open-Orbit Magneto-transport in Superconducting Pd₃Bi₂Se₂

We report magneto-transport and quantum oscillation measurements on single crystals of the superconducting topological metal Pd₃Bi₂Se₂. From these studies we mapped out the Fermi surface, revealing tubular structures oriented parallel to the ab-planes. These tubes carry open electron orbits when the magnetic field is applied along the c* direction and account for the observed non-saturating magnetoresistance and nonlinear, sign-changing Hall effect. Through angular-dependent de Haas–van Alphen (dHvA) oscillations and DFT calculations, we identify a dominant frequency (F_α = 150 T) corresponding to an approximately ellipsoidal electron pocket centered at 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 F_α orbit. The interplay of bulk superconductivity, nontrivial band topology, and open Fermi-surface orbits establishes Pd₃Bi₂Se₂ as a promising platform for exploring unconventional magneto-transport in correlated topological materials.