Superconductivity in the Endohedral Ga Cluster Compound PdGa

Superconductivity is observed below Tc = 1.6 K in an endohedral Ga cluster compound PdGa₅ using magnetization and heat capacity measurements. Electronic structure calculations show that the density of states (DOS) at the Fermi level is dominated by Ga s and p states and that the overall shape of DOS is similar to what was found in other endohedral Ga cluster superconductors, such as MoₓGa₅ₓ₊₁, ReGa₅, and T₂Ga₉ (T = Rh and Ir). Our results provide a more complete picture of the relationship between the valence electron count and superconductivity in the family of endohedral Ga cluster superconductors.