Electronic Structure and Formation Heat of Pu3M and PuM3 (M=Ga, In, Sn and Ge) Compounds

The equilibrium structure, electronic structure, and formation heat of Pu3M (PuM3) (M=Ga, In, Sn, and Ge) compounds with AuCu3 structure have been calculated using full potential linear augmented plane wave (FPLAPW) method within generalized-gradient approximation (GGA) including spin-orbit coupling (SOC) and spin polarization (SP). The calculated lattice parameters are in good agreement with the experimental values. Density of state analysis shows hybridization effects between Pu and M are governed by the competitions depending on the M amount: Pu 6d-Pu 5f, M p-Pu 6d, and M sp-M sp interactions. Electronegativity difference and electronic hybridization effect are two important factors to influence the formation heat and stability of Pu3M (PuM3) compounds. The larger is the electronegativity difference and the lower is M s-band or p-band center relative to the Fermi energy, the more negative is the formation heat and the more stable are Pu3M (PuM3) compounds.