Structural stability, electronic structure and f hybridization of PuM3 and Pu3M (M = Ge, Sn, Pb) intermetallic compounds

The ground-state equilibrium properties, the electronic structure and the structural stability of PuM3 and Pu3M (M = Ge, Sn, Pb) compounds are studied using density functional theory in the presence and in the absence of spin-orbit coupling (SOC). The calculated lattice parameters are in good agreement with the experimental values. The results for the electronic density of states (DOS) show that the Fermi level is situated in a "pseudogap" as a common feature for all these compounds, similar to what has been found for the PuTe system. The reason for the creation of the "pseudogap" is due to the strong pdf hybridization. The most unusual feature in the DOS of Pu3M compounds is the presence of a gap at the interval from -7.5 to -4eV, which is absent in the DOS of PuGe3 and PuSn3 and is smaller for PuPb3. In addition to that there is a strong hybridization between Pu 6d and M p orbitals in both PuM3 and Pu3M compounds. Also the cohesive energy calculations show that Pu3M structures are more stable than PuM3 structures. (c) 2006 Elsevier B.V. All rights reserved.