Electronic structure ofδ-plutonium and of single Al, Ga, and Sc impurities inδ-plutonium

Fully relativistic Korringa-Kohn-Rostoker calculations are reported for {δ}-Pu (fcc) at the experimentally observed {δ}-Pu and {α}-Pu densities. The calculated band structure at the {δ} density is compared with previous results. By using the Green's-function approach the density of states (DOS) and the partial local densities of states (PDOS) functions are presented for {δ}-Pu and for single impurities of Al, Ga, and Sc in {δ}-Pu. The effects of alloying and the stabilization of the {δ} phase are discussed in terms of the electronic structure of the host and the impurity PDOS functions. It is found that the impurity DOS functions below EF are similar at the {δ}-Pu density indicating similar changes in the electronic structure of {δ}-Pu upon alloying with these three metals. The coupling between the impurity p3/2 states and the Pu f5/2 states, which cut through EF, should yield diffuse f bands and no sharp Fermi surfaces for these materials. We speculate that the movement of these diffuse f bands relative to the s-d bands leads to less f bonding and the stability of the fcc phase.