Electronic structure of delta -plutonium and of single Al, Ga, and Sc impurities in delta -plutonium.

Abstract

Fully relativistic Korringa-Kohn-Rostoker calculations are reported for \ensuremath{\delta}-Pu (fcc) at the experimentally observed \ensuremath{\delta}-Pu and \ensuremath{\alpha}-Pu densities. The calculated band structure at the \ensuremath{\delta} 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 \ensuremath{\delta}-Pu and for single impurities of Al, Ga, and Sc in \ensuremath{\delta}-Pu. The effects of alloying and the stabilization of the \ensuremath{\delta} 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 ${E}_{F}$ are similar at the \ensuremath{\delta}-Pu density indicating similar changes in the electronic structure of \ensuremath{\delta}-Pu upon alloying with these three metals. The coupling between the impurity ${p}^{3/2}$ states and the Pu ${f}^{5/2}$ states, which cut through ${E}_{F}$, 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.