Many-body electronic structure of metallicα-uranium

Abstract

We present results for the electronic structure of $\ensuremath{\alpha}$-uranium using a recently developed quasiparticle self-consistent GW (QSGW) method. This is the first time that the $f$-orbital electron-electron interactions in an actinide have been treated by a first-principles method beyond the level of the generalized gradient approximation (GGA) or the local-density approximation (LDA) to the density-functional theory (DFT). We show that the QSGW approximation predicts an $f$-level shift upward of about 0.5 eV with respect to the other metallic $s\ensuremath{-}d$ states and that there is a significant $f$-band narrowing when compared to LDA band-structure results. We predict a considerable QSGW enhancement of the linear coefficient of specific heat. Nonetheless, because of the overall low $f$-electron occupation number in uranium, ground-state properties and the occupied band structure around the Fermi energy are not significantly affected. The correlations predominate in the unoccupied part of the $f$ states. This provides the first formal justification for the success of LDA and GGA calculations in describing the ground-state properties of this material.