Valence fluctuations and quasiparticle multiplets in plutonium chalcogenides and pnictides

The spectra of Pu chalcogenides and pnictides are computed with dynamical mean field theory within the local density approximation (LDA+DMFT) and interpreted with the aid of valence histograms and slave-boson calculations. We find the chalcogenides are mixed-valent (n(f)=5.2) materials with a strongly T-dependent low-energy density of states and a triplet of quasiparticle peaks below the Fermi level. Furthermore, we predict a doublet of reflected peaks above the Fermi level. In the pnictides, the raising of f(6) states relative to f(5) suppresses valence fluctuations, resulting in integral-valent (n(f)=5.0) local-moment metals.