Valence Fluctuations and Quasiparticle Multiplets in Pu Chalcogenides and Pnictides

The spectra of Pu chalcogenides and pnictides are computed with 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.