Electronic structure of actinide antimonides and tellurides from photoelectron spectroscopy

Abstract

Single crystals of $\mathrm{USb}$, $\mathrm{NpSb}$, $\mathrm{PuSb}$, $\mathrm{UTe}$, $\mathrm{NpTe}$ and $\mathrm{PuTe}$ were investigated by photoelectron spectroscopy, this included angular-resolved studies on the U compounds. The spectral features show little dependence on incident photon energy, suggesting they all contain comparable amounts of $5f$ and conduction character. In the case of $\mathrm{USb}$ interesting (and unexpected) momentum dependent effects are observed in the angular-resolved studies. In $\mathrm{PuTe}$, we confirm the presence of a strong three-peak structure near ${E}_{F}$, which has been interpreted as the signature of an intermediate valence state in similar materials. Hybridization of the $5f$ electrons with the conduction band is found within the series and the level of localization is shown to increase from $\mathrm{Te}$ to $\mathrm{Sb}$. A surprising correlation between the binding energy of the peak bearing most of the $5f$ weight in the photoemission spectrum and the magnetic moment is discovered within the series, for which some explanations are suggested.