Bulk5felectronic states of the uranium monochalcogenide US as seen via soft x-ray photoemission

Abstract

We have investigated the electronic states of the uranium monochalcogenide US, which is a typical ferromagnetic uranium compound, using soft x-ray photoemission spectroscopy (SX-PES). In early ultraviolet photoemission spectroscopy studies, two peak structures of the $\text{U}\text{ }5f$ states were observed and have been interpreted that one has an itinerant character around the Fermi level $({E}_{\text{F}})$ and the other located below ${E}_{\text{F}}$ has a character of localized $\text{U}\text{ }5f$ electrons. In this study, the intrinsic bulk valence-band spectrum of US was first deduced by estimating the contribution of surface states to the valence-band spectrum using core-level photoemission spectra. We conclude that the electronic structure of US can be basically described by the itinerant nature of the $\text{U}\text{ }5f$ electrons from comparison with theoretical valence-band spectra obtained by band-structure calculation in the local-density approximation.