Bulk 5f electronic states in uranium monochalcogenide US

TL;DR

This study uses soft x-ray photoemission spectroscopy to analyze the bulk electronic states of uranium monochalcogenide US, revealing that U 5f electrons exhibit an itinerant nature consistent with band-structure calculations.

Contribution

First to deduce the intrinsic bulk valence-band spectrum of US by separating surface state contributions, confirming the itinerant character of U 5f electrons.

Findings

U 5f electrons are mainly itinerant in US

Bulk valence-band spectrum aligns with band-structure calculations

Surface state contributions can be effectively separated

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 U 5f states were observed and have been interpreted that one has an itinerant character around the Fermi level (EF) and the other located below EF has a character of localized U 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 U 5f electrons from comparison with theoretical valence-band spectra obtained by band-structure calculation in the local-density approximation.