Electronic Structure and4f-Hole Lifetime in Rare-Earth Borides

Abstract

X-ray photoelectron spectra of rare-earth borides exhibit systematic variations of the $4f$ lifetime width with the rare-earth number across the series, with the $4f$ binding energy, and with the number of boron neighbors. Valence band spectra and theoretical band structures make it possible to understand these observations in terms of an interatomic Auger process, here a $5d\ensuremath{\rightarrow}4f$ recombination, with simultaneous excitation of an electron-hole pair from boron $2sp$ states.