Electron spectroscopy in narrow band f-electron compounds

Abstract

SummaryWe show by the combined means of high-resolution photoemission measurements at low temperatures on uranium and cerium compounds (including heavy fermions) and systematic resonant data on a series of uranium narrow-band compounds, that the "two-peaked" f-electron spectrum commonly found in cerium compounds is also found in uranium compounds. The 5f spectra consist of a superposition of features consistent with the band structure ground state plus a 5f satellite due to poorly-screened final state effects.

XPS valence bands of the URh1−xRuxGe solid solutions

“…It is worthwhile to mention that the position of this peak is usually taken as a measure of the localized 5f character. According to Arko et al [10] XPS spectra can be analyzed in terms of multiple channels. A well-screened structure lies at the Fermi level and a poorly screened structure at lower energy of about 1 eV.…”

Electronic structure ofUH3thin films prepared by sputter deposition

“…23 In these systems, the ground state has weakly itinerant 5f electrons, often via hybridization with the conduction band, e.g., in the heavy-fermion or Kondo systems. 24 Photoemission of a 5f electron, leaving a 5f photohole, then leads to two different final states.…”

“…In the second final state, the 5f photohole is screened by the filling of an empty 6d state. 23 Energetically this situation is less favorable, and the corresponding photoemission line lies at higher binding energy (poorly screened component). With approaching localization of the f state, when hybridization with extended states decreases, the probability of the d screened final state increases.…”

Metallic, band-like behaviour of EuBa2Cu3O6.7 as seen from UPS spectra Comparison with band calculations

“…We do not rule out correlation. Indeed, we believe the problem may be similar to heavy fermions [20] where correlations within a well-defined band structure lead to photoemission satellites in the valence bands [21]. Even NiO is now being interpreted in this fashion [22].…”