Bulk electronic structure of Ce compounds studied by x-ray photoemission and x-ray absorption spectroscopies.

Abstract

The results of a systematic x-ray absorption spectroscopy (XAS) investigation across the Ce ${\mathit{M}}_{4,5}$ and ${\mathit{N}}_{4,5}$ thresholds for ${\mathrm{CeCo}}_{2}$, ${\mathrm{CeRh}}_{2}$, ${\mathrm{CeRh}}_{3}$, and ${\mathrm{Ce}}_{7}$${\mathrm{Rh}}_{3}$ are reported. The data have been analyzed by employing a simplified version of the Anderson single-impurity model in the infinitely narrow bandwidth approximation for the extended states. The model has been applied to the bulk Ce 3d XPS spectra of these compounds. The bulk values of the Ce 4f-occupation number ${\mathit{n}}_{\mathit{f}}$ and of the 4f extended states interaction strength \ensuremath{\Delta} obtained have been checked by applying the model to the bulk sensitive Ce ${\mathit{M}}_{4,5}$ XAS line shapes. The possible influence of a configuration dependence of the hybridization strength in the ${\mathit{n}}_{\mathit{f}}$ and \ensuremath{\Delta} determination has been discussed. This joint analysis allowed us to obtain an accurate estimation of ${\mathit{n}}_{\mathit{f}}$. The Ce ${\mathit{N}}_{4,5}$ XAS line shapes are in agreement with the deduced trend of the 4f electrons interaction strength with the conduction electrons in the bulk.