Electronic structure of semiconducting Ce Fe4 P12: Strong hybridization and relevance of single-impurity Anderson model

Semiconducting skutterudite Ce Fe4 P12 is investigated by synchrotron x-ray photoemission spectroscopy (PES) and x-ray absorption spectroscopy (XAS). Ce 3d core-level PES and 3d-4f XAS, in combination with single-impurity Anderson model (SIAM) calculations, confirm features due to f0, f1, and f2 configurations. The Ce 3d-4f resonant-PES spectra provide the Ce 4f density of states (DOS), which indicates the absence of a Kondo resonance at the Fermi level, but can still be explained by SIAM with a small gap in non- f DOS. While Ce 4f partial DOS from band structure calculations is consistent with the main Ce 4f DOS, the importance of SIAM for core-level PES and XAS spectra quantifies the mixed valence for semiconducting Ce Fe4 P12, derived from strong hybridization between non- f conduction and Ce 4f DOS.