Electronic structure of the heavy fermion superconductor Ce2PdIn8: Experiment and calculations

The electronic structure of a heavy-fermion superconductor Ce2PdIn8 was investigated by means of X-ray photoelectron spectroscopy (XPS) and ab initio density functional band structure calculations. The Ce 3d core-level XPS spectra point to stable trivalent configuration of Ce atoms that is also reproduced in the band structure calculations within the generalized gradient approximation GGA+U approach. Analysis of the 3d9f2 weight in the 3d XPS spectra within the Gunnarsson-Schönhammer model suggests that the onsite hybridization energy between Ce 4f and the conduction band states, Δfs, is ∼120 meV, which is about 30 meV larger than Δfs in isostructural Ce2TIn8 compounds with T = Co, Rh, and Ir. Taking into account a Coulomb repulsion U on both the Ce 4f and Pd 4d states in electronic band structure calculations, a satisfactory agreement was found between the calculated density of states (DOS) and the measured valence band XPS spectra.