Photoemission study of an f-electron superconductor: CeRu₂

Photoemission study has been performed for a high-quality single crystal of CeRu₂, including resonant photoemission near the Ce 4^→d4f absorption edge and high-resolution photoemission at a low-photon energy. Resonant photoemission study provides evidence for the large hybridization between Ce 4f and conduction electrons, indicating mixed-valence in CeRu₂. It is found that the line shape of the high-resolution spectrum near the Fermi level depends on the experimental conditions and the sample surface treatment. Comparison of photoemission data to the calculated density of states reveals that band calculations provide a reasonably good description of the electronic structure of CeRu₂.