Surface and bulk electronic structure of Ce metal studied by high-resolution resonant photoemission

High-resolution resonant photoemission (PE) at the 4d→4f and 3d→4f thresholds is applied to study the electronic structure of Ce metal. Due to the different surface sensitivities, the resulting 4f PE spectra, which are almost free of non-4f background, reflect directly a substantial change in 4f electronic structure of α-Ce metal towards γ-like behavior at the surface. This finding resolves a longstanding discrepancy between the results of surface-sensitive 4f PE and those of bulk model calculations. Pure surface and bulk 4f PE signals are derived for α-Ce metal.