4f-derived electronic structure at the surface and in the bulk of α-Ce metal

Resonant photoemission experiments at the 4→d4f absorption threshold of {α}-Ce are reported. Separation of spectral bulk and surface contributions is achieved by quenching the Ce-derived surface emission with a Dy overlayer. As in previous works, the outermost surface layer of {α}-Ce is found to be {γ}-like. In contrast to theoretical predictions, however, the ``4f⁰ final-state'' signal of the surface is shifted to higher binding energy with respect to {α}-Ce and {γ}-Ce bulk emissions. The data are analyzed in the framework of the single-impurity Anderson model. Taking into account the influence of the autoionization channel to resonance process, a larger $4f$ hybridization is concluded than assuming solely a direct photoemission event.