Character of valence-band states in the Kondo surface alloys CeAgx/Ag(111) and CePt5/Pt(111)

The crystal and electronic structures of the CePt5 and CeAgx surface alloys have been investigated by means of low-energy electron diffraction and angle-resolved photoelectron spectroscopy. From measurements performed near the 4d-4f absorption edge we were able to infer the weight of the 4f-electron spectral function with respect to the single-particle density of states. While the typical Kondo features at the Fermi energy (Kondo resonance and spin-orbit partner) in the CePt5 surface alloy were observed, only the f0 ionization structure and the spin-orbit partner were present in the CeAgx case. From our experiments, and by comparison to model calculations, we were able to estimate the Kondo temperature in the two systems and investigate parameters contributing to the hybridization strength