Surface-electronic structure of α-like Ce compounds

Photoemission studies with varying degrees of surface sensitivity are reported for the Ce 3d core-level and Ce 4f valence-band regions of the α-like Ce compounds ${\mathrm{CeIr}}_2$, ${\mathrm{CePd}}_3$, and ${\mathrm{CeRh}}_3$. In all cases studied, strong changes of the 4f electronic structure at the surface towards a more localized γ-like behavior are observed, requiring a reanalysis of previously reported photoemission spectra of α-like Ce compounds. Implications for an improved understanding of the surface-catalytic properties of Ce systems, as well as of the surface-electronic structure of narrow-band materials, are pointed out.