Photoemission study of the epitaxial Ce/Pd(100) interface

The electronic state of cerium has been investigated by core-level and valence band photoemission spectroscopy in ultra-thin films of a Ce-Pd. monocrystalline compound obtained by epitaxial growth. Careful characterization of the surface leads us to the conclusion that the Ce configuration admixture is strongly reduced in the surface layer. By evaporating one extra monolayer of Pd, we were able to obtain core-level photoemission spectra without any surface contribution and to evidence an exceptional configuration mixing for the bulk ground state. The 4f spectral function obtained from photoemission measurements at the N-4.5 threshold also exhibits a very singular behavior and shed some new Light on the description of highly-hybridized 4f states in Ce compounds