PHOTOEMISSION-STUDY OF AN AUPDAU(111) MULTILAYER GROWN BY MBE

An Au/Pd/Au(111) multilayer system grown by molecular beam epitaxy has been studied by high-resolution x-rav photoelectron spectroscopy. An analysis of the dependence of the relative intensity of the Au and Pd core-level XPS lines on the take-off angle indicates that the thicknes s of the Pd sandwhich layer is approximately 5 monolayers. The photoel ectron spectra show the presence of more than one chemical environment for each element and suggest that the core-level photoelectron spectr a of Pd atoms in the interfacial layers and the inner layers of the Pd sandwich are split by approximately 0.6 eV. The photoelectron spectra of the valence band show that the Pd sandwich retains the high densit y of states at the Fermi energy that is characteristic of Pd metal.