A photoemission study of ultra-thin palladium overlayers on low-index faces of silver

Abstract

The growth mode and electronic structure of palladium adsorbed on the (100) and (111) surfaces of silver at room temperature have been studied using LEED, Auger electron spectroscopy, angle-resolved photoemission and work function measurements. For both surfaces and overlayer grows in a layer-by-layer mode for approximately three monolayers after which it begins to relax to the bulk palladium structure. At submonolayer coverages a p(1*1) lattice gas occurs on the (100) surface whereas flat monolayer platelets are formed immediately on the (111) surface. Electron energy-parallel momentum (E-k/sub ///) dispersion relations were measured for palladium monolayers supported on both surfaces. For the monolayer. The difference in position and width of the resonant bound palladium 4d state on an isolated palladium atom supported on the (100) surface in comparison with an impurity atom in the bulk is consistent with the change in coordination number.