Ag on Cu(001) and other noble-metal films studied by full-hemispherical photoelectron diffraction

An 8 monolayer Ag film has been deposited in situ on Cu(001) at room temperature. Its structure has been investigated by X-ray photoelectron diffraction, presented as full solid-angle intensity maps, and by low-energy electron diffraction. The formation of a compact Ag(111)-like overlayer with one preferential domain has been observed. Annealing the Ag film at about 300°C creates Ag islands on the Cu(001) substrate. The system is put into the context of eight other noble-metal (Ag, Au and Pt) films deposited on different substrates (Cu, Pt, Cu3Au, Bi2Sr2CaCu2O8+x). The crystalline orientation of the overlayers with respect to the substrate and the formation of a surface alloy are discussed.