Temperature-dependent formation and evolution of the interfacial dislocation network of Ag/Pt(111)

We have investigated the formation of a dislocation network that develops at the interface of a Ag film on Pt(111) and its evolution with film thickness at 600 K and above. This system is commonly considered to be representative of a surface-confined alloy, and we have studied the structure and topography of the films' surfaces up to thicknesses of 35 ML using high-resolution low-energy electron diffraction. The network is formed during the growth of the second layer and is fully developed already for films only a few layers thick. The spacing of the network varies between 5.8 and 6.6 nm when grown at 600 and 800 K, respectively. This dependence on the growth temperature is attributed to a temperature-dependent material mixing in the first (few) layers of the film. This mixing is irreversibly set by the deposition temperature and even persists during prolonged annealing at a temperature close to the desorption of Ag from Pt(111).