Nanoclustering of vacancies in thin metal films revealed by x-ray diffuse scattering

Abstract

The authors report the incorporation of unexpectedly large vacancy clusters into homoepitaxial Ag(001) films. These results, which are for a simple noble metal system, have important implications for understanding the atomic-scale kinetics of surfaces where current models have mostly ignored the role of vacancies. For films grown at 150 K, an average vacancy cluster exhibits a local dilatation volume of 750 Å3, which leads to a 1% compressive strain of the film. Vacancy clusters are observed even for films grown near room temperature. These in situ diffuse x-ray scattering experiments measure the local deformation around the cluster and, therefore, provide conclusive evidence of vacancy clusters.