Decay characteristics of surface mounds with contrasting interlayer mass transport channels

The decay characteristics of three-dimensional (3D) islands formed on surfa ces are investigated theoretically considering two types of interlayer mass transport mechanisms. If an adatom on a given layer can easily descend fro m any site along the periphery of the layer, an optimal island slope and a constant terrace width will be selected during the decay. In contrast,if th e adatom can descend primarily through selective (such as kinked) sites, th e decay will be accompanied by a gradual increase in the island slope. Thes e generic conclusions provide the basis for a microscopic understanding of the decay of nanostructures in fcc(111) and fcc(100) metal homoepitaxy and are applicable to other systems as well.