The shape evolution of two-dimensional islands through periphery diffusion biased by an electromigration force was studied numerically using a continuum approach. It was shown that the introduction of crystal anisotropy in the mobility of edge atoms induced a rich variety of migration modes, which include oscillatory and irregular behavior. A phase diagram in the plane of anisotropy strength and island size was constructed. The oscillatory motion could be understood in terms of stable facets that develop on one side of the island, and which the island then slides past. The facet orientations were determined analytically.

Complex Shape Evolution of Electromigration-Driven Single-Layer Islands. P.Kuhn, J.Krug, F.Hausser, A.Voigt: Physical Review Letters, 2005, 94[16], 166105 (3pp)