Formation mechanism of adatom islands on fcc (111) substrates

We explore the effects of various basic atomic processes on the island shapes of diffusion-limited-aggregate growth on a triangular lattice using kinetic Monte Carlo simulation. Edge diffusion and bond-reducing relaxation of double-coordinated adatoms, as well as single-coordinated adatoms, are proved to be essential to the island shape transition from fractal to irregularly compact and from irregularly compact to hexagonal islands, respectively. Shape transitions of adatom islands on fcc (111) substrates can be understood naturally by this model.