Island Shape Controls Magic-Size Effect for Heteroepitaxial Diffusion
arXiv:0908.3006 · doi:10.1063/1.3455848
Abstract
Lattice mismatch of Cu on Ag(111) produces fast diffusion for special "magic sizes" of islands. A size- and shape-dependent reptation mechanism is responsible for low diffusion barriers. Initiating the reptation mechanism requires a suitable island shape, a property not considered in previous studies of 1D island chains and 2D closed-shell islands. Shape determines the dominant diffusion mechanism and leads to multiple clearly identifiable magic-size trends for diffusion depending on the number of atoms whose bonds are shortened during diffusion.
9 pages, 3 figures