Island migration caused by the motion of the atoms at the border: Size and temperature dependence of the diffusion coefficient

The random motion of the atoms along the periphery of a two-dimensional island on a solid surface causes the island to diffuse. By using kinetic Monte Carlo simulations we show that the diffusion coefficient of the island has a power-law dependence on the island size. However, contrary to the predictions of simple models, the exponent depends on temperature and on the nature of the material.