Growth of ordered domains in a highly anisotropic two-dimensional system

We introduce and study a lattice-gas model characterized by a strong anisotropy of the atomic mobility in different directions. The kinetics of the model is investigated by two methods, Monte Carlo simulation of the lattice-gas model and numerical solution of mean-field kinetic equations. The growth kinetics of the p(2x2) rarefied ordered structure at low temperature is shown to exhibit a hierarchy of growth rates owing to different evolution of the components of the p(2X2) phase order parameter. The rate of growth increases when the concentration is decreased below the stoichiometric value. Specific kinetics of the jump-anisotropic model and the effective repulsion between ordered domains result in an unusual evolution of the concentration gradient versus time. The model is applied to describe peculiar experimental results on surface diffusion of Li atoms adsorbed on furrowed single-crystal-plane Mo (112).