GROWTH OF ORDERED DOMAINS IN A HIGHLY ANISOTROPIC 2-DIMENSIONAL SYSTEM

We introduce and study a lattice-gas model characterized by a strong a nisotropy of the atomic mobility in different directions. The kinetics of the model is investigated by two methods, Monte Carlo simulation o f the lattice-gas model and numerical solution of mean-field kinetic e quations. The growth kinetics of the p(2x2) rarefied ordered structure at low temperature is shown to exhibit a hierarchy of growth rates ow ing to different evolution of the components of the p(2X2) phase order parameter. The rate of growth increases when the concentration is dec reased below the stoichiometric value. Specific kinetics of the jump-a nisotropic model and the effective repulsion between ordered domains r esult in an unusual evolution of the concentration gradient versus tim e. The model is applied to describe peculiar experimental results on s urface diffusion of Li atoms adsorbed on furrowed single-crystal-plane Mo (112).