Precursor-mediated kinetics of domain growth

Lattice-gas models that allow the influence of precursor states on the kinetics of domain growth to be studied are presented and discussed. Monte Carlo simulations are performed on a square lattice with these models, for the case of equal and repulsive lateral interactions between nearest and next-nearest neighbors. The dynamics used in the simulations incorporate the energy barrier that an adsorbed molecule must surmount in order to migrate on a crystal surface. We find that domain growth is well described by l∼${\mathrm{At}}^{1/2}$, although during early stages of growth smaller exponents may be observed. The growth exponent of (1/2 holds regardless of the mobility of the precursor. We also find that the coefficient A in the growth law is proportional to the square root of the diffusion coefficient of the adsorbate particles.