1-D MONTE CARLO SIMULATION OF CLUSTER GROWTH

摘要

An important problem in surface physics is the ordering of adsorbed particles on a surface. We examine here the simple system of particles diffusing in one dimension and forming clusters. Our Monte Carlo simulations of this system incorporate parameters such as particle coverage and a probability factor for a particle to move to another lattice site. This factor G primarily indicates the "stickiness" of clusters: it equals 1 when a particle attached to the end of a cluster is immobile, and equals 0 when an attached cluster particle has the same probability to hop as an isolated one. This work shows the influence of the G factor and coverage on the cluster size distributions for initial conditions and after a large number of Monte Carlo time steps. We apply this model to simulate data for the experimental system of adsorbed dimer particles on the reconstructed Si(5 5 12)-2xl surface. This system forms dimer clusters aligned in one-dimensional rows on the surface. Our data indicate that the best fit to the experimental cluster size distributions occurs for G = 0.9, indicating that diffusing dimers have a high probability of sticking at the ends of existing clusters.