MODELING OF ELECTRON-STIMULATED MOBILITY AND DISORDERING OF ADSORBED PARTICLES

The electron-stimulated mobility and the electron-stimulated disorderi ng of adsorbed particles is studied for a two-dimensional lattice gas model on a square lattice using kinetical Monte Carlo simulations. Pai rwise nearest-neighbor repulsive interactions are considered which ind uce c(2 x 2) ordering of the lattice gas at low temperatures around ha lf coverage. Adsorbed particles are allowed to perform thermally activ ated as well as electron-induced jumps to nearest-neighbor sites. The calculations are performed taking full advantage of the numerical powe r of a supermassive parallel computer. It was found that the electron- induced mobility of adatoms causes the complete breakdown of the c(2 x 2) ordering at low temperatures if the fraction of electron-induced j umps exceeds a critical value. The breakdown of the ordering is accomp anied by substantial changes of the chemical and tracer surface diffus ion coefficients. (C) 1997 Elsevier Science B.V.