MOLECULAR-BEAM EPITAXY IN THE PRESENCE OF PHASE-SEPARATION

Experiments have shown that phase separation during the growth of soli d films by molecular beam epitaxy (MBE) is a phenomenon seen in a vari ety of systems. We study a MBE process where two types of particles ar e deposited simultaneously, and where the interatomic potential energy leads to phase separation. From a microscopic point of view, we descr ibe the system with a solid-on-solid model augmented by an Ising model to represent the phase separation. Monte Carlo simulations of this mo del show that for low deposition rates, a lamellar pattern emerges in the bulk, with a modulation parallel to the growth plane. We show how the temperature and the deposition rate can be used to tailor the wave length of the modulation. The effects of the phase separation on the s urface morphology create a modulation consisting of steps or grooves a t the interface between surface domains, which can be seen in the heig ht-height correlation function and in the surface width. The temperatu re dependence of the surface width at fixed deposition rate is also pr esented.