Surfactant-mediated surface growth: nonequilibrium theory
A number of recent experiments have shown that surfactants can modifiy the growth mode of an epitaxial film, suppressing islanding and promoting lyer-by-layer growth. hee, a set of coupled equations are introduced to describe the coupling between a growing interface and a thin surfactant layer deposited on the top of the nonequilibrium surface. The equations are derived using the main experimentally backed characteristics of the system and basic symmetry principles. The system is studied using dynamic-normalization-group scheme, which provides scaling relations between the roughness exponents. It is found that the surfactant may drive the system nto a novel phase, in which the surface roughness is negative, corresponding to a flat surface.