Modeling epitaxial film growth of C$_{60}$ revisited

Abstract

Epitaxial films evolve on time and length scales that are inaccessible to atomistic computer simulation methods like molecular dynamics (MD). To numerically predict properties for such systems, a common strategy is to employ kinetic Monte Carlo (KMC) simulations, for which one needs to know the transition rates of the involved elementary steps. The main challenge is thus to formulate a consistent model for the set of transition rates and to determine its parameters. Here we revisit a well-studied model system, the epitaxial film growth of the fullerene C60 on an ordered C60 substrate(111). We implement a systematic multiscale approach in which we determine transition rates through MD simulations of specifically designed initial configurations. These rates follow Arrhenius' law, from which we extract energy barriers and attempt rates. We discuss the issue of detailed balance for the resulting rates. Finally, we study the morphology of subatomic and multilayer film growth and compare simulation results to experiments. Our model enables further studies on multi-layer growth processes of C60 on other substrates.