Cluster structure of the C-60 hexagonal monolayer: Density-functional theory calculations

Abstract

We have investigated the ground-state structure of the freestanding C-60 hexagonal monolayer by using density-functional theory (DFT) calculations. In the most stable structure, C60 clusters align with an edge atom facing toward the layer plane with an intercluster distance of 9.77 angstrom. The [2 + 2] cycloaddition structure, which was used as a model in a previous DFT study, is found to be locally unstable in the present calculation. The cluster orientation of the ground-state structure is in good agreement with that of a C-60 hexagonal monolayer grown on an alkylthiol substrate reported in a recent scanning tunnelling microscopy experiment.