Thermally Driven Diffusion of a Magic Number Gold-Fullerene Cluster on a Au(111) Surface*

Metal clusters stabilized by surface passivation with organic molecules have potential applications in diverse fields such as optics, microelectronics, catalysis, and biochemical analysis. The diffusion of the organic-metal hybrid clusters on solid substrates seriously affect the performance of the clusters in many practical applications. Here, we report the observation of a mass migration of C₆₀-Au clusters at room temperature using scanning tunneling microscopy and molecular dynamic simulations. We found that the mass migration induced by thermal energy fluctuations, which is important for small systems. A close-packed C₆₀−Au cluster with a regular geometric shape can transfer into a liquid cluster owing to the sudden injection of thermal energy. The liquid cluster then migrates to a different site where it releases the extra energy and reassembles back into its initial structure. The break−reassembled behavior seems to be the dominant diffusion process for the C₆₀−Au cluster and perhaps also plays an important role in organic-metal hybrid clusters.
[J. Phys. Chem. C 2020, 124, 9990−9995]