Self-assembly of oxide-supported metal clusters into ring-like structures

Self-assembly is a phenomenon that continuously occurs at the nanoscale, as atoms form predetermined building blocks such as molecules and clusters, which then themselves gather into structures of a larger scale. The interplay of competing forces is a decisive factor in the emergence of these organized systems, but the precise mechanism by which this self-assembly progresses is seldom known. Using a combination of physical cluster deposition and atomic force microscopy, we have investigated the spontaneous formation of μm-sized rings of SiOx-supported metal nanoclusters. With the help of molecular dynamics simulations, we show that the competition between short-range van der Waals attractions and long-range repulsive dipolar forces, induced by the ionic surface, plays a key role in the self-assembly of these structures.