Tip-triggered Thermal Cascade Manipulation of Magic Number Gold-Fullerene Clusters in the Scanning Tunnelling Microscope.

We demonstrate cascade manipulation between magic number gold-fullerene hybrid clusters by channelling thermal energy into a specific reaction pathway with a trigger from the tip of a scanning tunnelling microscope (STM). The (C)-Au clusters, formed via self-assembly on the Au(111) surface, consist of n Au atoms and m C molecules; the three smallest stable clusters are (C)-Au, (C)-Au, and (C)-Au. The manipulation cascade was initiated by driving the STM tip into the cluster followed by tip retraction. Temporary, partial fragmentation of the cluster was followed by reorganization. Self-selection of the correct numbers of Au atoms and C molecules led to the formation of the next magic number cluster. This cascade manipulation is efficient and facile with an extremely high selectivity. It offers a way to perform on-surface tailoring of atomic and molecular clusters by harnessing thermal energy, which is known as the principal enemy of the quest to achieve ultimate structural control with the STM.