Atomic scale switches based on self-assembled surface magic clusters

Atomic scale switches working at room temperature represent the ultimate level of device miniaturization. Using scanning tunneling microscopy, we find a bistable switching between two mirror-symmetric configurations of self-assembled magic rare earth silicide clusters on the Si(111) 7 × 7 surface. Density functional theory reveals an energy barrier of 1.3 eV between the two cluster configurations, suppressing the switching even at room temperature. However, intentional switching between the two states is possible in the presence of a close tunneling tip due to a tip-induced lowering of the energy barrier.