Brownian Motion of Dislocations in Thin Films

The motion of edge dislocations in a single monolayer film of Cu on Ru(0001) was studied by time-resolved scanning tunneling microscopy. The dislocations were observed to make rapid 1D random walks in the film. This dislocation motion is attributed to the equilibrium thermal exchange of atoms between the solid film and the adatom gas covering the film. These results highlight a fundamental difference between the dynamics of dislocations in thin films and the bulk, which is in principle important in understanding the mechanical properties of thin films. © 1997 American Physical Society.