The motion of edge dislocations in a single monolayer film of Cu on Ru(00•1) was studied by means of time-resolved scanning tunnelling microscopy. It was observed that the dislocations made rapid 1-dimensional random (Brownian) walks in the film. This motion was attributed to an equilibrium thermal exchange of atoms between the solid film and an adatom gas which covered the film. It was estimated that there was 1 atomic exchange with each threading edge dislocation for each 30s at room temperature. These observations emphasized a fundamental difference between the dynamics of dislocations in thin films and in bulk material.

A.K.Schmid, N.C.Bartelt, J.C.Hamilton, C.B.Carter, R.Q.Hwang: Physical Review Letters, 1997, 78[18], 3507-10