Scanning tunnelling microscopic studies were made of a reversible tip-induced transition, between triangular and star-shaped networks, of partial dislocations on the basal (00·1) plane of highly oriented pyrolytic material. The transition between network geometries resulted from small variations (0.14V) in the tip-to-substrate voltage bias, and was attributed to the shear-induced motion of partial dislocations. The shear stress which required for the transition was estimated to be 5MPa. Dislocation motion occurred over distances of tens of nm, and at a time-scale of several minutes, thus permitting the dynamics of the transition between the 2 networks to be observed in real time. Atomically resolved images near to a dislocation revealed distortions, of the atomic lattice, which were consistent with glide of the surface basal plane. Analysis of the separation distance between pairs of dislocations yielded a surface stacking-fault energy of 2.1 to 4.5mJ/m2.

Scanning-Tunneling-Microscopy Study of Tip-Induced Transitions of Dislocation-Network Structures on the Surface of Highly Oriented Pyrolytic Graphite. S.R.Snyder, W.W.Gerberich, H.S.White: Physical Review B, 1993, 47[16], 10823-31