On Edge Dislocations in a Possible Relation to Structure of a Crystal Surface

Stresses around an edge dislocation near a free surface are calculated using two kinds of elastic representations (Volterra dislocations): One is a ring deformed by removal of a slice of uniform thickness and the other is a ring deformed by slip. Only the former is shown to yield a stable network plane of dislocations parallel to a free surface. The conditions of stability of the network plane are discussed in relation to a compressive surface stress. The network plane seems to give a possible explanation of superstructures observed on the (111) surfaces of diamond-type crystals.