Simulations were made of a screw dislocation in argon and xenon model crystals having various sizes. The number of atom rows in the crystal was 360 to 1400, and a Lennard-Jones (12-6) interatomic potential truncated at the third-nearest neighbor was used. The ordinary relaxation method was used to obtain the stable configuration of atoms in the crystal. It was found that the dislocation split into two Shockley partials, and that the configuration of the partials depended upon the boundary condition of the crystal surface. A method of modified boundary conditions was proposed in order to control the effect of the surface. The split dislocations were able to exist stably when their separation was within a definite range, which was understood by considering the balance of three forces: the interaction force between partials, the force due to stacking faults and the image force from the crystal surface. By taking the limiting value of the separation distance for a crystal of infinite size, the stacking fault energy was estimated to be 0.74 and 1.09mJ/m2 for argon and xenon, respectively.

Simulation of Dislocation Configuration in Rare Gas Crystals. Y.Kogure, T.Tsuchiya, Y.Hiki: Journal of the Physical Society of Japan, 1987, 56[3], 989-98