Stability of Vacancy Due to Noncentral Force Interactions in Diamond Structural Crystals

抄録

The formation of a vacancy in the diamond structural crystal is studied by a computer simulation as a many body problem of classical particles interacting with the noncentral force of the Keating strain energy potential. The simulation starts with making a vacant site in the perfect crystal. The relaxation of atoms around the vacant site is resisted by the restoring force of bond-bendings towards the equilibrium angle to be balanced stationarily by forming a stable vacancy. Without taking into account this noncentral force interaction, the formation of a vacancy is impossible. The formation and migration energies of a vacancy and the formation energy of a divacancy in Si and Ge are obtained from the computer simulations.