Abstract
We present a computer program (METADISE) for the simulation of one-dimensional defects within the Born model of ionic crystals, which includes a new generally applicable one-dimensional periodic sum for calculating the Coulombic potential and forces. We present the results from simulations of screw dislocations in MgO and NiO which show that, as predicted from elasticity theory the (a/2)〈110〉 dislocation is more stable than the a〈100〉 dislocation in both materials. In addition the a〈100〉 is stabilized by the presence of vacancies close to the dislocation core while the (a/2)〈110〉 is destabilized: however, all of the vacancies are bound to the dislocation.
