Molecular dynamics study of the defect behaviour in fluorite structure crystals close to the superionic transition

Large-scale molecular dynamics simulations have been performed on several fluorite structure crystals. As these simulations include 3630 ions the particle-particle/particle-mesh algorithm was used to model the Coulombic forces. The size of the simulations was large enough to enable the Frenkel defect behaviour of the crystals to be studied both above and below the superionic transition temperature t c, thereby enabling us to study the way in which the Frenkel defect model breaks down as the temperature of the crystals is increased through t c.