Classical and hybrid density-functional/classical molecular dynamics study of dislocation core in alumina ceramic

Abstract

We perform molecular-dynamics simulations to investigate the atomic and electronic structures of a basal edge dislocation in α-Al 2O3. The core structure consisting of two non-stoichiometric partial dislocations, which has been recently proposed by an experiment, is examined by an empirical interatomic-potential model and by a hybrid quantum/classical approach. The atomic rearrangements in the full and in the partial dislocation cores are analyzed. The local electronic structure in the full dislocation core is evaluated by the density-functional method applied for a quantum-cluster region in the hybrid simulations. Interaction potentials between partial dislocations are investigated by the classical model. Results preliminarily obtained show that the partials aligned normal to a basal plane ({0001}) has a short-ranged repulsive nature approximately within 8 Å. © 2009 The Japan Institute of Metals.