Molecular dynamics study of high-pressure alumina polymorphs with a tight-binding variable-charge model

Abstract A tight-binding variable-charge model aimed at performing large-scale realistic simulations of bulk, surfaces and interfaces of aluminum oxides have been developed. This model is based on the charge equilibration (QEq) method and explicitly takes into account the mixed iono–covalent character of the metal–oxygen bond by means of a tight-binding analytical approach in the second-moment approximation of the electronic structure. The parameters of the model were optimized to reproduce structural and energetic properties of the α-Al2O3 corundum structure at room temperature and pressure. The model exhibits a good transferability between five alumina polymorphs: corundum, Rh2O3(II)-type…