Solid-solid interface and solid solution of oxides with rock-salt structure: Lattice properties.

Abstract

The solid--solid metal oxide (MO) interface in the (100) orientation was modeled and its properties were investigated by molecular dynamics (MD). MD was used to model the temperature-dependent geometry in the interface region using standard interatomic potentials. The lattice structure across the MO-MO interface is found to change continually from one crystal to another, instead of an abrupt jump. The radial distribution function, average potential energy for each layer, the average interplanar spacing, and the mean-square displacement of the ions are reported. Results for (100) MgO-CoO and NiO-CoO interfaces are compared with pure-phase data; the (100) MgO-CoO interface also is compared with the MgO:CoO solid solution. A modification of the empirical pairwise potential using first-principles effective charges was found to give equally good results.