Atomistic simulation of surface effects in BaTiO[sub 3]

Abstract

Interatomic potentials for BaTiO3 are determined, in the framework of a shell model, by mapping first-principles potential energy surfaces for various ferroelectric distortions. Several bulk properties, such as lattice parameters, phase transition sequence, thermal expansivity, etc., are correctly reproduced by molecular dynamics simulations. To investigate whether the model will also prove successful for describing surface properties, such as structural relaxations and surface energies, we perform static calculations on periodic slabs to compare with recent ab initio studies of BaTiO3 surfaces, which are taken as benchmark results. The agreement is quite good in spite that the model was developed for the bulk material. The good description of the static surface properties constitutes an important first step to a further finite-temperature simulation study of the thickness dependence of ferroelectric transitions in BaTiO3 thin films.