Modification of a shell model for the study of the radiation effects in BaTiO3

In order to study the radiation effects in BaTiO3 ferroelectric crystal, a previously developed shell model is modified. The modifications include adding the ZBL universal potentials at short distances and distance-dependent spring constants for core–shell interactions. The phase transition sequences in BaTiO3 were correctly reproduced using molecular dynamics simulations with this modified shell model. Also, the calculated Frenkel pair formation energies agree well with results obtained by first principles calculations, which suggests that this model is suitable for the simulation of the radiation effects in BaTiO3. The dependence of polarization on the number of oxygen vacancies was also studied.