Polarization switching in epitaxial films of BaTiO₃: A molecular dynamics study

We use molecular dynamics simulations with a first-principles model Hamiltonian to study polarization switching in ultrathin epitaxial films of BaTiO₃ sandwiched by ideal electrodes as a function of temperature and epitaxial strain. We find that the coercive fields of polarization switching reduce with tensile epitaxial strain and as temperature increases up to the transition, and depend sensitively on the nature of the epitaxial constraint. Our results should be directly relevant to the design of high frequency ferroelectric random access memories made with ultrathin epitaxial ferroelectric films.