First-order phase transition in ferroelectric superlattice described by the transverse Ising model

The phase transition properties of a ferroelectric/ferroelectric superlattice described by the transverse Ising model, by taking into account the four-spin interactions have been studied with parameters imitating PbTiO3/BaTiO3. The period dependence of the Curie temperature of the superlattice is given. The phase transition behavior of the polarization and the susceptibility are calculated, which show the feature of first-order phase transitions. A ferroelectric–ferroelectric phase transition at low temperature is found for large-period superlattice.