Ferroelectric films described by the transverse Ising model

Materials Sciences has made an enormous progress in the preparation and the study of ferroelectric multilayers, thin films and superlattices. This progress opened the possibility to produce new materials, films and nanostructures whose properties can be exploited for the engineering of new material devices. The dielectric properties of these materials are a topic of research. The pseudospin theory based on the transverse Ising model is generally believed to be a good microscopic description of these systems. We discuss an LL layer film of simple cubic symmetry with nearest-neighbor exchange interaction in which the exchange interaction strength is assumed to be different from the bulk values in nsns surface layers. We derive and illustrate expressions for the phase diagrams, polarization profiles and susceptibility.