POLARIZATION AND DIELECTRIC SUSCEPTIBILITY OF FERROELECTRIC SUPERLATTICE

The temperature dependence of dielectric susceptibility as well as the spontaneous polarization of a ferroelectric superlattice were discussed based on the Ising model in a transverse field. When the slab thicknesses are larger, the temperature dependence of the spontaneous polarization shows a steplike structure. The dielectric susceptibility becomes infinite at the Curie temperature T-c and shows finite peaks corresponding to the rapid decrease in the spontaneous polarization near the bulk Curie point of each slab. The height of the finite peaks decreases with the decrease in the slab thicknesses. When they become so thin that the polarization profiles are predominantly controlled by the interface, the finite peaks in susceptibility as well as the steps in polarization disappear.