Strong dependence of dielectric properties on electrical boundary conditions and interfaces in ferroelectric superlattices

A computational study based on Landau-Ginzburg-Devonshire theory is carried out to understand the role of interfaces on the dielectric response of ferroelectric superlattices. Using heteroepitaxial (001) PbZr0.3Ti0.7O3/(001)SrTiO3 heterostructures on (001)SrTiO3 as an example, we show that electrostatic boundary conditions have a pronounced effect on the dielectric response far below the ferroelectric phase transition temperature. For a fixed total multilayer thickness, the average dielectric response can be improved significantly for superlattices with a small layer periodicity. This is due to the large total internal electric fields at the interlayer interfaces which originate from the polarization mismatch between layers. (C) 2014 AIP Publishing LLC.