Interface effects in ferroelectric bilayers and heterostructures

Abstract

We study the role of interlayer interfaces on the polarization response of ferroelectric-paraelectric bilayers using a nonlinear thermodynamic model. We carry out a numerical analysis for prototypical BaTiO3–SrTiO3 bilayers ranging from 40to800nm total thickness as a function of SrTiO3 fraction. There exists a critical fraction of SrTiO3 at which the polarization is suppressed due to the depolarization field arising from the interlayer coupling and a large dielectric response is predicted. It is shown that this critical fraction decreases with decreasing total bilayer thickness, indicating that the interfacial effects are more pronounced in thinner bilayers.