Effect of asymmetrical interface charges on the hystereses, domain configuration and phase transition characteristics of ferroelectric thin films

Abstract

We simulate the hystereses and phase transition properties of ferroelectric films with space charges in thick (~200 nm) and thin structures (~20 nm). Epitaxial (001) PbZr0.3Ti0.7O3 thin films sandwiched between metallic electrodes on (001) SrTiO3 substrate is taken as a model system. We show that space charge accumulated near the metal-ferroelectric interfaces gives rise to a very strong imprint where only one polarization orientation is favored regardless of the sign of the external field. The space charges, when asymmetrically distributed, also lead to a smearing of the phase transition. Single-domain approximation for asymmetrical distributions of planar space charges are discussed.