Theory of Giant Electromechanical Response from Ferroelectric Bilayers with Polydomain Structures due to Interlayer and Interdomain Coupling

摘要

The effect of interdomain ferroelastic coupling in ferroic multilayers is investigated theoretically. Specifically, we use nonlinear thermodynamics to analyze a heteroepitaxial ferroelectric PbZr_xTi_(1_x)O_3 (PZT) bilayer consisting of (001) tetragonal (T) PZT and (001) rhombohedral (R) PZT films. We predict for certain misfit strain regimes that interlayer and interdomain interactions lead to an adaptive domain structure in both the T and R layers and result in significant enhancements in the piezoelectricity compared to single-layer films. Our results demonstrate that electrostatic, magnetostatic, and elastic interactions in ferroic multilayers can be a generic route to generate ultrahigh susceptibilities.