Amplified strain-polarization response of geometrically structured surfaces

Variable polarization is a key feature of ferroelectrics, and achieving a high strain-polarization response is a critical goal for materials such as ferroelectrics. The strain-polarization response of ferroelectric materials is limited by the intrinsic piezoelectric coefficient e and flexoelectric coefficient f. The surface of ferroelectric materials exhibits a notable strain gradient, and designing structures with high surface strain gradients has the potential to overcome this limitation and achieve high strain-polarization responses. In this study, the phase field method is employed to evaluate the strain-polarization response of ferroelectric surface geometric structures within a multi-field coupling environment. Compared to rectangular structures, curved structures exhibit higher surface polarization under the same strain. This difference may be attributed to the varying energy absorption and release capacities of different geometries. Further adjustments to the geometric parameters of the curved structure reveal that increasing the width-to-diameter ratio under the same strain can enhance surface polarization, while increasing the length-to-diameter ratio under the same strain may reduce surface polarization.