Flexoelectric Effect in Thin Films: Theory and Applications

Abstract The flexoelectric effect describes phenomena where strain gradients induce electrical polarization and electric field gradients cause strain in materials. This specific type of electromechanical coupling effect is remarkable for being independent of material symmetry, Curie temperature, and it exhibits notable effects in small‐sized materials. The study of flexoelectric effects has provided fresh insights into materials science, particularly highlighting how thin‐film structures, with their unique geometrical and dimensional attributes, are highly responsive to flexoelectric influences, thereby offering significant opportunities for modulating electrical properties. Herein, this paper presents the fundamental concepts and theories underlying the flexoelectric effect are presented. Various methods for inducing this effect in thin films are explored, including the optimization of growth and deposition conditions, and the application of external mechanical stresses to create strain gradients. Additionally, recent advances in utilizing the flexoelectric effect to modulate ferroelectric domains, modify properties of thin films, and enhance functionalities in photovoltaic systems, nanogenerators, sensors, and actuators are reviewed. Finally, the challenges and future prospects for flexoelectric effects in advanced electronics are briefly presented.