Flexoelectricity causes surface piezoelectric-like effects in dielectrics

Author (s): Mohammadi, H.; Greco, F.; Codony, D.; Arias, I.
Journal: International Journal of Mechanical Sciences
Volume: 293
Pages: 110 - 162
Date: 2025

Abstract:
In this paper, we study the surface effects that bulk flexoelectric models exhibit in finite samples. We first show that flexoelectric materials do not exhibit electromechanical response under homogeneous loading when the body is infinite. However, when the size of the body is finite, due to the symmetry-breaking nature of surfaces, homogeneous loading (mechanical or electrical) can cause an electromechanical response near the surfaces. We obtain closed-form solutions for finite samples under different electromechanical loading conditions and show that the electromechanical response caused by the bulk flexoelectric effect is reminiscent of surface piezoelectricity, causing boundary layers in certain components of the strains and/or electric fields near the free surfaces.