Flexoelectric coefficient is a fourth-rank tensor arising from the coupling between strain gradient and electric polarization and thus exists in all crystals. It is generally ignored for macroscopic crystals due to its small magnitude. However, at the nanoscale, flexoelectric contributions may become significant and can potentially be utilized for device applications. Using the phase-field method, we study the mechanical switching of electric polarization in ferroelectric thin films by a strain gradient created via an atomic force microscope tip. Our simulation results show good agreement with existing experimental observations. We examine the competition between the piezoelectric and flexoelectric effects and provide an understanding of the role of flexoelectricity in the polarization switching. Also, by changing the pressure and film thickness, we reveal that the flexoelectric field at the film bottom can be used as a criterion to determine whether domain switching may happen under a mechanical force.


Materials Science and Engineering

Keywords and Phrases

Atomic force microscopy; Ferroelectric films; Ferroelectric thin films; Ferroelectricity; Nanotechnology; Phase transitions; Single crystals; Switching, Electric polarization; Ferroelectric polarization; Flexoelectric coefficients; Flexoelectric effects; Fourth-rank tensors; Mechanical switching; Phase field methods; Polarization switching, Polarization

International Standard Serial Number (ISSN)

0003-6951; 1077-3118

Document Type

Article - Journal

Document Version

Final Version

File Type





© 2015 American Institute of Physics (AIP), All rights reserved.

Publication Date

01 Jan 2015