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.
Y. Gu et al., "Nanoscale Mechanical Switching of Ferroelectric Polarization Via Flexoelectricity," Applied Physics Letters, vol. 106, no. 2, American Institute of Physics (AIP), Jan 2015.
The definitive version is available at https://doi.org/10.1063/1.4905837
Mechanical and Aerospace 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)
Article - Journal
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