Year: 2021
Type: preprint
Abstract: The flexoelectric behaviors of solids under high strain gradient can be distinct from that under low strain gradient. Using the generalized Bloch theorem, we investigate theoretically the transversal flexoelectric effects in bent MgO thinfilms. As a comparison, a centrosymmetric (100) film and a non-centrosymmetric (111) film are considered. Under bending, the mechanical responses of both films are linear elastic under low strain gradient but nonlinear elastic under high strain gradient. In the linear elastic regime, no internal displacements and thus no polarization contributed from ions are induced. Only in the nonlinear elastic regime, atoms adopt discernibly large internal displacements, leading to strong polarization from ions. Because the internal displacements of atoms of the (111) film are much larger than those of the (100) film, the obtained flexoelectric coefficient of the (111) film is also greater than that of the (100) film, revealing strong anisotropy of flexoelectricity of MgO film. Our results and the employed approach have important implications for the study of flexoelectric properteis of ionic solids.
Source: arXiv (Cornell University)
Authors: He, Chao, Tang, Jin-Kun, Yang, Yang, Chang, Kai, Zhang, Dong-Bo
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Awards: G2530725650, G3709029831, G8856087055
OpenAlex ID: W4200632020