Flexoelectricity refers to a linear coupling between the electric polarization and the strain gradient, such as bending or asymmetric compression. This effect is enhanced in nano-scale structures, where grain boundaries or dislocation cores induce the strain gradient. In this study, we theoretically investigate the flexoelectric polarization induced by misfit dislocations in a thin film. A nano-scale dislocation structure is modeled in a periodic SrTiO3 supercell, and then the structure is optimized by using neural-network-potential and first-principles approaches. We point out that a pyramidal TiO5 coordination forms near the dislocation cores, which in turn dominantly causes the sizable flexoelectric polarization.
@article{arxiv.2408.04985,
title = {Dislocation-induced flexoelectricity in SrTiO$_3$ nanostructure from first principles},
author = {Kunihiko Yamauchi and Thi Phuong Thao Nguyen and Tamio Oguchi},
journal= {arXiv preprint arXiv:2408.04985},
year = {2024}
}