Flexoelectricity has garnered much attention owing to its ability to bring electromechanical functionality to non-piezoelectric materials and its nanoscale significance. In order to move towards a more complete understanding of this phenomenon and improve the efficacy of flexoelectric-based devices, it is necessary to quantify microstructural contributions to flexoelectricity. Here we characterize the flexoelectric response of bulk centrosymmetric LaAlO3 crystals with different twin boundary microstructures. We show that twin boundary flexoelectric contributions are comparable to intrinsic contributions at room temperature and enhance the flexoelectric response by ~4x at elevated temperatures. Additionally, we observe time-dependent and non-linear flexoelectric responses associated with strain-gradient-induced twin boundary polarization. These results are explained by considering the interplay between twin boundary orientation, beam-bending strain fields, and pinning site interactions.
@article{arxiv.1911.02634,
title = {Twin Boundary Mediated Flexoelectricity in LaAlO$_3$},
author = {Christopher A. Mizzi and Binghao Guo and Laurence D. Marks},
journal= {arXiv preprint arXiv:1911.02634},
year = {2021}
}