Domain Engineering the Flexoelectric Response of BaTiO3-SrTiO3 Binary Films: A Phase Field Study

The flexoelectric effect describes the interplay between material polarization and strain gradient. While much research has focused on control strategies for flexoelectricity, the impact of ferroelectric domain structure on the flexoelectric effect remains elusive. Through phase field simulations, we conduct a comparative study on the flexoelectric response of two types of BaTiO3-SrTiO3 binary films: BaTiO3-SrTiO3 multilayers and (Ba,Sr)TiO3 solid solutions. Our findings reveal that the flexoelectric response of these two systems, at the same Ba/Sr ratio, differs not only in magnitude but also in other aspects like temperature dependence, linearity, and hysteresis, due to their different ferroelectric domain structures and evolution dynamics. Our study deepens our current understanding of flexoelectricity in ferroelectrics and suggests "domain engineering" as a potential way to tailor this effect.