Prediction of flexoelectricity in BaTiO3 using molecular dynamics simulations

Abstract

Flexoelectric effect, referring to the strain gradient induced polarization, widely exists in dielectric materials, but its molecular dynamics has not been studied so much so far. In this work, the radial distribution function of BaTiO3 and the phase transition temperatures have been investigated, and the results show that the core-shell potential model is effective and the structure of BaTiO3 is stable in a temperature range of 10 K–150 K. Molecular dynamics simulated hysteresis loops of BaTiO3 show that anisotropy can play an important role in the coercive field. Based on the rational simulation process, the effects of cantilever beam bent angle and fixed length on the polarization are analyzed. It is found that the small bent angle of the curved cantilever beam can give a proportional relationship with a fixed end length and a non-linear relationship is presented when the bent angle is much larger. The prediction of flexoelectric coefficient in BaTiO3 is 18.5 nC/m. This work provides a computational framework for the study of flexoelectric effect by using molecular dynamics.