The flexoelectricity of barium and strontium titanates from first principles

We present ab initio calculations of the longitudinal flexoelectricity for BaTiO3 and SrTiO3 using a direct approach. The calculated value for SrTiO3 agrees with recently reported measurements. For BaTiO3, however, the theoretical values are smaller than the measured ones; possible reasons for the discrepancy are discussed.