The flexoelectricity of barium and strontium titanates from first principles.

We present ab initio calculations of the longitudinal flexoelectricity for BaTiO(3) and SrTiO(3) using a direct approach. The calculated value for SrTiO(3) agrees with recently reported measurements. For BaTiO(3), however, the theoretical values are smaller than the measured ones; possible reasons for the discrepancy are discussed.