Atomic sublattice decomposition of piezoelectric response in tetragonal Pb Ti O 3, Ba Ti O 3, and K Nb O 3

The piezoelectric properties of tetragonal perovskites PbTiO3, BaTiO3, and KNbO3 under uniaxial strain along the [001] direction are calculated from first principles. In order to study the piezoelectric response of individual atomic sublattices, the total polarization P and piezoelectric constant d33 are decomposed into the contributions of A-site and B-site atoms. These three materials show different behaviors at the atomic scale. In PbTiO3, the Pb and Ti contribute almost equally to the polarization and d33. In KNbO3, most of the polarization and d33 are contributed by the ferroelectrically active Nb. But in BaTiO3, as the c axis increases, the contribution of Ba to d33 rises rapidly, reaching 50% of the total d33 at c = 4.30 Å. This means that the covalent bonding between Ba and O is significant and has an important impact on the piezoelectric response of BaTiO3.