First-principles study of the response to strain in BaTiO3/SrTiO3 superlattices

The effect of compressive strain on the polarization and dielectric properties of the BaTiO3/SrTiO3 (BST) superlattice is studied using a first-principles calculation. These properties are found to be tailored by in-plane compressive strain due to lattice mismatch between the superlattice and the substrate, which agrees with the response to stress in the BST rod of our previous study (Zheng et al 2007 Appl. Phys. Lett. 90 092905). The strain induces lattice distortion, the displacement of each atom and dynamical charge transfer between the Ti atom and the O atom in the BaTiO3/SrTiO3 superlattice. With increasing strain, the polarization value increases linearly, and the optical phonon modes harden which lead to the reduction in the static dielectric constant. Our results are expected to be of use for the design of properties of the epitaxial BST ferroelectric superlattice.