First-principles bulk-layer model for dielectric and piezoelectric responses in superlattices

In the first-principles bulk-layer model the superlattice structure and polarization are determined by first-principles computation of the bulk responses of the constituents to the electrical and mechanical boundary conditions in an insulating superlattice. In this work the model is extended to predict functional properties, specifically dielectric permittivity and piezoelectric response. A detailed comparison between the bulk-layer model and full first-principles calculations for three sets of perovskite oxide superlattices, PbTiO3/BaTiO3, BaTiO3/SrTiO3, and PbTiO3/SrTiO3, is presented. The bulk-layer model is shown to give an excellent first approximation to these important functional properties and to allow for the identification and investigation of additional physics, including interface reconstruction and finite-size effects. Technical issues in the generation of the necessary data for constituent compounds are addressed. These results form the foundation for a powerful data-driven method to facilitate discovery and design of superlattice systems with enhanced and tunable polarization, dielectric permittivity, and piezoelectric response.