Optimization of artificial antiferroelectrics from second-principles simulations

Under appropriate conditions, ferroelectrics are known to display ultra-short-period, highly-ordered stripe domain structures that are evocative of antipolar order in antiferroelectric materials. Such states originate so as to minimize the electrostatic energy of the ferroelectric subject to open-circuit-like boundary conditions (as e.g. in the thin PbTiO₃ layers of short-period PbTiO₃/SrTiO₃ superlattices); hence, it follows that the application of an external electric field – i.e., the control of the electrostatic boundary conditions – should allow us to access a strongly polarized state, and thus obtain genuinely antiferroelectric-like behavior. We have used second-principles simulations to pursue this concept, by investigating the antiferroelectric-like properties of PbTiO₃/SrTiO₃ superlattices and exploring to what extent they can be optimized through the design parameters allowed by these complex materials (e.g., layer thickness, epitaxial strain). In this talk I will summarize our most recent findings.