Ab initio based optimization of functional ferroelectrics
Ferroelectric perovskites are promising for energy harvesting and future efficient solid-state cooling devices based on the electrocaloric effect. However, large functional responses are often restricted to a small temperature range in the vicinity of ferroelectric transitions.
In this contribution we discuss the benefits of ab initio based molecular dynamics simulations to understand and optimize ferrolectric transitions in BaTiO3-based materials. Thereby, we consider the coupling between structure and functional responses on different scales employing atomistic potentials and the coarsed grained effective Hamiltonian approach. In particular, we focus on the impact of Ba-Sr substitution and domains on caloric and dielectric responses.
On the one hand, we find that homogenously distributed Sr mainly allows to adjust the optimal operation temperature.
On the other hand, we observe exotic domain structures and negative capacitance in inhomogenous materials.