Effective Hamiltonian methods for predicting the electrocaloric behavior of BaTiO3

The perovskite crystal BaTiO3 is modeled using a first-principles based effective Hamiltonian and molecular dynamics simulations are performed to estimate the pyroelectric response. The electrocaloric temperature change, ΔTΔT, is calculated for different temperatures and externally applied electric fields. It is found that it is possible to achieve a large ΔTΔT, around 5–6 K, for a relatively small electric field gradient, less than 100 kV/cm, if the applied fields have a small absolute magnitude.

► Demonstrate a freely available effective Hamiltonian model to study ECE in perovskite crystals.
► Use this method to predict the electrocaloric response.
► Apply this approach to the archetypal ferroelectric perovskite BaTiO3 (BTO).
► Demonstrate that indeed BTO can exhibit a large pyroelectric and ECE response.
► Large ECE achieved with a small electric field because there is no antiferroelectric phase.