Enhanced Electrocaloric Response in Electrostatically Frustrated Ferroelectrics

The electrocaloric effect (i.e., the temperature change of a material upon the adiabatic application of an electric field) can be large in ferroelectric compounds, to the extent of offering an eco‐friendly alternative to current, polluting and noisy, refrigeration technologies. So far, ferroelectric‐based electrocaloric devices employ materials (from perovskite oxides to polymers) that have been known for decades. At the same time, recent studies have shown that the functional response of a ferroelectric can be drastically enhanced by controlling its mechanical and electric boundary conditions. Here, we use atomistic second‐principles simulations to quantify how much the electrocaloric effect benefits from such an enhancement. Using ferroelectric/dielectric superlattices as representative model systems, we predict that temperature changes can indeed be increased significantly (more than two times at room temperature), suggesting electrostatic engineering—to induce very reactive frustrated ferroelectric states—as a promising route for electrocaloric optimization.