Electrocaloric Performance of High-Entropy Oxides from First Principles

The electrocaloric effect holds significant promise for advancing sustainable solid-state refrigeration technologies. High-entropy oxides [1] are potentially advantageous due to the thermal stability of their polar phases. In this work, we evaluate the phase stability and electrocaloric performance of the high-entropy perovskite (Na,Bi,Sr,Ba,Ca)TiO₃. A pivotal parameter in evaluating electrocaloric performance is the dependence of adiabatic electrocaloric temperature change as a function of temperature, which is intricately linked to the change of polarization with respect to temperature under a constant electric field [2]. To predict this parameter, we developed models for the temperature-dependent polarization P(T) of high-entropy oxides taking into account chemical disorder and local distortions. We systematically assess the efficiency and accuracy of the proposed models for mapping the temperature-dependent free energy landscape across high-entropy oxide compositions.

[1] Rost et al., Nature Communications 6, 8485 (2015)

[2] Nair et al., Nature 575, 468–472 (2019)