Perturbative approach to electrocaloric effects

The electrocaloric (EC) effect is the temperature change an insulator material undergoes upon the application of an electric bias. This phenomenon has been widely studied due to its potential as an alternative refrigeration technology. However, we still lack on a unified way to explain normal (increase of temperature under electric bias) and inverse (decrease of temperature) EC effects. In this work we show that, by expressing EC temperature and entropy changes as Taylor series of the applied electric field, one can qualitatively predict and explain all EC effects observed in ferroelectric and antiferroelectric materials. As an example, we present results obtained through second-principles simulations on prototype ferroelectric PbTiO₃.