High-throughput study of the static dielectric constant at high temperatures in oxide and fluoride cubic perovskites
Ambroise van Roekeghem, Jesús Carrete, Stefano Curtarolo, Natalio Mingo
Abstract
Using finite-temperature phonon calculations and the Lyddane-Sachs-Teller relations, we calculate ab initio the static dielectric constants of 78 semiconducting oxides and fluorides with cubic perovskite structures at 1000 K. We first compare our method with experimental measurements, and we find that it succeeds in describing the temperature dependence and the relative ordering of the static dielectric constant ${\ensuremath{\epsilon}}_{DC}$ in the series of oxides ${\mathrm{BaTiO}}_{3}$, ${\mathrm{SrTiO}}_{3}$, ${\mathrm{KTaO}}_{3}$. We show that the effects of anharmonicity on the ion-clamped dielectric constant, on Born charges, and on phonon lifetimes, can be neglected in the framework of our high-throughput study. Based on the high-temperature phonon spectra, we find that the dispersion of ${\ensuremath{\epsilon}}_{DC}$ is one order of magnitude larger among oxides than fluorides at 1000 K. We display the correlograms of the dielectric constants with simple structural descriptors, and we point out that ${\ensuremath{\epsilon}}_{DC}$ is actually well correlated with the infinite-frequency dielectric constant ${\ensuremath{\epsilon}}_{\ensuremath{\infty}}$, even in those materials with phase transitions in which ${\ensuremath{\epsilon}}_{DC}$ is strongly temperature dependent.