High-throughput study of the static dielectric constant at high temperatures in oxide and fluoride cubic perovskites
© 2020 American Physical Society. 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 ϵDC in the series of oxides BaTiO3, SrTiO3, KTaO3. 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 ϵDC 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 ϵDC is actually well correlated with the infinite-frequency dielectric constant ϵ∞, even in those materials with phase transitions in which ϵDC is strongly temperature dependent.
Van Roekeghem, A; Carrete, J; Curtarolo, S; Mingo, N
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