Pyroelectric Effect in Tetragonal Ferroelectrics BaTiO₃ and KNbO₃ Studied with Density Functional Theory

Abstract

We present a computational methodology for investigating the pyroelectric properties of anharmonic crystalline ferroelectrics. The description of phonon properties and pyroelectricity in perovskite ferroelectrics such as BaTiO3 and KNbO3 requires phonon anharmonicity to be taken into account. Our computational approach is based on density functional theory calculations. We use self-consistent phonon theory to describe phonon anharmonicity and to obtain finite-temperature atomic displacements. The Berry phase approach is used to obtain spontaneous polarization needed for the prediction of the primary pyroelectric coefficient. We calculate the fixed-volume primary pyroelectric coefficient and piezoelectric strain secondary pyroelectric coefficient for the tetragonal polymorphs of BaTiO3 and KNbO3. We also report the anharmonic phonon dispersions for the studied systems. The computationally relatively straightforward and cost-efficient approach offers a way of screening the pyroelectric coefficients of novel pyroelectric materials for energy harvesting and other microelectronic applications.

Band Gap and Polarization Tuning of Ion-Doped XNbO3 (X = Li, K, Na, Ag) for Photovoltaic and Energy Storage Applications

“…Finally, it could be mentioned that in order to understand the properties of ferroelectric materials and make a comparative analysis with other theoretical works, it could be of interest to study the intricate interplay of distortions and vacancies in these materials [ 35 ] or to investigate their pyroelectric properties with potential applications in energy harvesting and microelectronic devices [ 36 ].…”