First-principles calculations of the elastic anisotropy and thermodynamic properties of m-ZrO2 at high pressures and temperatures

Abstract

While the fundamental properties of monoclinic zirconia (m-ZrO2) are cataloged in high-throughput databases like the Materials Project, such data primarily rely on semilocal functionals that systematically underpredict the bandgap by ∼40% and fail to account for the intrinsic anharmonicity essential for high-temperature stability. This study employs the high-accuracy HSE06 hybrid functional to yield a bandgap of 5.75 eV, which is in excellent agreement with experimental vacuum ultraviolet measurements (5.83 eV). Furthermore, we provide a systematic mapping of thermodynamic properties across a wide range (0–1200 K, 0–16 GPa) with the Debye–Grüneisen model and quasi-harmonic approximation. Crucially, by utilizing DynaPhoPy and first-principles molecular dynamics at 300 and 1200 K, we explicitly demonstrate that high-temperature anharmonic effects stabilize the monoclinic lattice via frequency renormalization, providing a rigorous theoretical foundation for the monoclinic phase’s thermodynamic stability as it approaches the phase transition threshold (∼1443 K). This investigation contributes to a deeper understanding of the intrinsic properties of m-ZrO2 and provides valuable guidance for its expanded applications.