Influence of quartic anharmonicity on lattice dynamics and thermal transport properties of 16 antifluorite structures

This paper uses advanced first-principles calculation methods, combined with self-consistent phonon (SCP) theory, compressive sensing (CS) lattice dynamics, and Boltzmann transport equation (BTE), to calculate and study the lattice dynamics and phonon transport of 16 antifluorite structures. The lattice thermal conductivity ( kappa L ) of these materials was studied in detail by analyzing the quartic anharmonic renormalization of phonon frequencies and four-phonon (4ph) scattering, revealing the significant influence of quartic anharmonicity on their thermal transport properties. Our study shows that strong quartic anharmonic renormalization is observed for eight materials, leading to enhanced kappa L . In contrast, for the five materials, the weak quartic anharmonic effect leads to negligible changes in thermal conductivity. Three materials exhibit reduced kappa L due to phonon anharmonic renormalization. Furthermore, 4ph scattering rates (SRs) are important for many of the materials studied and can offset changes in frequency, leading to a reduction in thermal conductivity. At the same time, our calculations give an approximately linear relationship between kappa L and 4ph scattering, which suggests that structures with low kappa L have stronger 4ph scattering. Simultaneously, we chose Li 2 O, characterized by high kappa L , and Rb 2 Te, known for its low kappa L , to thoroughly examine their microscopic thermal transport mechanisms. This involved detailed analysis of the thermal conductivity spectrum kappa L ( omega ), scattering phase space, group velocity, and scattering processes. Finally, this study provides insights into the underlying physical mechanisms of thermal transport in 16 antifluorite materials and highlights the need to consider 4ph scattering for thermal transport in materials.