First-Principles Investigation of the Role of Oxygen Vibrational Properties in Regulating Lattice Thermal Conductivity during Deformation of HfO ₂

Ferroelectric materials exhibit significant application potential in non-volatile memories and micro/nanoelectronic devices owing to their spontaneous polarization. However, the role of domain structures in regulating their multiphysical coupling behaviors remains insufficiently understood. In this work, lead-free ferroelectric HfO 2 is investigated using first-principles calculations combined with the phonon Boltzmann transport theory to systematically elucidate the modulation mechanisms of 180° ferroelectric domain walls and external strain on lattice thermal conductivity. The results show that the type-1 180° domain wall possesses the lowest domain wall energy and is therefore the most stable configuration. Phonon dispersion analysis confirms that the system remains dynamically stable within the applied strain range. Low-frequency acoustic phonons are highly sensitive to external strain. In the frequency range of 2.5–5 THz, significant hybridization occurs between O and Hf atomic vibrations, with the vibrational contribution of the O10 atom progressively enhanced under strain. Phonons in this frequency window dominate heat transport. The lattice thermal conductivity exhibits a pronounced asymmetric response to strain: it remains approximately 11 W/mK under compressive strain but decreases markedly to about 6 W/mK at 5% tensile strain. Further analysis of phonon lifetimes, scattering phase space, and Gruneisen parameters indicates that tensile strain enhances anharmonic scattering of low-frequency phonons dominated by O10 vibrations, thereby significantly shortening phonon lifetimes and suppressing thermal transport. Additional mean square displacement (MSD) and electron localization function (ELF) analyses reveal that the O10 atom exhibits large vibrational amplitude and strong anharmonicity, and its vibrational behavior predominantly governs the reduction of thermal conductivity during deformation. These findings uncover the microscopic mechanism by which ferroelectric domain walls and strain synergistically regulate thermal transport in HfO 2 , providing theoretical guidance for thermal management and structural optimization of ferroelectric devices.