Anharmonic Phonon Renormalization Enhances Lattice Thermal Conductivity in LiMgVO₄

Metal vanadates have garnered attention for their diverse structures and multifunctionality. Here, we systematically investigate the thermodynamic and phonon transport properties of LiMgVO4 using first-principles calculations incorporating anharmonic phonon renormalization. The quasi-harmonic approximation is employed to evaluate the heat capacity, thermal expansion, and Gibbs free energy. Furthermore, we find that incorporating phonon renormalization leads to substantial thermal conductivity enhancement, particularly at low temperatures, with a room-temperature increase exceeding 60% compared to the harmonic treatment. This enhancement arises from the softening of third-order force constants, which significantly suppress three-phonon scattering rates. Additionally, the observed extension of phonon mean free paths upon phonon renormalization indicates that microstructural engineering, such as grain size control or orientation design, could be an effective route to tailor the thermal performance of LiMgVO4. These results provide essential thermophysical data for LiMgVO4 and offer valuable insights into its anharmonic behavior, aiding the design of thermally robust vanadate-based materials.