2017/11/08 by Yi Xia, Xia, Yi, Maria K. Y. Chan +1
Engineering · Materials Science · Physics and Astronomy · #FOS: Physical sciences #Ga2O3 and related materials #Gas Sensing Nanomaterials and Sensors #Materials Science (cond-mat.mtrl-sci) #Transition Metal Oxide Nanomaterials #cond-mat.mtrl-sci
paper · pdf · doi:10.48550/arxiv.1711.02819
openalex publication_date 2017/11/08 · arxiv created 2017/11/20 · arxiv updated 2017/11/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Vanadium dioxide (VO2) undergoes a first-order metal-insulator transition (MIT) upon cooling near room temperature, concomitant with structural change from rutile to monoclinic. Accurate characterization of lattice vibrations is vital for elucidating the transition mechanism. To investigate the lattice dynamics and thermal transport properties of VO2 across the MIT, we present a phonon renormalization scheme based on self-consistent phonon theory through iteratively refining vibrational free energy. Using this technique, we compute temperature-dependent phonon dispersion and lifetimes, and point out the importance of both magnetic and vibrational entropy in driving the MIT. The predicted phonon dispersion and lifetimes show quantitative agreement with experimental measurements. We demonstrate that lattice thermal conductivity of rutile VO2 is nearly temperature independent as a result of strong intrinsic anharmonicity, while that of monoclinic VO2 varies according to 1/T. Due to phonon softening and enhanced scattering rates, the lattice thermal conductivity is deduced to be substantially lower in the rutile phase, suggesting that Wiedemann-Franz law might not be strongly violated in rutile VO2.