Renormalized Phonon Microstructures at High Temperatures from First-Principles Calculations: Methodologies and Applications in Studying Strong Anharmonic Vibrations of Solids

Figure 2

Diffuse curves are TDEP phonon dispersions of rutile below 25 meV at (a) 300 K and (b) 1373 K, compared with the results from the FTVAC method (red circles). The white curves are phonon dispersions for the quasiharmonicity plus quartic anharmonicity calculated with all set to zero in (4). In (b), the dispersions are compared to the quasiharmonic dispersions (orange dashed curve) and the single quartic oscillator model (orange triangles). (c) Frozen phonon potential (black) of TA mode at R point with at 1373 K, showing the harmonic component (red) and quartic component (blue). The low temperature potential surface is also shown (dashed black). Reprinted figure with permission from Lan et al. [6]. Copyright by the American Physical Society.

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