2021/01/30 by Zhen Zhang, Renata M. Wentzcovitch
Earth and Planetary Sciences · Materials Science · Physics and Astronomy · #Ab initio #Anharmonicity #Condensed matter physics #Ferroelectric and Piezoelectric Materials #High-pressure geophysics and materials #Lattice (music) #Materials science #Phonon #Physics #Quantum mechanics #Quasiparticle #Superconductivity #Thermal Expansion and Ionic Conductivity #Thermal conductivity #Thermodynamics #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.103.144103
published as Phys. Rev. B 103, 144103 (2021)
arxiv created 2021/01/30 · openalex created_date 2021/02/15 · openalex publication_date 2021/04/12 · arxiv updated 2021/04/21 · openalex updated_date 2026/08/06
Lattice thermal conductivity (\ensuremathκlat) of MgSiO3 postperovskite (MgPPv) under the Earth's lower mantle high pressure-temperature conditions is studied using the phonon quasiparticle approach by combing ab initio molecular dynamics and lattice dynamics simulations. Phonon lifetimes are extracted from the phonon quasiparticle calculations, and the phonon group velocities are computed from the anharmonic phonon dispersions, which, in principle, capture full anharmonicity. It is found that throughout the lowermost mantle, including the D'' region, \ensuremathκlat of MgPPv is \ensuremath∼25% larger than that of MgSiO3 perovskite (MgPv), mainly due to MgPPv's higher phonon velocities. Such a difference in phonon velocities between the two phases originates in the MgPPv's relatively smaller primitive cell. Systematic results of temperature and pressure dependences of both MgPPv's and MgPv's \ensuremathκlat are demonstrated.