Breakdown of Minimal Mean Free Path Theory in MgSiO3 Perovskite

POSTER

Abstract

Understanding the lattice thermal conductivity at high temperatures is important for many applications. We characterize phonon quasiparticles numerically through a hybrid approach that combines ab initio molecular dynamics and lattice dynamics. We find no lower-bound limits on
phonon mean free paths in MgSiO3-perovskite. This contradicts the widely used minimal mean free path idea. The clear identification of phonon quasiparticles validates the use of the phonon gas model when phonon mean free paths are shorter than lattice constants of solids. Using the phonon quasiparticle properties, we have calculated the lattice thermal conductivity of MgSiO3 perovskite, a controversial topic of fundamental importance in geophysics.

Presenters

  • Renata Wentzcovitch

    Department of Applied Physics and Applied Mathematics and Department of Earth and Environmental Sciences, Lamont Doherty Earth Observatory, Columbia University, Applied Physics and Mathematics, Columbia University, Columbia Univ, Applied Physics and Applied Mathematics, Columbia University, Columbia University, Department of Applied Physics and Applied Mathematics, Department of Earth and Environmental Sciences, Lamont Doherty Earth Observatory, Columbia University

Authors

  • Renata Wentzcovitch

    Department of Applied Physics and Applied Mathematics and Department of Earth and Environmental Sciences, Lamont Doherty Earth Observatory, Columbia University, Applied Physics and Mathematics, Columbia University, Columbia Univ, Applied Physics and Applied Mathematics, Columbia University, Columbia University, Department of Applied Physics and Applied Mathematics, Department of Earth and Environmental Sciences, Lamont Doherty Earth Observatory, Columbia University

  • Philip B. Allen

    Physics and Astronomy, Stony Brook University, Stony Brook

  • Tao Sun

    Key Laboratory for Geodynamics, University of the Chinese Academy of Sciences

  • Dong-Bo Zhang

    Condensed Matter, Beijing Computational Science Research Center, Condensed Matter , Beijing Computational Science Research Center, Beijing Computational Science Research Center