skip to main content

Title: Calculation of the lattice thermal conductivity in granular crystals

This paper provides a general model for the lattice thermal conductivity in granular crystals. The key development presented in this model is that the contribution of surface phonons to the thermal conductivity and the interplay between phonon anharmonic scattering and phonon scattering by boundaries are considered explicitly. Exact Boltzmann equation including spatial dependence of phonon distribution function is solved to yield expressions for the rates at which phonons scatter by the grain boundaries in the presence of intrinsic phonon scattering mechanisms. The intrinsic phonon scattering rates are calculated from Fermi's golden rule, and the vibration parameters of the model are derived as functions of temperature and crystallographic directions by using a lattice dynamics approach. The accuracy of the model is demonstrated with reference to experimental measurements regarding the effects of surface orientation and isotope composition on the thermal conductivity in single crystals, and the effect of grains size and shape on the thermal conductivity tensor in granular crystals.
Authors:
 [1] ;  [2]
  1. Department of Physics, American University of Beirut, P.O. Box 11-0236, Riad El-Solh, Beirut 1107-2020 (Lebanon)
  2. Laboratoire d'Energie Moléculaire et Macroscopique, Combustion CNRS UPR 288, Ecole Centrale Paris, Voie des Vignes, F-92295 Châtenay-Malabry Cedex (France)
Publication Date:
OSTI Identifier:
22278024
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 7; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BOLTZMANN EQUATION; CRYSTAL STRUCTURE; DISTRIBUTION FUNCTIONS; GRAIN BOUNDARIES; GRAIN SIZE; MONOCRYSTALS; PHONONS; SCATTERING; SPACE DEPENDENCE; SURFACES; TEMPERATURE DEPENDENCE; TENSORS; THERMAL CONDUCTIVITY