Open AccessFirst-principles study of the thermal transport property of Y3Al5O12
Author(s) -
Chengcheng Liu,
Quanxi Cao
Publication year - 2010
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.59.2697
Subject(s) - phonon , thermal conductivity , anharmonicity , pseudopotential , condensed matter physics , brillouin zone , materials science , mean free path , brillouin scattering , heat capacity , phonon scattering , density of states , scattering , physics , thermodynamics , optics , laser , composite material
Based on density functional perturbation theory (DFPT) combined with the norm-conserving pseudopotential methodthe lattice dynamic simulation is presented. The total phonon density of statespartial phonon density of states and phonon dispersion spectrum of YAG are obtained. By using the special point sampling method within the first Brillouin zonethe special heat capacity and the population averaged group speed of phonon of YAG are calculated. The anharmonic phonon mean free path is calculated theoretically within anharmonic interaction and by using the Fermis golden rule scheme combined with the special point sampling method within the first Brillouin zone. We comprehensively considered two types of the phonon scattering mechanismsthe thermal conductivity of YAG ceramic is obtained. The result indicates that the grain boundary scattering plays a major role in the thermal resistance at low temperature in YAG ceramicwhile the three-phonon interaction contribution to the thermal resistance will prevail above a certain temperature. Meanwhilethe viewpoint held by Y. Sato et al. that the difference of the thermal conductivity of between YAG ceramic and single crystal can be ignored above room temperature is theoretically proved. The temperature variations of the calculated thermal conductivity and special heat capacity agree well with the experimental results.