Thumbnail
Access Restriction
Open

Author Liang, Zhi ♦ Jain, Ankit ♦ McGaughey, Alan J. H. ♦ Keblinski, Pawel
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ ANHARMONIC CRYSTALS ♦ DISLOCATIONS ♦ EQUILIBRIUM ♦ FORECASTING ♦ GALLIUM NITRIDES ♦ MEAN FREE PATH ♦ MOLECULAR DYNAMICS METHOD ♦ PHONONS ♦ POTENTIALS ♦ SIMULATION ♦ THERMAL CONDUCTIVITY
Abstract The bulk thermal conductivity of Stillinger-Weber (SW) wurtzite GaN in the [0001] direction at a temperature of 300 K is calculated using equilibrium molecular dynamics (EMD), non-equilibrium MD (NEMD), and lattice dynamics (LD) methods. While the NEMD method predicts a thermal conductivity of 166 ± 11 W/m·K, both the EMD and LD methods predict thermal conductivities that are an order of magnitude greater. We attribute the discrepancy to significant contributions to thermal conductivity from long-mean free path phonons. We propose that the Grüneisen parameter for low-frequency phonons is a good predictor of the severity of the size effects in NEMD thermal conductivity prediction. For weakly anharmonic crystals characterized by small Grüneisen parameters, accurate determination of thermal conductivity by NEMD is computationally impractical. The simulation results also indicate the GaN SW potential, which was originally developed for studying the atomic-level structure of dislocations, is not suitable for prediction of its thermal conductivity.
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-09-28
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 118
Issue Number 12


Open content in new tab

   Open content in new tab