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Title: Anisotropic thermal transport property of defect-free GaN

Abstract

Non-equilibrium molecular dynamics (MD) simulation is performed to calculate the thermal conductivity of defect-free GaN along three high-symmetry directions. It is found that the thermal conductivity along [001] direction is about 25% higher than that along [100] or [120] direction. The calculated phonon dispersion relation and iso-energy surface from lattice dynamics show that the difference of the sound speeds among the three high-symmetry directions is quite small for the same mode. However, the variation of phonon irradiation with direction is qualitatively consistent with that of the calculated thermal conductivity. Our results indicate that the anisotropic thermal conductivity may partly result from the phonons in the low-symmetry region of the first Brillouin zone due to phonon focus effects, even though the elastic properties along the three high-symmetry directions are nearly isotropic. Thus, the phonon irradiation is able to better describe the property of thermal conductivity as compared to the commonly used phonon dispersion relation. The present investigations uncover the physical origin of the anisotropic thermal conductivity in defect-free GaN, which would provide an important guide for optimizing the thermal management of GaN-based device.

Authors:
; ;  [1]
  1. Department of Mechanical Engineering, Southeast University, Nanjing 211189 (China)
Publication Date:
OSTI Identifier:
22611484
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 6; Journal Issue: 6; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANISOTROPY; BRILLOUIN ZONES; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; DEFECTS; DISPERSIONS; ELASTICITY; EQUILIBRIUM; GALLIUM NITRIDES; IRRADIATION; MOLECULAR DYNAMICS METHOD; OPTIMIZATION; PHONONS; SOUND WAVES; SURFACES; SYMMETRY; THERMAL CONDUCTIVITY; VELOCITY

Citation Formats

Ju, Wenjing, Zhou, Zhongyuan, E-mail: zyzhou@seu.edu.cn, E-mail: zywei@seu.edu.cn, and Wei, Zhiyong, E-mail: zyzhou@seu.edu.cn, E-mail: zywei@seu.edu.cn. Anisotropic thermal transport property of defect-free GaN. United States: N. p., 2016. Web. doi:10.1063/1.4955185.
Ju, Wenjing, Zhou, Zhongyuan, E-mail: zyzhou@seu.edu.cn, E-mail: zywei@seu.edu.cn, & Wei, Zhiyong, E-mail: zyzhou@seu.edu.cn, E-mail: zywei@seu.edu.cn. Anisotropic thermal transport property of defect-free GaN. United States. doi:10.1063/1.4955185.
Ju, Wenjing, Zhou, Zhongyuan, E-mail: zyzhou@seu.edu.cn, E-mail: zywei@seu.edu.cn, and Wei, Zhiyong, E-mail: zyzhou@seu.edu.cn, E-mail: zywei@seu.edu.cn. 2016. "Anisotropic thermal transport property of defect-free GaN". United States. doi:10.1063/1.4955185.
@article{osti_22611484,
title = {Anisotropic thermal transport property of defect-free GaN},
author = {Ju, Wenjing and Zhou, Zhongyuan, E-mail: zyzhou@seu.edu.cn, E-mail: zywei@seu.edu.cn and Wei, Zhiyong, E-mail: zyzhou@seu.edu.cn, E-mail: zywei@seu.edu.cn},
abstractNote = {Non-equilibrium molecular dynamics (MD) simulation is performed to calculate the thermal conductivity of defect-free GaN along three high-symmetry directions. It is found that the thermal conductivity along [001] direction is about 25% higher than that along [100] or [120] direction. The calculated phonon dispersion relation and iso-energy surface from lattice dynamics show that the difference of the sound speeds among the three high-symmetry directions is quite small for the same mode. However, the variation of phonon irradiation with direction is qualitatively consistent with that of the calculated thermal conductivity. Our results indicate that the anisotropic thermal conductivity may partly result from the phonons in the low-symmetry region of the first Brillouin zone due to phonon focus effects, even though the elastic properties along the three high-symmetry directions are nearly isotropic. Thus, the phonon irradiation is able to better describe the property of thermal conductivity as compared to the commonly used phonon dispersion relation. The present investigations uncover the physical origin of the anisotropic thermal conductivity in defect-free GaN, which would provide an important guide for optimizing the thermal management of GaN-based device.},
doi = {10.1063/1.4955185},
journal = {AIP Advances},
number = 6,
volume = 6,
place = {United States},
year = 2016,
month = 6
}