Spectral concentration of thermal conductivity in GaN—A first-principles study
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Spectral_concentration_of_thermal_conductivity_in_GaN.pdf
Description
Published version
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1.07 MB
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Adobe PDF
Checksum (MD5)
ebdccb3a3911345fb62dbffb6c0c0f52
Author(s)
Garg, Jivtesh
Luo, Tengfei
Chen, Gang
Date Issued
June 2018
Journal
Applied Physics Letters
Publisher
AIP Publishing
Citation
Garg, Jivtesh et al., "Spectral concentration of thermal conductivity in GaN—A first-principles study." Applied Physics Letters 112, 25 (June 2018): 252101 ©2018 Author(s)
Version
Final published version
Abstract
We find using first-principles analysis of thermal conductivity (k) in isotopically pure Gallium nitride (GaN) that almost 60% of the heat is conducted by phonons in a very narrow frequency range of 5-7 THz (spanning only 9% of the frequencies in GaN). This spectral focusing of thermal conductivity is found to be due to a combination of two effects - a large increase in lifetimes of phonons through suppression of anharmonic scattering in the 5-7 THz frequency range coupled with a large phonon density of states at the same frequencies. Understanding of the effect is provided by solving the phonon Boltzmann transport equation in the single mode relaxation time approximation along with the use of harmonic and anharmonic force constants derived from density functional theory. The results can have important implications for engineering the thermal performance of devices based on GaN. ©2018 Author(s).
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1063/1.5026903
