Spectral concentration of thermal conductivity in GaN—A first-principles study
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...
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| Format: | Article |
| Language: | English |
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AIP Publishing
2020
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| Online Access: | https://hdl.handle.net/1721.1/128109 |
| _version_ | 1811068704566280192 |
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| author | Garg, Jivtesh Luo, Tengfei Chen, Gang |
| author2 | Massachusetts Institute of Technology. Department of Mechanical Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Mechanical Engineering Garg, Jivtesh Luo, Tengfei Chen, Gang |
| author_sort | Garg, Jivtesh |
| collection | MIT |
| description | 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). |
| first_indexed | 2024-09-23T07:59:53Z |
| format | Article |
| id | mit-1721.1/128109 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T07:59:53Z |
| publishDate | 2020 |
| publisher | AIP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/1281092022-09-23T10:09:59Z Spectral concentration of thermal conductivity in GaN—A first-principles study Garg, Jivtesh Luo, Tengfei Chen, Gang Massachusetts Institute of Technology. Department of Mechanical Engineering 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). DARPA (Grant No. D15AP00094) Office of Naval Research - MURI Grant (No. N00014-16-1-2436) 2020-10-19T17:20:23Z 2020-10-19T17:20:23Z 2018-06 2018-02 2019-09-20T11:47:07Z Article http://purl.org/eprint/type/JournalArticle 1077-3118 https://hdl.handle.net/1721.1/128109 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) en https://dx.doi.org/10.1063/1.5026903 Applied Physics Letters 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. application/pdf AIP Publishing Other repository |
| spellingShingle | Garg, Jivtesh Luo, Tengfei Chen, Gang Spectral concentration of thermal conductivity in GaN—A first-principles study |
| title | Spectral concentration of thermal conductivity in GaN—A first-principles study |
| title_full | Spectral concentration of thermal conductivity in GaN—A first-principles study |
| title_fullStr | Spectral concentration of thermal conductivity in GaN—A first-principles study |
| title_full_unstemmed | Spectral concentration of thermal conductivity in GaN—A first-principles study |
| title_short | Spectral concentration of thermal conductivity in GaN—A first-principles study |
| title_sort | spectral concentration of thermal conductivity in gan a first principles study |
| url | https://hdl.handle.net/1721.1/128109 |
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