Reconstruction of phonon relaxation times from systems featuring interfaces with unknown properties
We present a method for reconstructing the phonon relaxation-time function τ[subscript ω]=τ(ω) (including polarization) and associated phonon free-path distribution from thermal spectroscopy data for systems featuring interfaces with unknown properties. Our method does not rely on the effective ther...
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| Format: | Article |
| Language: | English |
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American Physical Society
2018
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| Online Access: | http://hdl.handle.net/1721.1/115894 https://orcid.org/0000-0001-8695-1891 https://orcid.org/0000-0002-1670-2264 |
| _version_ | 1826194443495014400 |
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| author | Forghani Oozroody, Mojtaba Hadjiconstantinou, Nicolas |
| author2 | Massachusetts Institute of Technology. Department of Mechanical Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Mechanical Engineering Forghani Oozroody, Mojtaba Hadjiconstantinou, Nicolas |
| author_sort | Forghani Oozroody, Mojtaba |
| collection | MIT |
| description | We present a method for reconstructing the phonon relaxation-time function τ[subscript ω]=τ(ω) (including polarization) and associated phonon free-path distribution from thermal spectroscopy data for systems featuring interfaces with unknown properties. Our method does not rely on the effective thermal-conductivity approximation or a particular physical model of the interface behavior. The reconstruction is formulated as an optimization problem in which the relaxation times are determined as functions of frequency by minimizing the discrepancy between the experimentally measured temperature profiles and solutions of the Boltzmann transport equation for the same system. Interface properties such as transmissivities are included as unknowns in the optimization; however, because for the thermal spectroscopy problems considered here the reconstruction is not very sensitive to the interface properties, the transmissivities are only approximately reconstructed and can be considered as byproducts of the calculation whose primary objective is the accurate determination of the relaxation times. The proposed method is validated using synthetic experimental data obtained from Monte Carlo solutions of the Boltzmann transport equation. The method is shown to remain robust in the presence of uncertainty (noise) in the measurement. |
| first_indexed | 2024-09-23T09:55:54Z |
| format | Article |
| id | mit-1721.1/115894 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T09:55:54Z |
| publishDate | 2018 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/1158942022-09-26T14:40:45Z Reconstruction of phonon relaxation times from systems featuring interfaces with unknown properties Forghani Oozroody, Mojtaba Hadjiconstantinou, Nicolas Massachusetts Institute of Technology. Department of Mechanical Engineering Forghani Oozroody, Mojtaba Hadjiconstantinou, Nicolas We present a method for reconstructing the phonon relaxation-time function τ[subscript ω]=τ(ω) (including polarization) and associated phonon free-path distribution from thermal spectroscopy data for systems featuring interfaces with unknown properties. Our method does not rely on the effective thermal-conductivity approximation or a particular physical model of the interface behavior. The reconstruction is formulated as an optimization problem in which the relaxation times are determined as functions of frequency by minimizing the discrepancy between the experimentally measured temperature profiles and solutions of the Boltzmann transport equation for the same system. Interface properties such as transmissivities are included as unknowns in the optimization; however, because for the thermal spectroscopy problems considered here the reconstruction is not very sensitive to the interface properties, the transmissivities are only approximately reconstructed and can be considered as byproducts of the calculation whose primary objective is the accurate determination of the relaxation times. The proposed method is validated using synthetic experimental data obtained from Monte Carlo solutions of the Boltzmann transport equation. The method is shown to remain robust in the presence of uncertainty (noise) in the measurement. 2018-05-25T15:32:13Z 2018-05-25T15:32:13Z 2018-05 2018-03 2018-05-24T18:00:21Z Article http://purl.org/eprint/type/JournalArticle 2469-9950 2469-9969 http://hdl.handle.net/1721.1/115894 Forghani, Mojtaba and Nicolas G. Hadjiconstantinou. "Reconstruction of phonon relaxation times from systems featuring interfaces with unknown properties." Physical Review B 97, 19 (May 2018): 195440 © 2018 American Physical Society https://orcid.org/0000-0001-8695-1891 https://orcid.org/0000-0002-1670-2264 en http://dx.doi.org/10.1103/PhysRevB.97.195440 Physical Review B 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. American Physical Society application/pdf American Physical Society American Physical Society |
| spellingShingle | Forghani Oozroody, Mojtaba Hadjiconstantinou, Nicolas Reconstruction of phonon relaxation times from systems featuring interfaces with unknown properties |
| title | Reconstruction of phonon relaxation times from systems featuring interfaces with unknown properties |
| title_full | Reconstruction of phonon relaxation times from systems featuring interfaces with unknown properties |
| title_fullStr | Reconstruction of phonon relaxation times from systems featuring interfaces with unknown properties |
| title_full_unstemmed | Reconstruction of phonon relaxation times from systems featuring interfaces with unknown properties |
| title_short | Reconstruction of phonon relaxation times from systems featuring interfaces with unknown properties |
| title_sort | reconstruction of phonon relaxation times from systems featuring interfaces with unknown properties |
| url | http://hdl.handle.net/1721.1/115894 https://orcid.org/0000-0001-8695-1891 https://orcid.org/0000-0002-1670-2264 |
| work_keys_str_mv | AT forghanioozroodymojtaba reconstructionofphononrelaxationtimesfromsystemsfeaturinginterfaceswithunknownproperties AT hadjiconstantinounicolas reconstructionofphononrelaxationtimesfromsystemsfeaturinginterfaceswithunknownproperties |