Diffusive Phonons in Nongray Nanostructures
Nanostructured semiconducting materials are promising candidates for thermoelectrics (TEs) due to their potential to suppress phonon transport while preserving electrical properties. Modeling phonon-boundary scattering in complex geometries is crucial for predicting materials with high conversion ef...
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| Format: | Article |
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American Society of Mechanical Engineers (ASME)
2018
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| Online Access: | http://hdl.handle.net/1721.1/119823 https://orcid.org/0000-0003-0026-8237 https://orcid.org/0000-0002-4347-0139 |
| _version_ | 1826213803018158080 |
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| author | Romano, Giuseppe Kolpak, Alexie M. |
| author2 | Massachusetts Institute of Technology. Department of Mechanical Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Mechanical Engineering Romano, Giuseppe Kolpak, Alexie M. |
| author_sort | Romano, Giuseppe |
| collection | MIT |
| description | Nanostructured semiconducting materials are promising candidates for thermoelectrics (TEs) due to their potential to suppress phonon transport while preserving electrical properties. Modeling phonon-boundary scattering in complex geometries is crucial for predicting materials with high conversion efficiency. However, the simultaneous presence of ballistic and diffusive phonons challenges the development of models that are both accurate and computationally tractable. Using the recently developed first-principles Boltzmann transport equation (BTE) approach, we investigate diffusive phonons in nanomaterials with wide mean-free-path (MFP) distributions. First, we derive the short MFP limit of the suppression function, showing that it does not necessarily recover the value predicted by standard diffusive transport, challenging previous assumptions. Second, we identify a Robin type boundary condition describing diffuse surfaces within Fourier's law, extending the validity of diffusive heat transport in terms of Knudsen numbers. Finally, we use this result to develop a hybrid Fourier/BTE approach to model realistic materials, obtaining good agreement with experiments. These results provide insight on thermal transport in materials that are within experimental reach and open opportunities for large-scale screening of nanostructured TE materials. |
| first_indexed | 2024-09-23T15:54:46Z |
| format | Article |
| id | mit-1721.1/119823 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T15:54:46Z |
| publishDate | 2018 |
| publisher | American Society of Mechanical Engineers (ASME) |
| record_format | dspace |
| spelling | mit-1721.1/1198232022-10-02T05:01:47Z Diffusive Phonons in Nongray Nanostructures Romano, Giuseppe Kolpak, Alexie M. Massachusetts Institute of Technology. Department of Mechanical Engineering Romano, Giuseppe Kolpak, Alexie M. Nanostructured semiconducting materials are promising candidates for thermoelectrics (TEs) due to their potential to suppress phonon transport while preserving electrical properties. Modeling phonon-boundary scattering in complex geometries is crucial for predicting materials with high conversion efficiency. However, the simultaneous presence of ballistic and diffusive phonons challenges the development of models that are both accurate and computationally tractable. Using the recently developed first-principles Boltzmann transport equation (BTE) approach, we investigate diffusive phonons in nanomaterials with wide mean-free-path (MFP) distributions. First, we derive the short MFP limit of the suppression function, showing that it does not necessarily recover the value predicted by standard diffusive transport, challenging previous assumptions. Second, we identify a Robin type boundary condition describing diffuse surfaces within Fourier's law, extending the validity of diffusive heat transport in terms of Knudsen numbers. Finally, we use this result to develop a hybrid Fourier/BTE approach to model realistic materials, obtaining good agreement with experiments. These results provide insight on thermal transport in materials that are within experimental reach and open opportunities for large-scale screening of nanostructured TE materials. 2018-12-21T19:33:35Z 2018-12-21T19:33:35Z 2018-10 2018-06 2018-12-12T13:52:41Z Article http://purl.org/eprint/type/JournalArticle 0022-1481 1528-8943 http://hdl.handle.net/1721.1/119823 Romano, Giuseppe and Alexie M. Kolpak. “Diffusive Phonons in Nongray Nanostructures.” Journal of Heat Transfer 141, 1 (October 2018): 012401 © 2019 ASME https://orcid.org/0000-0003-0026-8237 https://orcid.org/0000-0002-4347-0139 http://dx.doi.org/10.1115/1.4040611 Journal of Heat Transfer 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 American Society of Mechanical Engineers (ASME) ASME |
| spellingShingle | Romano, Giuseppe Kolpak, Alexie M. Diffusive Phonons in Nongray Nanostructures |
| title | Diffusive Phonons in Nongray Nanostructures |
| title_full | Diffusive Phonons in Nongray Nanostructures |
| title_fullStr | Diffusive Phonons in Nongray Nanostructures |
| title_full_unstemmed | Diffusive Phonons in Nongray Nanostructures |
| title_short | Diffusive Phonons in Nongray Nanostructures |
| title_sort | diffusive phonons in nongray nanostructures |
| url | http://hdl.handle.net/1721.1/119823 https://orcid.org/0000-0003-0026-8237 https://orcid.org/0000-0002-4347-0139 |
| work_keys_str_mv | AT romanogiuseppe diffusivephononsinnongraynanostructures AT kolpakalexiem diffusivephononsinnongraynanostructures |