Green's function studies of phonon transport across Si/Ge superlattices
Understanding and manipulating coherent phonon transport in solids is of interest both for enhancing the fundamental understanding of thermal transport as well as for many practical applications, including thermoelectrics. In this study, we investigate phonon transmission across Si/Ge superlattices...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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American Physical Society
2014
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| Online Access: | http://hdl.handle.net/1721.1/88650 https://orcid.org/0000-0002-3968-8530 |
| _version_ | 1811089010109448192 |
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| author | Tian, Zhiting Esfarjani, Keivan Chen, Gang |
| author2 | Massachusetts Institute of Technology. Department of Mechanical Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Mechanical Engineering Tian, Zhiting Esfarjani, Keivan Chen, Gang |
| author_sort | Tian, Zhiting |
| collection | MIT |
| description | Understanding and manipulating coherent phonon transport in solids is of interest both for enhancing the fundamental understanding of thermal transport as well as for many practical applications, including thermoelectrics. In this study, we investigate phonon transmission across Si/Ge superlattices using the Green's function method with first-principles force constants derived from ab initio density functional theory. By keeping the period thickness fixed while changing the number of periods, we show that interface roughness partially destroys coherent phonon transport, especially at high temperatures. The competition between the low-frequency coherent modes and high-frequency incoherent modes leads to an optimum period length for minimum thermal conductivity. To destroy coherence of the low-frequency modes, scattering length scale on the order of period length is required. This finding is useful to guide the design of superlattices to reach even lower thermal conductivity. |
| first_indexed | 2024-09-23T14:12:24Z |
| format | Article |
| id | mit-1721.1/88650 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T14:12:24Z |
| publishDate | 2014 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/886502022-09-28T19:09:49Z Green's function studies of phonon transport across Si/Ge superlattices Tian, Zhiting Esfarjani, Keivan Chen, Gang Massachusetts Institute of Technology. Department of Mechanical Engineering Tian, Zhiting Esfarjani, Keivan Chen, Gang Understanding and manipulating coherent phonon transport in solids is of interest both for enhancing the fundamental understanding of thermal transport as well as for many practical applications, including thermoelectrics. In this study, we investigate phonon transmission across Si/Ge superlattices using the Green's function method with first-principles force constants derived from ab initio density functional theory. By keeping the period thickness fixed while changing the number of periods, we show that interface roughness partially destroys coherent phonon transport, especially at high temperatures. The competition between the low-frequency coherent modes and high-frequency incoherent modes leads to an optimum period length for minimum thermal conductivity. To destroy coherence of the low-frequency modes, scattering length scale on the order of period length is required. This finding is useful to guide the design of superlattices to reach even lower thermal conductivity. United States. Dept. of Energy. Office of Basic Energy Sciences (Award DE-FG02-09ER46577) 2014-08-11T13:27:00Z 2014-08-11T13:27:00Z 2014-06 2014-05 2014-07-23T20:47:51Z Article http://purl.org/eprint/type/JournalArticle 1098-0121 1550-235X http://hdl.handle.net/1721.1/88650 Tian, Zhiting, Keivan Esfarjani, and Gang Chen. “Green’s Function Studies of Phonon Transport Across Si/Ge Superlattices.” Phys. Rev. B 89, no. 23 (June 2014). © 2014 American Physical Society https://orcid.org/0000-0002-3968-8530 en http://dx.doi.org/10.1103/PhysRevB.89.235307 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 | Tian, Zhiting Esfarjani, Keivan Chen, Gang Green's function studies of phonon transport across Si/Ge superlattices |
| title | Green's function studies of phonon transport across Si/Ge superlattices |
| title_full | Green's function studies of phonon transport across Si/Ge superlattices |
| title_fullStr | Green's function studies of phonon transport across Si/Ge superlattices |
| title_full_unstemmed | Green's function studies of phonon transport across Si/Ge superlattices |
| title_short | Green's function studies of phonon transport across Si/Ge superlattices |
| title_sort | green s function studies of phonon transport across si ge superlattices |
| url | http://hdl.handle.net/1721.1/88650 https://orcid.org/0000-0002-3968-8530 |
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