Green's function studies of phonon transport across Si/Ge superlattices
Name
PhysRevB.89.235307.pdf
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277.24 KB
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Author(s)
Tian, Zhiting
Esfarjani, Keivan
Chen, Gang
Date Issued
June 2014
Journal
Physical Review B
Publisher
American Physical Society
Citation
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
Version
Final published version
Abstract
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.
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/10.1103/PhysRevB.89.235307
