Minimum thermal conductivity in superlattices: A first-principles formalism
Name
Garg-2013-Minimum thermal conductivity.pdf
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229.54 KB
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Adobe PDF
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Author(s)
Garg, Jivtesh
Chen, Gang
Date Issued
April 2013
Journal
Physical Review B
Publisher
American Physical Society
Citation
Garg, Jivtesh, and Gang Chen. "Minimum thermal conductivity in superlattices: A first-principles formalism." Phys. Rev. B 87, 140302(R) (April 2013). © 2013 American Physical Society
Version
Final published version
Abstract
The thermal conductivity of silicon-germanium superlattices is computed from density-functional perturbation theory using relaxation times that include both anharmonic and interface roughness effects. A decrease in the group velocity of low-frequency phonons in addition to the interface-disorder-induced scattering of high-frequency phonons drives the superlattice thermal conductivity to below the alloy limit. At short periods, interplay between decrease in group velocity and increase in phonon lifetimes with increase in superlattice period leads to a minimum in the cross-plane thermal conductivity. Increasing the mass mismatch between the constituent materials in the superlattice further lowers the thermal conductivity below the alloy limit, pointing to avenues for higher efficiency thermoelectric materials.
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.87.140302
