Direct Measurement of Room-Temperature Nondiffusive Thermal Transport Over Micron Distances in a Silicon Membrane
Name
Johnson-2013-Direct Measurement of Room-Temperature Nondiffusive Thermal Transport Over Micron Distances in a Silicon Membrane.pdf
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1.16 MB
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Author(s)
Johnson, Jeremiah A.
Maznev, Alexei
Eliason, Jeffrey Kristian
Nelson, Keith Adam
Cuffe, John
Minnich, Austin Jerome
Kehoe, Timothy
Torres, Clivia M. Sotomayor
Chen, Gang
Date Issued
January 2013
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Johnson, Jeremy A. et al. “Direct Measurement of Room-Temperature Nondiffusive Thermal Transport Over Micron Distances in a Silicon Membrane.” Physical Review Letters 110.2 (2013). © 2013 American Physical Society
Version
Final published version
Abstract
The “textbook” phonon mean free path of heat carrying phonons in silicon at room temperature is ∼40 nm. However, a large contribution to the thermal conductivity comes from low-frequency phonons with much longer mean free paths. We present a simple experiment demonstrating that room-temperature thermal transport in Si significantly deviates from the diffusion model already at micron distances. Absorption of crossed laser pulses in a freestanding silicon membrane sets up a sinusoidal temperature profile that is monitored via diffraction of a probe laser beam. By changing the period of the thermal grating we vary the heat transport distance within the range ∼1–10 μm. At small distances, we observe a reduction in the effective thermal conductivity indicating a transition from the diffusive to the ballistic transport regime for the low-frequency part of the phonon spectrum.
MIT Department
Massachusetts Institute of Technology. Department of Chemistry
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/PhysRevLett.110.025901
