### Session Y17: Nanostructures and Interfaces: Electrons, Phonons, and Plasmons

8:00 AM–10:48 AM, Friday, March 2, 2012
Room: 252A

Chair: Evan Glaser, Naval Research Laboratory

Abstract ID: BAPS.2012.MAR.Y17.5

### Abstract: Y17.00005 : Probing phonon surface scattering in nanostructures

8:48 AM–9:00 AM

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#### Authors:

Richard Robinson
(Cornell University, Department of Materials Science and Engineering)

Jared Hertzberg
(Cornell University, Department of Materials Science and Engineering)

Obafemi Otelaja
(Cornell University, Department of Materials Science and Engineering)

In insulating materials, heat is transmitted by atomic vibrations (phonons''). In nanostructured materials such as nanowires and nanosheets, the characteristic length scale of a material can be less than the mean free path of a phonon. The phonon transport is then drastically altered and becomes dominated by scattering from surfaces. We demonstrate a method to assess the scattering rate and transmission factor of phonons traversing a silicon nanosheet. Generation and detection of phonons is accomplished by a superconducting tunnel junction attached to the silicon nanostructure and operated at a temperature of 0.3K. Decay of excited states in the superconductor is employed as a tunable narrow-band source of phonons [1,2]. This tunable source enables investigation of the phonon mean free path as a function of phonon frequency and surface roughness, for frequencies from $\sim$100 GHz to $\sim$500 GHz in nanosheets 100 to 200 nm thick. This work is supported by DOE (DE-SC0001086). \\[4pt] [1] H. Kinder. Phys. Rev. Lett. 28, 1564 (1972)\\[0pt] [2] J. B. Hertzberg et al, Rev. Sci. Inst. 82, 104905 (2011).

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2012.MAR.Y17.5