Research Papers: Micro/Nanoscale Heat Transfer

Excitation of Single Phonon Modes in Nanoscale Waveguides

[+] Author and Article Information
Drew A. Cheney, Jennifer R. Lukes

Department of Mechanical Engineering and Applied Mechanics,  University of Pennsylvania, Philadelphia, PA 19104dcheney@seas.upenn.edu

J. Heat Transfer 134(4), 042403 (Feb 14, 2012) (9 pages) doi:10.1115/1.4005097 History: Received December 01, 2010; Revised August 22, 2011; Published February 14, 2012; Online February 14, 2012

We present a new computational method that excites guided phonon modes in nanoscale waveguides at a specific frequency and wavenumber. The method uses nonequilibrium molecular dynamics and Fourier analysis of particle displacements to extract mode shapes from single frequency excitations consisting of superposed spatial modes. These mode shapes are used to excite the waveguide inlet boundary so that single phonon modes are generated in the structure. Mode shapes and phonon spectra for a silicon planar waveguide with rigid wall boundaries are calculated to demonstrate the viability of the technique. This method improves upon molecular dynamics techniques that activate all possible phonon modes and are thus not able to isolate the contribution of any single phonon excitation. Application of our method will enable the computational investigation of single phonon mode propagation in nanostructures of varying geometry.

Copyright © 2012 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
Figure 1

Computational geometry of planar waveguide used to excite single frequency phonons. Actual length is much larger than that shown in the figure.

Grahic Jump Location
Figure 2

Schematic of relationship between rectangular grid points and equilibrium atomic positions. Dashed circle shows maximum distance within which an atom is included in the interpolation.

Grahic Jump Location
Figure 3

Full x-direction dispersion relation of planar waveguide calculated using MD. The low frequency, low wavenumber regime is enlarged and shown in Fig. 4.

Grahic Jump Location
Figure 4

(a) Wavenumber spectral amplitude for plate waveguide excited with randomly generated mode shapes and (b) location of spectral peaks on plate dispersion relation

Grahic Jump Location
Figure 5

Idealized geometry of planar waveguide used in SPW analysis

Grahic Jump Location
Figure 6

Wavenumber spectral amplitude for single mode excitations. Each line represents an individual simulation.

Grahic Jump Location
Figure 7

x-component of displacement resulting from single frequency boundary excitations with random lateral mode shape and phase difference

Grahic Jump Location
Figure 8

x-component of displacement of single (S1) mode extracted from Fourier analysis of randomly excited displacement field

Grahic Jump Location
Figure 9

Normalized mode shapes of possible modes at 1.75 THz. Wavenumbers are divided by 2π/a.



Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In