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Published February 2011 | public
Journal Article

Significant Reduction of Thermal Conductivity in Si/Ge Core-Shell Nanowires


We report on the effect of germanium (Ge) coatings on the thermal transport properties of silicon (Si) nanowires using nonequilibrium molecular dynamics simulations. Our results show that a simple deposition of a Ge shell of only 1 to 2 unit cells in thickness on a single crystalline Si nanowire can lead to a dramatic 75% decrease in thermal conductivity at room temperature compared to an uncoated Si nanowire. By analyzing the vibrational density states of phonons and the participation ratio of each specific mode, we demonstrate that the reduction in the thermal conductivity of Si/Ge core hell nanowire stems from the depression and localization of long-wavelength phonon modes at the Si/Ge interface and of high frequency nonpropagating diffusive modes.

Additional Information

© 2010 American Chemical Society. Received: October 22, 2010; Revised: November 30, 2010. Article ASAP December 09, 2010. Published In Issue February 09, 2011. The formula just below the table on page 4 was modified in the version of this paper published on December 9, 2010. The correct version published December 27, 2010. K.P.G. expresses his gratitude to ETH Zürich for a visiting professorship grant. J.V.G. recognizes the support of European Commission under the Nanopack project of the Seventh Framework Programme (2007-2013). Computational support from the Brutus Cluster at ETH Zurich is gratefully acknowledged. This work was supported by a grant from the Swiss National Supercomputing Centre-CSCS under Project ID s243.

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August 22, 2023
October 23, 2023