Vibrational mean free paths and thermal conductivity of amorphous silicon from non-equilibrium molecular dynamics simulations
Research output: Contribution to journal › Article › Scientific › peer-review
- Carnegie Mellon University
- CNRS Centre National de la Recherche Scientifique
The frequency-dependent mean free paths (MFPs) of vibrational heat carriers in amorphous silicon are predicted from the length dependence of the spectrally decomposed heat current (SDHC) obtained from non-equilibrium molecular dynamics simulations. The results suggest a (frequency)−2 scaling of the room-temperature MFPs below 5 THz. The MFPs exhibit a local maximum at a frequency of 8 THz and fall below 1 nm at frequencies greater than 10 THz, indicating localized vibrations. The MFPs extracted from sub-10 nm system-size simulations are used to predict the length-dependence of thermal conductivity up to system sizes of 100 nm and good agreement is found with independent molecular dynamics simulations. Weighting the SDHC by the frequency-dependent quantum occupation function provides a simple and convenient method to account for quantum statistics and provides reasonable agreement with the experimentally-measured trend and magnitude.
|Publication status||Published - 1 Dec 2016|
|MoE publication type||A1 Journal article-refereed|