Thermal transport in nanoclusters

Nonequilibrium and equilibrium molecular dynamics simulations are employed to study the thermal transport in sintered silicon nanoclusters made of 15 nm diameter nanoparticles arranged on a simple cubic lattice. Both simulation techniques indicate a reduction in the thermal conductivity from similar to 120 W/m K (bulk) to 1.5 W/m K (nanoclusters) at 500 K. This dramatic reduction is attributed to the reduced thermal conductivity of nanoparticle (15 W/m K) and most prominently to the nanosized constriction resistance due to necking between the two nanoparticles. Comparison with the existing models, radial distribution function and vibrational analysis show that the phonon transport in the nanosized neck region is ballistic rather than diffusive. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3590265]