  The effect on the vibrational and thermal properties of gradually
interconnected nanoinclusions embedded in an amorphous silicon matrix is
studied using MD simulations. The nanoinclusion arrangement ranges from an
aligned sphere array to an interconnected mesh of nanowires. Wave-packet
simulations scanning different polarizations and frequencies reveal that the
interconnection of the nanoinclusions at constant volume fraction induces a
strong increase of the mean free path of high frequency phonons, but does not
affect the energy diffusivity. The mean free path and energy diffusivity are
then used to estimate the thermal conductivity, showing an enhancement of the
effective thermal the effective thermal conductivity due to the existence of
crystalline structural interconnections. This enhancement is dominated by the
ballistic transport of phonons. Equilibrium molecular dynamics simulations
confirm the tendency although less markedly. This leads to the observation that
coherent energy propagation with a moderate increase of the thermal
conductivity is possible.

Mesoscale and Nanoscale Physics