Thermal transport in crystalline Si/Ge nano-composites: Atomistic simulations and microscopic models

Thermal transport in Si/Ge nano-composites, consisting of crystalline silicon as matrix and aligned germanium nanowires as inclusions, is investigated here through non-equilibrium and equilibrium molecular dynamics (MD) simulations. Our results show increasing of temperature gradient at the interface between silicon and germanium, which is limited in an interfacial phase of few lattices. A thermal boundary phase is included explicitly in our three-phase model, in companion with the modified effective medium theory, to be compared with MD simulation results with various nanowire concentrations. The results suggest that the presence of nanowires leads to a dramatic decrease of for heat transfer across nanowires arising from interfacial phase, while along the interfaces, the reduction of phonon mean free path due to interfacial scattering lowers of silicon matrix and germanium nanowires.