(218d) Computational Study of Thermal Transport in Si-Ge Nanostructures - Exploration of Phonon Scattering Contributions to Suppressed Conductivity

The rapid emergence of nanostructured materials, which tend to have thermal properties vastly different from their bulk counterparts, has stimulated their utilization for heat dissipation and thermoelectric applications.  However, the underlying physical mechanisms that dictate heat conduction still remain unclear.  In fact, phonon transport can be impeded by a plethora of possible phonon scattering mechanisms, including phonon-phonon, phonon-boundary, and phonon-impurity scattering, which are difficult to individually characterize experimentally.  To investigate these influences, our strategy is to use classical molecular dynamics simulations to explore the thermal transport in Si-Ge nanostructures.  In this talk, we present thermal conductivity results for nanostructures including Si-Ge polycrystalline alloys and nanowires.  We will discuss the physical origins of the thermal conductivities of these materials by means of the relative contributions of relevant phonon scattering events.  We anticipate that this fundamental understanding of phonon scattering behavior will contribute toward the design of nanostructured materials with improved thermoelectric performance.