(199k) Spatial Manipulation of Thermal Flux Profiles Using Nanostructure Boundaries

The precise manipulation of phonon (thermal carrier) transport properties is central to controlling thermal transport in semiconductor nanostructures. The control over thermal phonon transport to yield low thermal conductivities lies at the heart of creating efficient thermoelectrics with a high figure-of-merit (ZT). The physical understanding, prediction, and control of thermal phonon heat spectra and thermal conductivity accumulation functions has attracted significant attention in recent years. In this talk, we offer a unique insight into the nanoscale thermal transport phenomena by establishing the existence of thermal flux profiles nearly analogous to momentum flux profiles, and we utilize this understanding to advance the possibilities of manipulating heat by spatially modulating thermal transport in nanostructures. We show that phonon-boundary scattering influences the preferred thermal pathway used by energy during its flow in thermal transport nanostructures. The role of introducing boundaries with different surface conditions on resultant thermal flux is presented and methodologies to enhance these spatial modulations are discussed. This talk aims to advance the fundamental understanding on the nature of heat transport at nanoscale with potential applications in multiple research areas including thermoelectrics and optoelectronics.