Post date: Nov 24, 2013 10:27:14 PM
Our joint work with Richard Robinson's group (MSE/Cornell) on the role of surface scattering on phonon transport in nanostructures has just been accepted to Nano Letters! You can access the article online here.
Accurately characterizing the role of surface roughness of phonon transport and heat transfer is a difficult problem. In typically thermal transport experiments, phonons from a wide range of frequencies contribute to heat transfer and it is nearly impossible to resolve surface interactions for a particular phonon frequency. Richard Robinson's group has been working to address this issue by developing a microscale phonon spectrometer that can send phonons with specific frequencies through nanostructure devices. By running experiments at low temperatures, it is possible to resolve to role of surface scattering on phonon transport. In this joint publication, we used a combination of phonon spectrometer experiments and Monte Carlo simulations of phonon transmission to see how well common surface scattering models such as Ziman's specular parameter really do. We find that the specularity parameter estimated based on measured surface roughness underestimates the thermal resistance due to surface scattering, a finding with implications for thermal management in nanoscale electronics and the design of nanostructured thermoelectrics