Surface Phonon-polariton Mediated Thermal Conductivity Enhancement of Amorphous Thin Films

We predict theoretically that the effective in-plane thermal conductivity of polar, amorphous thin films can be increased by surface phonon-polaritons significantly beyond their intrinsic bulk values. We show that the thermal conductivity due to surface phonon-polaritons increases with decreasing film thickness. In particular, for a 40-nm-thick film of amorphous silicon dioxide, we calculate a total thermal conductivity of 4 W m−1 K−1 at 500 K, which is an increase of ∼100% over the intrinsic phonon thermal conductivity