Optimized thermal conductivity enhancement of polar nanotubes due to surface phonon-polaritons

Surface phonon-polaritons (SPP) are hybrid electromagnetic waves that are the result of the coupling between photons and phonons at the interface between two different media [1,2]. Taking into account that the surface effects predominate over the volumetric ones due to the high surface area/volume ratio in nanomaterials, the energy transport by SPP is expected to be particularly important in nano-sized polar media, whose bulk thermal conductivity is usually low and decreases as the size is scaled down. The potential applications of these surface waves to improve the thermal performance of nanoscale devices have been attracting significant research efforts in the last few years [3], however the contribution of the SPP to the thermal conductivity of these materials is not well understood to date, especially at nanoscale. The objective of this work is to quantify and optimize this contribution in nanotubes of circular cross section.