Change in thermal conductivity of cylindrical silicon nanowires induced by surface bonding modification

The impact of bond order loss of surface atoms on thermal conductivity of cylindrical silicon nanowires has been examined using the isotropic elastic continuum model. A core-shell structure with a modified Young's modulus in the surface skin of the wire has been used. Thermal conductivity is calculated from modified phonon dispersion relations based on recent developed bond-order-length-strength (BOLS) correlation. This work extends the previous linear approximation [Yeung Phys. Rev. B 74, 155317 (2006)] to calculate the phonon dispersion relation of torsional mode and longitudinal mode using the nonlinear approach. A significant increase in thermal conductivity is found compared to the case without using BOLS correlation.