Phonon transport and thermal conductivity in dielectric quantum wire

Using the scattering-matrix method, we investigate the acoustic phonon ballistic transmission and thermal conductivity in a dielectric quantum wire structure. We find that the transmission coefficient and the thermal conductivity are of quantum character, and sensitively depend on the geometric parameters and material nature of the structure. The transmission coefficient of the single acoustic phonon mode with differing frequency has different dependence on geometric configurations. Our results show that by adjusting the structural parameters and material nature one can control the thermal conductivity of the structure to match practical requirements in devices.