Phonon-wall interactions and frequency-dependent thermal conductivity in nanowires

Phonon-wall collisions (with smooth or rough walls) have a deep influence on the thermal conductivity of nanowires. Usually this influence is analyzed in the steady-state thermal conductivity. Here, by using a phonon-hydrodynamic model with slip heat flow along the walls, we explore the influence of phonon-wall collisions on frequency-dependent thermal conductivity, which imply a reduction of it with increasing frequency. Understanding of this dependence would allow one to obtain information on the collisions complementary to that of the steady states. (c) 2011 American Institute of Physics. [doi:10.1063/1.3565138]