Thermal conductance of cylindrical semiconductor nanowires modulated with phonon cavity

We study the effects of phonon cavities on the thermal conductance of cylindrical semiconductor nanowires by applying the scatter matrix method in combination with elastic wave continuum model. Our results show that the phonon cavity can enhance thermal conductance because of model coupling between phonon modes aroused in the phonon cavity, and phonon modes in the constrictions at lower temperatures. As the length of the phonon cavity increases, an oscillatory decay of the thermal conductance is exhibited at high temperatures. Compared with phonon cavities with lower wave velocities, phonon cavities with a higher wave velocity featured reduced thermal conductance at high temperatures. A brief analysis of these results is given.