Effects of dimensionality on the ballistic phonon transport and thermal conductance in nanoscale structures

Abstract

Using the scattering-matrix method, we investigate ballistic phonon transport and thermal conductance at low temperatures in a two-dimensional and a three-dimensional nanoscale structures modulated with a finite Cu/W superlattice. A comparative analysis for two-dimensional and three-dimensional models is made. The results show that the thermal conductance in three-dimensional model is larger than that in two-dimensional model for same structural parameters and temperature. In characteristics, however, the thermal conductance displays similar behaviors in both two-dimensional and three-dimensional models. Moreover, some interesting physical phenomena such as stop-frequency gap, resonant transmission, and universal quantized thermal conductance are observed in the structures. A brief analysis of these results is given.