Selective transmission and enhanced thermal conductance of ballistic phonon by nanocavities embedded in a narrow constriction

Abstract

The effects of nanocavities embedded in a narrow constriction on ballistic phonon transport in a semiconductor nanowire are investigated. It is shown that when more than one nanocavity is embedded in a narrow constriction with a fixed length, the nanowire has selective transmission and filter actions for the ballistic phonon. The number of resonant transmission peaks increases with the number n of cavities, while the frequencies of the main peaks are independent of n. The thermal conductance can be enhanced significantly, and the enhancement alters in different temperature ranges with the number n of cavities, depending on the competition between the transmission enhancement and scatter enhancement of the ballistic phonon. This structure may be a promising candidate for selective frequency generator and filter for the ballistic phonon in nanophononics.