Acoustic properties of cylindrical nanowires with the elastically dissimilar barriers

Abstract

We have theoretically investigated the effect of the coating made of the elastically dissimilar material on the acoustic phonon properties of semiconductor nanowires. It is shown that the acoustic impedance mismatch at the interface between the nanowire and the barrier coating affects dramatically the phonon spectra and group velocities in the nanowires. Coatings made of the materials with a small sound velocity (“acoustically slow”) lead to compression of the phonon energy spectrum and strong reduction of the phonon group velocities. The coatings made of the materials with a high sound velocity (“acoustically fast”) have an opposite effect. Our calculations reveal substantial re-distribution of the elastic deformations in coated nanowires, which results in modification of the phonon transport properties, and corresponding changes in thermal and electrical conduction.