Acoustic phonon transport through a double-bend quantum waveguide

TL;DR

This study uses the scattering matrix method to analyze how a double-bend quantum waveguide affects acoustic phonon transmission and thermal conductivity, revealing resonance behaviors and implications for phonon device design.

Contribution

It provides a detailed analysis of phonon transport in double-bend waveguides, highlighting the effects of structure dimensions and multiple bends on resonance and thermal properties.

Findings

Resonance peaks depend on the midsection dimensions.

Thermal conductivity first decreases then increases with temperature.

Multiple bends influence resonance and frequency gaps.

Abstract

In this work, using the scattering matrix method, we have investigated the transmission coefficients and the thermal conductivity in a double-bend waveguide structure. The transmission coefficients show strong resonances due to the scattering in the midsection of a double-bend structure; the positions and the widths of the resonance peaks are determined by the dimensions of the midsection of the structure. And the scattering in the double-bend structure makes the thermal conductivity decreases with the increasing of the temperature first, then increases after reaches a minimum. Furthermore, the investigations of the multiple double-bend structures indicate that the first additional double-bend structure suppresses the transmission coefficient and the frequency gap formed; and the additional double-bend structures determine the numbers of the resonance peaks at the frequency just above the gap region. These results could be useful for the design of phonon devices.