Significantly enhanced thermoelectric performance of molecular junction by twist angle dependent phonon interference effect
Suppressing phonon thermal conductance is one of the most important ways to improve the thermoelectric efficiency. In the present work, we theoretically analyzed phonon transport properties in the intermediate coupling molecular junction. We show that the twist angle can serve as an independent degree of freedom to manipulate phonon interference, and then more precisely regulate the thermal conductance of molecular junction. Moreover, the phonon mode-resolved calculation indicates that the conduction of in-plane phonon modes are strongly blocked, and only the out-of-plane phonon modes can transport through the molecuar junction. This makes it possible to further suppress phonon thermal conductance by twist angle, and then significantly improve the thermoelectric figure-of-merit of intermediate coupling molecular junction. This result suggests a more convenient way to manipulate heat transport, which have potential applications in phononic and thermoelectric molecular devices.