Phonon and carrier spectrum modification in thermoelectric quantum dot superlattices

Quantum dot superlattices have recently been proposed for thermoelectric applications. The predicted improvement of the thermoelectric figure of merit in such structures should come from the decreased lattice thermal conductivity due to additional boundary scattering and acoustic phonon spectrum modification, as well as change in the carrier transport and density of states. Here we outline a theoretical model to calculate carrier and phonon dispersion in such structures and present results for Ge/Si quantum dot superlattices. We argue that one can tune the mini-band carrier transport and phonon dispersion in such a way that electron-phonon coupling is suppressed. The latter may open up a novel way for the enhancement of the thermoelectric figure of merit.