Phonon-assisted thermoelectric effects in strongly interacting quantum dot

The joint effects of the electron–phonon interaction and Kondo effect on the charge and heat transport through a single molecule transistor are investigated by applying the improved canonical transformation and noncrossing approximation technique. We find that the electron–phonon interaction decreases the conductance, thermopower and the Wiedemann–Franz law in the Kondo regime due to the splitting and the decreasing of the main Kondo peak. However, the thermoelectric figure of merit achieves enhancement with the electron–phonon coupling strength increasing. In addition, the dip value of the thermopower at the Kondo temperature for the different electron–phonon coupling strength can give a straightforward reliable estimate of the electron–phonon coupling strength.