Peltier effect in noninteracting double quantum dots

Peltier effect is an important thermoelectric phenomenon which stands for the generation of temperature gradient of the interface between two dissimilar conductors by the electric current flowing through them. In this paper, we investigate the Peltier effect in serially coupled noninteracting double quantum dot system under a bias voltage. By means of an accurate hierarchical equations of motion approach, we first demonstrate that the local temperatures of the two dots differ from each other by applying an electric current through the dots. We then analyze theoretically the influence of interdot and dot-lead coupling on the thermopower and electric current. Finally, we elucidate the variation of Peltier heat and Joule heat with the interdot coupling and dot-lead coupling, which leads to the changes in the local temperature of the quantum dots.