Thermopower of the molecular state in a double quantum dot

The thermopower of the molecular state in a double quantum dot is studied using a mixed model, which combines the classical capacitance model and a valence-electron approach. Our calculations show that close to the triple points where the resonances of the two dots intersect, there are additional steplike structures in the thermopower that result from coupling of the “topmost” electronic states. Far away from the triple points, we find that, with increasing detuning, the steplike structures shift toward the center of two neighboring Coulomb blockade oscillations, while very far away from the triple points, the transport resembles that of a single dot of lower electrostatic energy. Our results are in qualitative agreement with experimental findings on the conductance of Blick et al. [Phys. Rev. Lett. 80, 4032 (1998)].