Thermoelectric and thermal rectification properties of quantum dot junctions

Abstract

The electrical conductance, thermal conductance, thermal power and figure of merit (ZT) of semiconductor quantum dots (QDs) embedded into an insulator matrix connected with metallic electrodes are theoretically investigated in the Coulomb blockade regime. The multilevel Anderson model is used to simulate the multiple QDs junction system. The charge and heat currents in the sequential tunneling process are calculated by the Keldysh Green function technique. In the linear response regime the ZT values are still very impressive in the small tunneling rates case, although the effect of electron Coulomb interaction on ZT is significant. In the nonlinear response regime, we have demonstrated that the thermal rectification behavior can be observed for the coupled QDs system, where the very strong asymmetrical coupling between the dots and electrodes , large energy level separation between dots and strong interdot Coulomb interactions are required.

Nonlinear heat transport in mesoscopic conductors: Rectification, Peltier effect, and Wiedemann-Franz law

“…Nonlinear effects in mesoscopic systems demand the application of large driving forces across small distances, a requirement within the scope of today's techniques. 11 Nonlinearities have been predicted to cause thermal rectification effects [12][13][14] and low temperature cooling. 15 A deep understanding of nonlinear effects is also needed for a careful assessment of the device performance of heat engines, 16 heat pumps, 17,18 and multiterminal heat-to-electric current converters.…”

Thermoelectric Properties of a T-Shaped Quantum Dot with Relatively Strong On-Site Coulomb Interaction

“…Thus from this point of view, zero value of the coefficient is corresponding to the case that the heat amount carried by each electron channel is equal to that by each hole channel. 33) Thus, the competition between electrons and holes 20,34) lead to the coefficient S antisymmetric with respect to the level position ¹U/2. Figure 6 describes the figure of merit ZT at different temperatures.…”

Theory of spin blockade, charge ratchet effect, and thermoelectrical behavior in serially coupled quantum dot system

“…23−27 However, these studies have focused only on the thermoelectrical properties of a single QD 23,26 or parallel QDs. 24,27 To reduce the temperature gradient across the QD junction, it is essential to study the case of N coupled QDs in serial. In this paper, we also investigate the thermoelectric effect of SCQD.…”

“…8(a) are similar to the typical thermal broadening behavior of a single dot with multiple energy levels. 24 It is noticed that S goes through zero when G e reaches a maximum or minimum (which occurs midway between two G e peaks). The positions of zero S are not affected by the temperature variation.…”

“…24, the electrical conductance G e and Seebeck coefficient S of a single QD with two energy levels were theoretically investigated. In the case of two identical quantum dots coupled together, Eq.…”