Kondo resonance assistant thermoelectric transport through strongly correlated quantum dot

We theoretically study the thermoelectric transport properties of a strongly correlated quantum dot system in the presence of Kondo effect, on the basis of accurate numerical evaluations. The thermocurrent versus gate voltage shows a distinct sawtooth line-shape at high temperature. In particular, the sign of current changes from positive (hole charge) to negative (particle charge) in the electron number N = 1 region due to Coulomb blockade effect. However, at low temperature, where Kondo effect takes place, the thermocurrent charge polarity reverses, together with also a significantly enhanced magnitude. As anticipated, the current sign can be analyzed by the occupation difference between particle and hole. Moreover, one could further define the characteristic turnover temperature, at which the influences of Coulomb blockade and Kondo resonance are in effective balance. When magnetic field is applied, a spin-polarized thermocurrent could be obtained, which could be tested in future experiments.
References:
1.Phys. Rev. Lett. 121, 206801 (2018).
2.Nano Lett. 19, 506-511 (2019).
3.Phys. Rev. B 94, 245125 (2016).