We theoretically studied the thermoelectric transport properties of a strongly correlated quantum dot system in the presence of the Kondo effect based on accurate numerical evaluations using the hierarchical equations of motion approach. The thermocurrent versus gate voltage shows a distinct sawtooth line-shape at high temperatures. In particular, the current changes from positive (hole charge) to negative (particle charge) in the electron number N = 1 region due to the Coulomb blockade effect. However, at low temperatures, where the Kondo effect occurs, the thermocurrent’s charge polarity reverses, along with a significantly enhanced magnitude. As anticipated, the current sign can be analyzed by the occupation difference between particle and hole. Moreover, the characteristic turnover temperature can be further defined at which the influences of the Coulomb blockade and Kondo resonance are in an effective balance. Remarkably, the identified characteristic turnover temperature, as a function of the Coulomb interaction and dot-lead coupling, possessed a much higher value than the Kondo temperature. When a magnetic field is applied, a spin-polarized thermocurrent can be obtained, which could be tested in future experiments.

中文翻译：

---

近藤共振通过强相关的量子点辅助热电传输

我们使用运动方法的分层方程，基于精确的数值评估，在近藤效应存在的情况下，从理论上研究了强相关量子点系统的热电输运性质。热电流对栅极电压在高温下显示出明显的锯齿线形状。特别地，电流在电子数N中从正（空穴电荷）变为负（粒子电荷）。由于库仑封锁效应，= 1个区域。但是，在发生近藤效应的低温下，热电流的电荷极性会反转，并且幅度会大大增强。如预期的那样，可以通过粒子和空穴之间的占有率差异来分析电流符号。此外，可以进一步定义特征周转温度，在该温度下，库仑封锁和近藤共振的影响达到有效平衡。值得注意的是，根据库仑相互作用和点-铅耦合确定的特征周转温度具有比近藤温度高得多的值。当施加磁场时，可以获得自旋极化的热电流，可以在以后的实验中对其进行测试。