Thermopower of few-electron quantum dots with Kondo correlations

The thermopower of few-electron quantum dots is crucially influenced by on-dot electron-electron interactions, particularly in the presence of Kondo correlations. In this paper, we present a comprehensive picture which elucidates the underlying relations between the thermopower and the spectral density function of two-level quantum dots. The effects of various electronic states, including the Kondo states originating from both spin and orbital degrees of freedom, are clearly unraveled. Such a physical picture is affirmed by accurate numerical data obtained with a hierarchical equations of motion approach. Our findings and understandings provide an effective and viable way to control the thermoelectric properties of strongly correlated quantum dot systems.