Spin and charge Kondo effects in capacitively coupled double quantum dots

Abstract

We investigate low-temperature spin and charge (orbital) Kondo effect of capacitively hierarchical equations of motion. In a charge stability diagram at finite interdot Coulomb repulsion, a line between triple points (LBTP) serves as the degeneracy of charge configuration states. With one electron difference on each dot, these charge configuration states can be regarded as pseudospins. It is shown that charge can also screen its counterpart through the high-order process using tunnelling-coupled reservoirs. In the charge configuration regime , in addition to the spin Kondo effect, the degeneracy and detuning of charge configuration states and may also cause a charge Kondo resonance that agrees with the experiments on triple-peak structures with differential conductance.