Transport properties of an Aharonov-Bohm ring with strong interdot Coulomb interaction

Based on the Keldysh Green's function technique and the equation-of-motion method, we investigate theoretically the electronic transport properties of an Aharonov-Bohm ring with embedded coupled double quantum dots connected to two electrodes in a symmetrical parallel configuration in the presence of strong interdot Coulomb interaction. Special attention is paid to the effects of the interdot Coulomb interaction on the transport properties. It has been shown numerically that the interdot Coulomb interaction gives rise to four electronic states in the ring. The quantum interferences between two strongly coupled electronic states and two weakly coupled ones lead to two Breit-Wigner and two Fano resonances in the linear conductance spectrum with the magnetic flux switched on or the imbalance between the energy levels of two quantum dots. The positions and shapes of the four resonances can be controlled by adjusting the magnetic flux through the device or energy levels of the two quantum dots. When the Fermi energy levels in the leads sweep across the weakly coupled electronic states, the negative differential conductance (NDC) is developed in the current-voltage characteristics for the non-equilibrium case.