Coherent transport through a coupled-quantum-dot system with strong intradot interaction

The coherent transport through a coupled-quantum-dot system with strong intradot interaction is investigated by the nonequilibrium Green’s-functions method. The conductance as a function of the chemical potential, and the I-V curves are presented. Both of them display oscillation structures, and the number of peaks depends on the energy spectrum of the dots. All the phenomena can be understood on the basis of the coupling between the multielectron states in the two dots. When the temperature is higher than the Kondo temperature, the coupling between the two dots is equivalent to the coupling between several renormalized resonant levels. The density of states of each level displays an unsymmetrical structure, and the coupling coefficients are modified by the electron occupancy in the dots.