Resonant tunneling through linear arrays of quantum dots

We theoretically investigate resonant tunneling through a linear array of quantum dots with subsequent tunnel coupling. We consider two limiting cases: (i) the strong Coulomb blockade, where only one extra electron can be present in the array; (ii) the limit of almost noninteracting electrons. We develop a density-matrix description that incorporates the coupling of the dots to reservoirs. We analyze in detail the dependence of the stationary current on the electron energies, tunnel matrix elements and rates, and on the number of dots. We describe interaction and localization effects on the resonant current. We analyze the applicability of the approximation of independent conduction channels. We find that this approximation is not valid when at least one of the tunnel rates to the leads is comparable to the energy splitting of the states in the array. In this case the interference of conduction processes through different channels suppresses the current.