Phonon-assisted tunneling through quantum dot stacks

The impact of electron-phonon interaction on the coherent transport through a quantum dot stack is investigated using the nonequilibrium Green's function technique. While the main resonance is due to the alignment of the single dot levels, satellite peaks occur due to resonances with phonon replica of the bare levels. This effect is analyzed in detail and we show that the inclusion of nondiagonal self-energies leads to a significant reduction of the induced current, which is interpreted as an interference effect.