Coherent and incoherent current drag in coupled quantum dots

We theoretically examine a current drag in coupled double quantum dots (DQDs). When a current is driven through a DQD by a bias voltage, it drags the current through the other DQD by the Coulomb interaction between the DQDs. In the quantum mechanical regime of coherent transport, the drag current shows two resonant peaks, a sharp peak due to a cotunneling process of two electrons and a broad due to the single electron resonance. The emission of LA phonons suppresses the former resonance and broadens the latter. In the large limit of the phonon emission rate (classical regime), the drag current still flows in an inelastic way, showing a plateau structure.