Optical Phonon Lasing in Semiconductor Double Quantum Dots

We propose optical phonon lasing for a double quantum dot (DQD) fabricated in a semiconductor substrate. We show that the DQD is weakly coupled to only two LO phonon modes that act as a natural cavity. The lasing occurs for pumping the DQD via electronic tunneling at rates much higher than the phonon decay rate, whereas an antibunching of phonon emission is observed in the opposite regime of slow tunneling. Both effects disappear with an effective thermalization induced by the Franck-Condon effect in a DQD fabricated in a carbon nanotube with a strong electron-phonon coupling.Comment: 8 pages, 4 figure

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

Theory of Nonlinear Transport for Ensembles of Quantum Dots

This article reviews our work on the description of electronic transport through self-assembled quantum dots. Our main interest is in the effect of Coulomb interaction on quantum dot charging (capacitance-voltage characteristics), on the average current (current-voltage characteristics), and on current fluctuations (quantum shot noise) in quantum dot layers embedded in pn- or resonant tunneling devices. Our studies show the particular importance of understanding those interaction mechanisms for future device applications