Tunable antiresonance, Fano interference, and negative differential conductance in serially-coupled vibrating molecular

In this work, we propose a theoretical model, a series-coupled vibrating double-quantum dots adiabatically connected to Luttinger liquid leads, to realize the controllability of quantum interference and decoherence. By means of the nonequilibrium Green function approach and Lang-Firsov canonical transformation technique, we investigate the effects of the intralead Coulomb interaction, interdot tunneling, and electron-phonon interactions on differential conductance. In the strong dot-lead tunneling regions the antiresonance features of destructive interference, Fano interference, and negative differential conductance (NDC) appear in the case of moderately strong intralead Coulomb interaction and electron-phonon interaction, and they can coexist under appropriate gate voltages. With the increase of the intralead interaction, the quantum interference is first enhanced and then weakened, and eventually decoherence emerges, leading to the disappearance of the intriguing features. In the weak dot-lead tunneling regime, there appears a characteristic pattern of positive and negative differential conductances. It is stressed that there is no requirement of the asymmetry in this system for the occurrence of the NDC and antiresonance dip. These results offer an understanding of the structure relationships between the quantum interference effects and parameters, which enables us to manipulate the quantum interference behavior of multi-functional devices in the future.

Automated summary

In this work, a theoretical model is proposed to achieve the controllability of quantum interference and decoherence. The effects of intralead Coulomb interaction, interdot tunneling, and electron-phonon interactions on differential conductance are investigated. The results show the appearance of destructive interference, Fano interference, and negative differential conductance in strong dot-lead tunneling regions, while a characteristic pattern of positive and negative differential conductances appears in the weak dot-lead tunneling regime.