Fano effect in a double T-shaped interferometer

摘要

We study the coherent transport in a one-dimensional lead with two side-coupled quantum dots using the Keldyshs Green function formalism. The effect of the interdot Coulomb interaction is taken into account by computing the first and second order contributions to the self-energy. We show that the Fano interference due to the resonance of one dot is strongly affected by the fixed parameters that characterize the second dot. If the second dot is tuned close to resonance an additional peak develops between the peak and dip of the Fano line shape of the current. In contrast, when the second dot is off-resonance and its occupation number is close to unity the interdot Coulomb interaction merely shifts the Fano line and no other maxima appear. The system we consider is more general than the single-dot interferometer studied experimentally by Kobayashi et al. [Phys. Rev. B 70, 035319 (2004)] and may be used for controlling quantum interference and studying decoherence effects in mesoscopic transport.