Transport through a multiply connected interacting mesoscopic system using the Keldysh formalism

Abstract

We apply the Keldysh formalism in order to derive a current formula easy to use for a system with many sites, one of which is interacting. The main technical challenge is to deal with the lesser Green function. It turns out that, in the case of the left-right symmetry, the knowledge of the lesser Green function is not necessary and an exact current formula can be expressed in terms of retarded Green functions only. The application is done for a triangular interferometer which gives a good account of the Fano-Kondo effect. It is found that the interference effects, in the context of Kondo correlations, give rise to a point in the parameters space where the conductance is temperature-independent. We include a comparison with the results from the Ng's ansatz, which are less accurate, but can be used also in the absence of the above mentioned symmetry.

Multiterminal Anderson impurity model in nonequilibrium: Analytical perturbative treatment

“…Such approximation is called the Ng's ansatz 32,33 . Although it might be be simple and handy, its validity is far from clear.…”

Kondo-Dicke resonances in electronic transport through triple quantum dots

“…There are, however, only a few papers on the Kondo phenomenon in electronic transport through triple-dot structures. [29][30][31][32][33][34][35] Such complex dot systems are of current interest from both fundamental and application points of view. Especially the interference effects in electronic transport attract much attention, as the multidot systems offer a unique possibility to study fundamental phenomena which were earlier observed in solid-state physics and/or quantum optics.…”

Dicke-like effect in spin-polarized transport through coupled quantum dots

“…This interferometer-like geometry allows observation of such quantum phenomena like the Aharonov-Bohm oscillations and the Fano antiresonance 1,2,3,4,5,6,7,8,9,10,11,12,13 . Conductance of systems consisting of three or more QDs reveals further interesting features of quantum transport 14,15,16,17,18,19,20,21,22,23,24 . Of particular importance seems to be the interference phenomenon 25,26,27,28,29 , which resembles the well known Dicke resonance in atomic physics 30,31,32 .…”