Abstract:Electron tunneling through a double quantum dot molecule side attached to a quantum wire, in the Kondo regime, is studied. The mean-field finite-U slave-boson formalism is used to obtain the solution of the problem. We investigate the many body molecular Kondo state and its interplay with the inter-dot antiferromagnetic correlation as a function of the parameters of the system.
“…This interpretation of DTQD systems is more adequate for molecular systems. Both side coupled dot systems, TQD and DTQD with Kondo resonances of interacting dots, have already been analyzed [22,24,[61][62][63][64], but here we generalize these considerations focusing on the role of phonons in electron transport through these structures.…”
We calculate the conductance through strongly correlated T-shaped molecular or quantum dot systems under the influence of phonons. The system is modelled by the extended Anderson–Holstein Hamiltonian. The finite-U mean-field slave boson approach is used to study many-body effects. Phonons influence both interference and correlations. Depending on the dot unperturbed energy and the strength of electron–phonon interaction, the system is occupied by a different number of electrons that effectively interact with each other repulsively or attractively. This leads, together with the interference effects, to different spin or charge Fano–Kondo effects.
“…This interpretation of DTQD systems is more adequate for molecular systems. Both side coupled dot systems, TQD and DTQD with Kondo resonances of interacting dots, have already been analyzed [22,24,[61][62][63][64], but here we generalize these considerations focusing on the role of phonons in electron transport through these structures.…”
We calculate the conductance through strongly correlated T-shaped molecular or quantum dot systems under the influence of phonons. The system is modelled by the extended Anderson–Holstein Hamiltonian. The finite-U mean-field slave boson approach is used to study many-body effects. Phonons influence both interference and correlations. Depending on the dot unperturbed energy and the strength of electron–phonon interaction, the system is occupied by a different number of electrons that effectively interact with each other repulsively or attractively. This leads, together with the interference effects, to different spin or charge Fano–Kondo effects.
“…This interpretation of DTQD systems is more adequate for molecular systems. Both side coupled dot systems, single TQD and double DTQD with Kondo resonances of interacting dots have already been analyzed [22,24,[61][62][63][64], but here we generalize these considerations focusing on the role of phonons in electron transport through these structures. Discussing the electron-phonon coupling in the introduced systems we consider three special cases: 1) local phonon modes are coupled solely to the open dots (l=1), 2) local phonon modes are coupled only to the interacting dots (l=2) or 3) single local phonon mode is equally coupled to both interacting dots (l=3).…”
We calculate the conductance through strongly correlated T-shaped molecular or quantum dot systems under the influence of phonons. The system is modelled by the extended Anderson-Holstein Hamiltonian. The finite-U mean-field slave boson approach is used to study many-body effects. Phonons influence both interference and correlations. Depending on the dot unperturbed energy and the strength of electron-phonon interaction the system is occupied by a different number of electrons which effectively interact with each other repulsively or attractively. This leads together with the interference effects to different spin or charge Fano-Kondo effects.
“…Fano resonances, which occur due to interference when a discrete level is weakly coupled to a continuous band, were recently observed in experiments on rings with embedded quantum dots 9 and quantum wires with sidecoupled dots 10 . The interplay between Fano and Kondo resonance was investigated using equation of motion 11,12 and slave boson techniques 13 . In this work we study a double quantum dot (DQD) in a side-coupled configuration ( Fig.…”
Section: Introductionmentioning
confidence: 99%
“…1), connected to a single conduction-electron channel. Systems of this type were studied previously using non-crossing approximation 14 , embedding technique 15 and slaveboson mean field theory 13,16 . Numerical renormalization group (NRG) calculations were also performed recently 17 , where only narrow regimes of enhanced conductance were found at low temperatures.…”
Section: Introductionmentioning
confidence: 99%
“…1), connected to a single conduction-electron channel. Systems of this type were studied previously using non-crossing approximation 14 , embedding technique 15 and slaveboson mean field theory 13,16 .…”
Conductance, on-site and inter-site charge fluctuations and spin correlations in the system of two side-coupled quantum dots are calculated using the Wilson's numerical renormalization group (NRG) technique. We also show spectral density calculated using the density-matrix NRG, which for some parameter ranges remedies inconsistencies of the conventional approach. By changing the gate voltage and the inter-dot tunneling rate, the system can be tuned to a non-conducting spin-singlet state, the usual Kondo regime with odd number of electrons occupying the dots, the two-stage Kondo regime with two electrons, or a valence-fluctuating state associated with a Fano resonance. Analytical expressions for the width of the Kondo regime and the Kondo temperature are given. We also study the effect of unequal gate voltages and the stability of the two-stage Kondo effect with respect to such perturbations.
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