Nonequilibrium Steady States and Fano-Kondo Resonances in an AB Ring with a Quantum Dot

TL;DR

This paper investigates electron transport in a quantum dot embedded in an Aharonov-Bohm ring under nonequilibrium conditions, revealing Fano-Kondo resonances, AB oscillations, and bias-induced resonance splitting using an extended SBMF approach.

Contribution

It extends the finite-U slave-boson mean-field method to nonequilibrium regimes and constructs a steady state, providing new insights into transport phenomena in strongly correlated quantum dot systems.

Findings

Fano-Kondo resonances and AB oscillations match NRG results in linear response.

Resonance peaks split into two at finite bias voltage.

Differential conductance shows zero-bias maximum or minimum depending on background transmission.

Abstract

Electron transport through a strongly correlated quantum dot (QD) embedded in an Aharonov-Bohm (AB) ring is investigated with the aid of the finite-U slave-boson mean-field (SBMF) approach extended to nonequilibrium regime. A nonequilibrium steady state (NESS) of the mean-field Hamiltonian is constructed with the aid of the C*-algebraic approach for studying infinitely extended systems. In the linear response regime, the Fano-Kondo resonances and AB oscillations of the conductance obtained from the SBMF approach are in good agreement with those from the numerical renormalization group technique (NRG) by Hofstetter et al. by using twice larger Coulomb interaction. At zero temperature and finite bias voltage, the resonance peaks of the differential conductance tend to split into two. At low bias voltage, the split of the asymmetric resonance can be observed as an increase of the conductance plateau. We also found that the differential conductance has zero-bias maximum or minimum depending on the background transmission via direct tunneling between the electrodes.