Coulomb-modified Fano interference in a double quantum dot Aharonov-Bohm ring

Abstract

By truncating the equation of motion of Green function within the second-order approximation, the Coulomb-induced changes of Fano interference in electronic transport through a double quantum dot (QD) Aharonov-Bohm (AB) ring are investigated. It shows that the Coulomb interaction in the reference-channel QD can remarkably modify the Fano interference. When studying the conductance vs the resonant-channel QD, we find that the presented Coulomb interaction in the reference-channel QD leads to the increase or decrease of the asymmetry of the Fano lineshape, as well as the inversion of the Fano lineshape, dependent on the appropriate Coulomb strength. In the case of the adjustable levels of both the QDs, the Coulomb-induced splitting of the nonresonant channel induces the destruction of the Fano interference; whereas two weak Fano lineshapes may appear in the conductance spectra when the many-body effect in the QD of the resonant channel is also considered. Interestingly, in the absence of magnetic field, when the different-strength electron interactions make the different-channel QD levels the same as each other, which state is resonant will keep empty regardless the adjustment of QD levels. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.