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

TL;DR

This paper investigates how Coulomb interactions modify Fano interference in electronic transport through a double quantum dot Aharonov-Bohm ring, revealing effects like lineshape symmetry changes and inversion dependent on interaction strength.

Contribution

It demonstrates the significant impact of Coulomb interactions on Fano interference patterns, including lineshape modifications and the emergence of new conductance features in a double quantum dot system.

Findings

Coulomb interaction can invert Fano lineshapes.

Coulomb effects can break Fano symmetry.

Many-body effects lead to complex conductance spectra.

Abstract

In this paper, the Coulomb-induced changes of Fano interference in electronic transport through a double quantum dot Aharonov-Bohm ring are discussed. It is found that the Coulomb interaction in the quantum dot in the reference channel can remarkably modify the Fano interference, including the increase or decrease of the symmetry of the Fano lineshape, as well as the inversion of the Fano lineshape, which is dependent on the appropriate strength of the Coulomb interaction. %But the nonzero Coulomb interaction %only leads to the emergence of two-group Fano lineshapes. When both the quantum dot levels are adjustable, the Coulomb-induced splitting of the nonresonant channel leads to the destruction of the Fano interference; whereas two blurry Fano lineshapes may appear in the conductance spectra when the many-body effect in the dot of the resonant channel is also considered. Interestingly, in the absence of magnetic field, when the different-strength electron interactions make one pair of levels of the dots in different channels the same, the corresponding resonant state keeps vacuum despite the adjustment of quantum dot levels.