Tuning of the Fano Effect through a Quantum Dot in an Aharonov-Bohm Interferometer (original) (raw)

The Fano Effect in Aharonov-Bohm Interferometers

2002

After briefly reviewing the Fano effect, we explain why it may be relevant to various types of Aharonov-Bohm interferometers. We discuss both closed (electron conserving) and open interferometers, in which one path contains either a simple quantum dot or a decorated quantum dot (with more than one internal state or a parallel path). The possible relevance to some hitherto unexplained experimental features is also discussed. 85.35.Ds * Dedicated to Peter Wölfle on the occasion of his 60th birthday

Buildup of Fano resonances in the time domain in a double quantum dot Aharonov-Bohm interferometer

Physical Review B, 2018

In this paper, we investigate transient quantum transport in a nanoscale Aharonov-Bohm (AB) interferometer consisting of a laterally coupled double quantum dot (DQD) coupled to the source and drain electrodes. The transient linear conductance is derived at finite temperature of the leads, and is divided into three terms contributed from different transport channels. By observing the transient linear conductance and time evolution of the elements of the reduced density matrix of the DQD system, we show the nature of how Fano resonance is built up in the time domain.

A Tunable Fano System Realized in a Quantum Dot in an Aharonov-Bohm Ring

We report a tunable Fano system realized in a quantum dot embedded in an Aharonov-Bohm interferometer on a two-dimensional electron gas. In the Coulomb oscillation, clear asymmetric line shapes were observed, which manifest the formation of the Fano state, i. e., a coherent mixture of localized-continuum states. The Fano interference can be tuned through the phase of electrons by the electrostatic gate and the magnetic flux piercing the ring. In addition, this effect was found to significantly affect the phase evolution of electrons.

Fano effect in a double T-shaped interferometer

The European Physical Journal B, 2009

We study the coherent transport in a one-dimensional lead with two side-coupled quantum dots using the Keldysh's Green function formalism. The effect of the interdot Coulomb interaction is taken into account by computing the first and second order contributions to the self-energy. We show that the Fano interference due to the resonance of one dot is strongly affected by the fixed parameters that characterize the second dot. If the second dot is tuned close to resonance an additional peak develops between the peak and dip of the Fano line shape of the current. In contrast, when the second dot is off-resonance and its occupation number is close to unity the interdot Coulomb interaction merely shifts the Fano line and no other maxima appear. The system we consider is more general than the single-dot interferometer studied experimentally by Kobayashi et al. [Phys. Rev. B 70, 035319 (2004)] and may be used for controlling quantum interference and studying decoherence effects in mesoscopic transport.

Fano resonance in a quantum wire with a side-coupled quantum dot

Physical Review B, 2004

We report a transport experiment on the Fano effect in a quantum connecting wire (QW) with a side-coupled quantum dot (QD). The Fano resonance occurs between the QD and the "T-shaped" junction in the wire, and the transport detects antiresonance or a forward scattered part of the wave function. While it is more difficult to tune the shape of the resonance in this geometry than in the previously reported Aharonov-Bohm-ring-type interferometer, the resonance purely consists of the coherent part of transport. Utilizing this advantage, we have quantitatively analyzed the temperature dependence of the Fano effect by including the thermal broadening and the decoherence. We have also proven that this geometry can be a useful interferometer for measuring the phase evolution of electrons at a QD.

Fano effect of a strongly interacting quantum dot in contact with a superconductor

Physical Review B, 2004

The physics of a system consisting of an Aharonov Bohm (AB) interferometer with a single level interacting quantum dot (QD) on one of its arms, and attached to normal (N) and superconducting (S) leads is elucidated. Here the focus is directed mainly on NAB -S junctions but the theory is capable of studying S-AB-S junctions as well. The interesting physics emerges under the conditions that both the Kondo effect in the QD and the the Fano effect are equally important. As the Fano effect becomes more dominant, the conductance of the junction is suppressed.