Fano resonances in the conductance of quantum dots with mixed dynamics

Abstract

We study the conductance fluctuations of an open quantum dot with underlying mixed dynamics. In addition to smooth conductance fluctuations, typical of chaotic quantum dots, we observe the occurrence of many sharp conductance peaks. Those are associated with localized states in the quantum dot and display a variety of Fano shape resonances. We show that the Fano q parameter in the presence of time-reversal symmetry is, in general, complex. We discuss the origin of the different Fano parameters and present a numerical study to support our theory.

Conductance fluctuations in chaotic bilayer graphene quantum dots

“…To gain a physical understanding of the persistent sharp conductance fluctuations in BGQDs, we analyze the resonance width, the localized states, and the local current patterns. Specifically, the transmission resonance is characterized by Fano profiles [74], where the width of the resonance can be related to the localization of the electronic states [53,57,75,76], leading to sharp conductance fluctuations. In particular, the quantum transport system can be effectively regarded as an isolated quantum dot described by a Hamiltonian matrix H, which is weakly coupled to two leads, one on each side of the dot region.…”

Quantum chaotic scattering in graphene systems

“…Even in the hyperbolic case, the transmission associated with the GQD contains sharper resonances as compared with that in the NRQD. This indicates a strong localization effect [12,13] in the GQD.…”

Probing Decoherence through Fano Resonances

“…In the limit q → ±∞, the symmetric Breit-Wigner shape is recovered while for q → 0 window (or "anti") resonances appear. For singlechannel scattering through systems with time-reversal symmetry (TRS) q is strictly real [13,14]. When TRS is broken, Eq.…”