Fano effect in a quantum-ring–quantum-dot system with tunable coupling

Abstract

Transport measurements are presented on a quantum ring that is tunnel-coupled to a quantum dot. When the dot is in the Coulomb blockade regime, but strongly coupled to the open ring, Fano line shapes are observed in the current through the ring, when the electron number in the dot changes by one. The symmetry of the Fano resonances is found to depend on the magnetic flux penetrating the area of the ring and on the strength of the ring-dot coupling. At temperatures above T=0.65 K the Fano effect disappears while the Aharonov-Bohm interference in the ring persists up to T=4.2 K. Good agreement is found between these experimental observations and a single-channel scattering matrix model including decoherence in the dot.

Fine structure of the local pseudogap and Fano effect for superconducting electrons near a zigzag graphene edge

“…Another issue this study focuses on is the connection between the local electronic structure of zigzag- infinite graphene, by analogy with similar quantum-dot structures 21,22,23,24 …”

Mesoscopic Fano effect in a spin splitter with a side-coupled quantum dot

“…The Fano interference originates from the two different contributions to transport: the so-called 'background' signal which is due to the electrons traveling around the ring without tunneling through the dot and the 'resonant' part given by electrons tunneling through the dot at least once before leaving the ring. Let us stress here that the mesoscopic Fano effect in a two-lead quantum ring with a side-coupled dot has been already experimentally observed by Fuhrer et al [16] in the absence of the spin-orbit coupling.…”

“…(2) What is the effect of the side-coupled dot on the spin and charge currents? To the best of our knowledge these issues have not been addressed before at the theoretical level, even though the side-coupled QD setup can be realized in experiments without much difficulty, as proved by Fuhrer et al [16].…”

Quantum transport through single and multilayer icosahedral fullerenes

“…This phenomenon was first studied by Fano in the spectrum of photoionization of atoms 42 and recently observed in the spectra of conductance of nanoscale systems. [43][44][45] Two types of antiresonances occur in the conductance spectrum: (i) multipath zeros arising from the vanishing of the Green function along interfering pathways between the sites of connections to the leads, and (ii) resonant zeros when the energy eigenvalues of the system are poles of the Green function for the connection sites. [46][47][48] In the following, we fix the number of connections in trilayer onions by choosing f ¼ 4 (f ¼ 2) between the two outermost (innermost) shells.…”