4,471 research outputs found
Quantum dots as scatterers in electronic transport : interference and correlations
Conductance through a system consisting of a wire with side-attached quantum
dots is calculated. Such geometry of the device allows to study the coexistence
of quantum interference, electron correlations and their influence on
conductance. We underline the differences between "classical" Fano resonance in
which the resonant channel is of single-particle nature and "many-body" Fano
resonance with the resonant channel formed by Kondo effect. The influence of
electron-electron interactions on the Fano resonance shape is also analyzed.Comment: 13 pages, 3 figures, to appear in Solid State Communications, elsart
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Spin-dependent Fano resonance induced by conducting chiral helimagnet contained in a quasi-one-dimensional electron waveguide
Fano resonance appears for conduction through an electron waveguide
containing donor impurities. In this work, we consider the thin-film conducting
chiral helimagnet (CCH) as the donor impurity in a one-dimensional waveguide
model. Due to the spin spiral coupling, interference between the direct and
intersubband transmission channels gives rise to spin-dependent Fano resonance
effect. The spin-dependent Fano resonance is sensitively dependent on the
helicity of the spiral. By tuning the CCH potential well depth and the incident
energy, this provides a potential way to detect the spin structure in the CCH.Comment: 14 pages, 6 figure
The Fano resonance for Anderson impurity systems
We present a general theory for the Fano resonance in Anderson impurity
systems. It is shown that the broadening of the impurity level leads to an
additional and important contribution to the Fano resonance around the Fermi
surface, especially in the mixed valence regime. This contribution results from
the interference between the Kondo resonance and the broadened impurity level.
Being applied to the scanning tunnelling microscopic experiments, we find that
our theory gives a consistent and quantitative account for the Fano resonance
lineshapes for both Co and Ti impurities on Au or Ag surfaces. The Ti systems
are found to be in the mixed valence regime.Comment: 4 pages, 5 figures, published versio
Understanding the Fano Resonance : through Toy Models
The Fano Resonance, involving the mixing between a quasi-bound `discrete'
state of an inelastic channel lying in the continuum of scattering states
belonging to the elastic channel, has several subtle features. The underlying
ideas have recently attracted attention in connection with interference effects
in quantum wires and mesoscopic transport phenomena. Simple toy models are
provided in the present study to illustrate the basics of the Fano resonance in
a simple and tractable setting.Comment: 17 pages, 1 figur
Coulomb-Modified Fano Resonance in a One-Lead Quantum Dot
We investigate a tunable Fano interferometer consisting of a quantum dot
coupled via tunneling to a one-dimensional channel. In addition to Fano
resonance, the channel shows strong Coulomb response to the dot, with a single
electron modulating channel conductance by factors of up to 100. Where these
effects coexist, lineshapes with up to four extrema are found. A model of
Coulomb-modified Fano resonance is developed and gives excellent agreement with
experiment.Comment: related papers available at http://marcuslab.harvard.ed
Photoinduced Fano-resonance of coherent phonons in zinc
Utilizing femtosecond optical pump-probe technique, we have studied transient
Fano-resonance in zinc. At high excitation levels the Fourier spectrum of the
coherent E phonon exhibits strongly asymmetric line shape, which is well
modeled by the Fano function. The Fano parameter (1/Q) was found to be strongly
excitation fluence dependent while depending weakly on the initial lattice
temperature. We attribute the origin of the Fano-resonance to the coupling of
coherent phonon to the electronic continuum, with their transition
probabilities strongly renormalized in the vicinity of the photoinduced
structural transition.Comment: 5 pages, 3 figures, to be published in Physical Review
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