Quantum interference effects in multi-channel correlated tunneling structures

Abstract

In multi-channel tunneling systems quantum interference effects modify tunneling conductance spectra due to Fano effect. We investigated the impact of Hubbard type Coulomb interaction on tunneling conductance spectra for the system formed by several interacting impurity atoms or quantum dots localised between the contact leads. It was shown that the Fano shape of tunneling conductance spectra strongly changes in the presence of on-site Coulomb interaction between localised electrons in the intermediate system. The main effect which determines the shape of the tunneling peaks could be not Fano interference but mostly nonequilibrium dependence of the occupation numbers on bias voltage.

Transport through a correlated polar side-coupled quantum dot transistor in the presence of a magnetic field and dissipation

“…The tunneling current for the symmetric coupling and in wide band limit (when is independent of energy) can be written as 89 where denotes the Fermi distribution function for S(D) electrons: and being respectively the chemical potential and the thermal energy of the source (drain) and is the spectral function which describes the excitations and is related to the Green functions as: where refers to the retarded (advanced) Green function and the lesser (greater) Green function for the QD 1 in the energy space and can be obtained by Fourier transformation from the corresponding time-dependent Green functions and which can be written as …”

“…Also, hybrid systems combining ferromagnets and semiconductors have been explored as alternative strategies 80 – 84 . But the presence of magnetic leads may cause undesirable effect because of its own magnetic field, so the use of non-magnetic leads has started gaining more focus 85 – 89 .…”