Effects of anisotropy and Coulomb interactions on quantum transport in a quadruple quantum-dot structure

Abstract

We present analytical and numerical investigation of spectral and transport properties of a quadruple quantum-dot (QQD) structure which is one of the popular low-dimensional systems in the context of fundamental quantum physics study, future electronic applications and quantum calculations. The density of states, occupation numbers and conductance of the structure were analyzed using the nonequilibrium Green's functions in the tight binding approach and the equation-of-motion method. In particular the anisotropy of hopping integrals and on-site electron energies as well as the effects of the finite intra- and interdot Coulomb interactions were investigated. It was found out that the anisotropy of the kinetic processes in the system leads to the Fano-Feshbach asymmetrical peak. We demonstrated that the conductance of QQD device has a wide insulating band with steep edges separating triple-peak structures if the intradot Coulomb interactions are taken into account. The interdot Coulomb correlations between the central QDs result in the broadening of this band and the occurrence of an additional band with low conductance due to the Fano antiresonances. It was shown that in this case the conductance of the anisotropic QQD device can be dramatically changed by tuning the anisotropy of on-site electron energies.

arXiv comment21 pages, 25 figures

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Cited by in corpus (7)

• Coulomb interactions induced perfect spin filtering effect in a quadruple quantum-dot cell
• Collapse of the Fano Resonance Caused by the Nonlocality of the Majorana State
• The influence of Coulomb correlations on nonequilibrium quantum transport in quadruple quantum-dot structure
• Formation of droplets of the order parameter and superconductivity in inhomogeneous Fermi-Bose mixtures (Brief review)
• Non-stationary spin-filtering effects in correlated quantum dot
• Spin-polarized transport in quadruple quantum dots attached to ferromagnetic leads
• Exact diagonalization study of double quantum dots in parallel geometry in zero-bandwidth limit