Volume 103, Number 4, August 2013
|Number of page(s)||5|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||16 September 2013|
Invariants of the single-impurity Anderson model and implications for conductance functionals
1 Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT) - D-76021 Karlsruhe, Germany, EU
2 Institut für Theorie der Kondensierten Materie, KIT - D-76128 Karlsruhe, Germany, EU
3 DFG- Center for Functional Nanostructures, KIT - D-76131 Karlsruhe, Germany, EU
Received: 3 June 2013
Accepted: 12 August 2013
An exact relation between the conductance maximum G0 at zero temperature and a ratio of lead densities is derived within the framework of the single-impurity Anderson model: , where and , denote the excess density in the left/right lead at distance x due to the presence of the impurity at the origin, x = 0. The relation constitutes a parameter-free expression of the conductance of the model in terms of the ground-state density that generalizes an earlier result to the generic case of asymmetric lead couplings. It turns out that the specific density ratio, , is independent of the distance to the impurity x, the (magnetic) band structure and filling fraction of the contacting wires, the strength of the onsite interaction, the gate voltage and the temperature. Disorder-induced backscattering in the contacting wires has an impact on that we discuss. Our result suggests that it should be possible, in principle, to determine experimentally the peak conductance of the Anderson impurity by performing a combination of measurements of ground-state densities.
PACS: 71.15.Mb – Density functional theory, local density approximation, gradient and other corrections / 85.65.+h – Molecular electronic devices
© EPLA, 2013
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