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Conductance of quantum wires: A numerical study of effects of an impurity and interactions

Agarwal, Amit and Sen, Diptiman (2006) Conductance of quantum wires: A numerical study of effects of an impurity and interactions. In: Physical Review B, 73 (4). 045332-1-14.

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Abstract

We use the nonequilibrium Green's function formalism and a self-consistent Hartree-Fock approximation to numerically study the effects of a single impurity and interactions between the electrons (with and without spin) on the conductance of a quantum wire. We study how the conductance varies with the wire length, the temperature, and the strengths of the impurity and interactions. The numerical results for the dependence of the conductance on the wire length and temperature are compared with the results obtained from a renormalization group analysis based on the Hartree-Fock approximation. For the spin-1/2 model with a repulsive on-site interaction or the spinless model with an attractive nearest neighbor interaction, we find that the conductance increases with increasing wire length or decreasing temperature. This can be explained using the Born approximation in scattering theory. For a strong impurity, the conductance is significantly different for a repulsive and an attractive impurity; this is due to the existence of a bound state in the latter case. In general, the large density deviations close to the impurity have an appreciable effect on the conductance at short distances which is not captured by the renormalization group equations.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to The American Physical Society.
Keywords: Physics,Condensed Matter;Dimensional Electron-Gas;Quantized Conductance;Single-Barrier;Reduction;Liquid.
Department/Centre: Division of Physical & Mathematical Sciences > Centre for High Energy Physics
Date Deposited: 22 Dec 2008 07:26
Last Modified: 19 Sep 2010 04:54
URI: http://eprints.iisc.ernet.in/id/eprint/16991

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