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Conductance and polarization in quantum junctions

Godby, R.W. and Bokes, P. (2004) Conductance and polarization in quantum junctions. Physical review B. Art. No. 245420. ISSN 1550-235X

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We revisit the expression for the conductance of a general nanostructure -- such as a quantum point contact -- as obtained from the linear response theory. We show that the conductance represents the strength of the Drude singularity in the conductivity $\sigma(k,k';i\omega \to 0)$. Using the equation of continuity for electric charge we obtain a formula for conductance in terms of polarization of the system. This identification can be used for direct calculation of the conductance for systems of interest even at the {\it ab-initio} level. In particular, we show that one can evaluate the conductance from calculations for a finite system without the need for special ``transport'' boundary conditions.

Item Type: Article
Copyright, Publisher and Additional Information: © 2004 American Physical Society. This is an author produced version of a paper published in Physical Review B and uploaded in accordance with the publisher's self archiving policy.
Institution: The University of York
Academic Units: The University of York > Physics (York)
Depositing User: Physics Import
Date Deposited: 19 Aug 2008 15:39
Last Modified: 24 Apr 2016 00:46
Published Version: http://dx.doi.org/10.1103/PhysRevB.69.245420
Status: Published
Refereed: Yes
URI: http://eprints.whiterose.ac.uk/id/eprint/4022

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