Asymptotic self-consistency in quantum transport calculations

H Mera; P Bokes; R W Godby

doi:10.1103/PhysRevB.72.085311

Asymptotic self-consistency in quantum transport calculations

H Mera, P Bokes, R W Godby

Physics

Research output: Contribution to journal › Article › peer-review

Abstract

Ab initio simulations of quantum transport commonly focus on a central region which is considered to be connected to infinite leads through which the current flows. The electronic structure of these distant leads is normally obtained from an equilibrium calculation, ignoring the self-consistent response of the leads to the current. We examine the consequences of this, and show that the electrostatic potential Delta phi is effectively being approximated by the difference between electrochemical potentials Delta mu, and that this approximation is incompatible with asymptotic charge neutrality. In a test calculation for a simple metal-vacuum-metal junction, we find significant errors in the nonequilibrium properties calculated with this approximation, in the limit of small vacuum gaps. We provide a scheme by which these errors may be corrected.

Original language	English
Article number	085311
Pages (from-to)	-
Number of pages	6
Journal	Physical Review B
Volume	72
Issue number	8
DOIs	https://doi.org/10.1103/PhysRevB.72.085311
Publication status	Published - Aug 2005

Bibliographical note

Keywords

VACUUM-METAL JUNCTIONS
ELECTRONIC-STRUCTURE
BARRIER
FORMULA
FIELD

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10.1103/PhysRevB.72.085311

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Cite this

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abstract = "Ab initio simulations of quantum transport commonly focus on a central region which is considered to be connected to infinite leads through which the current flows. The electronic structure of these distant leads is normally obtained from an equilibrium calculation, ignoring the self-consistent response of the leads to the current. We examine the consequences of this, and show that the electrostatic potential Delta phi is effectively being approximated by the difference between electrochemical potentials Delta mu, and that this approximation is incompatible with asymptotic charge neutrality. In a test calculation for a simple metal-vacuum-metal junction, we find significant errors in the nonequilibrium properties calculated with this approximation, in the limit of small vacuum gaps. We provide a scheme by which these errors may be corrected.",

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