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Title: Communication: Electronic and transport properties of molecular junctions under a finite bias: A dual mean field approach

We show that when a molecular junction is under an external bias, its properties cannot be uniquely determined by the total electron density in the same manner as the density functional theory for ground state properties. In order to correctly incorporate bias-induced nonequilibrium effects, we present a dual mean field (DMF) approach. The key idea is that the total electron density together with the density of current-carrying electrons are sufficient to determine the properties of the system. Two mean fields, one for current-carrying electrons and the other one for equilibrium electrons can then be derived. Calculations for a graphene nanoribbon junction show that compared with the commonly used ab initio transport theory, the DMF approach could significantly reduce the electric current at low biases due to the non-equilibrium corrections to the mean field potential in the scattering region.
Authors:
;  [1] ;  [1] ;  [2]
  1. Department of Physics and Graphene Research Centre, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore)
  2. (Singapore)
Publication Date:
OSTI Identifier:
22251382
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 139; Journal Issue: 19; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; DENSITY FUNCTIONAL METHOD; ELECTRON DENSITY; ELECTRONS; GRAPHENE; GROUND STATES; MEAN-FIELD THEORY; NANOSTRUCTURES; SCATTERING; TRANSPORT THEORY