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Title: Theory of charge transport in molecular junctions: From Coulomb blockade to coherent tunneling

We study charge transport through molecular junctions in the presence of electron-electron interaction using the nonequilibrium Green's function techniques and the renormalized perturbation theory. In the perturbation treatment, the zeroth-order Hamiltonian of the molecular junction is composed of independent single-impurity Anderson's models, which act as the channels where charges come through or occupy, and the interactions between different channels are treated as the perturbation. Using this scheme, the effects of molecule-lead, electron-electron, and hopping interactions are included nonperturbatively, and the charge transport processes can thus be studied in the intermediate parameter range from the Coulomb blockade to the coherent tunneling regimes. The concept of quasi-particles is introduced to describe the kinetic process of charge transport, and then the electric current can be studied and calculated. As a test study, the Hubbard model is used as the molecular Hamiltonian to simulate dimeric and trimeric molecular junctions. Various nonlinear current-voltage characteristics, including Coulomb blockade, negative differential resistance, rectification, and current hysteresis, are shown in the calculations, and the mechanisms are elucidated.
Authors:
;  [1]
  1. Department of Chemistry and Center for Emerging Material and Advanced Devices and Center for Quantum Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China)
Publication Date:
OSTI Identifier:
22420015
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 6; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CHARGE TRANSPORT; ELECTRIC CURRENTS; ELECTRIC POTENTIAL; ELECTRON-ELECTRON COLLISIONS; ELECTRON-ELECTRON COUPLING; ELECTRON-ELECTRON INTERACTIONS; ELECTRONS; GREEN FUNCTION; HAMILTONIANS; HUBBARD MODEL; IMPURITIES; MOLECULES; PERTURBATION THEORY; QUASI PARTICLES; TUNNEL EFFECT