2007/05/23 by San-Huang Ke, Harold U. Baranger, Weitao Yang
Engineering · Physics and Astronomy · #Molecular Junctions and Nanostructures #Organic Electronics and Photovoltaics #Quantum and electron transport phenomena #cond-mat.mes-hall #cond-mat.mtrl-sci
paper · pdf · doi:10.1063/1.2770718
published as J. Chem. Phys. 127, 144107 (2007) · 6 pages, 7 figures
arxiv created 2007/05/23 · openalex publication_date 2007/10/12 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We investigate electron transport through single conjugated molecules--including benzenedithiol, oligophenylene ethynylenes of different lengths, and a ferrocene-containing molecule sandwiched between two gold electrodes with different contact structures--by using a single-particle Green function method combined with density functional theory calculation. We focus on the effect of the basis set in the ab initio calculation. It is shown that the position of the Fermi energy in the transport gap is sensitive to the molecule-lead charge transfer which is affected by the size of basis set. This can dramatically change, by orders of magnitude, the conductance for long molecules, though the effect is only minor for short ones. A resonance around the Fermi energy tends to pin the position of the Fermi energy and suppress this effect. The result is discussed in comparison with experimental data.