Electron transport through single conjugated organic molecules: Basis set effects in ab initio calculations

Abstract

We investigate electron transport through single conjugated molecules - including benzenedithiol, oligo-phenylene-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.

6 pages, 7 figures

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Cited by in corpus (5)

• Advances and challenges in single-molecule electron transport
• Applicability of the Wide-Band Limit in DFT-Based Molecular Transport Calculations
• Benchmark density functional theory calculations for nano-scale conductance
• Green function techniques in the treatment of quantum transport at the molecular scale
• Contour integral method for obtaining the self-energy matrices of electrodes in electron transport calculations