Journal article
Robust conductance of dumbbell molecular junctions with fullerene anchoring groups
Computational Atomic-scale Materials Design, Department of Physics, Technical University of Denmark1
Department of Physics, Technical University of Denmark2
Theoretical Microfluidics Group, Theory Section, Department of Micro- and Nanotechnology, Technical University of Denmark3
Theory Section, Department of Micro- and Nanotechnology, Technical University of Denmark4
Department of Micro- and Nanotechnology, Technical University of Denmark5
The conductance of a molecular wire connected to metallic electrodes is known to be sensitive to the atomic structure of the molecule-metal contact. This contact is to a large extent determined by the anchoring group linking the molecular wire to the metal. It has been found experimentally that a dumbbell construction with C60 molecules acting as anchors yields more well-defined conductances as compared to the widely used thiol anchoring groups.
Here, we use density functional theory to investigate the electronic properties of this dumbbell construction. The conductance is found to be stable against variations in the detailed bonding geometry and in good agreement with the experimental value of G= 3 × 10-4G0. Electron tunneling across the molecular bridge occurs via the lowest unoccupied orbitals of C60 which are pinned close to the Fermi energy due to partial charge transfer.
Our findings support the original motivation to achieve conductance values more stable towards changes in the structure of the molecule-metal contact leading to larger reproducibility in experiments. © 2011 American Institute of Physics.
Language: | English |
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Publisher: | American Institute of Physics |
Year: | 2011 |
Pages: | 144104 |
ISSN: | 10897690 and 00219606 |
Types: | Journal article |
DOI: | 10.1063/1.3646510 |
ORCIDs: | Thygesen, Kristian Sommer |