| Autor: |
Perrin, M. L., Verzijl, C. J. O., Martin, C. A., Shaikh, A. J., Eelkema, R., van Esch, J. H., van Ruitenbeek, J. M., Thijssen, J. M., van der Zant, H. S. J., Dulić, D. |
| Rok vydání: |
2014 |
| Předmět: |
|
| Zdroj: |
Nature Nanotechnology 8, 282-287 (2013) |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1038/nnano.2013.26 |
| Popis: |
The characteristics of molecular electronic devices are critically determined by metal-organic interfaces, which influence the arrangement of the orbital levels that participate in charge transport. Studies on self-assembled monolayers (SAMs) show (molecule-dependent) level shifts as well as transport-gap renormalization, suggesting that polarization effects in the metal substrate play a key role in the level alignment with respect to the metal's Fermi energy. Here, we provide direct evidence for an electrode-induced gap renormalization in single-molecule junctions. We study charge transport in single porphyrin-type molecules using electrically gateable break junctions. In this set-up, the position of the occupied and unoccupied levels can be followed in situ and with simultaneous mechanical control. When increasing the electrode separation, we observe a substantial increase in the transport gap with level shifts as high as several hundreds of meV for displacements of a few \aa ngstroms. Analysis of this large and tunable gap renormalization with image-charge calculations based on atomic charges obtained from density functional theory confirms and clarifies the dominant role of image-charge effects in single-molecule junctions. |
| Databáze: |
arXiv |
| Externí odkaz: |
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