Applicability of the wide-band limit in DFT-based molecular transport calculations
| Autor: | Johannes S. Seldenthuis, C. J. O. Verzijl, J. M. Thijssen |
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| Rok vydání: | 2013 |
| Předmět: |
Physics
Condensed Matter - Mesoscale and Nanoscale Physics ab initio calculations Ab initio General Physics and Astronomy FOS: Physical sciences Function (mathematics) Functional imaging [IGMD 1] Computational physics Green's function methods Mesoscale and Nanoscale Physics (cond-mat.mes-hall) Molecular Transport Molecule Wide band Limit (mathematics) Physical and Theoretical Chemistry Ground state approximation theory Voltage drop density functional theory |
| Zdroj: | The Journal of Chemical Physics Journal of Chemical Physics, 138 (9), 2013 Journal of Chemical Physics, 138, 9, pp. 094102 Journal of Chemical Physics, 138, 094102 |
| ISSN: | 0021-9606 |
| Popis: | Item does not contain fulltext Transport properties of molecular junctions are notoriously expensive to calculate with ab initio methods, primarily due to the semi-infinite electrodes. This has led to the introduction of different approximation schemes for the electrodes. For the most popular metals used in experiments, such as gold, the wide-band limit (WBL) is a particularly efficient choice. In this paper, we investigate the performance of different WBL schemes relative to more sophisticated approaches including the fully self-consistent non-equilibrium Green's function method. We find reasonably good agreement between all schemes for systems in which the molecule (and not the metal-molecule interface) dominates the transport properties. Moreover, our implementation of the WBL requires negligible computational effort compared to the ground-state density-functional theory calculation of a molecular junction. We also present a new approximate but efficient scheme for calculating transport with a finite bias. Provided the voltage drop occurs primarily inside the molecule, this method provides results in reasonable agreement with fully self-consistent calculations. |
| Databáze: | OpenAIRE |
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