Beyond Marcus theory and the Landauer-Büttiker approach in molecular junctions: A unified framework
Charge transport through molecular junctions is often described either as a purely coherent or a purely classical phenomenon, and described using the Landauer–Büttiker formalism or Marcus theory (MT), respectively. Using a generalised quantum master equation, we here derive an expression for current...
| Váldodahkkit: | , , , |
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| Materiálatiipa: | Journal article |
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AIP Publishing
2018
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| _version_ | 1826281593718702080 |
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| author | Sowa, J Mol, J Briggs, G Gauger, E |
| author_facet | Sowa, J Mol, J Briggs, G Gauger, E |
| author_sort | Sowa, J |
| collection | OXFORD |
| description | Charge transport through molecular junctions is often described either as a purely coherent or a purely classical phenomenon, and described using the Landauer–Büttiker formalism or Marcus theory (MT), respectively. Using a generalised quantum master equation, we here derive an expression for current through a molecular junction modelled as a single electronic level coupled with a collection of thermalised vibrational modes. We demonstrate that the aforementioned theoretical approaches can be viewed as two limiting cases of this more general expression and present a series of approximations of this result valid at higher temperatures. We find that MT is often insufficient in describing the molecular charge transport characteristics and gives rise to a number of artefacts, especially at lower temperatures. Alternative expressions, retaining its mathematical simplicity, but rectifying those shortcomings, are suggested. In particular, we show how lifetime broadening can be consistently incorporated into MT, and we derive a low-temperature correction to the semi-classical Marcus hopping rates. Our results are applied to examples building on phenomenological as well as microscopically motivated electron-vibrational coupling. We expect them to be particularly useful in experimental studies of charge transport through single-molecule junctions as well as self-assembled monolayers. |
| first_indexed | 2024-03-07T00:31:08Z |
| format | Journal article |
| id | oxford-uuid:7fd720e8-b7e2-48cd-a86f-7b254004d35b |
| institution | University of Oxford |
| last_indexed | 2024-03-07T00:31:08Z |
| publishDate | 2018 |
| publisher | AIP Publishing |
| record_format | dspace |
| spelling | oxford-uuid:7fd720e8-b7e2-48cd-a86f-7b254004d35b2022-03-26T21:19:27ZBeyond Marcus theory and the Landauer-Büttiker approach in molecular junctions: A unified frameworkJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:7fd720e8-b7e2-48cd-a86f-7b254004d35bSymplectic Elements at OxfordAIP Publishing2018Sowa, JMol, JBriggs, GGauger, ECharge transport through molecular junctions is often described either as a purely coherent or a purely classical phenomenon, and described using the Landauer–Büttiker formalism or Marcus theory (MT), respectively. Using a generalised quantum master equation, we here derive an expression for current through a molecular junction modelled as a single electronic level coupled with a collection of thermalised vibrational modes. We demonstrate that the aforementioned theoretical approaches can be viewed as two limiting cases of this more general expression and present a series of approximations of this result valid at higher temperatures. We find that MT is often insufficient in describing the molecular charge transport characteristics and gives rise to a number of artefacts, especially at lower temperatures. Alternative expressions, retaining its mathematical simplicity, but rectifying those shortcomings, are suggested. In particular, we show how lifetime broadening can be consistently incorporated into MT, and we derive a low-temperature correction to the semi-classical Marcus hopping rates. Our results are applied to examples building on phenomenological as well as microscopically motivated electron-vibrational coupling. We expect them to be particularly useful in experimental studies of charge transport through single-molecule junctions as well as self-assembled monolayers. |
| spellingShingle | Sowa, J Mol, J Briggs, G Gauger, E Beyond Marcus theory and the Landauer-Büttiker approach in molecular junctions: A unified framework |
| title | Beyond Marcus theory and the Landauer-Büttiker approach in molecular junctions: A unified framework |
| title_full | Beyond Marcus theory and the Landauer-Büttiker approach in molecular junctions: A unified framework |
| title_fullStr | Beyond Marcus theory and the Landauer-Büttiker approach in molecular junctions: A unified framework |
| title_full_unstemmed | Beyond Marcus theory and the Landauer-Büttiker approach in molecular junctions: A unified framework |
| title_short | Beyond Marcus theory and the Landauer-Büttiker approach in molecular junctions: A unified framework |
| title_sort | beyond marcus theory and the landauer buttiker approach in molecular junctions a unified framework |
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