Complex band structure and electronic transmission eigenchannels
| Autor: | Søren Smidstrup, Kurt Stokbro, Gemma C. Solomon, Mikkel Strange, Anders Jensen, Matthew G. Reuter |
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| Rok vydání: | 2017 |
| Předmět: |
Physics
General Physics and Astronomy Conductance 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Molecular physics Transmission (telecommunications) Electrical resistivity and conductivity 0103 physical sciences Electronic transmission Density functional theory Almost surely Physical and Theoretical Chemistry 010306 general physics 0210 nano-technology Electronic band structure Eigenvalues and eigenvectors |
| Zdroj: | The Journal of chemical physics. 147(22) |
| ISSN: | 1089-7690 |
| Popis: | It is natural to characterize materials in transport junctions by their conductance length dependence, β. Theoretical estimations of β are made employing two primary theories: complex band structure and density functional theory (DFT) Landauer transport. It has previously been shown that the β value derived from total Landauer transmission can be related to the β value from the smallest |ki| complex band; however, it is an open question whether there is a deeper relationship between the two. Here we probe the details of the relationship between transmission and complex band structure, in this case individual eigenchannel transmissions and different complex bands. We present calculations of decay constants for the two most conductive states as determined by complex band structure and standard DFT Landauer transport calculations for one semi-conductor and two molecular junctions. The molecular junctions show that both the length dependence of the total transmission and the individual transmission eigenvalues can be, almost always, found through the complex band structure. The complex band structure of the semi-conducting material, however, does not predict the length dependence of the total transmission but only of the individual channels, at some k-points, due to multiple channels contributing to transmission. We also observe instances of vertical bands, some of which are the smallest |ki| complex bands, that do not contribute to transport. By understanding the deeper relationship between complex bands and individual transmission eigenchannels, we can make a general statement about when the previously accepted wisdom linking transmission and complex band structure will fail, namely, when multiple channels contribute significantly to the transmission. |
| Databáze: | OpenAIRE |
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