Multiband tight--binding approach to tunneling in semiconductor heterostructures: Application to $��X$ transfer in GaAs
| Autor: | St��vneng, J. A., Lipavsk��, P. |
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| Rok vydání: | 1993 |
| Předmět: | |
| DOI: | 10.48550/arxiv.cond-mat/9312061 |
| Popis: | We study tunneling in semiconductor heterostructures where the constituent materials can have a direct or indirect bandgap. In order to have a good description of the lowest conduction band, we have used the nearest-- neighbour $sp^3s^*$ tight--binding model put forward by P. Vogl {\em et al.}. A recursive Green--function method yields transmission coefficients from which an expression for the current density may be written down. The method is applied to GaAs/AlAs heterostructures. Electrons may traverse the AlAs barriers via different tunneling states $��_��$ and $��_X$ ($��X$ mixing). With an applied bias $V>0.5$ V electrons may enter the GaAs collector contact in both the $��$ and the $X$ valley ($��X$ transfer). We have studied a number of GaAs/AlAs structures. For very narrow barriers there is little $��X$ transfer, but AlAs barriers wider than about 25 ��act as ``$��X$ filters'', i.e., most transmitted electrons have been transfered to the $X$ valley. 25 pages (6 figures upon request) |
| Databáze: | OpenAIRE |
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