Author Topic: Calculation the bandstructure of bilayer AGNR with relative motion  (Read 2833 times)

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Offline ebrahim298

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Hi

 i'm a moderate user of ATK and have no problem with mono-layer GNR  but i have made a bilayer AGNR configuration with relative sliding motion as shown in the images. i want to turn it into device and calculate the transmission spectrum, but before turning it into device, i want to obtain the bandstructure of the configuration.  i'm using Slater-Koster method (ATK-13.8.1). could you please tell me:

1- how many k-point samples i should insert in a , b and c directions?

2- which basis set is prefered? there are only three options , Hobbit ,CP2k selfconsistent and CP2k non-selfconsistent.

3- what boundary conditions should be selected for poisson solver? are the default conditions suitable?
 
i'm looking forward to your answers.
very thank.

Offline Anders Blom

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You should first of all be aware of the fact that your system is not periodic in C, and thus you can't really obtain any band structure. Second, there is no immediately suitable built-in orthogonal Slater-Koster model in ATK for this problem, but you can try some of the DFTB model you list. To know which one is more suitable you must test them on something reasonable where you can compare to experiments or other theoretical results, like the band structure of a basic nanoribbon for instance. The default boundary conditions will generally be fine, unless you plan to add gates. In general, please read our tutorials, all points you ask are basically explained and usually in a tutorial for graphene...

Offline ebrahim298

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thanks a lot for your answer.
i know this structure is not periodic in Z direction but whether it means there is not any band gap in this structure? if there is a band gap in this structure, how can i get the band gap?
1- can i turn the device into bulk and get it's band gap ?
2-can i get the band gap through the transmission spectrum ?
3-are you sure Slater-Koster method is not proper for this structure? what about Extended Huckle?

thank you for your help.