[Wien] How to Generate SuperLattice

[Lyudmila Dobysheva]

06.05.2013 09:36, Yasir Ali wrote:
> I am intending to calculate optical properties of superlattice of ZnO
> and CdO i.e. ZnO/CdO/ZnO.
> Please tell me how to generate structure file of this system

Dear Yasir Ali,

To make a correct model for a research takes 80 % of time. This is why 
nobody is able to answer you. Only general words:
1. Make a calculation of bulk ZnO, check that all properties that you 
are interested in are correctly obtained.
2. Make command "x supercell" and obtain a larger cell. Repeat 
calculation for it, adjust the calculation parameters.
3-4. The same for CdO
5. Decide from your task which surfaces you are interested in: (100), 
(111), (110) or some different. Maybe they are different for ZnO and CdO 
(I don't know their structure but you must).
6. Again play with supercell in order to make two desirable structures. 
Maybe you'll have to do just other symmetries like hexagonal in case of 
a cubic crystal in (111) direction. Check all intermediate structures 
through images in Xcrysden. If you are lucky and their structure is the 
same, and surfaces are simply fitting, for example,  (100) for both, you 
can simply change atoms Zn for Cd in such a way that you have layers 
with desirable thickness. If they are thick enough, it is better to take 
different interlayer distances inside the layers of ZnO and CdO. 
Nevertheless, in both cases you'll have to make a relaxation of the 
lattice. And so on and so forth.
If you are not lucky and their structures absolutely differ, the most 
interesting thing starts, only paper and pencil will help you.

Best wishes
   Lyudmila Dobysheva
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