[Pw_forum] Unit cell problem

[Eyvaz Isaev]

Dear Mohsen,

--- On Wed, 6/2/10, mohsen modaresi <modaresi.mohsen at gmail.com> wrote:
 
>I work on ZnS, I faced with a problem. When i use a unit cell with 2 atom >every things is OK and the bandstructure has a very good agreement with >previous calculation but when i use bigger unit cell every things go >wrong, Where is the problem of my calculation

Unclear, what is wrong. If you mean you have different band structure for 2-atomic and 16-atomic unit cells, there is nothing wrong. As you used 2x2x2 supercell, your band structure is downfolded (now you have a BZ which is 8 times smaller that the original BZ). 

Instead, you can compare DOS, they should be the same for the formula unit. 

Bests,
Eyvaz.

-------------------------------------------------------------------------
Prof. Eyvaz Isaev, 
Department of Physics, Chemistry, and Biology (IFM), Linkoping University, Sweden 
Theoretical Physics Department, Moscow State Institute of Steel & Alloys, Russia, 
isaev at ifm.liu.se, eyvaz_isaev at yahoo.com