[Pw_forum] band structure of graphene-size effect of unit cell

[xirainbow]

Dear Loc Duong Dinh：
The band structure must be different between 2 and 8 atoms in every unit
cell.
The coordinate of M point of 2 atoms is different from that of 8 atoms, for
the length of primitive vectors are different.
Furtheremore, there are 8 valence electrons in 2 atoms' unit cell. However,
there are 32 velence electrons in 8 atoms' unit cell.
I think you can refer to textbook of solid state physics for more
imformation.
On Thu, Jul 22, 2010 at 11:16 AM, loc duong ding <mambom1902 at yahoo.com>wrote:

> Dear all,
>
> I have a problem when I calculate band structure of graphene. The band
> structure
> of graphene calculated by unit of 2 atoms and 8 atoms is different. the gap
> at
> gama point as well as M point are totally different.
>
>
> In general case, unit of 2 atoms and unit of 8 atoms both create graphene
> strucutre. I can not unserstand why they are different? Is my understanding
> is
> wrong?
>
>
> I know this is the general question but I hope I can receive helpful
> instructions.
>
>
> I aprreciate all ypur helps.
>
> Sincerely,-----------------------------------------------
> Loc Duong Dinh
> Ms-Ph.D Student
> Sungkyunkwan Advanced Institute of Nanotechnology,
> Sungkyunkwan University,
> Suwon, 440-746, Korea
> Email: mambom1902 at yahoo.com, ddloc at skku.edu
>
>
>
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-- 
____________________________________
Hui Wang
School of physics, Nankai University, Tianjin, China
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