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

[loc duong ding]

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