Solution LAB3 graphene

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• Graphene has an honeycomb lattice and we can define the unit cell by considering an hexagonal lattice and two atoms per cell. The CC distance is 0.142nm. An input file can be set using an hexagonal bravais lattice as:

&system  
ibrav= 4, celldm(1) =4.6542890, celldm(3)=something appropriate, nat= 2, ntyp= 1, [...]  
/ 
ATOMIC_POSITIONS {crystal}  
C 0.0000000 0.0000000 0.000000  
C 0.3333333 0.6666666 0.000000

• Graphene is a quasi-metal, pay attention to the smearing
• K point sampling on the plane. If multiple of 3 you can include the high symmetry point K in your sampling