A question about Brillrouin zone route

[yongjunwinwin]

When I calculate the band structure using the unit cell of bulk graphene, which contain two carbon atoms, the brillrouin zone route can be set to G,M,K,G, just as the tutorials suggest. But as I enlarge the cell using repetition ( because I want to substitute  boron atom for one carbon atoms ), but when I want to calculate the band structure of it, the default Brillouin zone route is G, Z ,but as far as I know such BZ is used in graphene nanoribbon andI cannot change to G,M,K,G, the cell used in calculation and the band structure is attached. Could anyone explain what was the prolbem? Thanks in advance!

[Anders Blom]

What happens is that ATK only knows the standard symmetry symbols if the structure is defined via the classes corresponding to particular Bravais lattices, like Hexagonal(a,c). When you make the supercell, the structure is converted into a generic cell, without known symmetries.

You have basically two choices: either convert it back to a hexagonal class in the Builder, or specify the k-points manually. The second option requires a few lines of scripting, so let's focus on the first one, which is simple in this case anyway.

In fact, it's as trivial as changing the lattice type from "Unit cell" to "Hexagonal" in the Builder (the drop-down menu under Lattice parameters), right after you have made the repetition.

[yongjunwinwin]

Thanks very much for your reply, it's really helpful!

[zh]

Another issue is the folding of Brillrouin zone when the supercell is used.