QuantumATK Forum
QuantumATK => General Questions and Answers => Topic started by: donmbringer on August 6, 2012, 15:55
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Hi. I am facing the problem when building bilayer graphene. I tried as what Quantumwise staff said, to start by graphite in database, and then change the coordinates of the second layer very close to the first layer. But, it seems that this does not work when calculating the Band strcutrue.
In addition, I am trying to build graphene nanomesh by starting with graphene, repeat for 4*4, delete 6 carbon atoms and add the hydrogen. This seems to be fail as well.
Could you please give me hand？ Why was I wrong and how to solve this problem?
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I saw the staff said " by just changing the c lattice constant while keeping the layer separation fixed", so i just adjusted the coordinate of the second layer, but it seems that what I did is not correct.
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Not the c coordinate, the c lattice constant. That is, keeping the c coordinate but making the cell longer in this direction.
The approach to make the nanomesh seems reasonable, but it's unclear what doesn't work. Also, "nanomesh" is not a standard term, so perhaps you can specify a bit clearer what you want to make.
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The figure has been put in the attachment, i started from graphene, but when I calculated the band sturcture, the points were locked at G Z, rather than G K M G
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Change the lattice to hexagonal, using Bulk Tools>Lattice Parameters (take care the structure is not distorted!) then you can use symmetry points for the hexagonal lattice.
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Hello, I am trying to build a Nanomesh.I started from Graphene.Then I repeated it for 4*4 times and removed 6 C atoms. But to make it as a sheet when i am repeating the structure its getting separated from each-other. What should i do to make it like a complete sheet?
One more doubt abot the bandstructure is...What will be the Brillouin zone for the structure...Please Help...
Thanking You.
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What do you mean separated? I tried what I assume corresponds to what you do, it looks fine (see picture):
- Insert graphene from database
- Repeat 4x4x1
- Remove one hexagon (maybe you want something else, but that's less important)
- Repeat 4x4x1 again
As for the Brillouin zone, you should always do the computations in the smallest possible cell (i.e. the cell you have before doing the last step above). You will need to switch it to the Hexagonal class in Bulk Tools>Lattice Parameters to be able to access the hexagonal symmetry points.