k point length too high

Total energy, geometry optimization, DFT+U, spin....

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MPis86
Posts: 6
Joined: Wed Jan 11, 2012 5:57 pm

k point length too high

Post by MPis86 » Fri May 03, 2013 11:44 am

Dear Abinit users,

I want to calculate the band structure and wavefunctions in a BZ path with k-points having reduced coordinates exceeding 1.
When I do such calculation Abinit stops claiming that the reduced coordinates of kpoints must be between -1 and 1.
Is there a way to bypass this problem?

I know that I can use symmetry operations to take the point back inside the first BZ, unfortunately I want to avoid such procedure.

To be more specific
I want to calculate the band structure of graphene on Pt that have a 2x2 direct space supercell with respect to freestanding 1x1 graphene. Then I want to exclude the bands deriving from the folding of bands in the reduced BZ and compare the obtained band structure with the one of freestanding graphene.
I know that I can obtain only the "unfolded" bands by calculating the superposition of the 2x2 wavefunction with the 1x1 ones. So I have to calculate the band energies and wavefunctions on exactly the same k-points in both the 2x2 and the 1x1 calculations. However for the 2x2 calculation this implies that some kpoints have reduced coordinates exceeding 1.

Thanks in advance,
Michele

Seba Darshan
Posts: 63
Joined: Mon Feb 17, 2014 5:19 am

Re: k point length too high

Post by Seba Darshan » Mon May 05, 2014 10:18 am

hai

I am also doing band structure calculation on intrinsic undoped graphene.
I am now trying to study the adsorption of gas molecules on graphene supercell.
But I am not clear of how to define the unit cell of a 4 by 4 graphene supercell. Can you help me to create a 4 by 4 supercell.
How I need to define acell and rprim variables for creating a 4 by 4 supercell.

Regards
Seba

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