Can anybody tell me how to take KPOINTS during calculation of Band Structure using HSE06 functional for the Hexagonal and Body Centered Tetragonal system.I copied from IBZKPT file and added KPOINTS along high symmetry lines with zero weight But i always face the following WARNING :
"Your generating k-point grid is not commensurate to the symmetry of the lattice. This can cause slow convergence with respect to k-points for HF type calculations suggested SOLUTIONS:
1) if not already the case, use automatic k-point generation
2) shift your grid to Gamma (G) (e.g. required for hex or fcc lattice)"
To solve the problem i used ISYM = 0 and NELMIN = 10 in INCAR and used Automatic K-mesh but it still could not resolve the case.I think i was wrong in adding desired KPOINTS with correct coordinates along high symmetry lines. So, my concern is how to take correct coordinates of such KPOINTS for the above system. I have attached INCAR (second SC run) and KPOINTS and Band diagram using GNUPLOT.
There are two issues here.
First: selection of symmetry points for the band calculation. In this case, you have to use the high symmetry points of your system and construct a path for the band calculation. I suggest you to look in the link bellow or to read the paper:
Link: https://en.wikipedia.org/wiki/Brillouin_zone
(this is a link to Wikipedia. Use as a shortcut and rapidly information source BUT read the paper below)
Paper: https://doi.org/10.1016%2Fj.commatsci.2010.05.010
Second: after you selected the path, you have to do convergence studies using different number of k-points.
https://doi.org/10.1016%2Fj.commatsci.2010.05.010
Dinesh Thapa and SK M would you please share me how did you solved this problem? I am facing the same issue but I didn't solve it yet. Any help is welcome. Thanks in advance.
You have to change the name of file with high symmetry Kpts to IBZKPT after you generate high symmetry Kpts because this is a ISTART = 1 run.
Facing the same problem..... can anyone please share......?
Thanks....
Dinesh Thapa Just checking your KPOINTS file..... it's all right except that you have extra lines on your KPOINTS file which shouldn't be there. Hopefully, this will help others(thought the question is 2017).
Yisehak Gebredingle may be you are right. But how those extra lines have come to the k-mesh, file is to be understood.
Second thing is the actual question was about the warning, which can be ignored some times, but frankly not sure. As I cant remember how its sorted out or not occurred during my work. in case I get to know what I did I come back and share here for others to learn or get some hint. AS of now I feel Bishal Babu Dumre has given some idea, if that works, then it should be fine.
hi all,
i just got same warning message, i tried the suggestion of Bishal Babu Dumre , but not successful.
if i understood correctly what he says, i copied KPOINTS file as IBZKPT (so after that, both KPOINTS and IBZKPT files are same). and made ISTART=1 (though i dont have WAVECAR file (as ISTART=1 exp[ects WAVECAR file to be present).
But still i got same warning, not sure if we can ignore it.
Can Bishal, tell us, if the method i did is correct? if not what is solution?
Regards
Did you find a solution Because I having the same problem with that warning?
Dinesh Thapa
Hi Jesus Luis Alberto Ponce ,
i have not solved the problem, but simply ignored, as i THINK [not sure though] it did not affect the band structure.
Rather i actually adopting Wannierisation of the band, after HSE wave function generation. so this warning did not find there, so far.
Dear SK M and Yisehak Gebredingle ,
For the KPOINTS file in hybrid functional (HSE06) you need to copy the kpoints from the OUTCAR file of an SCF.
In order to do it, you need to do an SCF that will give you the right KPOINTS.
after an SCF with searching "k-points in reciprocal lattice" in OUTCAR, you will find the kpoints which is made by 4 column. please copy this to your IBZKPTS and rename it to KPOINTS which can be used for Band calculation. JUST note that you should set the 4th column numbers to zero (0.0).
Best Regards
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