Hello,
I calculated Si HSE bandstructure using this web site for https://www.vasp.at/wiki/index.php/Si_HSE_bandstructure but we obtained the zig-zag electronic band structure. How can i solve this zig-zag electronic band structure. Do you have any idea ?
Thanks
Hi Merve Özcan
you can have a look at your KPOINTS file of HSE06 band structure calculations, that first you have random KPOINTS from IBZKPT and then you have the actual high symmetry path for band structure with a weight equal to zero.
These random KPOINTS from IBZKPT is giving you the zigzag band structure, which you need to skip. Your actual band structure starts from the point where the high symmetry path starts.
So just skip the initial kpoints, then you will get the HSE band structure, which will also have the same curves as PBE.
Hope this helps!
Hi Payal Wadhwa
Thank you very much for your reply. I didn't quite understand how to create ' These random
KPOINTS from IBZKPT is giving you the zigzag band structure, which you need to skip.
Your actual band structure starts from the point where the high symmetry path starts’ in the
calculation.
My calculation steps:
1. Standard self-consistent (SC) run (standard DFT calculation). I ran the VASP program.
2. HSE self-consistent calculation restarting from (step 1) WAVECAR.
3. One special point is we first need to move the IBZKPT at step 2 to the KPOINTS file and
also add the k-points read from OUTCAR at non-SC calculation (PBE-bant structure) to this
KPOINTS file with zero weight (eg Si HSE band structure calculation – Vaspwiki,
https://www.vasp.at/wiki/index.php/Si_HSE_bandstructure).
a. We created KPONITS as briefly described above.
b. I changed the HSE tag in the INCAR in step 2:
ALGO = Normal
NERMIN = 10
c. I got the WACECAR created in step 2. Is this true?
When the band gap is zig-zag, I thought about the change options in this step. For example I
got CHGCAR in step 2 or 1. etc.
I ran the VASP program and I got vasprun.xml
4. I obtained the band structure with the help of P4vasp program using vasprun.xml. The band
structure is zig-zag.
I would be very grateful if you could write me how to do these steps correctly for the HSE
calculation (or if possible, could you send me your sample calculation files for the HSE
calculation). Thank you again for your help.
Hi Merve Özcan
you can have a look at the KPOINTS file of HSE calculations in the Vaspwiki link you shared
Automatically generated mesh 26 Reciprocal lattice 0.00000000000000 0.00000000000000 0.00000000000000 1 0.16666666666667 0.00000000000000 0.00000000000000 8 0.33333333333333 0.00000000000000 0.00000000000000 8 0.50000000000000 0.00000000000000 0.00000000000000 4 0.16666666666667 0.16666666666667 0.00000000000000 6 0.33333333333333 0.16666666666667 0.00000000000000 24 0.50000000000000 0.16666666666667 0.00000000000000 24 -0.33333333333333 0.16666666666667 0.00000000000000 24 -0.16666666666667 0.16666666666667 0.00000000000000 12 0.33333333333333 0.33333333333333 0.00000000000000 6 0.50000000000000 0.33333333333333 0.00000000000000 24 -0.33333333333333 0.33333333333333 0.0000000000000 12 0.50000000000000 0.50000000000000 0.00000000000000 3 0.50000000000000 0.33333333333333 0.16666666666667 24 -0.33333333333333 0.33333333333333 0.16666666666667 24 -0.33333333333333 0.50000000000000 0.16666666666667 12 0.00000000 0.00000000 0.00000000 0.000 0.00000000 0.05555556 0.05555556 0.000 0.00000000 0.11111111 0.11111111 0.000 0.00000000 0.16666667 0.16666667 0.000 0.00000000 0.22222222 0.22222222 0.000 0.00000000 0.27777778 0.27777778 0.000 0.00000000 0.33333333 0.33333333 0.000 0.00000000 0.38888889 0.38888889 0.000 0.00000000 0.44444444 0.44444444 0.000 0.00000000 0.50000000 0.50000000 0.000
In the starting there are 16 kpoints with finite weight from (0.00000000000000 0.00000000000000 0.00000000000000) to (-0.33333333333333 0.50000000000000 0.16666666666667), then 10 kpoints with weight zero, from (0.00000000 0.00000000 0.00000000) to (0.00000000 0.50000000 0.50000000)
Zigzag bands are coming from the kpoints having finite weight, actual Band structure path starts from the kpoint having weight zero. So, please skip the initial few kpoints to get the HSE band structure.
Hope this helps!
Hi Payal Wadhwa
Thank you very much again. Please find the attachment that you requested files.
Hi Merve Özcan
Thank you for sharing your files.
You can have a look at your KPOINTS file, it is starting like
Reciprocal lattice
0.00000000000000 0.00000000000000 0.00000000000000 1 (where first three columns are the coordinates of kpoints and 4th column is the weight)
and in the middle you can also see
-0.25000000000000 0.50000000000000 0.25000000000000 6
(Due to these random KPOINTS, zigzag bands are coming.)
After this point you can see kpoints with zero weight
0.50000000 0.50000000 0.50000000 0.000
KPOINTS with zero weight is actually the point where high symmetry path starts.
So, i just wanted to emphasize that when you plot your band structure, skip the initial few kpoints having zigzag portion, and consider the kpoints where the curve starts like in PBE bands.
If you are not able to get an idea, I am sharing a picture below of HSE bands, where the initial bands are zigzag, and after that curved bands start.
So, you just need to plot your HSE bands from x-coordinate = 2.2 (say, in the plot i am sharing).
Hope this helps!
Best regards,
Payal
Hi Payal Wadhwa
Thank you very much for your effort. Its done as you suggested. Everything is ok just now. Many many thanks again.
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