[Wien] contradictory band gap in case.scf and band.agr

[Gavin Abo]

I have probably overlooked in your conversion when you mentioned whether 
you were using a shifted or non-shifted k-mesh; If you happened to have 
used a shifted k-mesh in yourperovskites calculation, then you might try 
the calculation again with a non-shifted k-mesh during "x kgen":

https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg15445.html
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg19427.html
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg15445.html

Kind Regards,

Gavin
WIEN2k user

On 9/10/2022 4:20 AM, Dr. K. C. Bhamu wrote:
> Thanks Prof. Marks for your suggestions.
>
> My system is non-sp and non-SO type.
>
> I didn't do any mistake with k-path as Its a cubic system and its 
> brillouin zone is very simple.
>
> I do agree with the k-mesh as with very fine mesh narrow band gap 
> systems may show metallic character.
> In one of my case it is happening.
>
>
> But in a separate case where I didn't change the k-mesh after SCF for 
> band structure calculation, the band structure should show the same 
> band gap as I am getting with the grep command. No?
>
> Thanks
> Bhamu
>
> On Sat, Sep 10, 2022, 3:11 PM Laurence Marks 
> <laurence.marks at gmail.com> wrote:
>
>     I can think this can occur in numerous ways, all a minor mistake:
>
>     1. You forgot to include -orb when you did the bands.
>     2. You had too small a k-mesh for the scf, the fine one for the
>     bands shows a metal.
>     3. Your grep showed just the "up" spin, not both.
>     4. You did not fully converge.
>     5. You forgot -so in the band.
>     6. You have a mistake in your k-mesh for the bands.
>     7. Something else similar.
>
>     Just my guesses, I suggest you check carefully. Number 7 is most
>     likely.
>
>     --
>     Professor Laurence Marks
>     Department of Materials Science and Engineering, Northwestern
>     University
>     www.numis.northwestern.edu <http://www.numis.northwestern.edu>
>     "Research is to see what everybody else has seen, and to think
>     what nobody else has thought" Albert Szent-Györgyi
>
>     On Fri, Sep 9, 2022, 10:45 PM Dr. K. C. Bhamu
>     <kcbhamu85 at gmail.com> wrote:
>
>         Dear Users
>
>         Greetings,
>
>         I am trying to compute the band structure of some ABX3
>         perovskites systems with Wien2k_19.2 compiled with intel
>         compilers.
>         When I grep the band gap from case.scf, I am getting some
>         values (~0.7eV) while when I plot the band structure, the VBM
>         is significantly crossing the Fermi level and the gap between
>         CBM and VBM is much lesser than the one I grepped from
>         case.scf file.
>         In some case, VBM and VBM are overlapping while case.scf file
>         is showing a clear band gap.
>
>         I have updated Fermi energy in case.insp files.
>
>         I never faced such an issue in the past.
>
>         I am wondering if you would like to help me out.
>
>         Regards
>         Bhamu
>
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