[DFTB-Plus-User] Bang gap not matching

[Thomas Niehaus]

Hello,

On 6/25/24 16:36, Achyut Subedi wrote:
> Hello everyone,
>
> I have been doing DFTB calculation for a system ( COFs ) for the 
> calculation of band gaps. I optimised the geometry first, and then did 
> DOS calculation and then Band structure calculation.
>
> In each step I am getting a detailed.out file that contains 
> information about the Fermi Energy Level. But the value of Fermi 
> energy level is different in the detailed.out file from step 2 and 
> step 3. What could be the reason?
The sampling of the Brillouin zone is not the same for both calculations.
>
> Also, from dos_total.dat, I tried to find the band gap by 
> subtracting the energy level that has 0 DOS around Fermi level but the 
> value of Band gap that I get from the band structure calculation is 
> completely different with high order of magnitude. ( 3.9 eV from DOS 
> and 1.93eV from band structure calculation )
> What could be the possible solution to this problem?

You k-Path for the band structure calculations does possibly not contain 
the valence band maximum and the conduction band minimum.

Best Thomas

>
> Please let me know if any of us need more information in this regard.
>
> -- 
> Best Regards
> Er. Achyut Subedi
> Registered Mechanical Engineer
> (IOE, TU, Nepal)
> +977-9847703110
>
> _______________________________________________
> DFTB-Plus-User mailing list
> DFTB-Plus-User at mailman.zfn.uni-bremen.de
> https://MailInBlack.univ-lyon1.fr/securelink/?url=https://mailman.zfn.uni-bremen.de&key=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

-- 
Prof. Dr. Thomas Niehaus
Institut Lumière Matière
UMR5306 CNRS
Université Claude Bernard Lyon 1
Domaine Scientifique de La Doua
10 rue Ada Byron
69622 Villeurbanne CEDEX, France
--
Office: Brillouin building, 4th floor, room 006
Tel: +33 472 431 571
Home page:http://ilm-perso.univ-lyon1.fr/~tniehaus
Lab:http://ilm.univ-lyon1.fr
  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.zfn.uni-bremen.de/pipermail/dftb-plus-user/attachments/20240627/fe35c600/attachment.htm>