[DFTB-Plus-User] DFTB+U

[Bálint Aradi]

Dear Toufik,

The +U correction in DFTB+ is absolutely analogous to the "usual" +U 
corrections in DFT codes, so your possibilities are similar. Whether the 
gap size is the best quantity to look at, when you choose the UJ 
constant, is up to your judgement, there are various ways for 
determining such values. I'd suggest to consult the DFT literature about 
this, as this is not DFTB-specific.

The only thing to note is, that according to my experience (due to the 
localization caused by the compressed basis), the UJ-values in DFTB are 
usually smaller than corresponding values in ab initio DFT calculations. 
That means, similar shifts in energy levels can be achieved with smaller 
UJ-values.

Best regards,

Bálint

On 10.03.21 10:15, toufik esssakhri wrote:
> Dear all,
> 
> For DFTB+U calculations, is it possible to make an energy optimization 
> and to fit the the band gap to the experimental value for the choice of 
> the suitable UJ constant?
> 
> Thank you
> Toufik
> 
> _______________________________________________
> DFTB-Plus-User mailing list
> DFTB-Plus-User at mailman.zfn.uni-bremen.de
> https://mailman.zfn.uni-bremen.de/cgi-bin/mailman/listinfo/dftb-plus-user
> 


-- 
Dr. Bálint Aradi
Bremen Center for Computational Materials Science, University of Bremen
http://www.bccms.uni-bremen.de/cms/people/b-aradi/


-------------- next part --------------
A non-text attachment was scrubbed...
Name: OpenPGP_signature
Type: application/pgp-signature
Size: 840 bytes
Desc: OpenPGP digital signature
URL: <http://mailman.zfn.uni-bremen.de/pipermail/dftb-plus-user/attachments/20210310/b72c606d/attachment.sig>