[Pw_forum] need help

[Ari P Seitsonen]

Dear Halima,

   Could you please provide the relevant part of the output file(s), and/or 
the input files? How did you determine the band gap from the DOS? If 
the plots are not too large, also them, please.

   The only case I could think of such a difference is if the k point mesh 
in one of the calculations (DOS) is too scarse and the extrema are left 
out (often, but not necessarily, at the Gamma point).

     Greetings from Sunny Zurich,

        apsi

-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
   Ari P Seitsonen / Ari.P.Seitsonen at iki.fi / http://www.iki.fi/~apsi/
   Institut für Chemie der Universität Zürich, CH-8057 Zürich
   Tel: +41 44 63 54 497  /  Mobile: +41 79 71 90 935


On Thu, 20 Feb 2014, Halima Zaari wrote:

> 
> dear all
> i have a question about the value of  band gap:
>  the value extracted from the dos (2.5 ev) does not match to that   taken
> from the band structure,(3.5eV)  even if the calculation was done with the
> same parameters nothing is changed. knowing that the value of the band
> structure is very close to the experimentalone . that we can consider as the
> correct value or it must be identical ??
> how we can explain this diffrence??
> thank for your help[cleardot.gif]
> 
> --
> H.ZAARIPhD Student in laboratory of magnetism and physics of high energy
> Faculty of Sciences in Rabat - Morocco
> Email: halimazaari at gmail.com
>