[Pw_forum] Tetrahedra occupations not provided for NSCF and DOS

[Lorenzo Paulatto]

Dear Bushan,
it is perfectly fine. Actually, smearing is in general more reliable and
better tested than tetrahedra. The latter can be more efficient, it may
give nicer picture for the density of states (DOS), and avoids introducing
an arbitrary smearing value.

In particular, in the case of graphene, using tetrahedra can be plain
wrong; if I remember correctly it does not work properly for 2D systems.
This is quite obvious when doing the phonon DOS, that does not go to zero
at zero frequency, as it should. I don't know if it is a problem also for
the electronic DOS.


On 24 May 2017 at 08:41, B S Bhushan <ecebhushan at gmail.com> wrote:

> Dear QE experts,
>
> I have extracted DOS of a 50 atom graphene system.
> While performing SCF I have considered occupations=smearing, smearing=mv,
> degauss=0.005.
> However, while performing "NSCF", I forgot to change the occupations to
> Tetrahedra and left the occupations option same as in SCF
> (occupations=smearing, smearing=mv, degauss=0.005).
>
> My doubt is, Is it OK to have non-tetrahedra occupations for NSCF ?.
> Can I proceed to further calculations on the basis of obtained DOS for
> this system?
>
> Thank you very much giving your precious time.
>
> your's sincerely,
> B S Bhushan
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum
>



-- 
Dr. Lorenzo Paulatto
IdR @ IMPMC -- CNRS & Université Paris 6
phone: +33 (0)1 442 79822 / skype: paulatz
www:   http://www-int.impmc.upmc.fr/~paulatto/
mail:  23-24/421 Boîte courrier 115, 4 place Jussieu 75252 Paris CX 05
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20170524/a9d68867/attachment.html>