[Pw_forum] Nickel doped graphene supercell scf calculation with nspin=2 stopped

[Rolly Ng]

Dear Prof. Paolo,

Thanks for the advice. I am rerunning scf with pw.x on CPU now and I have already set mixing mode as "local-TF". I also keep nbnd to default and I suppose by default nbnd is (number of electrons/2)*1.2 for the doped graphene supercell (with smearing as a metal).

I will report my finding after.

Thank you,
Rolly  

PhD, Research Fellow,
Department of Physics and Materials Science,
City University of Hong Kong
Tel: +852 3442 4000
Fax:+852 3442 0538

-----Original Message-----
From: pw_forum-bounces at pwscf.org [mailto:pw_forum-bounces at pwscf.org] On Behalf Of Paolo Giannozzi
Sent: Monday, July 18, 2016 2:17 PM
To: PWSCF Forum
Subject: Re: [Pw_forum] Nickel doped graphene supercell scf calculation with nspin=2 stopped

You are using the GPU-enabled version of QE. Try the normal version first. You do not need more than a few bands over the Fermi energy.
Setting mixing_mode='TF-local- improves the convergency.

Paolo

On Sat, Jul 16, 2016 at 6:34 PM, Rolly Ng <rollyng at gmail.com> wrote:
> Dear QE experts,
>
> I would like to compute the DOS of Nickel doped graphene supercell 
> with QE v5.3.0, and our group has already done that with DMol3.
>
> Our previous publication can be found here, Ding, N., Lu, X., Wu, 
> C.-M.L., 2012. Comput. Mater. Sci. 51, 141–145.
>
> Now, I like to refine the computation with QE, so at first I used 
> "relax" to get the optimized structure of a graphene supercell with of 
> 72 Carbon atoms and a Nickel atom was added at the center to replace one of the carbons.
>
> Then I run scf with nspin=2 and starting magnetization (1) = 0.5 where 
> (1) refers to the Nickel atom, the scf converged. However, at the very 
> end pw.x stopped with the following error.
>
>      WARNING: integrated charge=   294.76903202, expected= 302.00000000
>
>
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>      Error in routine electrons (1):
>      charge is wrong
>
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> %%%%%%%%
>
>      stopping ...
>
> I googled and found that it may be related to smearing and nbnd, I 
> have already set smearing to 0.002 Ry (312K) and I have increased nbnd 
> to 400 but it is still running.
>
> Can anyone help me to resolve the issue? Please find my input and 
> output attached.
>
> Thank you very much,
> Rolly
>
> --
> PhD. Research Fellow,
> Dept. of Physics & Materials Science,
> City University of Hong Kong
> Tel: +852 3442 4000
> Fax: +852 3442 0538
>
>
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--
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222

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