[Pw_forum] 60 atom Grain boundary...
Haruhiko Dekura
adadadad3018 at gmail.com
Tue Jan 25 20:26:47 CET 2011
Dear Elie Moujaes
Sorry for posting again.
>(1) is changing the mesh in the DOS program means decreasing DeltaE?
I'm sorry I wrote a little confusing description.
I meant to say that, in my previous posting, the checking of the convergence
in Fermi-energy with respect to the mesh of k-points in nscf calculation".
You will/should observe the convergence as the increase of k-mesh. After you
get the sufficient condition in the k-mesh, you will obtain more reliable
value of Fermi-energy in DOS calculation.
(note that, in my opinion, if you want to get the precise value as much as
possible, the decision of the value of Fermi-energy should be done by
counting number of electrons with looking output file obtained by DOS
calculation (by the checking of integrated DOS).
>(2) Concerning the convergence against smearing, does this mean that one
has to decrease degauss (mine is degauss=0.01) to get better results?
If you already checked the convergence of, for example, the total energy in
your system against change of degauss ( and the number of k-points), I think
it is no problem.
( Note: Your "degauss =0.01" is about 0.13 eV which value is within the
error of the value of Fermi-energy which you reported. So I'm a little
worried about the value of degauss. Did you check the change of Fermi-energy
against the "degauss" ?
Perhaps, my comments to you are incorrect ( if so, it lead the waste of time
in your life, I want to say very sorry for confusing you, in advance).
I hope you can get better result.
Haruhiko Dekura
========================================
Haruhiko Dekura
Postdoctoral Fellow
Senior Research Fellow Center, Ehime University, 2?5 Bunkyo-cho, Matsuyama,
Ehime 790-8577, Japan
=====================================
>
>
> Thank you very much for your help. I have just got some few more questions:
>
> (1) is changing the mesh in the DOS program means decreasing DeltaE?
>
> (2) Concerning the convergence against smearing, does this mean that one
> has to decrease degauss (mine is degauss=0.01) to get better results?
>
> You will find below a part of the bands input file.
>
> &control
> prefix='GBdensity',
> calculation='bands',
> restart_mode='from_scratch',
> pseudo_dir =
> '/exp/home/caiapo/emoujaes/espresso/espresso-4.1.3/pseudo/',
> outdir='/exp/home/caiapo/emoujaes/espresso/Moujaes-Results/',
>
> /
> &system
> ibrav= 0, celldm(1) =1.889725989, nat=60, ntyp= 1, ecutwfc =40.0,
> ecutrho = 160.D0, occupations='smearing', smearing='mp', degauss=0.01
> /
> &electrons
> conv_thr=1.D-5,
> mixing_beta=0.1D0,
>
> /
>
> CELL_PARAMETERS (alat)
> 24.064488464 0.000772242 0.000000000
> -0.000547177 6.503051170 0.000000000
> 0.000000000 0.000000000 8.470514812
>
>
> ATOMIC_SPECIES
> C 12.0107 C.pz-rrkjus.UPF
>
> ATOMIC_POSITIONS (angstrom)
> C -11.330758616 -3.527803203 0.000000000
> C -10.659793092 -1.160339161 0.000000000
> C -12.039843315 -7.112619698 0.000000000
> C -12.041158182 -5.732701936 0.000000000
> C -10.941089654 -4.881442842 0.000000000
> C -10.331417950 -2.543878336 0.000000000
> C -8.972994221 -3.016349126 0.000000000
> C -8.181174559 -0.722870888 0.000000000
> C -9.522448653 -6.774832629 0.000000000
> C -9.676361200 -5.364937582 0.000000000
> C -8.645931928 -4.406311082 0.000000000
>
> ..........
> ...........
>
>
> Thanks again
>
> Elie Moujaes
> University of Nottingham
> NG7 2RD
> UK
>
>
>
>
>
> Date: Wed, 26 Jan 2011 01:42:39 +0900
> From: adadadad3018 at gmail.com
> To: pw_forum at pwscf.org
> CC: dekura at sci.ehime-u.ac.jp
> Subject: Re: [Pw_forum] 60 atom Grain boundary... (Elie Moujaes)
>
>
>
>
>
> Dear Elie Moujaes
>
>
>
>
> Do you mean that your calculated Fermi-energy in C60 system is not located
> at which the DOS becomes zero even though you got the reasonable band
> structure.
>
>
> If so, I recommend a check for the convergence of Fermi-energy.
>
> For example,
>
>
> please check the energy convergence against
>
>
> (1) increase of the number of k-points in nscf calculation, after you
> confirm that the KS energy spectrum is converged sufficiently in SCF
> calculation (and also should check the convergence against the smearing
> width)
>
>
> (2) change in the mesh in DOS calculation.
>
>
>
>
> May be you will get more reliable and better result.
>
>
>
>
> Hope this helps.
>
>
>
>
> Best Regards.
> Haruhiko Dekura
>
>
>
>
>
>
> ========================================
>
>
> Haruhiko Dekura
>
>
> Postdoctoral Fellow
>
>
> Senior Research Fellow Center, Ehime University, 2?5 Bunkyo-cho, Matsuyama,
> Ehime 790-8577, Japan
> =====================================
>
>
>
>
>
> Dear all,
>
> I am trying to get the band structure and the DOS of a Grain boundary
> system of 60 atoms.
>
> (1) The band structure seems ok but when I am trying to set the Fermi
> energy to be the reference (i.e at 0) where two bands cross, it is not
> working i.e. I am still getting that the two bands still cross at a negative
> value (my Fermi energy is -0.098eV). Why is this happening?
>
> (2) The DOS of the system is not zero at zero energy (maybe this is a
> consequence of 1) and it is a bit wiggly as well (see graph attached)
>
>
> Thanks in advance
>
> Regards
>
> Elie Moujaes
> University of Nottingham
> NG7 2RD
> UK
>
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