[Pw_forum] LDA+U and occupations matrix problems / call for NC P Cu & Co
Ricardo Faccio
rfaccio at fq.edu.uy
Mon Apr 27 16:26:48 CEST 2009
Dear Stefano
Thanks for your quick response. I found the CVS log in the mailing list, but
I decided to write you since the problem persist. Now I'm attaching my input
file, which I used to perform U=1.0d-8 eV, U= 3.5 eV and U= 7 eV. Making a
revision of the problem, I found the only difference regards in the GGA
xc-potential. Maybe it is the problem; I found some early posts indicating
that GGA+U is not yet implemented. If it is the case sorry, but in the
meanwhile I'll comment I little bit on the problem.
1) U=1.0d-8 eV, everything is ok, since there is no U and pwscf runs in the
normal GGA procedure, this is the initial occupations matrix for one Co atom
atom 5 spin 1
occupations
0.400 0.000 0.000 0.000 0.000
0.000 0.400 0.000 0.000 0.000
0.000 0.000 0.400 0.000 0.000
0.000 0.000 0.000 0.400 0.000
0.000 0.000 0.000 0.000 0.400
atom 5 spin 2
occupations
1.000 0.000 0.000 0.000 0.000
0.000 1.000 0.000 0.000 0.000
0.000 0.000 1.000 0.000 0.000
0.000 0.000 0.000 1.000 0.000
0.000 0.000 0.000 0.000 1.000
This is normal for the d7 pseudo for Co, and in the last step we found:
occupations
atom 5 spin 1
occupations
0.532 0.000 0.000 0.000 0.000
0.000 0.434 0.000 0.000 0.000
0.000 0.000 0.434 0.000 0.000
0.000 0.000 0.000 0.993 0.000
0.000 0.000 0.000 0.000 0.435
atom 5 spin 2
occupations
0.976 0.000 0.000 0.000 0.000
0.000 0.992 0.000 0.000 0.000
0.000 0.000 0.992 0.000 0.000
0.000 0.000 0.000 0.995 0.000
0.000 0.000 0.000 0.000 0.935
2) In the case of U=3.5 eV (for both Cu & Co)
In the first scf cycle the occupations matrix looks like the one in the U=0
case, but in the second scf step I found:
atom 5 Tr[ns(na)]= 14.9317605
atom 5 spin 1
eigenvalues: 0.2107738 0.2794264 0.2794264 0.5053719 0.5799705
eigenvectors
1 0.0000000 0.0000000 0.0000000 -1.0000000 0.0000000
2 0.0000000 -0.8886367 0.4586119 0.0000000 0.0000000
3 0.0000000 -0.4586119 -0.8886367 0.0000000 0.0000000
4 0.0000000 0.0000000 0.0000000 0.0000000 -1.0000000
5 -1.0000000 0.0000000 0.0000000 0.0000000 0.0000000
occupations
0.580 0.000 0.000 0.000 0.000
0.000 0.279 0.000 0.000 0.000
0.000 0.000 0.279 0.000 0.000
0.000 0.000 0.000 0.211 0.000
0.000 0.000 0.000 0.000 0.505
atom 5 spin 2
eigenvalues: 2.5970604 2.6187425 2.6187425 2.6211004 2.6211456
eigenvectors
1 1.0000000 0.0000000 0.0000000 0.0000000 0.0000000
2 0.0000000 -0.8592401 0.5115724 0.0000000 0.0000000
3 0.0000000 0.5115724 0.8592401 0.0000000 0.0000000
4 0.0000000 0.0000000 0.0000000 0.0000000 1.0000000
5 0.0000000 0.0000000 0.0000000 -1.0000000 0.0000000
occupations
2.597 0.000 0.000 0.000 0.000
0.000 2.619 0.000 0.000 0.000
0.000 0.000 2.619 0.000 0.000
0.000 0.000 0.000 2.621 0.000
0.000 0.000 0.000 0.000 2.621
The occupations jumps from 1 to 2.6 always in the second scf, and stands in
this value until the end of the scf procedure. As I mentioned before, I
didn't use the U_projection_type flag for these three cases. I resolved the
problem adding the explicitly the flag: U_projection_type = 'norm-atomic',
since 'atomic' leads to the same erratic occupations matrix. The problem is
only related with Co electrons, since Cu always presents occupations terms
in the range of 0 to 1.
But as I mentioned before, maybe the problem is that “GGA+U” is not yet
implemented.
Thanks once again
Ricardo
-------------------------------------------------------------------------
Dr. Ricardo Faccio
Prof. Adjunto de Física
Mail: Cryssmat-Lab., Cátedra de Física, DETEMA
Facultad de Química, Universidad de la República
Av. Gral. Flores 2124, C.C. 1157
C.P. 11800, Montevideo, Uruguay.
E-mail: rfaccio at fq.edu.uy
Phone: 598 2 924 98 59
598 2 929 06 48
Fax: 598 2 9241906
Web: http://cryssmat.fq.edu.uy/ricardo/ricardo.htm
---------------------------------------------------------------------------------
----- Original Message -----
From: "Stefano de Gironcoli" <degironc at sissa.it>
To: "PWSCF Forum" <pw_forum at pwscf.org>
Sent: Monday, April 27, 2009 3:49 AM
Subject: Re: [Pw_forum] LDA+U and occupations matrix problems / call for NC
PP Cu & Co
> Dear Ricardo Faccio,The problem of normalization of atomic wavefunctions
> in LDA+U should have been solved about one year ago in the cvs version and
> incorporated in recent distributions. I include below the CVS log message
> of that correction that should clarify the change.It should be possible to
> repeat your calculations without the norm-atomic flag on and atomic
> wavefunctions should be renormalized on the atomic grid, that is in a
> configuration independent way, hence forces and stress should be
> ok).Please report any problem that you may experience,best, stefano>>
> date: 2008/07/14 21:50:33; author: degironc; state: Exp; lines: +84 -0>
> Normalization of atomic wavefuncitons is checked (only for those with>
> non-negative occupation) after pseudopotential reading and if it found to>
> be different from 1 by more than 1.d-6 the wavefunction is renormalized.>>
> Should make no difference in all usual cases since atomic wfcs are only>
> used in order to generate the initial set of trial wfcs and normalization>
> is not important there...>> It is VERY important for LDA+U calculations
> using atomic wfc in the > progector> (the default case) since proper
> normalization is assumed and lack of > it leads> to disasters.>> Hopefully
> this will solve many of the difficulties people have encounterd> when
> using LDA+U with older RRKJ pseudopotentials, where normalization> was not
> imposed properly (and nobody realizes except when doing LDA+U) or>
> pseudopotentials of unknown origin.
>
>
>
>
> Ricardo Faccio wrote:> Dear Pwscf users>> I'm a newbie using pwscf, and I’m
> trying to reproduce some full-potential > all-electrons results from a
> previous work using WIEN2k. My system is a > cuprate/colbatite YBaCuCoO5.
> I succeed running the lda+u calculations, but I > found the previous
> discussed problem regarding the lack of normalization in > some PP (non
> norm-conserving). I worked with the UPF's files from the QE web > page:
> Cu.pbe-d-rrkjus.UPF and Co.pbe-nd-rrkjus.UPF. The problem of >
> occupations higher than 1 was resolved with the flag: U_projection_type =
> > 'norm-atomic'. But I am interested in checking the stresses and forces,
> in > order to verify my previous equilibrium solution and these are not >
> implemented for such correction ('norm-atomic').>> For these reason I
> would like to ask you for a PBE-Norm-conserving PP for Cu > and Co, if
> anyone has it available. I think this is the fattest solution in > order
> to avoid the U dependency upon normalization (through > U_projection_type)
> and for checking my previous results. But, if I have no > answers, I will
> try to generate these files from myself (but it is a little > bit more
> complicated that ATOMS implemented in SIESTA).>> Thanks in advance and
> sorry for the inconvenience.>> Ricardo
> Faccio>> ------------------------------------------------------------------------->
> Dr. Ricardo Faccio> Prof. Adjunto de Física> Mail: Cryssmat-Lab.,
> Cátedra de Física, DETEMA> Facultad de Química, Universidad de la
> República> Av. Gral. Flores 2124, C.C. 1157> C.P. 11800,
> Montevideo, Uruguay.> E-mail: rfaccio at fq.edu.uy> Phone: 598 2 924 98
> 59> 598 2 929 06 48> Fax: 598 2 9241906> Web:
> http://cryssmat.fq.edu.uy/ricardo/ricardo.htm>>
> _______________________________________________> Pw_forum mailing list>
> Pw_forum at pwscf.org> http://www.democritos.it/mailman/listinfo/pw_forum>
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