[Wien] problems with convergence of SCF for AFM HoPtBi

[Fecher, Gerhard]

seems to be a more general problem with the rare earth and is related to the 4f electrons,
I recently tested some pure RE elements (and compounds) and found that similar problems occur in most cases
sometimes the cycles went smooth, and at a certain point rather everything (from ENE to MMI) started to oscillate in consecutive cycles. 
In some cases it became worth when using larger number of k-points.

Convergence was reached when using TEMP 0.002 and a lower mixing (0.05 or lower)
and it took long (> 400 cycles) to reach convergence in many cases (ec 0.00001 cc 0.001).
(but there is still no guarentee, depending on the magnetic state).

As probably all RE (even Lu) need LDA+U or something to heal the 4f problem, it might be helpful in some cases to use +U (about a half Ry) from beginning.

Maybe someone has more experience with the 4f and can share it here.

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."

====================================
Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden
________________________________________
Von: Wien [wien-bounces at zeus.theochem.tuwien.ac.at] im Auftrag von Laurence Marks [L-marks at northwestern.edu]
Gesendet: Donnerstag, 1. November 2018 00:13
An: A Mailing list for WIEN2k users
Betreff: Re: [Wien] problems with convergence of SCF for AFM HoPtBi

I strongly suggest that you also look at the magnetic moments and what is going on at the Fermi energy and with the 4f. Both :DIS &:ENE are relatively crude tests and often don't tell the whole story.

HDLO can also be important for large RMTs similar to what you have.

Last, but not least, did you use runafm?

_____
Professor Laurence Marks
"Research is to see what everybody else has seen, and to think what nobody else has thought", Albert Szent-Gyorgi
www.numis.northwestern.edu<http://www.numis.northwestern.edu>

On Wed, Oct 31, 2018, 4:10 PM tran at theochem.tuwien.ac.at<mailto:tran at theochem.tuwien.ac.at> <tran at theochem.tuwien.ac.at<mailto:tran at theochem.tuwien.ac.at>> wrote:
Hi,

Can you show us how :DIS and :ENE are changing (grep them in case.scf).

FT

On Wednesday 2018-10-31 21:35, Kefeng wang wrote:

>Date: Wed, 31 Oct 2018 21:35:38
>From: Kefeng wang <wangkf80 at gmail.com<mailto:wangkf80 at gmail.com>>
>Reply-To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at<mailto:wien at zeus.theochem.tuwien.ac.at>>
>To: wien at zeus.theochem.tuwien.ac.at<mailto:wien at zeus.theochem.tuwien.ac.at>
>Subject: [Wien] problems with convergence of SCF for AFM HoPtBi
>
>Dear all,
>I am using wien17.1 to perform the DFT calculations for  HoPtBi. For the Non-magnetic case, the convergence for the SCF calculation has been achieved using 8000
>k points while for the AFM case, it is not convergent at all using 4096 k points after 100 iterations. The charge and energy keep fluctuating. However, for
>GdPtBi with the same lattice structure and AFM order, the corresponding calculations are convergent.  I felt very confused. Thanks a lot for your help!
>
>
>The struct file for HoPtBi is shown below:
>
>R   LATTICE,NONEQUIV.ATOMS:  6 160 R3m
>MODE OF CALC=RELA unit=bohr
>  8.860595  8.860595 43.407874 90.000000 90.000000120.000000
>ATOM  -1: X=0.87500000 Y=0.87500000 Z=0.87500000
>          MULT= 1          ISPLIT= 4
>Pt1        NPT=  781  R0=.000005000 RMT= 2.50000     Z:  78.
>LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                     0.0000000 1.0000000 0.0000000
>                     0.0000000 0.0000000 1.0000000
>ATOM  -2: X=0.37500000 Y=0.37500000 Z=0.37500000
>          MULT= 1          ISPLIT= 4
>Pt2        NPT=  781  R0=.000005000 RMT= 2.50000     Z:  78.
>LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                     0.0000000 1.0000000 0.0000000
>                     0.0000000 0.0000000 1.0000000
>ATOM  -3: X=0.00000000 Y=0.00000000 Z=0.00000000
>          MULT= 1          ISPLIT= 4
>Ho1        NPT=  781  R0=.000010000 RMT= 2.50000     Z:  67.
>LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                     0.0000000 1.0000000 0.0000000
>                     0.0000000 0.0000000 1.0000000
>ATOM  -4: X=0.50000000 Y=0.50000000 Z=0.50000000
>          MULT= 1          ISPLIT= 4
>Ho2        NPT=  781  R0=.000010000 RMT= 2.50000     Z:  67.
>LOCAL ROT MATRIX:    1.0000000 0.0000000 0.                     0.0000000 0.0000000 1.0000000
>ATOM  -5: X=0.75000000 Y=0.75000000 Z=0.75000000
>          MULT= 1          ISPLIT= 4
>Bi1        NPT=  781  R0=.000005000 RMT= 2.50000     Z:  83.
>LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                     0.0000000 1.0000000 0.0000000
>                     0.0000000 0.0000000 1.0000000
>ATOM  -6: X=0.25000000 Y=0.25000000 Z=0.25000000
>          MULT= 1          ISPLIT= 4
>Bi2        NPT=  781  R0=.000005000 RMT= 2.50000     Z:  83.
>LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>                     0.0000000 1.0000000 0.0000000
>                     0.0000000 0.0000000 1.0000000
>   6      NUMBER OF SYMMETRY OPERATIONS
> 1 0 0 0.00000000
> 0 1 0 0.00000000
> 0 0 1 0.00000000
>       1
> 0 0 1 0.00000000
> 1 0 0 0.00000000
> 0 1 0 0.00000000
>       2
> 0 1 0 0.00000000
> 0 0 1 0.00000000
> 1 0 0 0.00000000
>       3
> 0 1 0 0.00000000
> 1 0 0 0.00000000
> 0 0 1 0.00000000
>       4
> 1 0 0 0.00000000
> 0 0 1 0.00000000
> 0 1 0 0.00000000
>       5
> 0 0 1 0.00000000
> 0 1 0 0.00000000
> 1 0 0 0.00000000
>       6
>
>Best,
>Wang
>
>