[Wien] Different GGA+U results for different wien2k versions

[Laurence Marks]

Let me add a little to what Fabien said.

In a +U calculation, and also -eece (and perhaps some others) it is
possible:
a) To have different local minima with different spin/orbital states
b) To get stuck in a trap.

Case a) is "real" for the functional used. While local minimum are not
present in all systems, sometimes they are, for instance low versus high
spin for Cr, and parity of the density matrix eigenvectors for DyScO3. It
is possible that you have different spin states in your runs.

Case b) is when :DIS and :PLA appear to have converged, but the density
matrix or orbital potential (:MV) has not. Changes in the orbital terms
increase :DIS, so appear to be a minimum if that is all you look at, but in
reality it is not because the orbital tems are not self-consistent. With
17.1 I added a better scaling of the orbital potential which reduces the
possibility of getting stuck in a trap.

On Tue, Jul 31, 2018 at 6:05 AM, tran at theochem.tuwien.ac.at <
tran at theochem.tuwien.ac.at> wrote:

> So, now you should check what results you obtain with 17.1 when
> starting the calculation with the files (.clm/sum/up/dn, .dmat/up/dn,
> .vorb/up/dn,) obtained with 16.1.
>
>
> On Tuesday 2018-07-31 12:31, Chouaib AHMANI FERDI wrote:
>
> >Date: Tue, 31 Jul 2018 12:31:11
> >From: Chouaib AHMANI FERDI <ahmaniferdichouaib at gmail.com>
> >Reply-To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.
> at>
> >To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>
> >Subject: Re: [Wien] Different GGA+U results for different wien2k versions
> >
> >Dear Mr Tran,
> >
> >Thank you for your response.
> >
> >I did not start the calculations on Version_17.1 using old files from
> version_16.1
> >The only file in common is the .struct file
> >
> >the same parameters are chosen for the calculations in both versions,
> namely : RKmax, Energy seperation, K-points, approximation : GGA-PBE and
> SAME U VALUE (J =
> >0)
> >
> >Sincerely,
> >
> >On Tue, Jul 31, 2018 at 11:26 AM Chouaib AHMANI FERDI <
> ahmaniferdichouaib at gmail.com> wrote:
> >      Dear M. Marks
> >
> >Thank you for your response.
> >
> >VERSION_16.1 :
> >the bottom of the file .in1 :
> >---
> >K-VECTORS FROM UNIT:4  -12.2       1.5  1125   emin / de (emax=Ef+de) /
> nband
> >---
> >i didn't modify the lower value
> >The energy to separate core and valence states is set to -9.2 Ry in all
> of the calculations because of P atoms
> >
> >the files .output1up_1 .output1up_2 .output1up_3 and .output1dn_1 ...
> gives :
> >---
> >  0 EIGENVALUES BELOW THE ENERGY  -12.20000
> >---
> >multiple times as you go through the file
> >
> >VERSION_17.1
> >the bottom of the file .in1 :
> >---
> >K-VECTORS FROM UNIT:4  -12.2       1.5  1101   emin / de (emax=Ef+de) /
> nband
> >---
> >the files .output1up_1 .output1up_2 .output1up_3 and .output1dn_1 ...
> gives the same as in VERSION_16.1
> >---
> >  0 EIGENVALUES BELOW THE ENERGY  -12.20000
> >---
> >
> >I noticed that nband is a little bit different in the two versions
> >I guess there's no ghostbands
> >
> >what so you think ?
> >
> >Sincerely,
> >
> >
> >
> >
> >On Sun, Jul 29, 2018 at 3:58 PM <tran at theochem.tuwien.ac.at> wrote:
> >      Hi,
> >
> >      Did you start the calculation with VERSION_17.1 using the
> >      files form the old calculation?
> >
> >      F. Tran
> >
> >      On Sunday 2018-07-29 16:21, Chouaib AHMANI FERDI wrote:
> >
> >      >Date: Sun, 29 Jul 2018 16:21:12
> >      >From: Chouaib AHMANI FERDI <ahmaniferdichouaib at gmail.com>
> >      >Reply-To: A Mailing list for WIEN2k users <
> wien at zeus.theochem.tuwien.ac.at>
> >      >To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.
> at>
> >      >Subject: [Wien] Different GGA+U results for different wien2k
> versions
> >      >
> >      >Greetings Wien2k users,
> >      >
> >      >I have some results of a compound from Wien2k_16.1 a long time ago
> with GGA+U
> >      >When I tried the same calculations on the sam compound with
> VERSION_17.1 I found different results.
> >      >for example : I had a Band GAP of 1.4 eV with GGA+U U=7eV in
> Version_16.1
> >      >while i have 3.8 eV with GGA+U U=7eV in Version_17.1, I noticed
> that this value is close to VASP results on the same structure same U value
> >      and slightly
> >      >different parameters
> >      >This remark is valid for another compound where the Version_17.1
> gives band gap closer to VASP results for the same value of U
> >      >
> >      >Another issue is that when I try to calculate the Density Of
> States, some low energy bands (below 8 eV) do not show, (maybe they are not
> >      calculated) while
> >      >Version_16.1 they were shown
> >      >
> >      >Could someone explain ?
> >      >
> >      >Sincerely,
> >      >
> >      >
> >      >C.Ferdi
> >      >
> >      >
> >      >--
> >      >-----------------------------------------------------
> >      >AHMANI FERDI Chouaïb
> >      >Laboratoire Matériaux Nanomatériaux
> >      >Nanomagnétisme et Enseignement des Sciences
> >      >École Normale Supérieure
> >      >Université Mohammed V, Rabat.
> >      >Tel : +212 6 94 59 57 60
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> >
> >--
> >-----------------------------------------------------
> >AHMANI FERDI Chouaïb
> >Laboratoire Matériaux Nanomatériaux
> >Nanomagnétisme et Enseignement des Sciences
> >École Normale Supérieure
> >Université Mohammed V, Rabat.
> >Tel : +212 6 94 59 57 60
> >
> >
> >
> >--
> >-----------------------------------------------------
> >AHMANI FERDI Chouaïb
> >Laboratoire Matériaux Nanomatériaux
> >Nanomagnétisme et Enseignement des Sciences
> >École Normale Supérieure
> >Université Mohammed V, Rabat.
> >Tel : +212 6 94 59 57 60
> >
> >
>



-- 
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 ; Corrosion in 4D: MURI4D.numis.northwestern.edu
Partner of the CFW 100% program for gender equity, www.cfw.org/100-percent
Co-Editor, Acta Cryst A
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