Re: [Wien] regarding Fermi level.

2017-01-21 Thread Nacir GUECHI 
Thanks. **
Nacir GUECHI
Dr. Physique de la matière solide.Enseignant-Chercheur à l'université du Dr. 
Yahia FARES de Médéa,  Algeria (www.univ-media.dz).Laboratoire d'études des 
surfaces et interfaces des matériaux solides (L.E.S.I.M.S), université Sétif1 
(Algeria)http://laboratoires.univ-setif.dz/L.E.S.I.M.S/ 

Le Samedi 21 janvier 2017 17h27, "Fecher, Gerhard"  a 
écrit :
 

 This issue was recently discussed
http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg14791.html

Please search the mailing list

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-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Nacir GUECHI 
[guechi...@yahoo.fr]
Gesendet: Samstag, 21. Januar 2017 16:35
An: A Mailing list for WIEN2k users
Betreff: [Wien] regarding Fermi level.

Dear wien2k users.
- For semiconductors the fermi level would lie at the bottom of the gap 
(E-Ef=0eV) at T=0K.
- When temperature increases (example T=300K) the Fermi level will remain at 
the bottom of the gap or moves to anothar potition ? please any comment about 
fermi level at finite temperature would useful for me.


**
Nacir GUECHI
Dr. Physique de la matière solide.
Enseignant-Chercheur à l'université du Dr. Yahia FARES de 
Médéa,  Algeria (www.univ-media.dz).
Laboratoire d'études des surfaces et interfaces des matériaux solides 
(L.E.S.I.M.S), université Sétif1 (Algeria)
http://laboratoires.univ-setif.dz/L.E.S.I.M.S/
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Re: [Wien] regarding Fermi level.

2017-01-21 Thread Fecher, Gerhard 
This issue was recently discussed
http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg14791.html

Please search the mailing list

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-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Nacir GUECHI 
[guechi...@yahoo.fr]
Gesendet: Samstag, 21. Januar 2017 16:35
An: A Mailing list for WIEN2k users
Betreff: [Wien] regarding Fermi level.

Dear wien2k users.
- For semiconductors the fermi level would lie at the bottom of the gap 
(E-Ef=0eV) at T=0K.
- When temperature increases (example T=300K) the Fermi level will remain at 
the bottom of the gap or moves to anothar potition ? please any comment about 
fermi level at finite temperature would useful for me.


**
Nacir GUECHI
Dr. Physique de la matière solide.
Enseignant-Chercheur à l'université du Dr. Yahia FARES de 
Médéa,  Algeria (www.univ-media.dz).
Laboratoire d'études des surfaces et interfaces des matériaux solides 
(L.E.S.I.M.S), université Sétif1 (Algeria)
http://laboratoires.univ-setif.dz/L.E.S.I.M.S/
___
Wien mailing list
Wien@zeus.theochem.tuwien.ac.at
http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
SEARCH the MAILING-LIST at:  
http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html

[Wien] regarding Fermi level.

2017-01-21 Thread Nacir GUECHI 
Dear wien2k users.- For semiconductors the fermi level would lie at the bottom 
of the gap (E-Ef=0eV) at T=0K.- When temperature increases (example T=300K) the 
Fermi level will remain at the bottom of the gap or moves to anothar potition ? 
please any comment about fermi level at finite temperature would useful for me. 

 **
Nacir GUECHI
Dr. Physique de la matière solide.Enseignant-Chercheur à l'université du Dr. 
Yahia FARES de Médéa,  Algeria (www.univ-media.dz).Laboratoire d'études des 
surfaces et interfaces des matériaux solides (L.E.S.I.M.S), université Sétif1 
(Algeria)http://laboratoires.univ-setif.dz/L.E.S.I.M.S/___
Wien mailing list
Wien@zeus.theochem.tuwien.ac.at
http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
SEARCH the MAILING-LIST at:  
http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html

Re: [Wien] Mixer surprise when using PBE0 hybrid on-site functional

2017-01-21 Thread Laurence Marks 
:MV is in case.scfm, e.g. grep :MV *.scf. A value of 1D-2 is well
converged, 1D0 is maybe OK, 1D1 or more is problematic and can indicate a
problem if :DIS etc is small.

N.B., you can also look at the quadrature fit of x lapw0 -eece in
case.output0

---
Professor Laurence Marks
"Research is to see what everybody else has seen, and to think what nobody
else has thought", Albert Szent-Gyorgi
http://www.numis.northwestern.edu
Corrosion in 4D http://MURI4D.numis.northwestern.edu
Partner of the CFW 100% gender equity project, www.cfw.org/100-percent
Co-Editor, Acta Cryst A


On Jan 21, 2017 01:27, "Xavier Rocquefelte" <
xavier.rocquefe...@univ-rennes1.fr> wrote:

> Dear Laurence
>
> Thank you so much for your detailled replies.
>
> I agree that something curious happens here. In particular, my surprise is
> why the convergency is fast and leads to a ferromagnetic solution in GGA+U
> and not in PBE0 on-site hybrid. These two schemes must be quite similar in
> the way they correct the GGA eigenvalues. I will continue to test the
> different options of mixer. Just one question, I didn't know the :MV
> keyword. Where should I find it?
>
> Best Regards
>
> Xavier
> Le 20/01/2017 à 22:16, Laurence Marks a écrit :
>
> I can provide some partial responses, although there are also some things
> that I don't understand. Some of this (maybe most) is not the mixer but in
> other parts of Wien2k.
>
> First, the old (2008) version is there if you use MSEC1, but I have not
> tested it and it may fail. Better is to use MSEC3 which is almost the old
> version. For some classes of problems this is more stable than MSR1, and
> works better. If you are talking about the pre-multisecant version (BROYD)
> that vanished some time ago.
>
> Second, there is a nasty "feature" particularly for +U (eece) cases, which
> is partially discussed in the mixer Readme. There is no guarantee that a
> solution exists -- the KS theorem is for densities but U is an orbital
> term. It is very possible to have cases where there is no fixed-point
> solution. The older MSEC1 (maybe BROYD) could find a fake solution where
> the density was consistent but the orbital potential was not. The latest
> version is much better in avoiding them and going for "real" solutions
> rather than being trapped. For orbital potentials it is very important to
> look at :MV to check that one really has a self-consistent orbital
> potential.
>
> Third, there are cases where PBE (and all the GGA's in Wien2k that I have
> tested) give unphysical results when applied to isolated d or f electrons
> as done for -eece. I guess that the GGA functionals were not designed for
> the densities of just high L orbitals. This leads to very bad behavior of
> the mixing. I know of no way to solve this in the mixer, it is a structural
> problem. It goes away if LDA is used as the form for VXC in -eece.
>
> Fourth, larger problem with low symmetry (P1 in particular) can certainly
> behave badly. Part of this might be "somewhere" in Wien2k coding, part of
> it is generic to a low symmetry problem. In many cases these have small
> eigenvalues in the mixing Jacobian which are removed when symmetry is
> imposed. All one can do is use MSEC3 or some of the additional flags (see
> the mixer README) such as "SLOW".
>
> Fifth...probably exists, but I can't think of it immediately.
>
> On Fri, Jan 20, 2017 at 2:03 PM, Xavier Rocquefelte <
> xavier.rocquefe...@univ-rennes1.fr> wrote:
>
>> Dear Colleagues
>>
>> I did recently a calculation which has been published long time ago
>> using a old WIEN2k version (in 2008).
>>
>> It corresponds to a spin-polarized calculation for the compound CuO. The
>> symmetry is removed and the idea is to estimate the total energies for
>> different magnetic orders to extract magnetic couplings from a mapping
>> analysis. Such calculations were converging fastly without any trouble
>> in 2008.
>>
>> Here I have started from the scratch with a case.cif file to generate
>> the case.struct file and initializing the calculation in a standard
>> manner.
>>
>> Then I wanted to have the energy related to a ferromagnetic situation
>> (not the more stable). I have 8 copper sites in the unit cell I am using.
>>
>> When this calculation is done using PBE+U everything goes fine. However
>> when PBE0 hybrid on-site functional is used we observed oscillations and
>> the magnetic moment disappear, which is definitely not correct. It
>> should be mentionned that the convergency is really bad. If we do a
>> similar calculation on the cristallographic unit cell (2 copper sites
>> only) the calculations converge both in PBE+U and PBE0.
>>
>> The convergency problems only arises for low-symmetry and high number of
>> magnetic elements. I didn't have such problems before and I wonder if we
>> could still use old mixer scheme in such situations. Looking at the
>> userguide, it seems that the mixer does not allow to do as before and
>> PRATT mixer is too slow.
>>
>> Did you encounter similar