[Wien] Problems in convergence due to application of mBj potential
Laurence Marks
L-marks at northwestern.edu
Thu Aug 30 16:12:42 CEST 2012
I think using mBJ and MSR1a is the idea -- is it valid/better compared
to just mBJ with PBE refined positions? I think it might be, but it is
hard to say.
And, of course, without -so.
On Thu, Aug 30, 2012 at 8:48 AM, Peter Blaha
<pblaha at theochem.tuwien.ac.at> wrote:
> Once again:
>
> Do you mean MSR1 or MSR1a ???? The little "a" makes a big difference
> and you can only compare PRATT and MSR1 for mBJ, but not MSR1a.
>
> Of course, a second try could be to use MSR1a and mBJ (without SO) and
> check how much the structure changes.
>
>> performance of MRS1a and PRATT when using mBJ in the band structure
>> calculation (as described in section 4.5.9 of the WIEN_12 Users
>> Guide). So, I was trying to improve the band gap and spin splittings
>> of the system (not to relax it) with mBJ, this is the reason why I
>> switched the -so option in this calculation (but not in the previous
>> structure optimization for the reasons you described).
>> Now, I know that MSR1a try to optimize the structure, what means it
>> is not an ordinary SCF cycle, so SOC is an unappropriated option as
>> you posted. I am sorry for the misunderstanding.
>> I will try a new structure optimization using MSR1a-mBJ with the
>> same parameters employed in the MSEC1-PBE case, allowing a fair
>> comparison between their performances. I promise to report the result
>> as soon as possible.
>> Thank you for your attention,
>> Luis
>>
>>
>>
>> 2012/8/30 Peter Blaha <pblaha at theochem.tuwien.ac.at>:
>>> For sure, forces are NOT ok when you switch on spin-orbit coupling.
>>>
>>> But please: think about the physics: InP is not that heavy and is a
>>> semiconductor. You do NOT need SO for any structural relaxation as
>>> it has negligible effects anyway.
>>> (However, you may NEED SO for bandstructure properties, effective
>>> masses,....,
>>> but calculate this afterwards with fixed positions, NEVER with MSR1a but
>>> with MSR1).
>>>
>>>
>>> Furthermore, in your mail it sounds as if you mixed up various schemes
>>> with WIEN2k.
>>>
>>> When using MSR1 you do NOT optimize positions (only "electrons"),
>>> MSR1a you ALWAYS will optimize positions (in fact, when you do
>>> not
>>> have case.inM, it will be generated automatically !)
>>>
>>> And for both schemes you use the command run_lapw !
>>>
>>> Alternatively, you can use min_lapw (and MSR1, not MSR1a), which will
>>> also optimize positions (and if case.inM does not exist, will generate
>>> it automatically).
>>>
>>> Both, MSR1a or min_lapw accept "constraint positions", when you execute
>>> x pairhess -copy (creates case.inM)
>>> edit case.inM and set some values to zero for constraining them.
>>> x pairhess -copy (so that the constrains are honored in the hessian for
>>> PORT).
>>>
>>> PS: At least for insulators (but usually even for difficult 3d-metallic
>>> systems)
>>> I strongly recommend MSR1a over min_lapw, as it is almost always much
>>> faster and more stable. The only problem left is to determine a unique way
>>> when to stop MSR1a (this means: what stopping criteria one should use),
>>> but when you accept some remaining forces (less than 5 mRy/bohr),
>>> even this is not a serious problem and default criteria (or even a bit
>>> larger value than 2.0 in case.inM) are sufficient and reasonable.
>>>
>>> PPS: When one tries MSR1a together with mBJ, I'd first converge mBJ (at
>>> least
>>> partly) with MSR1 (or PRATT and later on MSR1), and then remove case.in0_grr
>>> (this will fix the value of "c" in mBJ and make things for MSR1a more
>>> stable).
>>>
>>>
>>> Am 29.08.2012 19:03, schrieb Luis Carlos Ogando Dacal:
>>>
>>>> Dear Prof. Laurence Marks,
>>>>
>>>> Let me answer you using your previous message.
>>>>
>>>>> First, a reminder. Using MSR1a with mBJ is a computational experiment.
>>>>> It may not give reasonable results, or it might -- I do not know and I
>>>>> am not sure that anyone does, yet. The "standard" method is not to
>>>>> vary the atomic positions with mBJ, but this may not be optimal.
>>>>
>>>>
>>>> Yes, I know. I just tested MSR1a as you asked the WIEN mailing list
>>>> in a message you sent in August, 22. I will keep on the calculation
>>>> using the standard and reliable methods. My report was just a little
>>>> contribution to your efforts.
>>>>
>>>>> One thing to check, in your case what are the positions like in the
>>>>> substrate? Assuming that you have made this thick enough (e.g. 20 au
>>>>> or more) in the center the positions should be close to those with PBE
>>>>> and/or the bulk. If they are wildly different this implies that the
>>>>> bulk lattice parameters for PBE do not match well those from mBJ. (Of
>>>>> course, if you have only used 2 layers or so of substrate you cannot
>>>>> test this.)
>>>>
>>>>
>>>> Actually, I did not optimized the structure using MSR1a. I did it
>>>> in a previous calculation with MSEC1 and PBE with case.inM fixing the
>>>> substrate positions. Only after that, I used mBJ to improve the gap.
>>>> When I employed mBJ with PRATT (0.2 followed by 0.4 mixing factors) I
>>>> got the convergence in the SCF cycle and a smooth decrease in ETEST.
>>>> In the MSR1a test, I noticed abrupt changes in ETEST and after the
>>>> last iteration I got the message "energy in SCF NOT CONVERGED".
>>>> As I was not optimizing the structure when using MSR1a, I had not a
>>>> case.inM file and all the atoms changed position during MSR1a
>>>> calculations. Despite the fact that I used a thin substrate (I will
>>>> improve this in a next step), the atomic positions changed only by a
>>>> factor of 10^(-3) when compared to the previously PBE relaxed
>>>> structure (It is important to remember that MSR1a did not converged
>>>> and I used the last generated case.struct to compare with PBE relaxed
>>>> structure)
>>>>
>>>>> When you say "it did not converge with MSR1a", what exactly do you
>>>>> mean? It may be better to send the case.struct and case.scf files to
>>>>> my email directly.
>>>>
>>>>
>>>> I was talking about the message at the end of the MSR1a calculation
>>>> ("energy in SCF NOT CONVERGED"). I have not calculated any physical
>>>> property of the system.
>>>> I will send you the files in another message.
>>>>
>>>>> If you fix some atoms in case.inM, then the ones which are not fixed
>>>>> will move. While some people argue that this is OK, I have
>>>>> reservations. If you fix all the atoms in case.inM then MSR1a will
>>>>> crash on you -- you have to use MSR1 (or MSEC3).
>>>>
>>>>
>>>> All the best,
>>>> Luis
>>>>
>>>>
>>>>
>>>>> On Wed, Aug 29, 2012 at 7:50 AM, Luis Carlos Ogando Dacal
>>>>> <ogando at ieav.cta.br> wrote:
>>>>>>
>>>>>> Dear Prof. Laurence Marks (and WIEN2k users),
>>>>>>
>>>>>> I would like to report my recent experience in using MSR1a with
>>>>>> mBJ. I have a semiconductor system composed by In and P atoms that I
>>>>>> relaxed using PBE. After that, I tried the mBJ SCF cycle using PRATT
>>>>>> as recommended in section 4.5.9 of the WIEN Users Guide. I got the
>>>>>> convergence after a long cycle (strict convergence criteria), but no
>>>>>> convergence was obtained with MSR1a.
>>>>>> If you want any detail of my system and/or calculation, just send
>>>>>> me an e-mail.
>>>>>> Another point, my system tries to simulate a substrate and a cap
>>>>>> stressed layer. As a consequence, I need to fix the substrate atoms
>>>>>> during the SCF cycles. I would like to know if this can be done with
>>>>>> case.inM when using MSR1a (or any other way). I believe that fixing
>>>>>> atoms leads MSR1a to behave like MSR1. Is this right ?
>>>>>> All the best,
>>>>>> Luis Ogando
>>>>>>
>>>>>>
>>>>>>
>>>>>> 2012/8/22 Laurence Marks <L-marks at northwestern.edu>:
>>>>>>>
>>>>>>> I am sure Peter had a typo - I think he meant MSR1 not MSR1a. Whether
>>>>>>> MSR1a
>>>>>>> is a good idea with mBJ is currently unclear; there was a recent
>>>>>>> discussion
>>>>>>> of this, look in the email archives.
>>>>>>>
>>>>>>> A good topic where readers of this list could contribute is testing
>>>>>>> whether
>>>>>>> MSR1a with mBJ is physically reasonable and reporting back.
>>>>>>>
>>>>>>> On Aug 22, 2012 8:47 AM, "Madhav Ghimire" <ghimire.mpg at gmail.com>
>>>>>>> wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> Dear Prof. Marks,
>>>>>>>> Thank you very much for replying immediately. I was just replying
>>>>>>>> to
>>>>>>>> your post.
>>>>>>>> As in userguide of wien2k, it is suggested to edit the case.inm and
>>>>>>>> change
>>>>>>>> MSR1a with PRATT as MSR1a leads to convergence problems in mBj. Hence,
>>>>>>>> I
>>>>>>>> performed the calculations by changing MSR1a with PRATT.
>>>>>>>> I will follow to what you suggest right now and report within a day or
>>>>>>>> two.
>>>>>>>> Please let me know more if I have to be cautious somewhere in the
>>>>>>>> calculations.
>>>>>>>> Thanks.
>>>>>>>> Madhav
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On Wed, Aug 22, 2012 at 8:21 PM, Laurence Marks
>>>>>>>> <L-marks at northwestern.edu>
>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Can you send the case.scf file to me directly? I am curious why MSR1
>>>>>>>>> does
>>>>>>>>> not converge well for some mBJ and there are some things printed in
>>>>>>>>> case.scfm which may explain.
>>>>>>>>>
>>>>>>>>> ---------------------------
>>>>>>>>> Professor Laurence Marks
>>>>>>>>> Department of Materials Science and Engineering
>>>>>>>>> Northwestern University
>>>>>>>>> www.numis.northwestern.edu 1-847-491-3996
>>>>>>>>> "Research is to see what everybody else has seen, and to think what
>>>>>>>>> nobody else has thought"
>>>>>>>>> Albert Szent-Gyorgi
>>>>>>>>>
>>>>>>>>> On Aug 21, 2012 9:50 PM, "Madhav Ghimire" <ghimire.mpg at gmail.com>
>>>>>>>>> wrote:
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Dear wien users and developers,
>>>>>>>>>> I am working on some 3d TM oxides. With a normal scf cycle
>>>>>>>>>> with or
>>>>>>>>>> without inclusion of U value, I got good convergence in energy and
>>>>>>>>>> charge.
>>>>>>>>>> This oxide material is reported to have a bandgap of approx. 0.3 eV.
>>>>>>>>>> In GGA,
>>>>>>>>>> I do not observe any gap. In the meantime even with very high value
>>>>>>>>>> of U,
>>>>>>>>>> the bandgap do not open up. Because of this, I tried to implement
>>>>>>>>>> mBj
>>>>>>>>>> potential (in order to find the bandgap) both with and without
>>>>>>>>>> inclusion of
>>>>>>>>>> U, but the energy and charge do not converge.
>>>>>>>>>> Rather even for a large number of iteration (199), the energy and
>>>>>>>>>> charge
>>>>>>>>>> remains constant without convergence (shown below).
>>>>>>>>>>
>>>>>>>>>> For GGA without mBj the scf cycle smoothly converges as below:
>>>>>>>>>> in cycle 22 ETEST: .0000236850000000 CTEST: .0038743
>>>>>>>>>> in cycle 23 ETEST: .0000184300000000 CTEST: .0012996
>>>>>>>>>> in cycle 24 ETEST: .0000174650000000 CTEST: .0006011
>>>>>>>>>> in cycle 25 ETEST: .0000037600000000 CTEST: .0007451
>>>>>>>>>> in cycle 26 ETEST: .0000016050000000 CTEST: .0001163
>>>>>>>>>>
>>>>>>>>>>> stop
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> while with mBj+GGA, energy and charge convergence remains constant
>>>>>>>>>> above cycle 103 and could not converge as below:
>>>>>>>>>> in cycle 193 ETEST: .2112103950000000 CTEST: 2.0591251
>>>>>>>>>> in cycle 194 ETEST: .2112103950000000 CTEST: 2.0591251
>>>>>>>>>> in cycle 195 ETEST: .2112103950000000 CTEST: 2.0591251
>>>>>>>>>> in cycle 196 ETEST: .2112103950000000 CTEST: 2.0591251
>>>>>>>>>> in cycle 197 ETEST: .2112103950000000 CTEST: 2.0591251
>>>>>>>>>> in cycle 198 ETEST: .2112103950000000 CTEST: 2.0591251
>>>>>>>>>> in cycle 199 ETEST: .2112103950000000 CTEST: 2.0591251
>>>>>>>>>>
>>>>>>>>>>> energy in SCF NOT CONVERGED
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Does anyone have experienced this type of problems. If so, please
>>>>>>>>>> let me
>>>>>>>>>> know how it can be converged. I followed all the steps as described
>>>>>>>>>> in
>>>>>>>>>> previous wien mail and userguid but could not solve.
>>>>>>>>>> Your help to solve this issue will be higly appreciated.
>>>>>>>>>> Thanks in advance
>>>>>>>>>>
>>>>>>>>>> Madhav Ghimire
>>>>>>>>>>
>>>>>>>>>> --
>>>>>>>>>> MANA, National Institute for Materials Science (NIMS)
>>>>>>>>>> 1-1 Namiki, Tsukuba, Ibaraki, Japan
>>>>>>>>>> Phone: +81-29-851-3354 (ex.4115)
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> _______________________________________________
>>>>>>>>>> Wien mailing list
>>>>>>>>>> Wien at zeus.theochem.tuwien.ac.at
>>>>>>>>>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> --
>>>>>>>>>> MANA, National Institute for Materials Science (NIMS)
>>>>>>>>>> 1-1 Namiki, Tsukuba, Ibaraki, Japan
>>>>>>>>>> Phone: +81-29-851-3354 (ex.4115)
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> _______________________________________________
>>>>>>>>> Wien mailing list
>>>>>>>>> Wien at zeus.theochem.tuwien.ac.at
>>>>>>>>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> MANA, National Institute for Materials Science (NIMS)
>>>>>>>> 1-1 Namiki, Tsukuba, Ibaraki, Japan
>>>>>>>> Phone: +81-29-851-3354 (ex.4115)
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Wien mailing list
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>>>>>>>
>>>>>> _______________________________________________
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>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Professor Laurence Marks
>>>>> Department of Materials Science and Engineering
>>>>> Northwestern University
>>>>> www.numis.northwestern.edu 1-847-491-3996
>>>>> "Research is to see what everybody else has seen, and to think what
>>>>> nobody else has thought"
>>>>> Albert Szent-Gyorgi
>>>>> _______________________________________________
>>>>> Wien mailing list
>>>>> Wien at zeus.theochem.tuwien.ac.at
>>>>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>>>
>>>> _______________________________________________
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>>>>
>>>
>>> --
>>>
>>> P.Blaha
>>> --------------------------------------------------------------------------
>>> Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
>>> Phone: +43-1-58801-165300 FAX: +43-1-58801-165982
>>> Email: blaha at theochem.tuwien.ac.at WWW:
>>> http://info.tuwien.ac.at/theochem/
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>
> --
>
> P.Blaha
> --------------------------------------------------------------------------
> Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
> Phone: +43-1-58801-165300 FAX: +43-1-58801-165982
> Email: blaha at theochem.tuwien.ac.at WWW: http://info.tuwien.ac.at/theochem/
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--
Professor Laurence Marks
Department of Materials Science and Engineering
Northwestern University
www.numis.northwestern.edu 1-847-491-3996
"Research is to see what everybody else has seen, and to think what
nobody else has thought"
Albert Szent-Gyorgi
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