[Wien] Problems in convergence due to application of mBj potential
Luis Carlos Ogando Dacal
ogando at ieav.cta.br
Thu Aug 30 15:34:21 CEST 2012
Dear Prof. Blaha,
Actually, in the MRS1a-mBJ calculation I used a case.struct
previously relaxed with MSCE-PBE. My intention was just to compare the
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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