[Wien] Problems in convergence due to application of mBj potential
Luis Carlos Ogando Dacal
ogando at ieav.cta.br
Wed Aug 29 19:03:44 CEST 2012
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)
>>>>
>>>>
>>>
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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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