[CP2K-user] [CP2K:20713] Incorrect Band gaps from simple calculations

[Lucas Lodeiro]

Here you can find detailed information on how to use a correct input for
hybrid functionals in CP2K, particularly there is a detailed input for
HSE06.

https://www.cp2k.org/_media/events:2018_summer_school:cp2k-uk-stfc-june-2018-sanliang-ling.pdf
https://github.com/cp2k/cp2k/tree/master/tests/QS/regtest-hfx-wfn-fitting

Regards - Lucas

El jue, 12 sept 2024 a las 14:33, Thomas Kasel (<tomkasel at gmail.com>)
escribió:

> I will admit I am new to CP2K and used a lot of setting I found online in
> various powerpoints.
> I am trying to call the HSE06 functional.
>
> Regards,
> Tom
> On Thursday, September 12, 2024 at 11:54:59 AM UTC-5 Lucas Lodeiro wrote:
>
>> Hi
>>
>> there are many weird things from my point of view.
>> the main ones are:
>> *CUTOFF of 600 eV (44 Ry), which is less than the used RELCUTOFF of 60
>> Ry... you must use N times the RELCUTOFF for the CUTOFF.
>> *small cell without kpoints... you must use supercell (4x4x4 for example)
>> or kpoint mesh to properly get the electronic structure.
>> *your functional definition does not make sense to me... which functional
>> form are you pointing out?
>> *why add all virtual orbitals? it is not useful at all, and very
>> expensive.
>>
>> Regards - Lucas
>>
>>
>> El jue, 12 sept 2024 a las 12:48, Thomas Kasel (<tomk... at gmail.com>)
>> escribió:
>>
>>> The original files are in the first posting. But I suppose those are no
>>> longer relevant. I have attached my input,  basis set, and pseudopotential
>>> for silicon. Thank you for all your help.
>>>
>>> Cheers,
>>> Tom
>>>
>>> On Thursday, September 12, 2024 at 2:56:57 AM UTC-5 Jürg Hutter wrote:
>>>
>>>> Hi
>>>>
>>>> Obviously, you have a serious problem in your (secrete) input.
>>>> Without further information it is impossible to help.
>>>>
>>>> regards
>>>> JH
>>>>
>>>> ________________________________________
>>>> From: cp... at googlegroups.com <cp... at googlegroups.com> on behalf of
>>>> Thomas Kasel <tomk... at gmail.com>
>>>> Sent: Wednesday, September 11, 2024 10:34 PM
>>>> To: cp2k
>>>> Subject: Re: [CP2K:20694] Incorrect Band gaps from simple calculations
>>>>
>>>> I managed to find a way to print the HOMO - LUMO gap from the pdos. The
>>>> only problem now is that for some reason I get a band gap of 85 eV for
>>>> silicon when using a hybrid functional.
>>>>
>>>> On Tuesday, September 10, 2024 at 1:54:25 PM UTC-5 Thomas Kasel wrote:
>>>> Thanks to your suggestions I managed to get the SCF to converge for PBE
>>>> based upon playing with the mixing. The only problem is now that CP2K is
>>>> not printing the HOMO-LUMO gap. Is there a setting I can specify to force
>>>> print the gap?
>>>>
>>>> Regards,
>>>> Tom
>>>>
>>>> On Tuesday, September 10, 2024 at 4:45:21 AM UTC-5 Jürg Hutter wrote:
>>>> Hi
>>>>
>>>> For silicon: if you are using the unit cell (with 2 atoms) you need a
>>>> large number of k-points.
>>>> In this case SCF needs diagonalization and an appropriate mixing
>>>> scheme. I would also add smearing
>>>> of occupation numbers. If you have this working, you can start
>>>> investigating basis sets for convergence.
>>>>
>>>> For graphene: The problem is the Dirac cone at the K special point.
>>>> Selecting a matching cell and k-point
>>>> sampling is mandatory to get correct results. There is ample literature
>>>> addressing this problem.
>>>>
>>>> regards
>>>> JH
>>>>
>>>> ________________________________________
>>>> From: cp... at googlegroups.com <cp... at googlegroups.com> on behalf of
>>>> Thomas Kasel <tomk... at gmail.com>
>>>> Sent: Monday, September 9, 2024 10:50 PM
>>>> To: cp2k
>>>> Subject: [CP2K:20677] Incorrect Band gaps from simple calculations
>>>>
>>>> Hello All,
>>>>
>>>> As a test I am trying to accurately (relatively) reproduce the band
>>>> gaps of silicon and graphene structures using PBE. I have however, run into
>>>> an issue where graphene gives a band gap of 1.2 eV while silicon gives a
>>>> band gap of 0.18 eV, the exact opposite of what one would expect. I would
>>>> like to ask what it is I am doing wrong in my calculations. Attached is a
>>>> zip file containing all my input files including basis set and
>>>> pseudopotentials.
>>>>
>>>> Additionally, I cannot seem to get the SCF to converge unless I
>>>> specify:
>>>>
>>>> &OT
>>>> PRECONDITIONER FULL_ALL
>>>> MINIMIZER CG
>>>> &END OT
>>>>
>>>> Why is this setting so critical to SCF convergence in these cases?
>>>>
>>>> Cheers and thanks in advance,
>>>> Tom
>>>>
>>>> --
>>>> You received this message because you are subscribed to the Google
>>>> Groups "cp2k" group.
>>>> To unsubscribe from this group and stop receiving emails from it, send
>>>> an email to cp2k+uns... at googlegroups.com<mailto:
>>>> cp2k+uns... at googlegroups.com>.
>>>> To view this discussion on the web visit
>>>> https://groups.google.com/d/msgid/cp2k/cf2a1d8d-c40c-4da4-9857-38cd2b7e7e91n%40googlegroups.com
>>>> <
>>>> https://groups.google.com/d/msgid/cp2k/cf2a1d8d-c40c-4da4-9857-38cd2b7e7e91n%40googlegroups.com?utm_medium=email&utm_source=footer>.
>>>>
>>>>
>>>> --
>>>> You received this message because you are subscribed to the Google
>>>> Groups "cp2k" group.
>>>> To unsubscribe from this group and stop receiving emails from it, send
>>>> an email to cp2k+uns... at googlegroups.com<mailto:
>>>> cp2k+uns... at googlegroups.com>.
>>>> To view this discussion on the web visit
>>>> https://groups.google.com/d/msgid/cp2k/519f408c-fb0c-4c48-9a70-a36fbdc02f23n%40googlegroups.com
>>>> <
>>>> https://groups.google.com/d/msgid/cp2k/519f408c-fb0c-4c48-9a70-a36fbdc02f23n%40googlegroups.com?utm_medium=email&utm_source=footer>.
>>>>
>>>>
>>> --
>>> You received this message because you are subscribed to the Google
>>> Groups "cp2k" group.
>>>
>> To unsubscribe from this group and stop receiving emails from it, send an
>>> email to cp2k+uns... at googlegroups.com.
>>> To view this discussion on the web visit
>>> https://groups.google.com/d/msgid/cp2k/d83110d8-d806-4b3c-b35e-c3050ad192b1n%40googlegroups.com
>>> <https://groups.google.com/d/msgid/cp2k/d83110d8-d806-4b3c-b35e-c3050ad192b1n%40googlegroups.com?utm_medium=email&utm_source=footer>
>>> .
>>>
>> --
> You received this message because you are subscribed to the Google Groups
> "cp2k" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to cp2k+unsubscribe at googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/cp2k/ca98c3ff-4af2-4797-822a-085d9e89c007n%40googlegroups.com
> <https://groups.google.com/d/msgid/cp2k/ca98c3ff-4af2-4797-822a-085d9e89c007n%40googlegroups.com?utm_medium=email&utm_source=footer>
> .
>

-- 
You received this message because you are subscribed to the Google Groups "cp2k" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cp2k+unsubscribe at googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/cp2k/CAOFT4PJo1dXQaRnQ16DzJa0wSwEhgJj_UDcUXtndL6QOr4nEMA%40mail.gmail.com.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20240915/7f73d1d4/attachment-0001.htm>