[Pw_forum] DFT+U and non-collinear calculations
Pietro Bonfa'
pietro.bonfa at fis.unipr.it
Wed Apr 30 17:30:27 CEST 2014
Dear Prof. Giannozzi,
thanks for this very precious information. I'll try and see if I succeed
in a reasonable amount of time. I'll eventually report back on the results.
Kind regards,
Pietro Bonfa'
On 04/30/2014 05:01 PM, Paolo Giannozzi wrote:
> On Wed, 2014-04-30 at 11:41 +0200, Pietro Bonfa' wrote:
>
>> So this looks like a bug in the 5.1rc1 version. I'll try to figure out
>> why this happens with the help of diffs files.
>
> this is not going to be simple, because I made extensive changes to the
> implementation of DFT+U in order to speed it up. There is no test for
> the DFT+U case with noncolinear magnetization, so problems may go
> unnoticed for a long time (thank you for noticing it). If you are
> willing to dig into the code: the problem apparently arises after
> rev. 10181,
> http://qe-forge.org/gf/project/q-e/scmsvn/?action=browse&path=%
> 2F&view=rev&revision=10181
>
> Paolo
>
>> Thanks for your help,
>> kind regards,
>> Pietro Bonfa'
>>
>>
>> On 04/30/2014 11:00 AM, Alex Smogunov wrote:
>>> Dear Pietro.
>>> I have tried your input with QE 5.0, it works fine for me, try it.
>>> The problem could also arrise from diagonalization method though it is
>>> strange...
>>> Try to set diagonalization = 'cg'.
>>> good luck,
>>> Alexander
>>>
>>>
>>>
>>> 2014-04-29 17:18 GMT+02:00 Pietro Bonfa' <pietro.bonfa at fis.unipr.it
>>> <mailto:pietro.bonfa at fis.unipr.it>>:
>>>
>>> Dear Dr. Alexander Smogunov,
>>>
>>> the short digression on the non-linear core corrections was intended to
>>> explain why I need DFT+U to correctly reproduce the insulating and
>>> magnetic ground state of La2CuO4.
>>>
>>> I attached a modified version of example 11 (that I called example12).
>>> I set all the parameters to zero just to check if everything is working
>>> properly. I tried also with realistic values for U and J but I obtained
>>> the same errors.
>>>
>>> Thanks,
>>> kind regards,
>>> Pietro Bonfa'
>>>
>>>
>>>
>>> On 04/29/2014 04:13 PM, Alex Smogunov wrote:
>>> > Dear Pietro.
>>> > It should work, in principle, at least for US PPs ... even though
>>> > I do not understand what is the relation between non-linear core
>>> > corrections and
>>> > the need for DFT+U together with spin-orbit, moreover you set up
>>> all the
>>> > parameters
>>> > essentially to zero. Anyway the code should run even in this case.
>>> Could
>>> > you provide the complete
>>> > input file, please?
>>> > regards,
>>> > Alexander
>>> >
>>> >
>>> >
>>> > 2014-04-28 10:52 GMT+02:00 Pietro Bonfa'
>>> <pietro.bonfa at fis.unipr.it <mailto:pietro.bonfa at fis.unipr.it>
>>> > <mailto:pietro.bonfa at fis.unipr.it
>>> <mailto:pietro.bonfa at fis.unipr.it>>>:
>>> >
>>> > Dear All,
>>> >
>>> > I would like to compare the total energies of various
>>> non-collinear
>>> > magnetic configurations in La2CuO4 (LCO).
>>> >
>>> > I started working with pseudopotentials from the PSLibrary,
>>> the GBRV
>>> > library and some home brewed norm conserving Cu pseudos. After
>>> a short
>>> > analysis I realized that the experimentally observed
>>> insulating and
>>> > antiferromagnetic ground state is obtained only if I remove
>>> non-linear
>>> > core corrections. This holds true for both my NC pseudos and
>>> the Cu
>>> > pseudo from PSL 1.0.0 (I didn't try GBRV).
>>> >
>>> > Nonetheless, since studying the magnetic ground state of LCO
>>> without
>>> > using non-linear core corrections does not make much sense to
>>> me, I
>>> > tried DFT+U with noncolin and lspinorb flags set to true.
>>> >
>>> > More precisely, I added the following lines to example 11 in the
>>> > QE-5.1rc1 release
>>> >
>>> > lda_plus_u=.true.
>>> > lda_plus_u_kind=1
>>> > Hubbard_U(1)=1.d-10
>>> > Hubbard_J(1,1)=1.d-10
>>> > Hubbard_J(2,1)=0.0
>>> >
>>> > Depending on the pseudopotential type (PAW, US or NC) I get
>>> errors like:
>>> >
>>> > from cdiaghg : error # 19
>>> > eigenvectors failed to converge
>>> > or
>>> > from cdiaghg : error # 109
>>> > S matrix not positive definite
>>> >
>>> > So my question is: is lda+u and non-collinear magnetism still not
>>> > implemented, is this a bug or me doing something utterly wrong?
>>> >
>>> > Thanks,
>>> > kind regards,
>>> > Pietro Bonfa'
>>> >
>>> > --
>>> > Pietro Bonfa' - PhD student
>>> > Dipartimento di Fisica e Scienze della Terra "Macedonio Melloni"
>>> > Viale delle Scienze 7A
>>> > 43124 Parma - Italy
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>>>
>>> --
>>> Pietro Bonfa' - PhD student
>>> Dipartimento di Fisica e Scienze della Terra "Macedonio Melloni"
>>> Viale delle Scienze 7A
>>> 43124 Parma - Italy
>>>
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>>
>>
>
--
Pietro Bonfa' - PhD student
Dipartimento di Fisica e Scienze della Terra "Macedonio Melloni"
Viale delle Scienze 7A
43124 Parma - Italy
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