[Pw_forum] DFT+U and non-collinear calculations

[Alex Smogunov]

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>:

> 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>>:
> >
> >     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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> >
> >
> >
> >
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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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