[Pw_forum] DFT+U and non-collinear calculations

[Alex Smogunov]

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>:

> 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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