[Pw_forum] electrical polarization calculations for non-collinear magnetism

[Xun-Wang Yan]

Dear Gabriele Sclauzero,
    Thanks for your reply,
 the electric polarization calculation for noncolinear magnetism is not
available for espresso-4.0.4 version, which can be found from the code
'bp_c_phase.f90'.
  For this calculation , the nelec bands(in my calculation,87 bands) should
be  dealt with.
I found the 'nscf' calculation is finished, and next step to calculate
electric polarization with berry phase method is not implemented,
i.e.the running process stop at the code 'bp_c_phase.f90' .
In bp_c_phase.f90, the  nspin=1 and nspin=2 cases is supported,   there is
not  noncolin=.true.  case.
how to modify the bp_c_phase.f90 to include the noncolin=.true. case for
electric polarization calculation?
your suggestion and comment are expected.

Bests

Xun-Wang

2009/3/27 Gabriele Sclauzero <sclauzer at sissa.it>

>
> Xun-Wang Yan wrote:
> > &system
> >    ibrav=14,
> >    celldm(1)=9.73748132, celldm(2)=1.155067564,celldm(3)=1.000000,
> >    celldm(4)=-0.144291712,celldm(5)=-0.500000,celldm(6)=0.288583423,
> >    nat=12, ntyp=5,
> >    ecutwfc=30, ecutrho=300,
> >    report=10,
> >    occupations='fixed',degauss=0.00,
> >    noncolin=.true.
> >    starting_magnetization(2)=0.5
> >    angle1(2)=90.0
> >    angle2(2)=0.0
> >    starting_magnetization(3)=0.5
> >    angle1(3)=90.0
> >    angle2(3)=120.0
> >    starting_magnetization(4)=0.5
> >    angle1(4)=90.0
> >    angle2(4)=-120.0
> >    nbnd=87
>
>
>
> >
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> >      task #         3
> >      from c_phase : error #         1
> >      Polarization only for insulators and no empty bands
> >
>  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> >
> > I look over 'bp_c_phase.f90' , and find that electrical polarization
> > calculation is applicable for nspin=1 and nspin=2.
>
> I don't know if this calculation is available for noncolinear calculation,
> but if you pay
> attention to the error message, what it says is different. You need to deal
> with an
> insulator (and you are) and you must compute only nelec bands, i.e. NOT
> adding extra bands
> through the nbnd keyword, as you're doing.
> Retry after removing the nbnd line.
>
> GS
>
>
> > I want to know to how to modify the bp_c_phase.f90 to implement the
> > electrical polarization calculation for non-collinear magnetism.
> > Any comments are welcome , many thanks in advance.
> >
> > regards,
> > Xun-wang Yan
> > ========================================
> > Institute of Theoretical Physics, CAS
> > Address: No.55, Zhong-Guan-Cun East Road
> > Beijing, China
> > Email: xwyan at itp.ac.cn
> > <http://sun.itp.ac.cn/src/compose.php?send_to=fjma%40itp.ac.cn>
> >           yanxunwang2008 at gmail.com <mailto:yanxunwang2008 at gmail.com>
> > ===================
> >
> >
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> --
>
>
> o ------------------------------------------------ o
> | Gabriele Sclauzero, PhD Student                  |
> | c/o:   SISSA & CNR-INFM Democritos,              |
> |        via Beirut 2-4, 34014 Trieste (Italy)     |
> | email: sclauzer at sissa.it                         |
> | phone: +39 040 3787 511                          |
> | skype: gurlonotturno                             |
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