[Pw_forum] How to calculate magnetization density when SOC is on

[soroush pakseresht]

Dear Andrea and Gabriele,

First, let me thank both of you for your valuable comments and feedbacks.
As suggested by Andrea, I used bands.x with lsigma=.true. . It seems to be
working. Now I can see the results for Mx, My and Mz components of
magnetization. However, something seems to be wrong. The magnetization which
I get for the same band but at k and -k are exactly the same. Due to the
strong spin-orbit coupling, I am expecting that the direction of
magnetization at k becomes opposite to that at -k. Is it due to some
symmetry constraints, which I might have not turned off during the SCF and
NSCF calculations? Any idea?

Looking forward for your response,
Saeed

On Mon, Jan 17, 2011 at 7:55 PM, Andrea Dal Corso <dalcorso at sissa.it> wrote:

>
> On Mon, 2011-01-17 at 11:48 +0100, Gabriele Sclauzero wrote:
> > Hi Soroush
> >
> > On 01/15/2011 02:50 PM, soroush pakseresht wrote:
> > > Hi everybody,
> > >
> > >
> > > Can anybody tell me how I can calculate the magnetization
> > > M=M(Mx,My,Mz) for a system with spin-orbit coupling.
> >
> > Usually the three components of the total non-collinear magnetization
> > are printed at the end of the calculation, e.g.
> >
> >      The total energy is the sum of the following terms:
> >
> >      one-electron contribution =   -90.33299784 Ry
> >      hartree contribution      =    49.63924278 Ry
> >      xc contribution           =   -28.28794844 Ry
> >      ewald contribution        =    -0.25003496 Ry
> >      smearing contrib. (-TS)   =    -0.00000505 Ry
> >
> >      total magnetization       =     0.00     0.00     0.11 Bohr
> > mag/cell
> >      absolute magnetization    =     0.11 Bohr mag/cell
> >
> >
> >
> > > I'd like to know the total value of Mx, My, Mz for each band at a
> > > given kpoint.
> > >
> >
>
> You can use the program bands.x with the flag lsigma=.true. .
> Please check INPUT_BANDS for more info.
>
> HTH
>
> Andrea
>
>
> > What you're asking for is somehow the magnetization carried by the
> > individual KS eigenstates. I think that for this you'll have to modify
> > the PWscf or PostProc code. For instance you could start from pp.x and
> > modify the option plot_num=7 by performing the integral of the
> > resulting spin-density over the whole unit cell (should be the sum
> > over the FFT components, perhaps multiplied by some normalization
> > factor).
> > Maybe it's easier to implement this directly in PWscf. At the moment
> > the code first computes the total spin-density (which is the sum over
> > bands and k-points of the individual KS densities) in sum_band.f90
> > (search for 'domag') and then the magnetization by integrating the
> > components of the spin-density (see compute_magnetization in
> > PW/electrons.f90). You can modify sum_band.f90 by adding a call to a
> > function analogous to compute_magnetization but for each single KS
> > state.
> >
> >
> > HTH
> >
> > GS
> >
> > >
> > >
> > > Thanks
> > >
> > > --
> > > Soroush Pakseresht
> > > Advanced Science Institute (RIKEN)
> > > Saitama-Japan
> > >
> > >
> > >
> > > _______________________________________________
> > > Pw_forum mailing list
> > > Pw_forum at pwscf.org
> > > http://www.democritos.it/mailman/listinfo/pw_forum
> > >
> >
> >
> > --
> >
> > Gabriele Sclauzero, EPFL SB ITP CSEA
> > PH H2 462, Station 3, CH-1015 Lausanne
> > _______________________________________________
> > Pw_forum mailing list
> > Pw_forum at pwscf.org
> > http://www.democritos.it/mailman/listinfo/pw_forum
> --
> Andrea Dal Corso                    Tel. 0039-040-3787428
> SISSA, Via Bonomea 265              Fax. 0039-040-3787249
> I-34136 Trieste (Italy)             e-mail: dalcorso at sissa.it
>
>
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>



-- 
Soroush Pakseresht
Advanced Science Institute (RIKEN)
Saitama-Japan
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