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

[Gabriele Sclauzero]

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.

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
>
>
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>    


-- 

Gabriele Sclauzero, EPFL SB ITP CSEA
PH H2 462, Station 3, CH-1015 Lausanne

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