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[verstraete@pcpm.ucl.ac.be]

Hi James,

You're absolutely right, even if the wavefunctions are full spinors you 
can always calculate the average of the spin operator and get a spin up 
and spin down value. For the moment this isn't in abinit, but it should be 
fairly easy to add (I had thought about it a while).

I expect (could someone confirm?) that you just need to calculate 
|psi_up|^2 and |psi_down|^2 separately. The sum of the two is 1 by 
normalization, and with the current implementation of SO (perturbation 
theory) the two spinor bits should correspond to spin up and down 
(Xavier?).

This might even already be in the code, when the total orthogonalization 
and normalization is done. The loops over spinor component are always 
innermost after sums over plane waves. You'd just need to output the 
numbers then.

If you keep the numbers for each band and kpoint in a big array, and pass 
it up to scfcv, you can call tetrahedron with the spin weights in 
dos_fractions(:,:,:) and get a DOS weighted accordingly (make a new 
partial_dos_flag value).

cool.

Matthieu



On Tue, 14 Sep 2004, James Raynolds wrote:

> To all,
>
> I need to get a spin-projected density of states for a magnetic system
> including spin-orbit.  With spin-orbit one is forced to use spinor
> wavefunctions (nspinor=2) which mix the spin-up and spin-down components.
> In a magnetic system, however, it is still resonable to compute the
> expectation value of the spin operator to get a spin-projected density of
> states.
>
> Is this possible in abinit as it stands or do I need to write some code of
> my own to get it?
>
> Thanks for any help anyone can give me.
>
> Sincerely,
> Jim Raynolds

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Matthieu Verstraete               mailto:verstraete@pcpm.ucl.ac.be 
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