[Wien] Optics with spin-orbit interaction

[Peter Blaha]

> 	I am trying to calculate optical properties of a ferromagnetic
> system using WIEN2k_03 (Release 18/01/2003). I start with Fe as a test
> case. When I do calculation without SO, the Epsilon_2 spectra for up-spin
> and down-spin are different.
>
> 	However when I include SO, both *.outputjointup and
> *.outputjointdn are exactly the same. I am getting the same plasma
> frequency for up and down-spin. I will try to describe the procedure that
> I followed:
>
> 1. I did the calculations upto self-consistency.
> 2. Incresed the k-mesh.
> 3. Replaced TOT by FERMI in the 1st line and TETRA by ROOT in 3rd line
>    of *.in2c
> 4. runsp_lapw -so -s lapw1 -e lcore ; to get FERMI weights
> 5. x opticc -so (-up/-dn) and
> 6. x joint (-up/-dn)
>
> 	I believe that the above-mentioned procedure is correct. I am
> unable to understand why I am getting same spectra for up and down spins.
> Herewith I have attached *.inso, *.inop and *.injoint files. Could you
> kindly look into those files and tell me why I am getting the
> same Epsilon_2 spectra for both spin channels?

Spin-orbit couples spin-up and down! Thus each single eigenstate has a
mixture of spin-up and dn. When calculating the matrixelements, also
"crossterms" occur and a strict seperation of up and dn is no longer
possible. Thus when calculating "-so -up" the -up (or -dn) just tells the code
that the calculation is spinpolarized, but otherwise it calculates
the total epsilon.

Regards
                                      P.Blaha
--------------------------------------------------------------------------
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
--------------------------------------------------------------------------