[Wien] external magnetic field using orb with spin-orbit interaction

[Peter Blaha]

Ups. Sorry. I was not sure what you really calculated.

If you do plain GaAs (I somehow thought about magnetic impurities in 
GaAs), the starting with runsp_c_lapw is perfectly fine.

On 9/29/20 1:13 PM, Mikhail Nestoklon wrote:
> Thank you for the comments.
> This is option 4 of orb package "Interaction with the external magnetic 
> field" mentioned in page 127 of UG around (7.2). So, U=0.
> After your mail I realized that both "case.energysodn" 
> AND "case.energysoup" contain the information I was looking for 
> (splitting of the two- or four-times degenerate states in Gamma-point by 
> the magnetic field) and now do not understand why I thought they should 
> be different. Indeed, no more up and down spins after spin-orbit. Maybe, 
> I was confused by the fact that there are two files in the output.
> Thank you for clarifying this.
> I will try to do the full cycle without runsp_c_lapw at all, maybe there 
> is a difference.
> Sincerely yours,
> Mikhail Nestoklon
> 
>     Вторник, 29 сентября 2020, 13:05 +03:00 от Peter Blaha
>     <pblaha at theochem.tuwien.ac.at>:
>     You miss the physics of spin-orbit interaction.
> 
>     Spin-orbit MIXES spin-up and dn (spin is no longer a good
>     quantumnumber).
> 
>     This means that each eigenvalue will contain contributions of spin-up
>     AND spin-dn. In many cases one spin will dominate, but they can also be
>     completely mixed.
> 
>     Of course, one can still project spin-up and dn out and this is done in
>     WIEN2k.
>     The amount of spin-up and dn for each eigenvalue can be found in the
>     case.norm* files.
> 
>     Regards
> 
>     PS: I don't understand your procedure. When you do runsp_c_lapw, you
>     FORCE spin-up and dn to be the same. Once you have a non-spinpolarized
>     density, it is very hard to get back to a magnetic state (except when
>     the runsp_c scf cycle is not done to full convergence).
> 
>     So how could you find some splitting of spin-up and dn states ???
> 
>     And what U did you use (for which elements/states ??)
> 
>     On 9/29/20 11:47 AM, Mikhail Nestoklon wrote:
>      > Dear wien2k community,
>      > I am trying to estimate the g-factors in
>     bulk semiconducting material.
>      > From the mail list and user guide I learned that orb may be used for
>      > this purpose (as discussed in beginning of this thread [1] and in
>      > section 7.4 of UG).
>      > Using the GaAs as a reference semiconductor I do the following steps
>      > (case.inorb and case.indmc files are more or less the same as in
>     [1]):
>      > $ init_lapw -b -vxc 13 -sp
>      > $ runsp_c_lapw
>      > $ init_so_lapw
>      > $ runsp_lapw -so -orb
>      > In the end of this procedure I indeed see some splitting of
>     spinup and
>      > spindown states in conduction band which corresponds to g-factor
>     about 2
>      > in the files case.energydn and case.energyup. But, as far as I
>      > understand, these results are before lapwso (i.e., without spinorbit
>      > interaction). In particular, for the valence band these numbers are
>      > completely useless. My expectation was that files "case.energysodn"
>      > and "case.energysoup" should have the energies of spinup and spindown
>      > states with spinorbit. However, these files are equivalent (only some
>      > mysterious numbers in first two lines are slightly different).
>      > Am I doing something wrong or some additional steps needed to extract
>      > energies with spin-orbit interaction?
>      > Thank you in advance.
>      > [1]
>     https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg13399.html
>      > Sincerely yours,
>      > Mikhail Nestoklon
>      >
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>     --
> 
>                                             P.Blaha
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                                       P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
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