[Wien] Slab symmetry with SOC

[Peter Blaha]

For a spin-polarized case you should use init_so and the program 
symmetso.  Symmetso should give you the proper symmetries and one should 
use the struct file produced by symmetso. There should be a 
classification of each of the symmetry operations of the non-so case 
according to A, B or none.

I can hardly comment on a specific feature without doing the slab myself.

Please have a look into the lecture notes about spin-orbit coupling and 
the reduction of symmetry due to so (from our web-site). There is a plot 
and table for a small specific example.

Hwoever, note two remarks:   sgroup is completely irrelevant for this 
(as it does not know about spin-orbit).

symmetso is obviously not as much tested as sgroup or symmetry. So be 
sure to use the latest version.
If you have doubts about symmetso, I need the struct file and the 
specific concerns.

On 12/13/2013 10:00 AM, pluto at physics.ucdavis.edu wrote:
> Dear WIEN2k experts,
>
> Unfortunately nobody has commented on my email below.
>
> I believe that in my 15-atom Fe(001) slab, with magnetization along 100
> and SOC included, there will be a mirror 100 plane (space group 6).
> However, I have a feeling that there are more symmetries. For example I
> have a feeling, that there should be an inversion symmetry, or at least
> that the 100 axis should be a two-fold rotation axis. I am not able to
> include these symmetries.
>
> My calculations work well with fully primitive cell, and also with space
> group 6 (actually sgroup rotates the slab, so that mirror plane becomes
> 001, but this of course does not matter). But I think that in every
> problem one should include the necessary symmetries a priori, not only to
> save time, but to avoid some spurious results.
>
> Could you please give me at least some hint? I could also send my slab if
> necessary.
>
> Regards,
> Lukasz
>
>
>
>
>
> On 12/5/2013 10:03 AM, pluto at physics.ucdavis.edu wrote:
>
> Dear WIEN2k experts,
>
> I am calculating 29-atom Fe(001) slab with SOC with easy axis along [100].
>
> Without SOC one can find more symmetries, and one has only 15 inequivalent
> atoms. However, when performing the calculation with such slab the results
> are different compared to the complex calculation with "pure" slab of 29
> atoms. I believe that the correct result in this calculation is that
> surface bands along [100] and [-100] are the same, and bands along [010]
> and [0-10] are different. So one should have 3 slightly different set of
> surface bands: along [100] (identical to [-100]), [010], and [0-10].
>
> Of course on the opposite surfaces of the slab things will have the
> inversion symmetry.
>
> I believe that one of the programs, e.g. symmetso should in principle be
> able to find out, whether the symmetries are correct or not, and produce
> the correct struct file, which is possibly a bit more symmetric than the
> original file.
>
> Please advise.
>
> Regards,
> Lukasz
>
>
>
>
>
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-- 

                                       P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
Email: blaha at theochem.tuwien.ac.at    WWW: 
http://info.tuwien.ac.at/theochem/
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