SO has no inversion symmetry Think about the spin when you apply an inversion.
Ciao Gerhard DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy: "I think the problem, to be quite honest with you, is that you have never actually known what the question is." ==================================== Dr. Gerhard H. Fecher Institut of Inorganic and Analytical Chemistry Johannes Gutenberg - University 55099 Mainz ________________________________________ Von: [email protected] [[email protected]]" im Auftrag von "[email protected] [[email protected]] Gesendet: Freitag, 13. Dezember 2013 18:02 An: [email protected] Betreff: Re: [Wien] Slab symmetry with SOC Dear Prof. Blaha, dear Wien2k users, I attach the most symmetric slab which I was able to produce. I try with 15 atoms in order to save time with testing, later I am planning to do a larger slab. You could see that now the surface normal is <100>, I started with <001>, but sgroup swapped axes -- but this is fine. So now the in-plane magnetization is along <001>, and it's the same as the mirror plane normal axis (becuase the space group is the 6_Pm with the unique c-axis). I believe that my system should have an inversion symmetry even with SOC. And at the same time I believe that the two surface atoms (in this case atom 1 and atom 15) should have their unique positions (they should not be merged into a single position as they would without SOC). I would appreciate the advice on how to make a spin-polarized calculation with SOC on this slab with included inversion symmetry. So far I have a mirror plane, so it would also be ok to only add a 2-fold 180deg rotation around the magnetization axis. Regards, Lukasz On 12/13/2013 11:22 AM, Peter Blaha wrote: > 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, [email protected] 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, [email protected] 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 >> >> >> >> >> >> _______________________________________________ >> Wien mailing list >> [email protected] >> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien >> SEARCH the MAILING-LIST at: http://www.mail-archive.com/[email protected]/index.html -- Dr. Lukasz Plucinski _______________________________________________ Wien mailing list [email protected] http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien SEARCH the MAILING-LIST at: http://www.mail-archive.com/[email protected]/index.html
