[Wien] Calulating optical property with spin-orbit coupling

[Peter Blaha]

Most likely your problems are due to the old WIEN2k version where such
a procedure was not implemented.

In my current version I think I do NOT need to change anything in the code.


> Well, I guess I've just fixed the problem by recovering a few lines
> which were commented out originally in lapw2.F,  describing that in the
> case of including SO, just artificially increase the number of electrons
> twice (elecn=elecn*2.0d0, around line 207 in lapw2.F) then estimate the
> Fermi level, and then recover the number of electrons to the original
> value. After modifying the code that way, lapw2 estimates the Fermi
> level correctly with -SO flag, and the resultant optical spectra also
> seems correct. Do you have any comment about this?
> 
>  
> 
> Chang-Youn 
> 
>  
> 
>   _____  
> 
> From: wien-bounces at zeus.theochem.tuwien.ac.at
> [mailto:wien-bounces at zeus.theochem.tuwien.ac.at] On Behalf Of Moon,
> Chang-Youn
> Sent: Tuesday, September 27, 2005 3:30 PM
> To: wien at zeus.theochem.tuwien.ac.at
> Subject: [Wien] Calulating optical property with spin-orbit coupling
> 
>  
> 
> Dear users,
> 
>  
> 
> I'm trying to calculate the optical property of an semiconductor
> material, and I'm following the user's guide for non-spin polarized
> calculation with spin-orbit (SO)  interaction (page 127). When I didn't
> include the SO switch, the resultant optical spectra ( the imaginary
> part of dielectric matrix) seemed to be reasonable, but when I did
> include the SO, the spectra seemed to be very strange. I guess it
> resulted from the erroneous estimation of Fermi level in executing lapw2
> with -fermi and -so switch to generate weight files. When SO is
> included, the number of band becomes doubled because in this case the
> spin-up and spin-down states merge. Then, the number of occupied band
> should be also doubled, but I found that the lapw2 execution with -fermi
> and -so switch also just gave me the same number of occupied band with
> the case without -so switch,  and hence giving erroneously low value of
> Fermi level. I tried to fix this problem by goring through the source
> codes, but I couldn't. Do you think this is definitely a bug of the
> program, or I did something wrong? I attach the first few lines (for one
> k-point) of 'case.weight' files with (case.weight1) and without
> (case.weight2) -SO flag in executing lapw2 with -fermi flag. You'll see
> the evident error in determining the Fermi level in the latter case
> comparing to the former one.  I'm using wien2k version 3 released on
> 18/01/2003.
> 
>  
> 
> Thanks,
> 
>  
> 
> Chang-Youn Moon
> 
> National Renewable Energy Laboratory
> 
>  
> 
> 


                                      P.Blaha
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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/
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