[Wien] AFM supercell

[Peter Blaha]

Most likely you did some error in setting up the symmetry (crash in dstart because euqivalent atoms not ok or
sym.ops.are not ok,...) or in the arrangement of the magnetic moments (flipping the spin of an "incorrect" atom).

Note: when you try a FM Cr calculation (bcc), the magnetism will disappear (as you observed) since FM
is not stable at all.

Also Cr has a spin density wave, so in some supercells it may happen that you get different moments,....

ROBERTO LUIS IGLESIAS PASTRANA schrieb:
> Dear all
> 
> I'm trying to run an AFM calculation in a 16 atom Cr supercell. I want to have the Cr magnetic moment values 

for reference purposes, in order to compare to other systems of the same size and later larger ones. The normal

bcc unit cell AFM calculation runs fine, following the procedures outlined in the UG, section 4.5.4, and I get

the same magnetic moments for both Cr atoms in the cell but with different signs.
>  I set up a 16 atom supercell and then flip the spins of the Cr atoms in consecutive pairs in case.inst. I 

also tried to flip just the second 8 atoms, unphysical as it may be, and consequently there is a crash in dstart.

When I perform either a runsp_lapw or a runafm_lapw calculation I always get zero, or close to zero magnetic

  moments in all sixteen Cr atoms, as if the system was in a nonmagnetic state. The question is: What else do

I need to do in order to get final magnetic moments with the same absolute values but with alternate different

signs, as for the bcc unit cell? Or am I writing nonsense?
> I'm using WIEN2k_08.3 and running in 8 processors via k-point parallelization.
> 
> Thanks in advance
> 
> Roberto
> 
> ---------------------------------------
> Roberto Iglesias
> Physics Department
> University of Oviedo
> Calvo Sotelo, s/n
> 33007 Oviedo
> SPAIN
> Tel: +34985102898
> Fax: +34985103324
> email: roberto at uniovi.es
> ---------------------------------------
> 
> --------------------------------------
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien

-- 

                                       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/
--------------------------------------------------------------------------