The virtual crystal approximation will not work well in a case with
active d-electron elements.
You have to use supercells.
Am 08.02.2016 um 14:32 schrieb Farshad Nejadsattari:
Dear Professor Blaha, Wien2k community and experts,
I am working on the compound Al72Ni9Fe19. This system crystallizes
in the space group P63/mmc (No. 194). Two of the Wyckoff sites are
partially occupied by Fe and Ni atoms, I would like to know how to
construct the master input file, (case.struct) for this system since
both atoms occupy the same Wyckoff sites but with different proportions.
I have looked through the mailing list and have not found anything
particular regarding this type of problem. The atomic positions are
given below:
*_Atom_**_Wyckoff Site_ _ (x,y,z)_*
*_
_*
Al(1) 2/a/
(0,0,0)
Al(2) 6/h/
(0.4647,0.9294,0.25)
Al(3) 12/k
/(0.1935,0.3870,0.9392)
0.6786Fe(1)+0.3114Ni(1) 2/d/
(1/3,2/3,3/4)
0.6786Fe(2)+0.3114Ni(2) 6/h/
(0.1256,0.2512,0.25)
As seen above, the iron and nickel atoms occupy the Wyckoff sites
at an approximate 2/1 (Fe/Ni) ratio. Your assistance towards
constructing the case.struct file for this compound is truly appreciated.
With regards,
Farshad Nejadsattari,
PhD candidate in condensed matter physics,
University of Ottawa, Canada
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