[Wien] How to use wien2k to calculate defect formation energy?

[Stefaan Cottenier]

>     In WIEN2k-FAQ, it said 
> it is usually NOT possible just to double the cells and leave all atoms at their ideal and equivalent positions. This would lead to large multiplicities (e.g. in big supercells even more than 48 atoms could be "equivalent" and of course there is NO SPACEGROUP corresponding to this type of cell, since they all can be reduced by translation symmetry.
> But when we want to calculate the defect formation energy ,we need to calculate the nenergy of defect-free system.
>So how to calculate the defect formation energy with wien2k?
>  
>
Calculate the energy for the defect-free single cell (not supercell),
and multiply it by the ratio between the volumes of the supercell and
the single cell. Just take care of your k-mesh, to have numbers of
comparable accuracy: if the k-mesh for the supercell is b*b*b and that
supercel is n*n*n times the single cell, then a comparable k-mesh for
the single cell is nb*nb*nb.

Stefaan


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