[Pw_forum] IFCs and Difference between unit cell and supercell
giannozz at democritos.it
Fri Oct 19 17:40:03 CEST 2012
On Thu, 2012-10-18 at 16:50 -0400, Jingjie Zhang wrote:
> The structure is FCC with two atoms. [,,,] the a1, a2, a3 are
> conventional cell vectors or the primitive cell vectors?
they are primitive cell vectors for the fcc lattice.
> When I use supercell: simple cubic with 8 atoms to build silicon
> structure, the omega is different at gamma point with the omega from
> the structure with FCC.
in order to get exactly the same number, you have to use either
a converged grid of k-points, or exactly the same k-points.
> And the thing most confuse me is that the point group is different
> in this structure: 43m. Can anyone explain why this happen please?
can you explain what you mean? what is different from what exactly?
Paolo Giannozzi, IOM-Democritos and University of Udine, Italy
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