[Wien] Slab convergence -- continuation

[Laurence Marks]

On Sun, Sep 26, 2010 at 11:57 AM, Lukasz Plucinski
<pluto at physics.ucdavis.edu> wrote:
>  Dear Laurence, Prof. Blaha,
>
>
> So far I used default (spin up) for instgen. Do you mean that in case.inst
> file I should use "unpolarized" Au for most atoms in Fe1Au20 slab, and e.g.
> "up" Au only for 2-3 Au atoms near the surface ? (see below for example
> inputs for Au) Or maybe I should use "unpolarized" for all Au atoms ?

Unpolarized for all Au

>
> I understand case.inst only provide the starting configuration ? Is there a
> way to make some Au atoms permanently non-magnetic ?

I don't think so.

>
> In  the meantime I am having problems with getting inversion symmetry in my
> Fe/Au(001) slab. I created the Fe1Au19Fe1 slab with very precise positions.
> I also tried to force the equivalent positions for all but mid-slab Au
> atom... however, sgroup always finds the 99 (P4mm) group. I believe the
> concept of my slab is correct because I was able to reproduce the results of
> Li and Freeman JMMM 75, 201 (1988) for Fe1Au5 slab. I just paste this slab
> below, where theoretical Au bulk lattice constant of 4.11 A was used. I will
> keep working on this, but maybe there is some procedure I should use to get
> the inversion symmetry (to get rid of the complex version of the program).

The structure you sent is P4mm, with only one Fe. This about it, it is
not that hard.
>
> Regards,
> Lukasz

-- 
Laurence Marks
Department of Materials Science and Engineering
MSE Rm 2036 Cook Hall
2220 N Campus Drive
Northwestern University
Evanston, IL 60208, USA
Tel: (847) 491-3996 Fax: (847) 491-7820
email: L-marks at northwestern dot edu
Web: www.numis.northwestern.edu
Chair, Commission on Electron Crystallography of IUCR
www.numis.northwestern.edu/
Electron crystallography is the branch of science that uses electron
scattering and imaging to study the structure of matter.