[Pw_forum] Stacking AB Bilayer

[Ari P Seitsonen]

Dear Mohssine El Bachra,

   How about trying different values...? :)  QE does not get broken even if 
you fail to give it the correct coordinates right away. ;)

   Namely, it is more rewarding and useful if you figure out those 
coordinates yourself, as this is still a "trivial" case. A good test, 
beyond the rough visual inspection, is to check if you reach the expected 
symmetry in the new geometry. For some reason, probably because you wanted 
it that way, the system below is not exactly planar. Sometimes in such 
layered systems it is also more useful to centre the coordinates around z 
= 0 (or z = c/2), as it is easier for the code to find symmetries that 
might involve operations that couple coordinates at z and -z (inversion, 
mirror, rotations, ...).

     Greetings from Paris,

        apsi

-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
   Ari Paavo Seitsonen / Ari.P.Seitsonen at iki.fi / http://www.iki.fi/~apsi/
     Ecole Normale Supérieure (ENS), Département de Chimie, Paris
     Mobile (F) : +33 789 37 24 25    (CH) : +41 79 71 90 935


On Sat, 6 Feb 2016, Mohssine El Bachra wrote:

> Dear All
> How to build a stacking AB configuration ( the atomic positions) ?
> the positions that i have used for stacking AA are : 
> 
> C       0.666666600   0.333333300   0.009596479
> C       0.333333300   0.666666600   0.066303521
> C       0.666666600   0.333333300   0.238196479
> C       0.333333300   0.666666600   0.294903521
> 
> I want to get a stack like the one in the picture.
> 
> thank you for your help,
> 
> -----------------------------------------------------------
> 
> Mohssine El Bachra
> Lab of Magnetism and Physics of Height Energy (LMPHE)
> Phd Student Faculty of Science Rabat
> Morocco
> 
> 
>