The ABINIT Users Mailing List ( CLOSED )

[cszakacs@mun.ca]

Hello all,

Recently I started to use Abinit (so I am a very new user), and I was going
trough the examples. They were very useful and I figured out lots of things,
especially when I am dealing with bulk. 

Now, I want to move ahead and I am trying to construct a slab unit cell for a
wurtzite structure (ZnO) in order to build a 3d surface.

I checked already the example 4 (with the Al surface) from the tutorial, but I
still don't understand some things.

My approach is the following, I am starting from the bulk structure to make a
larger so called slab unit cell like this:

acell  2*6.14 9.83
rprim  1.0 0.0 0.0
       -0.5 sqrt(0.75) 0.0
       0.0 0.0 2.0 

#atom type
ntypat 2
znucl 30 8
#def of atoms
natom 8
typat 1 1 2 2
      1 1 2 2

xred 1/3 2/3 0.0
     2/3 1/3 0.5
     1/3 2/3 0.375
     2/3 1/3 0.875
     1/3 2/3 1.375
     2/3 1/3 1.875
     1/3 2/3 2.375
     2/3 1/3 2.875

practically I am puting 2 bulks on the top of eachother. 

But I know that I am wrong because it gives me an error (two of the atoms are
located at the same point)

And even if I change the acell c parameter, let's say I've doubled it, nothing
changes. 
And I am not sure even how the vacuum layer is defined, it should be 
controlled
by the rprim I guess, but what it does, it puts space between the atoms..not
between layers.


Probably I am looking in a totally wrong direction.
Maybe some of
you ar more familiar with surface construction, so I would kindly ask for your
opinion or advice in this matter.

Thank you

Regards,

-- 
Csaba Sz.
Memorial University
Dept. of Chemistry
St. John's, NL