[Wien] (no subject)

[K.V.P.Lata]

Thankyou very much for the suggestions. I tried both, but didn't get
the structure I was hoping
to get. Second one seemed simpler. About the second option, where I
generate two bulk slabs, one for Fe and one for MgO,
I have some questions.

1. I first generated the Fe struct input, then used the supercell
program to introduce vacuum
towards the bottom of the Fe slab. In this, for simplicity I used 3
cells along only z-direction,
and the vacuum needs to be introduced after the third one
(bottommost). I want to attach the MgO
slab in the vacuum. You had written that the vaccuum needs to be big
enough to accommodate
the MgO slab. I do not know how to control *from* which point *to*
which point the vaccuum is needed.
In other words I imagine that I want all Fe atoms arranged till some
value of 'z' and the rest of the cell
should be vaccuum, of same size as MgO whcih I will attach later. But
whatever I use for the magnitude of
vaccuum (only along z), it is pushed towards the end of the slab and
vaccuum is introduced only in the last layer !
I dont know what mistake I am doing.

Could you tell me what is the 'repeat atoms' for and what is the
problem in the abov eprocedure ? Also, I am facing a problem
in shifting the atoms. Since my entire Fe slab is ~ 8 Angstroms along
z, with (0,0,0) at the top of the slab,
I want to shift the MgO slab by this amount. I use the optional shift.
If the lattice constant of MgO ~ 4.12
Angstroms, then whatever shift I input as fractional coordinates, the
MgO block is getting cut. I thought
I am shifting the origin along the Z-axis, but that doesnt seem to be happening.

Eagerly waiting for your response,

Best,
Krish