Hello again
How to reproduce this structure of NiO if we consider the two atoms of Ni
(up and dn ) as inequivalent.
Here is the structure
NiO structure
http://4.bp.blogspot.com/-EzItbno5RvU/VHi-n_0yT5I/AJk/Hyf7Qhg_3ao/s1600/Antiferro-NiO.png
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Mr: A.Reggad
Laboratoire de Génie
This problem is quite interesting;
You have Ni in a FCC arrangement, so you have Ni tetrahedra, so how can you
place them in an antiferromangnetic order???
It is frustratng!!! Well this is known as geometric frustration, which is a
very interesting field!!!
On the opposite stance immagine a
Thank you Mr Delamora for your reply
First, we can create the structure of Cr with 2 ways:
1- with one atom and bcc lattice (0,0,0) or
2- with two atoms and P lattice (0,0,0) and (.5,.5,.5)
But the second way allows us to do the antiferromagnetic calculation by
flipping the spins of one atom.
Here I make the structures step by step
***
Here you have;
aaa.struct-cub-F
with supercell =
aaa.struct-cub-P
change angles
aaa.struct-89.999
with initialize calc and x sgroup =
aaa.struct-rho
with supercell =
aaa.struct-hex
with supercell =
You are confused, the Cr structure is B, and you can easily separate the up and
dn, while the NiO is F and there you have a clear frustration.
In what I have just sent the problem is not as simple.
De: wien-boun...@zeus.theochem.tuwien.ac.at
Answering your question of NiO with a P lattice;
If you take a P structure with 4 Ni and 4 O then you can flip two Ni atoms and
you have an antiferro in the 100 direction, which is not the one that you sent
in the figure
In my earlier message you can see the antiferro ordering in the 111.
Both
Hi Fabien,
Thanks for your reply and suggestions. I went with RKmax up to 12Ry
and it turned out that 11 and 12 should be okay, since the splitting
starts to oscillate (change in the increasing trend with increased
RKmax). Concerning the non smooth behavior of the curve I did several
test
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