[Pw_forum] The stability of monolayer compound
paulatto at sissa.it
Wed Apr 29 12:00:27 CEST 2009
In data 29 aprile 2009 alle ore 03:31:44, 程迎春 <yccheng.nju at gmail.com>
> 1, Is it possible to get the mono layered compounds( AlN, BC2N, GaN,
Dear 程迎春, this mailing list is not intended for scientific discussion,
but for technical assistance regarding Quantum-espresso; often some
scientific notions are involved in the discussions, but only accidentally.
Furthermore, there is little chance you will get a good answer to such a
specific question frm this mailing list, although it may happen that some
of ther readers have specific knowledge on your topic.
Personally, I have no idea if it's possible.
> 2, From the theoretical interests, how to study the stability of mono
> layered compounds by first-principles calculation?
This is a more pertinent question!
You can do a calculation for the material in the bulk configuration first,
in order to obtain the equilibrium cell parameters and atomic positions.
Then you can carve out a single layer in the same way you do for graphene,
extending the cell along the direction perpendicular to the plane (usually
z) until the periodic images don't interact anymore (the total energy
At this point there are several stability tests you can do:
1. how high is the energy of an isolated plane compared to a plane in the
bulk, i.e how much does the inter-layer bonds contribute to total energy?
2. does the plane structure reform spontaneously if you perturb breaking
3. phonons can be somehow linked to structural stability, I don't know the
details, but you can find lot of literature on this argument
4. ... whatever you can think of, use graphene as a reference of something
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