Should the oriatation of the cell be like hexagonal lattices

[saray1360]

Dear all,

I have got abit mixed up by the way different articles make supercells. As an example the below article:

http://arxiv.org/PS_cache/cond-mat/pdf/0511/0511274v3.pdf

for making the super cell for the single layer ZnO:

1. How should we make the unit cell?
2. How amny atoms should we consider there in a unit cell? (should it be more than two atoms: 1-zn and 1-O necessarilly, why?)
3. Should the oriatation of the cell be like hexagonal lattices (90 90 120) or we should change it to a cubic one? (90 90 90)


Regards,
Sara

 

[Modey3]

Hello,

It all depends on what you want to calculate, but a supercell should be chosen with calculation time in mind. For simple lattice parameter and band structure structure calculations, try to use the smallest supercell as possible; i.e. minimize the number of atoms in your supercell. If you are planning on doing ab-initio molecular-dynamics you will want to keep the number of atoms as small as possible because calculation time scales with the number of atoms.

 

[charng]

I would like to provide some clarification on the orientation of the cell for creating supercells. The orientation of the cell can be either hexagonal or cubic, depending on the specific material being studied. In the case of ZnO, which is a hexagonal crystal, it would be appropriate to use a hexagonal lattice for the supercell. This is because the lattice parameters of the supercell should match those of the original crystal in order to accurately represent its properties.

Regarding the unit cell, it is important to consider the number of atoms in order to accurately represent the crystal structure. In the case of ZnO, the unit cell should have at least two atoms (1-Zn and 1-O) to represent the basic repeating unit of the crystal. However, depending on the specific properties being studied, it may be necessary to include more atoms in the unit cell.

I hope this helps clarify any confusion about creating supercells for ZnO or other materials. It is important to carefully consider the crystal structure and properties when determining the orientation and size of the unit cell for creating accurate supercells. Thank you for bringing up this important topic for discussion.