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I am calculating the electronic structure of a crystal ABC4, which has 4A atoms, 4B atoms and 32C atoms. The C atoms have 1/2 site occupancy.

Does anybody know how to deal with partial site occupancy?

Some previous posts suggested to build a supercell and remove atoms to account for the 1/2 occupancy. However, in my case there are many possibilities for that.

How can one determine how big the supercell needs to be and which atoms to remove?

Thanks.

Hi Lilia,

supercells are the only way. Typically I would double the unit cell in one direction and remove half of the C atoms.
If there are many possibilities, you need to calculate them all. However, you might omit the nonsense stuff, like full occupation in half the unit cell.

Cheers,

alex

Hi

You should use special quasirandom structures. It will allow you to (1) consider the 1/2 site occupancy and (2) avoid having to build several different supercells for the configuration averaging.

Cheers