Random Alloy

[Hesam]

Hello

I was wondering if I can create random alloys like InGaAs in ATK?

Thanks

[zh]

At the current stage, it is not possible, because the methods such as virtual crystal approximation and coherent-potential-approximation are not implemented in ATK.

[Hesam]

Thanks but what about totally random alloy model? I mean putting the atoms randomly in case of alloy (i.e. putting Indium or Gallium randomly in In(x)Ga(1-x)As).

[Nordland]

Yes this can be done however the challenge is to figure out how In(x)Ga(1-x)As looks like.

[Hesam]

Thanks, could you explain how?

There is an option to replace a selected atom in a crystal to any atom. If there be a way to loop over all cations and based on a random number select the cation would be Indium or Gallium (comparing random number to x), then we can create In(x)Ga(1-x)As easily.

[zh]

Even in such way, it is difficult to make sure that the created structures make sense. The random alloys do not have an ordered structure. To have statistical sampling, you may have to calculate huge candidate structures for  given x and supercell size.  You may refer to "http://prb.aps.org/abstract/PRB/v82/i2/e024203". In a word, it is unfeasible to create a reliable structure of random alloy by replacing the atoms randomly and simply.

[Shinji Usui]

Dear Hesam

If you want to create a completely random structure of alloy, Packmol (http://www.ime.unicamp.br/~martinez/packmol/) will be a good tool to try.

BR
Shinji