How to find ground state of a solid solution slab structure

Alloy Theoretic Automated Toolkit (ATAT)
1

Dear Axel,

I am new to cluster expansion and ATAT.

I am trying to calculate a solid solution structure (Mn doped CeO2) of a surface. I was just wondering what is the best way to proceed.

I guess it is not Ok to use the clusters obtained from bulk structure to calculate a surface. Is it right?

If that is right, Is ATAT able to help me automate the process of constructing the clusters for a surface? and Do I need to have two sets of clusters, where one set represent bulk-like structure and one set represents surface structure?

Thank you in advance for the help.

Best regards,

Runhong

2

You are right that you cannot use the results of a bulk Cluster expansion for the surface.

You need to setup a unit cell that is a slab geometry.
(The same as if you set up the calculations yourself for a surface, except that you take the smallest possible unit cell along the surface.)

You then run the maps code with the -2d option, which only considers supercel along the surface.

That should be it. But be patient! Slab calcs are much more demanding that the small cell used for bulk calcs.