How can I compute the phase boundaries between ground states of two different parent lattices, i.e. coming from two cluster expansion of differing lat.in?
If it is a binary alloy, you can use phb. Use the -d1= and -d2= options to specify the directories where the two cluster expansions (CE) reside. Make sure that both cluster expansions use the same references energies.
On way to ensure this, is to copy the ref_energy.out of one CE into a ref_energy.in file for the other CE and rerun maps there.
Let me know if you need the way to proceed for multicomponent alloys.
So I would have three sublattices in my case, of which one sublattice is hosting 2 different atomic species. I guess in this case I might need the procedure for multicomponent alloys.
Actually, this is a "pseudo-binary", so phb should work.
I assume the ref energies are for the two end members. If these are two different parent lattices, say bcc and fcc, how can they have the same end member energies?
The reference energy is what is subtracted from the actual energies (this is just for convenience - to avoid the large atomic energy from showing up in the answer). The actual energies of the end members on the two lattices still differ, it’s just that make sure the code subtract the same quanityt from each of them.
For simplicity, the reference energies can just be 0.
Got it. They should adhere to the same reference points to make proper comparison.