Reproducing AuCu phase diagram & other questions

Alloy Theoretic Automated Toolkit (ATAT)
1

Hi
I’ve been trying to learn how to use the ATAT by reproducing the AuCu phase diagram seen in the articles. I’ve run into some trouble with reproducing some of the phase boundaries. What’s the input/method of finding the boundaries marked with red in the attached AuCu phase diagram? I’ve tried different inputs for the phb to no avail. I’m thinking I’m supposed to find the starting values for phb from the emc2 calculations, but I don’t really see it from the output I’ve gotten so far.
[attachment deleted]

Secondly, I’ve tried producing a phase diagram between GaAs in zincblende structure and Bi in a hexagonal structure. What I did was make a clusterexpansion for zincblende Ga-AsBi ( with As and Bi completely in one fcc sublattice ) and a AsBi clusterexpansion for the hexagonal structure. I then used phb for the ground states of pure GaAs for the zincblende structure and pure Bi for the hexagonal structure. What I got from it is represented in the second attachment(calculation is still ongoing, so it’s not finished). Is what I did sensible? Would there have been an easier/more proper way to do the phase diagram between zincblende GaAs and hexagonal Bi?

2

Regarding Cu-Au, you can start a phb run from 0K with ground states 1 and 2. Let it run until it stops when the disordered phase appear. Then run phb from that same temperature and chemical potential, once for ground states 1 and -1 (disordered state) and once with ground state -1and 2.

Regarding your second question, it looks like problem with more than one compoditional degree of freedom, so phb is not the right tool. You need to use memc2, which can give you free energies via thermodynamic integration. You would then need to compute common tangents yourself.

A new alternstive is to use sqs2tdb which builds a Calphad model using SQSs. This is more approximate but slot quicker. Read the doc and see if you like this way.

3

Thank you, I’ll try those things.