chemical potential in the emc2 code

Alloy Theoretic Automated Toolkit (ATAT)
1

Hi everyone,

I have a problem using the emc2 code when I try to produce the free energy surface as a function of temperature and composition, as in Figure 5.4 in the user manual. The command is

emc2 -gs=4 -mu0=1.5 -mu1=1.5 -dmu=0.04 -T0=300 …

I guess my question is how can I know a good initial guess of the value mu0? I tried using mu0=1.5 as provided in the manual and it just told me that the chemical potential may not stabilize the ground state that I’m interested in. Any way to figure mu0 out before doing this calculation?

Thanks!

2

the chemical potential (for input) is normalized so that it is an integer at a wo-phase boundary.
So to stabilize your pure A-phase, anything between 0 and 1 should work, for the next phase, start with something between 1 and 2 and so on. Your gs_str.out tells you which phase is which.