Mixing of fcc/bcc and hcp systems

Alloy Theoretic Automated Toolkit (ATAT)
1

Dear Dr. Axel and ATAT users,

I have a clarification to seek on generating SQS/supercells for solutions involving A and B when their respective structures are different.

Suppose I consider LiCl-CeCl3 system where LiCl is fcc and CeCl3 is hcp. In LiCl, Li occupies (0,0,0) and Cl at (1/2,1/2,1/2). In CeCl3, Ce occupies (1/3,2/3,1/4) and Cl occupies (0.3866,0.085,1/4).

Now, I wish to create various random structures for LiCl-CeCl3 system at various mole-fractions of LiCl; x(LiCl)=0.25,0.5 and 0.75 for getting the 0K enthalpy of mixing.

Can anybody suggest on this, if at all this is possible in ATAT…

Thank you
Regards,
Suddhasattwa Ghosh

2

There is no shortcut possible here - you would need to do fcc SQS and hcp SQS over all compositions.
After adding a ideal solution free energy, you would get a reasonable free energy model for the fcc and hcp phases separately. Then it’s standard solution thermodynamics: common tangents etc.