doping atoms using Monte Carlo Method

Dear Lammps Experts,

I am new to lammps and for doping Zr-atoms in a Cu-bicrystal sample, I have tried using “SET” command to replace certain fraction of Cu atoms and then applying “fix atom/swap” command for the MC part. Are there any alternate ways to dope Zr in Cu-bicrystal sample??

The reason I am asking this is that the paper I am trying to follow explains the procedure in a different way. According to it, “The bicrystal sample was relaxed at different temperatures (between 600 to 1200K). Thereafter, doping with Zr solutes was simulated using a Monte Carlo method in a variance-constrained semi grand canonical ensemble after every 100 molecular dynamics steps, with target global composition of Zr fixed to different values that increases in small increments.”

If I want to follow the above procedure, could you please let me know which commands should I look for. Any piece of information would be appreciated. Please, let me know if you need any further information regarding this.

Thank you.