I am running a lammps program to get the phase transition diagram. one for gold and the other for silicon. I am measuring the melting point by investigating the growth of each phase at different temperatures. by this method, I get a rough value of the melting temperature. but I want a precise measure of the melting point. I know I have to "use an order parameter to measure the growth of each phase". So my question is how to do that? should I calculate the potential at the end of each simulation for the different temperatures and plot potential energy vs temperature diagram. or is there a more accurate/effective way to do it? below is the code I used in my simulation for gold"
units metal boundary p p p atom_style atomic variable a equal 4.0782 lattice fcc $a region box block 0 10 0 10 0 10 create_box 2 box create_atoms 1 box region box2 block 0 5 0 10 0 10 set region box2 type 2 group solid type 1 group melt type 2 mass * 196.97 pair_style eam pair_coeff * * Au_u3.eam timestep 0.002 neighbor 0.3 bin neigh_modify delay 0 every 1 check yes thermo 100 thermo_style custom step pe ke etotal temp vol press density atoms dump 1 all custom 500 dump.all id type x y z dump_modify 1 first yes # melt just the 'melt' region first velocity melt create 1000.0 556578 fix 1 melt nvt temp 1000.0 5000.0 0.2 run 10000 unfix 1 # now relax the entire structure to its local minimum min_style cg minimize 1e-4 1e-6 100 1000 run 0 # now you can test which phase melts or grows at a given temperature, e.g. 1500 K velocity all create 1500.0 1234 fix 1 all nvt temp 1500.0 1500.0 0.2 fix 2 all press/berendsen iso 0.0 0.0 1000.0 run 5000