Segregation-Polycrystal-workflow/HEA MCMD.lmp at main · Jingbei-Bai/Segregation-Polycrystal-workflow · GitHub

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# Hybrid MC/MD relaxation of a CoCrFeMnNi polycrystal at 300 K
# MD is performed in the NPT ensemble, and multiple atom-swap MC moves are
# inserted during the trajectory to enhance chemical equilibration.

units           metal
atom_style      atomic
boundary        p p p
read_data       after_mc.lmp

# Thermodynamic conditions
variable        temp    equal 300.0
variable        press   equal 0.0
variable        seed    equal 12345
variable        n_swap  equal 100

# Interatomic potential
pair_style      meam
pair_coeff      * * library.meam Co Ni Cr Fe Mn CoNiCrFeMn.meam Co Ni Cr Fe Mn

# Initial minimization and velocity assignment
minimize        0 1.0e-8 1000 1000
reset_timestep  0
velocity        all create ${temp} ${seed} mom yes rot no

# MD: anisotropic NPT relaxation for the polycrystal
fix             npt_relax all npt temp ${temp} ${temp} 0.1 aniso ${press} ${press} 1.0

# MC: pairwise atom swaps among all five species
fix             sw12 all atom/swap 50 ${n_swap} 10001 ${temp} types 1 2
fix             sw13 all atom/swap 50 ${n_swap} 10002 ${temp} types 1 3
fix             sw14 all atom/swap 50 ${n_swap} 10003 ${temp} types 1 4
fix             sw15 all atom/swap 50 ${n_swap} 10004 ${temp} types 1 5
fix             sw23 all atom/swap 50 ${n_swap} 10005 ${temp} types 2 3
fix             sw24 all atom/swap 50 ${n_swap} 10006 ${temp} types 2 4
fix             sw25 all atom/swap 50 ${n_swap} 10007 ${temp} types 2 5
fix             sw34 all atom/swap 50 ${n_swap} 10008 ${temp} types 3 4
fix             sw35 all atom/swap 50 ${n_swap} 10009 ${temp} types 3 5
fix             sw45 all atom/swap 50 ${n_swap} 10010 ${temp} types 4 5

# Output
thermo          100
thermo_style    custom step temp pe press vol lx ly lz
dump            traj all custom 500 hea_hybrid_relaxation.lammpstrj id type x y z

# Run the hybrid MC/MD simulation
timestep        0.001
run             500000

# Save the relaxed structure
write_data      hea_hybrid_relaxed_300K.data

# Example run command:
# mpiexec -np 4 lmp -in in.lmp -pk omp 4 -sf omp