[lammps-users] About fix deposit

Dear Steve,

I modified the input script again with the same notion, and now it indeed works without that error message but with another problem: Warning: Particle deposition was unsuccessful.

I want to simulate a deposition process of carbon atoms deposited on silicon substrate, and following is the content of my input script for your reference. The silicon substrate consists of two atom types, 1 for fixed atoms and 2 for mobile ayoms, type 3 is carbon atoms. There are also some unclear questions for me accompanying this input script. One is whether need I define the lattice configuration for carbon, too? Another is whether need I create carbon atoms for the region of “inserted volume”?

Any advice or comment is highly appreciated.

units metal
boundary s s p

atom_style atomic
lattice diamond 5.43

region box block 0 10 0 20 0 6
create_box 3 box

pair_style tersoff
pair_coeff * * SiC.tersoff Si Si C

neighbor 0.3 bin
neigh_modify delay 5

region substrate block 0 10 0 10 0 6
create_atoms 2 region substrate
group substrate region substrate
region fixed block 0 10 0 1 0 6
group fixed region fixed
set group fixed type 1

region insert block 3 7 15 18 1 5

mass 1 28
mass 2 28
mass 3 12

compute new2d substrate temp

velocity substrate set 0 0 0
fix 1 all nve
fix 2 fixed setforce 0.0 0.0 0.0
fix 3 all deposit 11 3 100 29494 region insert rate -1 units box

timestep 0.001
dump 1 all atom 100 dump.deposit

thermo 100
thermo_modify temp new2d
run 1000

Best regards,

All the lattice command does for fix deposit is define a length
scale. You're not creating atoms on a lattice. If it says
unsucessful deposition, it means it couldn't insert what you
asked without overlaps. Read the doc page for fix deposit
carefully and play with the various parameters.