# Stacking fault energy calculation

Dear all,

I am trying to create stacking fault using LAMMPS. The orientation of the system is [-2 1 1] [1 1 1] [0 1 -1] along x,y and z axes respectively and divided the simulation box into top and bottom regions. Now the top region is displaced relative to the bottom region in steps of 0.1A^ in order to get the stacking fault and get the energy of the system after each displacement to calculate the Stacking Fault Energy (SFE). For the system with free surface along y axis and periodic along x and z axis (PSP) the calculated stacking fault energy using the above method for displacement of b (magnitude of Shockley partial burgers vector) is 44mJ/m^2 ( reported value of SFE for Cu) . But for the system with periodic boundary conditions along all three directions (PPP), I have the following problem:

1. The diplacement of atoms by ‘b’ corresponds to the unstable position and 1.5b corresponds to stable position.
2. The SFE is 1416mJ/m^2 (very high) , for the displacement of 1.5 b.

Please help me to solve the problem.

Please find the attached LAMMPS script.

With regards,
Kamalakshi

in.stackingF1 (2.23 KB)

This doesn’t seem like a problem for the LAMMPS mailing list. You should discuss this with your advisor and colleagues.

One general comment: when you have PBC by shifting the top layer you are essentially creating two stacking faults – make sure these two are identical.

Ray