[lammps-users] HOW TO CALCULATE ELASTIC COEFICIENTS WITH LAMMPS?

hi
i want calculate the elastic coeficients C11 C12, C44 for a semiconductor using lammps, i find papers and books where explain to calculate with the tensor stress and strain.

there are some other method for calculate Elastic coeficients without using stress.

thanks for all in advance.

Perhaps Aidan wants to answer this. He has computed elastic coeffs
with LAMMPS.

Steve

Hola,

The script appended below will generate T=0 elastic constants for an LJ
crystal. In case this gets messed up in transit, I also add it as an
attachment. You can modify it for other crystals and potentials.

Calculating elastic constants at finite temperature using MD is a tricky
business for which there is no simple solution. One way is to apply finite
deformations in the spirit of this script, but sampling the before and after
states in long dynamics runs.

Another way is to run Rahman-Parrinello NPT (coming soon to LAMMPS), measure
the elastic compliance tensor from the strain fluctuations, and invert to
get the elastic constant tensor. This method is formally very pure, but in
practice is notoriously slow to converge.

Aidna

in.elfcclj (16.8 KB)