I am running a minimization for a cylindrical sample of Fe. I am trying to use a potential in .setfl format. When I minimize the sample it does things such as make the structure different (bcc->hcp) and also adds something that looks like a GB. I checked with another potential for Fe which is in the .eam.alloy format but that doesn’t do any thing weird. I am new to Lammps and would like to know if it is an issue with the command using the .setfl file or is probably an error with the potential file. FeCuNi-with-ZBL.eam.alloy (949.6 KB) FeNiCrCoAl-heaweight.setfl (1.7 MB) witheam_potential.txt (3.2 KB) withsetfl.txt (3.2 KB)
Here is a picture describing how they differ for the same sample (grey is hcp (.setfl) and black is bcc):
Technically speaking, all EAM potentials contain the same kind of information, just in different formatting and the difference between the pair styles is just in the functions that read the potential files.
Thus any difference in behavior has to have its origin in the potential files themselves and for that you have to look at the providence of the individual potentials, i.e. look up the publications describing them and specifically looking up for which use case they were parameterized.
Here is one potential problem: both your potential files are for alloys. This does not automatically mean that they produce good results for the pure element. Also, the FeCuNi potential seems to include some ZBL potential derived modification. You have to very carefully check how you have to use that.
Considering that the NIST interatomic potentials database currently holds 23 potentials for pure Fe, the question arises why you are trying to use those alloy potentials for pure Fe and not a potential for pure Fe.
The question is more a question of “are you using a suitable potential file?”.
Thanks for the response. I wanted to simulate a system with multiple elements, but Fe was doing something weird in that system. As a trial to understand what the error was, I was trying various potentials to compare pure Fe. It turns out that fcc Fe stabilizes with this potential, not bcc. Thanks!
