Dear all,
I have calculated necessary parameters including elastic constants, specific heat, equilibrium lattice constants, cohesive energies, migration and formation energies of defects and ... using DFT method for a binary alloy. Now I need to produce an EAM/alloy format file to be used in my MD simulations. Can anyone introduce me to a tool to do this task?
Any recommendation is appreciated. Thanks
To make a long story short, it is a very hard task to develop a potential. I would suggest to try the already developped potentials. You can see if there is a potential for your alloy e.g. at the NIST Interatomic Potentials repository. Then You need to check if necessary parameters are reproduced well or not (compared to the DFT results).
If there is no potential or the parameters You need are reproduced not accurate enough, You would have to develop the potential. There are several approaches of obtaing interatomic potentials: force-matching, stress-matching, semi-emperical ways etc. I could recomend a free open-source force-matching code PotFit ( potfit.net ), maybe there are open codes for other methods too.
It is not so easy to develop an empirical potential. The core task is to minimize a multicompone function. To produce a group of parameters that well describe the properties of the system of intererest, sometimes, you have to specfy a series of inital values of the paramters, since the fitting possiby only finds the local minima of the function. In this case, the physical intuition is important.
To make a long story short, it is a very hard task to develop a potential. I would suggest to try the already developped potentials. You can see if there is a potential for your alloy e.g. at the NIST Interatomic Potentials repository. Then You need to check if necessary parameters are reproduced well or not (compared to the DFT results).
If there is no potential or the parameters You need are reproduced not accurate enough, You would have to develop the potential. There are several approaches of obtaing interatomic potentials: force-matching, stress-matching, semi-emperical ways etc. I could recomend a free open-source force-matching code PotFit ( potfit.net ), maybe there are open codes for other methods too.
To generate EAM potential you can use the following FORTRAN code available at below mentioned link. For only following elements EAM potentials can generated using the Zhou's potential: Cu, Ag, Au, Ni, Pd, Pt, Al, Pb, Fe, Mo, Ta, W, Mg, Co, Ti, Zr.
https://github.com/CFDEMproject/LAMMPS/tree/master/tools/eam_database
LAMMPS can be used to perform MD simulations and calculate the properties from EAM potential.
http://lammps.sandia.gov/doc/pair_eam.html
https://sites.google.com/site/eampotentials/
Dear Afshin,
Depending on the alloy that you want to study and the properties that you are interested in, this paper about Fe-Cr alloys could be useful for you.
A. Caro, D. A. Crowson, and M. Caro. Classical Many-Body Potential for Concentrated Alloys and the Inversion of Order in Iron-Chromium Alloys. Phys Rev Lett 95, 075702 (2005)
Later, following those ideas we developed an EAM interatomic potential for the Li-Pb alloy, with emphasis in the properties of the liquid phase.
A. Fraile, S.Cuesta-López, D. Schwen, A. Caro and J.M. Perlado. Interatomic potential for the compound-forming Li-Pb liquid alloy. Journal of Nuclear Materials 448, 1-3, (2014)
Best regards
Alberto
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