Dear LAMMPS Users,
I am trying to calculate the interaction between the solid Au and TiO2.
Problem is that I can not find the force field to cover those elements at once.
Is there any other solution to solve this problem? or any other force field which can calculate this system?
The combination of a metal and an oxide is one of the most challenging combinations to model with classical potentials. For an accurate description you would need to be able to represent the changing polarization around the edges and on the surfaces of the oxide and also how the strongly polar oxide polarizes the very polarizable metal (due to its very mobile electrons).
You may have found that with a model like COMB or COMB3 you can model the TiO2 well, and EAM can be used for the Au. Those you can combine in LAMMPS using pair style hybrid, but that would result in an extremely simplified description of the Au - TiO2 interaction (e.g. via a simple LJ interaction) that would completely disregard the polarization of Au due to TiO2.
Thus, if you want a realistic description of that interface you would probably have to use some kind of DFT or other ab initio or semi-empirical method where you model the (valence) electrons explicitly (unlike in a classical model).
Thank you for your thoughtful explanation.
Now I understand what I have done. I just found that the Au and TiO2 are separated and explode when I use universal LJ at openKIM for the simulation.
The interaction I want to simulate is stress and strain propagation through the interface between them. So, based on your explanation, it seems nearly impossible to describe the interaction using the classical method.
Maybe I have to find another way to describe this.
Thank you, have a nice day!