Which potential is more reasonable for predicting the crack of graphene during nanoindentation

Dear all,

Recently I have used different potentials to simulate the nanoindentation of monolayer graphene. The dump files were visualized using Ovito. When using Tersoff potential (SiC.tersoff), we can obviously observe the crack in the graphene when the indent depth is about 2 nm (similar with the result of Nano letters 2014, 14:7145-7152), but not any cracks when the indentor depth is up to 4 nm when using airebo potential (CH.airebo, pair_style airebo 2.5 0 0). But if I modify rcmin_CC from 1.7 to 2.0 in CH.airebo, crack can be predicted when the indent depth is about 2 nm. I doubt which potential shall be used in our simulations.

Another question is that when we use the following sentences to output the Load as a function of indentor displacement,

These are Qs for the literature and your model, not really LAMMPS Qs.