Thanks for your replies.
The error is "It is needed to set attributes like q " when I used “Fixed efield” commands which endorses your opinion about AIREBO potential, and it obviously says it is charge-based potential.
For your information, I was told, my professor, to do the simulation with this force field, and somehow I am limited to use this. Otherwise, I have strong reasons to prove that it is not the right FF in my case.
I am not quite sure, but according to some articles which I read about electronic properties of graphene maybe I should use DFT (Density Function Theory) approach in order to determine the electron structure of the lattice and then define an interaction between those and charged particles. ? Now, my question is that how I can implement DFT in lammps?
Of course, I know other codes like GAUSSIAN do this.