Thanks for your reply!
But now I need to calculate the potential value of a point in space generated by an atom with net charge under three-dimensional periodic boundary, according to your reply, it can’t be calculated by LAMMPS?
Your description of what you want to compute and is too vague (and a bit confusing) to give a specific answer.
But I have explained the situation sufficiently. Please read up on the theory and understand why the total coulomb energy of a periodic system with a non-neutral unit cell must be infinity. Then you can draw your own conclusions.
Axel.