[lammps-users] possible bug in tersoff potentials?

Dear support, I perform a simulation that couple cluster of gold and sheet of graphene.
The pair style are described by the following lammps command
pair_style hybrid tersoff eam lj/cut/opt 8.768
pair_coeff * * tersoff SiC.tersoff NULL C
pair_coeff 1 1 eam Au_u3.eam
pair_coeff 1 2 lj/cut/opt 0.022 2.74 8.768

I move the atoms by nve without thermostat, however I found that the energy is not conserved. If I set up the lj coeff as follow
pair_coeff 1 2 lj/cut/opt 0.0 0.0 0.0
and the I move only the gold atoms the energy is conserverd. Howerve if I perform the same operation with the graphene atoms the energy is not conserved. Why?

Best regard

Nicola

gold_graphite.tar.gz (3.97 MB)