Strange result for 1.0 K Graphene simulation

Dear All,

I am doing the simulation for graphene in free space using NVT ensemble. I tried to do one width to test my result first before I do the simulation for the larger size. I ran the simulation at 1 K (very low temperature). I applied the periodic boundary condition in y-direction (in my attachment picture), so I assume the length of my graphene will be infinity. I expected for this only 1 K temperature, the graphene will still remain like the initial condition (no change). But the thing happen is my tiny graphene bend in this very low temperature (please take a look in my attachment picture). So, Is there anything wrong in my simulation? Why is that seems not stable even I applied the PBC? Is there any suggestion for this case?

Thanks for your advance,


Here my Lammps input code:

atom_style atomic

read_data data.zigzag1

mass 1 12.01

timestep 0.00005

pair_style tersoff
pair_coeff * * SiC_Erhart-Albe.tersoff C

neighbor 4.0 bin
neigh_modify every 1 delay 0 check yes

thermo_style custom step temp pe etotal press vol
thermo 1


What does it do when you run NVE, or minimize it?