Graphene sheet curling up

I am simulating a graphene sheet sandwiched between Al alloy particles using the following code.

dimension 3
units metal
boundary p p p
atom_style atomic
atom_modify map array
comm_modify cutoff 5.25

variable sixth equal “1/6”

variable twothirds equal “2/3”

variable alattice equal “2.4595”

variable a1lattice equal “1”

variable a2lattice equal “1.73203”

lattice custom {alattice} a1 {a1lattice} 0 0 a2 0 {a2lattice} 0 basis 0 0 0 basis 0.5 {sixth} 0 basis 0.5 0.5 0 basis 0 ${twothirds} 0

variable boxside equal 200

variable xside equal “round(v_boxside/v_a1lattice/v_alattice/2)” #round ensures that we get complete unit cells

variable yside equal “round(v_boxside/v_a2lattice/v_alattice/2)”

region box block -{xside} {xside} -{yside} {yside} -3 3 units lattice

region graphene block -{xside} {xside} -{yside} {yside} 0 0.1 units lattice

create_box 4 box

create_atoms 4 region graphene

mass * 12.011

The issue is that when I increase the temperature of the system, the graphene sheets curl up, as shown in pic1. I expected them to look like in pic2 after the alloy melts.

Any suggestion is highly appreciated.

Have a look at your post. Is it properly formatted? Does it look exactly like your input??

It doesn’t, right? So please study the forum guidelines post and learn how to properly format quoted text.

That said, what you are asking for is not a LAMMPS issue but a question of how you set up and perform your simulation and that makes it a topic for discussion with your adviser or somebody else that knows and cares about your research. On top of that, the behavior of compound materials crucially depends on the force field used for each component and how they interact. If you get different behavior, then most likely your settings are different than in the simulation that created PIC2. You don’t provide that information (for either simulation) so there is not much to say, and - again - this would be a discussion of the science and not a topic for a forum discussion the software.