Single layer and Bilayer Graphene Thermal Conductivity

I currently investigating the thermal conductivity of single-layer and bilayer graphene using the Green-Kubo formulation. Turns out, that the simulation result state that single-layer graphene has smaller thermal conductivity than the bilayer. But in some references, single-layer graphene should have a bigger conductivity than the bilayer.

BLG: average conductivity: 35.6204113146072[W/mK] @ 300 K, 0.048845290288972 /A^3
SLG: average conductivity: 27.3376297284215[W/mK] @ 300 K, 0.0282603883307204 /A^3

I’ve made sure these two systems have the same length and width of cells, only different in thickness. Any suggestion to validate this issue? Here I attracted the simulation input file and the structure. I appreciate your answer, thank you!

  1. LAMMPS input file
  2. SLG structure
  3. BLG structure

What you are asking about is not really a question about LAMMPS but about the validity of your research. That is a topic for discussions with your adviser/colleagues and not so much for the forum here.
Even if it was not off-topic, this kind of inquiry is unlikely to prompt any response as it would require significant effort to reproduce, validate, and review your results. That is effectively what you are supposed to do :wink:.

There are many things that can impact the validity of your results. For example, there is always the question how much of it is “ballistic”, i.e. transported by momentum transfer of the atoms and how much is “electronic”, i.e. due to the electron mobility. With classical MD you are only modelling the first part. Another item to look into is whether your results are sufficiently well statistically converged. With that in mind, it is rarely a good idea to quote results with all digits of precision that are computed, but rather you should determine how far they are statistically converged and round accordingly.