I am working on Ti coating on top of diamond layer to figure out how the diamond in-plane thermal conductivity changes as the Ti coating thickness is changed. I am using LAMMPS for my NEMD simulation.
Now, my understanding was that the heat will go from source side to the sink side. As Ti is bonded to C, during this heat progression, Ti atoms will also be affected as heat is travelling from source of the diamond to the sink of the diamond. Kindly, keep in mind that, I did not define source and sink region in the Ti since electron is the main carrier in Ti, it will not be feasible.
My guess was since Ti is metallic, applying Ti coating on diamond will increase the in-plane thermal conductivity value. But I am getting completely opposite result. As Ti thickness is increased, in-plane thermal conductivity gradually decreased. Why is that?
Which forcefield are you actually using? Is it taking electron transport into account? And how well is it supposed to reproduce thermal conductivity of both diamond and titanium?
Also, are you sure your simulations are long enough so that you are in a stationary state? Which algorithm are you using for your heat sink/source? What are your periodic boundary conditions? NEMD is tricky in general so it is important to do the sanitary checks and provide more details if you want a insightful answer.
