Mismatch in thermal conductivity of Nickel


I am using Non Equilibrium Molecular Dynamics + Two Temperature Model to find out the thermal conductivity of Nickel nanowire (specifically) that has been deposited around a Carbon Nanotube. I have divided both, Nickel and carbon into 100 grids along the length and have imposed separate Langevin thermostats for each material on the ends, 350 K and 250 K respectively. To get the temperature gradient along the length, I am observing the temperature of the grids in the central region. However, the temperature outputs (for Nickel) of the command “fix ave/chunk” and “fix ttm” are significantly different from each other. There is a mismatch in the MD output and TTM output for Nickel temperatures and therefore, the thermal conductivity obtained from these two methods differs. Should they not be the same once the steady state has been reached?

I have attached the input script. The command fix “ttm” has been included as “mttm”.

Lammps version: 26 Jan 2017


Input_Script_Combined.txt (4.66 KB)