[lammps-users] Thermal interface

Hello users,

I am working on CNT - Silicon interface using Tersoff potential for all atomic interactions. In the following code, Cold and hot are two regions at the center of CNT and silicon. I am using Periodic boundary conditions in X direction which is the axis of CNT. The coordinates of all atoms are read from an input file. I had defined the masses as 12 & 28 for both of them. The NVT part of the code was working well the average temp of 300K at the end of it. But when i move the system to NVE and start adding & removing heat, the average temperature of the system is increasing upto 600K. I don’t know why this is happening even though the total energy is constant.

1-d Structure

units metal
dimension 3
boundary p s s

atom_style atomic

pair_style tersoff

read_data coordinates.txt

pair_coeff * * SiC.tersoff C Si

velocity all create 300 873586443 dist gaussian

fix 1 all nvt 300.0 300.0 0.5 drag 0.4

#output of varaibles
timestep 0.001

thermo 1000
run 40000

unfix 1

fix 4 all nve

fix 7 cold heat 1 0.5
fix 8 hot heat 1 -0.5

timestep 0.0005

run 500000


It looks like you are measuring the temperature just by
thermo output of "temp", which is averaged across all atoms.
Probably not what you want. I would define computes
that measure the temperatue of non-heat atoms.