[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

Thanks
Ajit

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.

Steve