Damping factor in 'fix langevin'

I greatly appreciate the help. Reducing the integration timestep
actually solved the problem.

I am trying to reproduce a paper in which by gradually increasing the
velocity of the upper wall we intend to find the critical shear at which
the no slip condition at wall no longer holds and we get pure slip.

I am relatively new to MD and LAMMPS aswell.
I am presently going through the schneider and stoll paper which has
been cited in the LAMMPS manual. Do you have any other suggestion from
where I can get an insight on langevin thermostating.

Thanxx again.