Minus thermal conductivity

Hi all user and developers,

I am simulating a honeycomb structured solid with sutaible LJ parameters which are taken from the literature and I want to observe anisotropic behavior of the thermal conductivity of the material using Green-Kubo. I am getting very accurate results in xy plane but I obtain minus thermal conductivity value for z direction. I think maybe initial configuration of the material can be one of the reasons as it is different than xy plane in that direction. Do you have any idea about this, what can cause minus value for Green-Kubo integral and how to solve it or is there any one who experienced it before? Thanks in advanceā€¦

Tolga AKINER, BSc.

Bogazici University

Mechanical Engineering Department