  Using non-equilibrium molecular dynamics method(NEMD), we have found that the
thermal conductivity of multilayer graphene nanoribbons monotonously decreases
with the increase of the number of layers, such behavior can be attributed to
the phonon resonance effect of out-of-plane phonon modes. The reduction of
thermal conductivity is found to be proportional to the layer size, which is
caused by the increase of phonon resonance. Our results are in agreement with
recent experiment on dimensional evolution of thermal conductivity in few layer
graphene.
