Length-dependent lattice thermal conductivity of graphene and its macroscopic limit

In this paper, we report a non-equilibrium molecular dynamics study on the length-dependent lattice thermal conductivity of graphene with lengths up to 16 mu m at room temperature. In the molecular dynamics simulations, whether the non-equilibrium systems reach the steady states is rigorously investigated, and the times to reach the steady states are found to drastically increase with the lengths of graphene. From the ballistic to the diffusive regime, the lattice thermal conductivities are explicitly calculated and found to keep increasing in a wide range of lengths with finally showing a converging behavior at 16 mu m. That obtained macroscopic value of the lattice thermal conductivity of graphene is 3200 W/mK. (C) 2013 AIP Publishing LLC.