We present a theory for the lattice thermal conductivity ${\kappa }_L$ of multilayer graphene (MLG) and graphite, which is based on an exact numerical solution of the Boltzmann equation for phonons. Dominant contributions to ${\kappa }_L$ from out-of-plane or flexural phonons are found, which is consistent with previous findings for single-layer graphene (SLG). However, the interaction between graphene layers in MLG and graphite breaks a selection rule on phonon-phonon scattering, causing their ${\kappa }_L$s to be much lower than that of SLG. ${\mathrm{C}}^{13}$ isotopes are shown to be an important scattering mechanism, accounting for an ∼15% additional drop in the ${\kappa }_L$ of these systems. We demonstrate that the ${\kappa }_L$ values converge to that of graphite after only about five layers, a consequence of weak interlayer coupling. These findings are qualitatively consistent with recent measurements of ${\kappa }_L$ for MLG.

• Received 25 May 2011

DOI:https://doi.org/10.1103/PhysRevB.83.235428