Lattice thermal conductivity of bilayer graphene

A model for the calculation of lattice thermal conductivity (LTC) of a bilayer graphene is developed considering the explicit contributions from in-plane and out-of-plane phonons and their dispersive nature. Numerical calculations of LTC are presented for 10phonons to be scattered by sample boundaries, impurities and other phonons via umklapp process. At low temperatures, the flexural acoustic phonon contribution is found to be dominant, whereas at higher temperatures longitudinal and transverse acoustic phonons become important; the contribution from flexural optical phonons is negligible over entire temperature range. Our results are found to be in good agreement with available experimental data. A single linear-acoustic-phonon-branch dispersion approximation is found to underestimate (overestimate) LTC at low (high) temperatures.