  We examine thermal transport in graphene supported on SiO2 using molecular
dynamics simulations. Coupling to the substrate reduces the thermal
conductivity (TC) of supported graphene by an order of magnitude, due to
damping of the flexural acoustic (ZA) phonons. However, increasing the strength
of the graphene-substrate interaction enhances the TC of supported graphene,
contrary to expectations. The enhancement is due to the coupling of graphene ZA
modes to the substrate Rayleigh waves, which linearizes the dispersion and
increases the group velocity of the hybridized modes. These findings suggest
that the TC of two-dimensional supported graphene is tunable through surface
interactions, providing a novel possibility for controlled energy flow in
nanomaterials.
