First-principles study of heat transport properties of graphene nanoribbons

We combine density-functional theory and the nonequilibrium Green's function method to study the thermal conductance of graphene nanoribbons with armchair and zigzag edges. Zigzag ribbons have higher thermal conductance than armchair ribbons of comparable widths due to an anisotropy in phonon dispersion for graphene nanoribbons: low-frequency bands in zigzag ribbons are more dispersive than those in armchair ribbons. The edges with and without hydrogen-passivation modify the atomic structure and ultimately influence the phonon thermal transport differently for the two ribbon types.