The thermal conductivity of hybrid graphene-graphane nanoribbons (GGNRs) have been investigated using nonequilibrium molecular dynamics simulations. The interface between graphene and graphane leads to a Kapitza resistance with strongly dependence on the imposed heat flux direction. We introduce GGNRs as promising thermal rectifiers at room temperature. By calculating phonon spectra, underlying mechanisms were investigated.

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The thermal conductance of straight and corrugated monocrystalline silicon nanowires has been measured between 0.3 K and 5 K. It is demonstrated that the corrugation strongly reduces the thermal transport by reducing the mean free path of the phonons. The experimental averaged mean free path is remarkably smaller than the smaller diameter of the nanowire, evidencing a phonon thermal transport reduced below the Casimir limit. Monte Carlo simulations highlight that this effect can be attributed to significant multiple scattering of ballistic phonons occuring on the corrugated surfaces. This result suggests an original approach to transforming a monocrystalline material into a phonon glass.

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