Coupled surface plasmon/phonon polaritons and hyperbolic modes are known toenhance radiative transport across nanometer vacuum gaps but usually requireidentical materials. It becomes crucial to achieve strong near-field energytransfer between dissimilar materials for applications like near-fieldthermophotovoltaic and thermal rectification. In this work, we theoreticallydemonstrate extraordinary near-field radiative transport between ananostructured metamaterial emitter and a graphene-covered planar receiver.Strong near-field coupling with two orders of magnitude enhancement in thespectral heat flux is achieved at the gap distance of 20 nm. By carefullyselecting the graphene chemical potential and doping levels of silicon nanoholeemitter and silicon plate receiver, the total near-field radiative heat fluxcan reach about 500 times higher than the far-field blackbody limit between 400K and 300 K. The physical mechanisms are elucidated by the near-field surfaceplasmon coupling with fluctuational electrodynamics and dispersion relations.The effects of graphene chemical potential, emitter and receiver doping levels,and vacuum gap distance on the near-field coupling and radiative transfer areanalyzed in detail.
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