Graphene-based enhancement of near-field radiative-heat-transfer rectification

We present a thermal device based on the near-field interaction between two\nsubstrates made of a polar and a metal-insulator-transition material. As a\nresult of the temperature dependence of the optical properties, this device\nacts as a thermal rectifier, implying a strong asymmetry in the heat flux when\nreversing the two temperatures. By covering both substrates with a graphene\nsheet we show a significant enhancement of rectification coefficient. By\ninvestigating the flux spectral properties along with its distance dependence,\nwe prove that this enhancement is associated to a change in the power-law\ndependence of heat flux with respect to the separation distance in the\nelectrostatic regime due to the presence of graphene sheets. Our results\nhighlight the promising role of graphene-based hybrid structures in the domain\nof nanoscale thermal management.\n