Multiple surface plasmon polaritons mediated near-field radiative heat transfer between graphene/vacuum multilayers

Modulating the photon tunneling probability is the key to control the near-field radiative heat transfer (NFRHT) between two objects. It has been found that multiple body-vacuum interfaces can enable plentiful resonance modes which significantly amplify photon tunneling probability. In the present paper we demonstrate that a graphene/vacuum multilayers can support coupled multiple surface plasmon polaritons (MSPPs), not only enhancing but also suppressing the photon tunneling, hence the NFRHT. We demonstrate that, due to the plentiful symmetric and anti-symmetric branches produced by the coupling of MSPPs, enhancement of NFRHT is most prominent as the middle gap is comparable to the separation distance. Moreover, by adjusting the separation distances, number of layers and chemical potentials, several interesting phenomena are observed in the multilayers, hence providing more possibilities to modulate NFRHT. We find that the optimized enhancement of heat transfer exhibits a 1/d dependency, which means that compared to the bulk system, the decline of NFRHT in the multilayers versus gap width is delayed. This phenomenon has never been noted in a graphene or graphene-based system before. With a large separation distance, the enhanced heat transfer of multilayer over single layer is weak, even vanishes. As the separation distance is far below the gap width, the multilayer system reveals an apparent suppressed of heat transfer. While this suppression effect can be switched into enhancement one by adjusting the chemical potential to a large value. Physical mechanism behind the above findings is understood in detail by analyzing the photon tunneling probabilities and reflection coefficients. This work can be instructive for both experimental design and fabrication of thermal radiation devices based on graphene.