Near-field heat transfer between graphene/hBN multilayers

Abstract

We study the radiative heat transfer between multilayer structures made by a periodic repetition of a graphene sheet and a hexagonal boron nitride (hBN) slab. Surface plasmons in a monolayer graphene can couple with a hyperbolic phonon polaritons in a single hBN film to form hybrid polaritons that can assist photon tunneling. For periodic multilayer graphene/hBN structures, the stacked metallic/dielectric array can give rise to a further effective hyperbolic behavior, in addition to the intrinsic natural hyperbolic behavior of hBN. The effective hyperbolicity can enable more hyperbolic polaritons that enhance the photon tunneling and hence the near-field heat transfer. However, the hybrid polaritons on the surface, i.e. surface plasmon-phonon polaritons, dominate the near-field heat transfer between multilayer structures when the topmost layer is graphene. The effective hyperbolic regions can be well predicted by the effective medium theory (EMT), thought EMT fails to capture the hybrid surface polaritons and results in a heat transfer rate much lower compared to the exact calculation. The chemical potential of the graphene sheets can be tuned through electrical gating and results in an additional modulation of the heat transfer. We found that the near-field heat transfer between multilayer structure does not increase monotonously with the number of layer in the stack, which provides a way to control the heat transfer rate by the number of graphene layers in the multilayer structure. The results may benefit the applications of near-field energy harvesting and radiative cooling based on hybrid polaritons in two-dimensional materials.

Magnetoplasmonic manipulation of nanoscale thermal radiation using twisted graphene gratings

“…The near-field radiative heat transfer has been investigated between two suspended graphene sheets [19,20], two graphene sheets patterned in ribbon arrays [21], graphene disks [22][23][24][25] and multilayer graphene systems [26][27][28][29][30][31][32].…”

Graphene-based thermal repeater

“…Moreover, the amplification is sorely confined near the interface of the substrate, due to the surface characteristics of graphene surface plasmon polaritons (SPPs).The lack of the connecting between the particles and the substrate, and the nature of SPPs both restrict the relay effect.Graphene exhibits intriguing electronic properties including the presence of strongly confined SPPs which can be excited to transport energy in photonic channels [13,14]. This has been exploited for a more efficient RHT between hybrid periodic structures [15] and between nanoparticles [16]. Recently, by using multilayer structures, the RHT between NPs has been shown to be further increased thanks to a resonant coupling between the substrate surface modes and the NPs resonances [17].…”

“…Recently, by using multilayer structures, the RHT between NPs has been shown to be further increased thanks to a resonant coupling between the substrate surface modes and the NPs resonances [17]. In addition, some unique phenomena are observed in multilayered graphene system [15,18,19], and one of the most important features is the multiple SPPs excited by the multilayered graphene. The effect provides the possibility to strengthen the SPPs near the interface of the substrate, in other words, as surface modes, the SPPs can spread further from the interface.…”

Gate-Tunable Near-Field Heat Transfer

“…For the sake of comparison with the ITO and doped Si cases examined previously, we set the vacuum gap thickness to d = 16 nm in order to maintain the same distance between the SiC interfaces for all three examined materials. We model graphene with the Drude model, by first computing its optical conductivity, which connects to permittivity via g (ω) = 1 + iσ/( o ωL g ), while taking into account the temperature dependence of both interband and intraband contributions [35,70]. The charge carrier density N graphene and Fermi level E F are connected via E F = h|v F | πN graphene [33,69], where v F is the Fermi velocity.…”