Near-field radiative thermal modulation enabled by static magnetic fields

Abstract

We propose a thermal modulation structure composed of two identical graphene-coated NaBr plates separated by a nanoscale vacuum gap (d). A static magnetic field perpendicular to the graphene sheet induces TE–TM hydrid surface plasmon polaritons between graphene and vacuum gap (called the hybrid GSPPs) and enhances the coupling of the hybrid surface plasmon polaritons in graphene to the surface phonon polaritons in the reststrahlen band of NaBr (called the coupled SPh–SPPs). The hybrid GSPPs and coupled SPh–SPPs play a key role in the thermal modulation. The heat flux is modulated by changing the static magnetic field, the Fermi level (EF) and carrier mobility (μ) in graphene. When the magnetic field varies from 0 to 30 T, the modulation contrast as high as 3.42, 3.25 and 4.48 is acquired at (d, EF, μ)=(60.64 nm, 0.2 eV, 1000 cm2/V · s), (100 nm, 0.21 eV, 1000 cm2/V · s) and (100 nm, 0.2 eV, 2500 cm2/V · s), respectively. The work opens new routes to magnetically modulate near-field radiative heat flux in graphene-based structures, and provides some guidance for applications in thermal management of nano/microscaled devices.