Magnetic field control of near-field radiative heat transfer and the realization of highly tunable hyperbolic thermal emitters

Abstract

We present a comprehensive theoretical study of the magnetic field dependence of the near-field radiative heat transfer (NFRHT) between two parallel plates. We show that when the plates are made of doped semiconductors, the near-field thermal radiation can be severely affected by the application of a static magnetic field. We find that irrespective of its direction, the presence of a magnetic field reduces the radiative heat conductance, and dramatic reductions up to 700% can be found with fields of about 6 T at room temperature. We show that this striking behavior is due to the fact that the magnetic field radically changes the nature of the NFRHT. The field not only affects the electromagnetic surface waves (both plasmons and phonon polaritons) that normally dominate the near-field radiation in doped semiconductors, but it also induces hyperbolic modes that progressively dominate the heat transfer as the field increases. In particular, we show that when the field is perpendicular to the plates, the semiconductors become ideal hyperbolic near-field emitters. More importantly, by changing the magnetic field, the system can be continuously tuned from a situation where the surface waves dominate the heat transfer to a situation where hyperbolic modes completely govern the near-field thermal radiation. We show that this high tunability can be achieved with accessible magnetic fields and very common materials like n-doped InSb or Si. Our study paves the way for an active control of NFRHT and it opens the possibility to study unique hyperbolic thermal emitters without the need to resort to complicated metamaterials.

Nonreciprocal radiative heat transfer between two planar bodies

“…Ref. 39 considered near-field heat transfer between two planar structures incorporating magneto-optical materials, but did not specifically address whether the observed effect is a manifestation of nonreciprocity.…”

Near-Field Heat Transfer between Multilayer Hyperbolic Metamaterials

“…In addition, the possibility of having larger conduction by thermal radiation inside an HM than conduction by phonons and electrons has been discussed [56] as well as the thermodynamical potentials, the general laws of thermal radiation inside HM [57] and the coherence properties in the vicinity of HM [58]. Recently, also tunable hyperbolic thermal emitters have been introduced [59], and it was proposed to make the use of the hyperbolic 2D plasmons in graphene ribbons for elevated near-field heat fluxes [60].…”

Photon Thermal Hall Effect

“…1. When a magnetic field is applied in the direction parallel to the z-axis, the permittivity tensor of InSb particles takes the following form [16,17]…”