Tunable magnetic field effects on the near-field radiative heat transfer in planar three-body systems

Recently, the application of an external magnetic field to actively control the near-field radiative heat transfer (NFRHT) has emerged as an appealing and promising technique. Most prior studies have shown that the externally static magnetic field can only reduce the near-field flux transferred between two planar magneto-optical (MO) structures, yet so far the thermomagnetic effect in many-body systems consisting of such structures has not been revealed. Here, we investigate how the presence of an external static magnetic field modifies the nanoscale heat transfer in a MO many-body configuration comprising three noncontact slabs made of $n$-doped InSb. To this end, we first generalize a general Green's function approach for the calculation of the radiative energy transfer in many-body planar geometries composed of materials with complex optical anisotropy. Based on this approach, we show that the presence of a third MO body allows for either the reduction or even the enhancement of the NFRHT between MO slabs by applying external magnetic fields, which depends on the interplay between the zero-field surface waves and propagating hyperbolic modes induced by fields. Our study not only deepens the understanding of the active control of the nanoscale heat transfer via the applied magnetic field, but also paves the way for the magnetic regulation of energy fluxes in complex macroscopic many-body systems.