Extremely large thermal magnetoresistance and magnetic-field-driven transport-regime transition in macroscopic magneto-optical many-body systems

Controlling near-field heat transport is crucial for the development of alternative energy applications. In recent years, the application of an external magnetic field to actively control noncontact heat transport has emerged as a highly appealing technique, and some exotic subwavelength-scale thermomagnetic phenomena have been predicted, especially in magneto-optical (MO) dipole systems. Here, we report two additional near-field thermomagnetic effects that can occur in macroscopic planar MO many-body systems. First, we predict an extremely large thermal magnetoresistance for nanoscale heat transport in a simple MO configuration comprising several interacting $\mathrm{In}\mathrm{Sb}$ planar slabs. It is found that the thermal resistance at room temperature can be substantially increased up to the order of 10 000% with a relatively strong magnetic field. We elucidate that this striking variation benefits from the multibody planar architecture, which allows us to transform an effective energy tunneling arising from zero-field cavity surface modes into a feeble tunneling mediated by field-induced hyperbolic modes. We also show the possibility of reducing the required field through structural optimization. Subsequently, we predict a magnetic-field-driven transition between superdiffusive and ballistic transport by further examining the radiative transport regime in a periodic $\mathrm{In}\mathrm{Sb}$ many-slab configuration under the action of external fields. This peculiar transition is associated with a field-induced alteration in the polarization of the dominant modes of transport. Our predicted thermomagnetic effects not only enrich the community of many-body energy transport but also provide guidelines for the development of advanced thermal management of elegant MO multibody architectures.