Polarization-independent nonreciprocal radiation in polar dielectric-Weyl semimetal planar heterostructure

Abstract

The polarization-independent nonreciprocal radiation is highly demanded for controlling light-matter interactions in tailoring and enhancing radiative heat transfer. An obvious violation of Kirchhoff’s law and strong nonreciprocity (η) has been achieved in a form of heterostructure composed of polar dielectric, Weyl semimetals (WSMs) and silver (Ag) substrate. By manipulating the structural parameters, a remarkable result of nonreciprocal radiation is realized under both transverse electric (TE) and transverse magnetic (TM) wave incidence. The peak value of η is 0.53 and 0.37 for TM and TE polarizations, respectively, at the resonance wavelength of 8.7 μm. By changing the azimuthal angle of incidence, η spectra can be effectively manipulated. The distribution map of η is symmetrical with ϕ=90°, and η=0 for both TM and TE polarizations. Our results provide a much simpler way to prove the violation of Kirchhoff’s law and could lead to the advancement of high efficiency nonreciprocal thermal radiation.