Polarization-Independent Nonreciprocal Narrowband and Wide-angle Thermal Emission based on Rotated Weyl Semimetals

Nonreciprocal thermal emission significantly boosts energy conversion efficiency by enabling independent control over emissivity and absorptivity. Most existing nonreciprocal thermal emitters are limited to a single polarization, whereas realizing polarization-independent nonreciprocal emission holds even greater significance. In this work, we demonstrate a Weyl semimetal (WSM)/Si/WSM/Ag heterostructure comprising the top and bottom WSM layers rotated at distinct angles. The results demonstrate a narrowband and wide angular nonreciprocal emission with both TM and TE polarizations, exhibiting a strong nonreciprocity exceeding 0.86 at a resonant wavelength of 9.22 μm, while preserving robust angular stability (Δθ=43° for TM and Δθ=60° for TE). Impedance-matching analysis and field distributions elucidate the underlying physical mechanism. Furthermore, the effects of the rotation angles and the Si-layer thickness on the nonreciprocal performance are also comprehensively analyzed. This work advances nonreciprocal thermal emitters toward higher efficiency, offering promising prospects in thermal management and thermophotovoltaics.