Multifunctional nonreciprocal thermal emitter with switchable magnitude, sign, and reconfigurability driven by VO₂ and GST

A multifunctional nonreciprocal thermal emitter comprising the twisted Weyl semimetals (T-WSM), Ge₂Sb₂Te₅ (GST), vanadium dioxide (VO₂), Weyl semimetals (WSM), and Ag layers is proposed. By tuning the phase-change temperatures, the magnitude, sign, and reconfigurability of nonreciprocity are dynamically controlled. At 8.84 µm, the emitter maintains an "on" state at <i>T</i> = 300 K, which transforms into an "off" state for <i>T</i> > 300 K. The magnitude modulation of over 85.8% offers the emitter favorable thermal switching performance. The difference in reconfigurable nonreciprocity is reduced to 10.1%. The analysis of polarization conversion reveals the inherent mechanism of absorption and emission at different phase-change temperatures. The electric field distributions demonstrate that the high absorption and emission properties are attributed to the Brewster mode and the intrinsic loss of phase-change materials. The robustness and intermediate phases are comprehensively analyzed. The proposed design is promising for applications in thermal control and thermal management.