Vanadium Dioxide as a Natural Disordered Metamaterial: Perfect Thermal Emission and Large Broadband Negative Differential Thermal Emittance

Thermal radiation from conventional emitters, such as the warm glow of a light bulb, increases with temperature: the hotter the bulb, the more it glows. Thermal emitters that buck this trend could lead to many unconventional thermal devices. Researchers have engineered such a (meta)material by exploiting the unique structural and electronic phase changes of vanadium oxide at around 70${}^{\ensuremath{\circ}}$C.