Dynamically dual-tunable dual-band to four-bandmetamaterial absorbers based on bulk Dirac semimetaland vanadium dioxide

In this work, we investigate dynamically dual-tunable dual-band, triple-band, and four-band metamaterial absorbers (MAs) based on a bulk Dirac semimetal (BDS) and vanadium dioxide (VO2). Due to the bright-bright mode coupling between BDS rods, the dual-band, triple-band, and four-band MAs can be realized when the VO2 is in a fully metallic state. The average absorptivity of the absorption peaks in the three MAs reaches 97%, 98.6%, and 96.4% respectively. The physical mechanism can be explained by the radiating two-oscillator model. The resonant frequencies and absorptance intensities at absorption peaks in each MA can be dynamically tuned by varying the BDS Fermi energy and the VO2 conductivity.