A metamaterial absorber with electrically and thermally tunable absorption frequency and absorptivity

A dual-tunable "perfect" metamaterial absorber composed of a "Tian-zi"-shaped bulk Dirac semimetal (BDS) resonator and strontium titanate (STO) is proposed in this work and systematically studied by performing numerical simulations. From the acquired results, it is demonstrated that the absorber can achieve 99% absorption rate at 2. 613 1 THz when the BDS Fermi energy is 40 meV and the STO temperature is 400 K. Moreover, both dynamics dual-tuning of the absorption frequency and absorption rate of the absorber can be successfully achieved by varying the BDS Fermi energy level and the STO temperature. Additionally, the absorber's performance is theoretically analyzed using both coupled mode theory (CMT) and equivalent circuit model (ECM). Finally, the changes in the absorber's absorption spectrum are further discussed when each parameter of the model is modified, providing thus a solid theoretical basis for the design of dual-tunable filters and absorbers.