Tunable BIC metamaterials with Dirac semimetals

Proposed by von Neuman and Wigner in 1929, bound states in the continuum (BIC) exhibit the merits of ultrahigh Q-factor and strongly confined modes, solving the inherent high dissipation of metamaterials (MMs) and plasmonic devices. Dirac semimetal (DSM) possesses the advantages of high carrier mobility and outstanding tunable properties, which provides avenues for the design of performance functional devices. This review focuses on recent progresses of the DSM (graphene and 3D Dirac semimetals, e.g. Cd₃As₂) and other novel materials (e.g. MoS₂, borophene, GaSe) based BIC MMs, including the effects of Fermi levels, resonators types, and operation frequency ranges. Some related interesting phenomena, such as tunable Fano resonance, strong epsilon-nearly-zero and nonlinear harmonic effects, together with a brief prospect on the future development trends of DSM MMs, have been given and discussed. This work also provides a useful guideline to understand the tunable mechanism of the DSM devices and develop high performance functional devices applied in the fields of wireless communications, security detection, and sub-millimeter astronomical observations, e.g. filters, modulators and polarizers.