Regulation mechanism of epsilon-negative monolayer graphene/CaCu₃Ti₄O₁₂ metacomposites for boosting electromagnetic shielding

Any tissue or cell in the body can be attacked by electromagnetic (EM) radiation, especially causing serious damage to human orthopedics. The ideal metacomposites with low-dispersion weakly negative permittivity and freely tuned response characteristics are promising for high-performance EM shielding which effectively protects human orthopedics. Herein, unveiling the precisely regulation mechanism of epsilon'-negative response and subsequently clarifying the perfect EM shielding effect of metacomposites is crucial for the development of this field. In this work, we offered the systematical research on the epsilon'-negative properties at 100 MHz-1 GHz region, along with the percolation effect, dielectric loss and impedance character, demo for monolayer graphene/CaCu3Ti4O12 (MLGR/CCTO) nanocomposites. Further, we firstly brought up an effective evaluation method for frequency dispersion of epsilon'-negative response, especially directed against the Drude-type frequency spectrum, which reflected the strength and stability of plasmonic oscillations within the 3-dimensional (3D) carbon networks. By performing the density functional theory (DFT) calculations of the interfaces between MLGR and CCTO, we successfully demonstrated the regulation of dielectric response mechanism which includes the abundant electric dipoles assembled at MLGR/CCTO interfaces and the plasmonic state consisting of multitude free electrons in MLGR sheets. These results exactly correspond to the obtained boosting EM shielding performance of epsilon'-negative metacomposites, which will stimulate the development of conventional EM devices by integrating exotic EM effects, to fuse metacomposites and universal functional composites.