Multifunctional Yb3Si2C2 with High‐Performance Terahertz Shielding for Future 6G Communications.

The development of next‐generation 6G communications is anticipated to expand into extreme environments, necessitating superior terahertz (THz) electromagnetic interference (EMI) shielding materials. Herein, structural stability, electronic and optical properties of rare earth silicide carbide Yb3Si2C2 are investigated using first principles density functional calculations and semi‐classical Boltzmann transport theory. The calculation results show Yb3Si2C2 is determined to be experimentally synthesized with high temperature stability with a certain fluctuating C2 pair orientation. In addition, Yb3Si2C2 is identified as a soft, tough, and damage‐resistant ceramic with low shear deformation resistance and easy cleavage, ensuring its durability in irradiation environments. Due to the layered structure and excellent electrical conductivity, Yb3Si2C2 demonstrates high reflectivity and low transmittance for terahertz electromagnetic waves, along with 62% solar absorptivity and 33% IR emissivity. Remarkably, the total shielding effectiveness of Yb3Si2C2 with thicknesses of 5 µm and above follows the widely‐used Simon's formula. The average total shielding effectiveness of 5 µm‐thick and 10 µm‐thick Yb3Si2C2 across the entire THz region reaches 63 and 110 dB, respectively, which turns out to be the top compared to the results reported. Therefore, the multifunctional intrinsic properties of Yb3Si2C2 materials hold great promise for miniaturized, high‐performance terahertz EMI shielding, even in extreme environments. [ABSTRACT FROM AUTHOR]