Fixed‐Point Atomic Regulation Engineered Low‐Thickness Wideband Microwave Absorption

Abstract Atomic doping is widely employed to fine‐tune crystal structures, energy band structures, and the corresponding electrical properties. However, due to the difficulty in precisely regulating doping sites and concentrations, establishing a relationship between electricity properties and doping becomes a huge challenge. In this work, a modulation strategy on A‐site cation dopant into spinel‐phase metal sulfide Co₉S₈ lattice via Fe and Ni elements is developed to improve the microwave absorption (MA) properties. At the atomic scale, accurately controlling doped sites can introduce local lattice distortions and strain concentration. Tunned electron energy redistribution of the doped Co₉S₈ strengthens electron interactions, ultimately enhancing the high‐frequency dielectric polarization (ɛ′ from 10.5 to 12.5 at 12 GHz). For the Fe‐doped Co₉S₈, the effective absorption bandwidth (EAB) at 1.7 mm increases by 5%, and the minimum reflection loss (RL_min) improves by 26% (EAB = 5.8 GHz, RL_min = −46 dB). The methodology of atomic‐scale fixed‐point doping presents a promising avenue for customizing the dielectric properties of nanomaterials, imparting invaluable insights for the design of cutting‐edge high‐performance microwave absorption materials.