arXiv2026
BPN is a 2D carbon allotrope that exhibits promising potential for applications across a wide range of fields. In this work, we systematically investigated the adsorption characteristics of Fe atoms on monolayer and bilayer BPN using first-principles calculations. Structural optimization and adsorption energy analysis reveal that, for monolayer BPN, the adsorption strength gradually enhances with increasing Fe coverage, indicating a strengthening of Fe-substrate interactions. An Fe/C ratio of 50% corresponds approximately to completion of the first Fe adsorption layer on the BPN surface. For bilayer BPN, the energetically preferred adsorption site for Fe atom is located at the center of the interlayer four-membered ring, with an average adsorption energy of -4.3 eV. Mechanical properties are further evaluated for pristine and Fe-decorated BPN. The results demonstrate that monolayer and bilayer BPN possess relatively high in-plane Young's and shear moduli, indicative of excellent in-plane mechanical stability. For monolayer BPN, Fe adsorption has only a limited effect on the in-plane mechanical response at low coverages, whereas a noticeable enhancement in stiffness emerges at higher Fe loadings. In contrast, the out-of-plane mechanical response of bilayer BPN is significantly affected by Fe incorporation. The effective out-of-plane elastic constant C33 of pristine bilayer BPN is calculated to be 24.59 GPa, indicating relatively weak interlayer interactions and facile deformation along the out-of-plane direction. Notably, this property can be substantially enhanced by interlayer Fe adsorption, with C33 increasing dramatically to 515.63 GPa upon an Fe/C ratio of 25 %. The transport calculations reveal pronounced anisotropy in the conductivity normalized by the relaxation time σ / τ, with markedly different values along the two in-plane crystallographic directions.