Elucidating the modulation mechanism of intercalation on the electronic structure of bilayer graphene: A first-principles study

Abstract

Elucidating the modulation mechanism of elemental intercalation on the electronic structure of bilayer graphene (BLG) is essential for revealing low-dimensional electronic behaviors and enabling high-performance next-generation electronic and spintronic devices. Based on first-principles calculations, this paper systematically investigates the modulation effects of 36 elements on the electronic characteristics and magnetic properties of the BLG. To accurately handle the strong d-orbital correlation effect in transition metal-intercalated systems, the DFT + U method was employed throughout the study. Results show: Alkali/alkaline-earth metals are dominated by charge transfer; as atomic radius increases (Li → K, Be → Ca), interlayer coupling and the “energy level splitting” effect weaken regularly, leading to gapless metallic characteristics. Intercalation with Ti, V, Mn, Fe, and Co not only shifts the Fermi level upward and forms relatively flat energy bands (enhancing electronic localization) but also induces magnetism in the system. Main-group nonmetals (H, C, N, P, and Cl) trigger spin polarization through orbitals hybridization, broaden the distribution of hybridized energy bands, and form narrowed or isolated energy levels near the Fermi level. This study provides a quantitative guideline for regulating the metallicity, spin polarization strength, and bandgap properties of BLG, thereby facilitating the customization of graphene-based electronic and spintronic devices.