Curvature-enhanced spin polarization and dimensionality-dependent electronic reconstruction in Fe-doped SiC nanostructures: a DFT+U investigation

Abstract In this work, we present a comprehensive first-principles investigation of the electronic, magnetic, and structural properties of Fe-doped SiC nanostructures, including nanotube (NT) and nanosheet (NSh) geometries, within the framework of spin-polarized density functional theory (DFT + U ). The substitutional incorporation of Fe at the Si site (1Fe@1Si) preserves the structural integrity of both systems while inducing significant modifications in their electronic behavior. The results reveal a substantial band gap reduction from ∼1.67 eV to ∼0.37 eV in the NT and from ∼2.47 to ∼0.19–0.20 eV in the NSh, accompanied by pronounced spin splitting near the Fermi level. The Fe-doped NT exhibits quasi-metallic characteristics in one spin channel, whereas the NSh retains a reduced-gap semiconducting nature. Spin-polarized total and partial density of states (TDOS and PDOS) analyses confirm that magnetism originates primarily from Fe 3d states and their hybridization with neighboring C 2p orbitals, leading to strong p–d coupling and spin polarization. Mulliken population analysis indicates a total magnetic moment of 4.005 μ B for the NT and 2.047 μ B for the NSh, highlighting the role of dimensionality in magnetic behavior. Furthermore, energy decomposition and force analyses demonstrate that both systems are energetically stable, with localized lattice distortions concentrated near the dopant site and governed by a balance between electrostatic and exchange–correlation interactions. The enhanced spin polarization and quasi-metallic behavior in the NT suggests superior potential for spintronic applications.

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