Hybrid nanobud-array structures (C₂₄)_n/MoS₂ and (C₂₄V)_n/MoS₂: Two-dimensional half metallic and ferromagnetic materials

Two-dimensional (2D) hybrid nanobud-array structures, (C₂₄)_n/MoS₂ and (C₂₄V)_n/MoS₂, are designed by grafting (C₂₄)_n or (C₂₄V)_n fullerene arrays onto the surface of 2D monolayer MoS₂ (ML-MoS₂). Our density functional theory (DFT) computations show that the attachment of the (C₂₄)_n array onto the ML-MoS₂ surface turns the 2D semiconductor (ML-MoS₂) into a half metal, while the attachment of the (C₂₄V)_n array onto the ML-MoS₂ surface turns the 2D semiconductor into a ferromagnetic (FM) metal. Our non-equilibrium Green's function (NEGF) computation indicates that the zigzag direction of the hybrid nanobud-array structures is more preferential for electron transport than the armchair direction. For the (C₂₄)_n/MoS₂ system, the grafted (C₂₄)_n array not only can markedly increase the electron conductivity of ML-MoS₂ but can also induce spin-polarized transport, that is, the spin-up state exhibits higher conductivity than the spin-down state. After placing a V atom between every two-neighboring C₂₄ fullerenes along the zigzag direction, the conductivity is further enhanced. In contrast to (C₂₄)_n/MoS₂, for (C₂₄V)_n/MoS₂, the spin-down state exhibits higher conductivity than the spin-up state due to the strong contribution of the V 3d state to the spin-down state. The FM metal (C₂₄V)_n/MoS₂ entails a magnetic moment of 2.3 μ_B per V atom. These results suggest that the 2D hybrid nanobud-array structures can be tailored as nanoelectronic parts with different electronic and transport properties by design.