Investigating the electronic and magnetic properties of VS₂ monolayer with and without vacancy defects

Two-dimensional (2D) transition metal dichalcogenides (TMDCs) are promising for spintronic applications due to their tunable electronic and magnetic properties. The electronic and magnetic properties of the H–VS₂ 4 × 4 monolayer and its vacancy-defected structures are studied using first-principles density functional theory (DFT) calculations. The perfect H–VS₂ monolayer exhibits semiconducting behavior with a bandgap of 0.649 eV and 0.911 eV in the spin-up and spin-down channels, respectively, and a magnetic moment of 0.911 µ_B per formula unit, consistent with its intrinsic ferromagnetism. Introducing vacancies—single vanadium (V_V), single sulfur (V_S), double vanadium (V_2V), double sulfur (V_2S), and combined vanadium-sulfur (V_VS)—significantly alters these properties. Notably, the V_2S-defected structure exhibits half-metallicity with a 100% spin-polarization, characterized by a semiconducting spin-up channel (0.52 eV bandgap) and a metallic spin-down channel. This half-metallic behavior, combined with a robust magnetic moment of 0.911 µ_B, positions V_2S–defected VS₂ as a promising candidate for spintronic devices, such as spin valves and magnetic sensors. Our findings highlight the role of defect engineering in tailoring TMDCs for advanced nanotechnology applications.