Defect Engineering in MoS₂ Monolayers: A First-Principles Study of Electronic and Magnetic Properties

Abstract

Two-dimensional transition metal dichalcogenides such as MoS₂ exhibit fascinating physical properties that can be tuned through defect engineering. In this study, density functional theory (DFT) was employed to explore the effects of sulfur vacancies and transition metal doping on the electronic and magnetic properties of monolayer MoS₂. Structural optimization and electronic band structure analysis revealed that sulfur vacancies introduced mid-gap states, reducing the bandgap from 1.8 eV to 1.2 eV, thereby improving conductivity. Transition metal doping with Fe and Co induced local magnetic moments, with magnetic moments ranging from 0.5–1.8 μB per dopant atom. Spin-polarized density of states analysis confirmed half-metallic behavior in Fe-doped systems, suggesting applications in spintronic devices. Charge density mapping showed strong hybridization between Mo 4d and dopant 3d orbitals, enhancing magnetic exchange interactions. These findings provide a theoretical framework for tailoring MoS₂ monolayers for next-generation nanoelectronic and spintronic devices.