First principles investigation of emergence of defect induced magnetism in ReS ₂ monolayer: a route towards 2D spintronics applications

Rhenium disulfide (ReS₂) and related two-dimensional transition metal dichalcogenides (TMDCs) have emerged as promising candidates for spintronic applications, primarily due to the possibility of tailoring their magnetic and electronic properties through defect engineering. In this work, we carry out a comprehensive first-principles investigation of eighteen intrinsic point defects in monolayer ReS₂, including single vacancies, vacancy complexes, and antisite defects, under both Re-rich and S-rich growth conditions. Our results reveal a much richer defect-induced magnetic landscape than previously reported, indicating that magnetism in ReS₂ is not limited to defects involving rhenium atoms alone. In particular, we find that the emergence of magnetic moments is highly sensitive to the specific defect site and local atomic environment. Notably, the<i>V</i>_2Redefect exhibits contrasting magnetic behavior depending on its configuration, being magnetic in one case while remaining nonmagnetic in another. Several defect configurations are found to significantly modify the electronic structure, leading to semiconductor-to-half-metal transitions in case of<i>V</i>_1Re+3Sdefect and/or semiconductor-to-half-semiconductor transitions with pronounced bandgap narrowing in case of other defect configurations. These changes are expected to have implications for charge transport and carrier recombination processes. Importantly, we identify previously unexplored defect configurations in ReS₂that exhibit robust and stable magnetic moments. By linking defect formation energetics and changes in the electronic structure, this study provides fundamental insight into how defect type and spatial arrangement induces magnetic ordering. Overall, our findings highlight the potential of defect-engineered ReS₂ monolayers for future spintronic and quantum device applications.