Synergetic Effect of Substitutional Dopants and Sulfur Vacancy in Modulating the Ferromagnetism of MoS₂ Nanosheets

The activation and modulation of the magnetism of MoS₂ nanosheets are critical to the development of their application in next-generation spintronics. Here, we report a synergetic strategy to induce and modulate the ferromagnetism of the originally nonmagnetic MoS₂ nanosheets. A two-step experimental method was used to simultaneously introduce substitutional V dopants and sulfur vacancy (V_s) in the MoS₂ nanosheet host, showing an air-stable and adjustable ferromagnetic response at room temperature. The ferromagnetism could be modulated by varying the content of V_s through Ar plasma irradiation of different periods, with a maximum saturation magnetization of 0.011 emu g^-1 reached at the irradiation time of 6 s (s). Experimental characterizations and first-principles calculations suggest that the adjustable magnetization is attributed to the synergetic effect of the substitutional V dopants and V_s in modulating the band structure of MoS₂ nanosheets, resulting from the strong hybridization between the V 3d state and the V_s-induced impurity bands. This work suggests that the synergetic effect of substitutional V atoms and V_s is a promising route for tuning the magnetic interactions in two-dimensional nanostructures.