Identifying the effects of oxygen on the magnetism of WS2 nanosheets.

In this paper, the microstructure and magnetic properties of the exfoliated and sulfurized WS2 nanosheets were researched to identify the effects of oxygen on magnetism. The exfoliated WS2 nanosheets were prepared by a liquid exfoliation method, and then the sulfurized WS2 nanosheets were obtained after sulfurization of the exfoliated WS2 nanosheets. The exfoliated WS2 nanosheets show paramagnetism, and contain 1T and 2H phases, sulfur vacancies and some oxygen. The sulfurized WS2 nanosheets with an intrinsic structure exhibit an ordered magnetic signature. A combination of detailed experimental research and first-principles calculation demonstrates that oxygen in the structure of WS2 nanosheets would not induce magnetic moments, which can even suppress the spin-polarized edge states. These results identified the effects of oxygen on the magnetism of WS2 nanosheets and would promote its application in spintronics.