Ta Doping Enhanced Room-Temperature Ferromagnetism in 2D Semiconducting MoTe2 Nanosheets

Room temperature ferromagnetic semiconductors remain one of the most puzzling issues to be solved in tens of years. Nowadays, 2D ferromagnetic transition metal dichalcogenides (TMDCs) nanosheets attract continuous interest due to their exceptional electronic structure and properties. Here, it is identified that semiconducting 2H-phase MoTe 2 few/mono-layer mixed nanosheets present a room temperature ferromagnetic property with Curie temperature above 400 K, although the MoTe 2 bulk counterpart shows diamagnetic properties. The origin of such observed room temperature ferromagnetism is attributed to the combination of their structural defects including Te vacancies, disorders, and amorphous imperfections and edge-states caused by reduced dimensionality. Moreover, a distinct enhancement of ferromagnetic properties at room temperature is revealed by a non-magnetic Ta doping strategy. Such structural defects and edge-states modulated ferromagnetism offers a feasible strategy to search for more robust room temperature ferromagnetic TMDCs nanosheets, which is essential to explore novel electronic and spintronic devices where both carrier charge and spin freedom can be controlled.