Ultrahigh-temperature ferromagnetism in MoS₂ Moiré superlattice/graphene hybrid heterostructures

Realizing high-temperature ferromagnetism in two-dimensional (2D) semiconductor nanosheets is significant for their applications in next-generation magnetic and electronic nanodevices. Herein, this goal could be achieved on a MoS₂ Moiré superlattice grown on the reduced graphene oxide (RGO) substrate by a hydrothermal approach. The as-synthesized bilayer MoS₂ superlattice structure with rotating angle (ϕ = 13° ± 1°) of two hexagonal MoS₂ lattices, possesses outstanding ferromagnetic property and an ultra-high Curie temperature of 990 K. The X-ray absorption near-edge structure and ultraviolet photoelectron spectroscopies combined with density functional theory calculation indicate that the covalent interactions between MoS₂ Moiré superlattice and RGO substrate lead to the formation of interfacial Mo-S-C bonds and complete spin polarization of Mo 4d electrons near the Fermi level. This design could be generalized and may open up a possibility for tailoring the magnetism of other 2D materials.