Ferromagnetism in two-dimensional materials via doping and defect engineering

Ferromagnetism in 2D materials has attracted extensive interest due to its possible applications for spintronics devices. Zigzag edges and defects, such as vacancies, can induce ferromagnetism in 2D materials. Alternatively, doping with a magnetic element can also introduce ferromagnetism in 2D materials. In this chapter, we introduce the research of magnetism in different 2D materials, such as graphene, boron nitride, SnO, black phosphors, and transition-metal dichalcogenide (TMD) by both theoretical calculations and experimental investigations. From the theoretical results, the ground state of pure 2D materials and the ferromagnetism after doping with a nonmagnetic element or magnetic element is discussed and introduced. In addition, the effect of defects is also discussed in detail. By introducing vacancies, the formation energy of magnetic element doping is strongly reduced and by the control of defects, the ferromagnetism in 2D materials can be manipulated. Experimentally, room-temperature ferromagnetism has been observed in magnetic element-doped TMD 2D materials by ion implantation.