Ferromagnetism in nitrogen-doped graphene

Metal-free magnetism in graphene has remained a subject of intense research, and many research groups have invested in understanding the roles of doping, structural defects and edge structure in finite-sized nano-flakes. However, a robust long-range magnetic order has remained elusive. In this context, nitrogen-doped graphene is experimentally proposed to be a promising candidate, though the corresponding exchange mechanism endures unclear and is essential to tune further and manipulate magnetism. In this talk, we will systematically discuss the local moment formation and the concurrent interaction between various defect complexes. The importance of adatom diffusion on the differential defect abundance will be elaborated. We will establish that the direct exchange mechanism between the delocalized magnetic moment originating from the π-electron at the prevalent triazine complex to be responsible for the observed ferromagnetism. We will also discuss the role of B co-doping that further improves ferromagnetism. The present results not only provide the microscopic understanding but also direct to a synthesis strategy towards robust magnetism.