Long-range and strong ferromagnetic graphene by compensated n-p codoping and π-π stacking

Generating magnetism in graphene and preserving its extraordinary properties are essential to the development of graphene-based spintronics. By using first-principles calculation methods, we propose a new scheme based on compensated n-p codoping and non-covalent π-π stacking with F4-TCNQ, to engineer some hybrid structures of Fe/graphene/F4-TCNQ. Our results firstly show that F4-TCNQ adsorption on graphene can preserve the original electronic properties of graphene by minimizing the distortion of carbon-carbon lattices due to non-covalent π-π interaction between graphene and F4-TCNQ. Moreover, F4-TCNQ adsorption on graphene can lead it to p-type, which is in agreement with experimental finding. Then, n-type Fe adatom on F4-TCNQ/graphene system forms very stable hybrid Fe/graphene/F4-TCNQ system due to compensated n-p codoping interaction. Further calculations reveal that a long-range and strong ferromagnetic coupling of two Fe adatoms is realized by F4-TCNQ exchange interaction in the hybrid Fe/graphene/F4-TCNQ system. This study provides a new method to realize ferromagnetic graphene and preserve its extraordinary properties, which will open a promising way to tailor the electronic properties and magnetic properties of graphene so as to be suited for future application in nanoelectronics and spintronic devices.