A quantum explanation of the magnetic properties of Mn-doped graphene

Mn-doped graphene is investigated using first-principles calculations based on the density functional theory (DFT). The magnetic moment is calculated for systems of various sizes, and the atomic populations and the density of states (DOS) are analyzed in detail. It is found that Mn doped graphene-based diluted magnetic semiconductors (DMS) have strong ferromagnetic properties, the impurity concentration influences the value of the magnetic moment, and the magnetic moment of the 8×8 supercell is greatest for a single impurity. The graphene containing two Mn atoms together is more stable in the 7×7 supercell. The analysis of the total DOS and partial density of states (PDOS) indicates that the magnetic properties of doped graphene originate from the p–d exchange, and the magnetism is given a simple quantum explanation using the Ruderman–Kittel–Kasuya–Yosida (RKKY) exchange theory.