Investigation of doping effects on magnetic properties of the hydrogenated and fluorinated graphene structures by extra charge mimic.

The effects of electron and hole doping on the magnetic properties of hydrogenated and fluorinated graphene structures are theoretically investigated by additional charge mimic. The studied hydrogenated and fluorinated graphene with different electronic structures display different relations between magnetism and charge, in which the spin moment of the former has the maximum value without charge, followed by linearly and symmetrically decreasing with increase of the positive and negative charge (hole and electron doping), while the latter continuously but not linearly increases its spin moment with the charge variation and finally achieves a maximum at certain positive charge doping. Moreover, the phase transition from ferromagnetism to nonmagnetism occurs. With the analysis of the spin-polarized band structures, the electron and hole doping effects on spin moment in the hydrogenated graphene mainly arise from the shifts of the Fermi level, while that in the fluorinated graphene not only results from the shifts of Fermi level, but also from the relative shifts between up- and down-spin band lines. The discovery of the effects of electron and hole doping on magnetism provides fundamental insight on functionalized graphene, rendering new promising potentials for unique spintronics applications.