Insights into enhanced ferromagnetic activity of P doping graphene-ZnO monolayer with point defects

The ferromagnetic properties and origin of P doping graphene-ZnO (g-ZnO) monolayer without or with defects including O vacancy (VO) and Zn vacancy (VZn) are discussed in detail using the first principles method in this paper. In order to describe the electronic structure correctly, the GGA + U (PBE functional in GGA) method is adopted. The most stable structures of P doping g-ZnO monolayer without or with defects including VO and VZn are obtained. When O atoms in g-ZnO monolayer is replaced by P, the impurity level caused by P is near Fermi level and P-3p orbital is spin polarized, and the system is ferromagnetic. VZn produce weakly bound O-2p electrons, which spin in the same direction and leads to the ferromagnetism of g-ZnO system. Both of the mechanism can be obtained at room temperature. Meanwhile Curie temperature (Tc) of Zn16O15P1 and Zn16O14P2 is higher than room temperature. Therefore, P doping ZnO monolayer is a potential diluted magnetic semiconductor.

Automated summary

This paper discusses the ferromagnetic properties and origin of P-doped graphene-ZnO monolayers with and without defects. It is found that P doping leads to ferromagnetism in the system, and VZn induces ferromagnetism by producing O-2p electrons with the same spin direction. Both mechanisms can be observed at room temperature, and the Curie temperature of the doped systems is higher than room temperature, suggesting the potential of P-doped ZnO monolayers as diluted magnetic semiconductors.