The local magnetic moment and electron transfer of ZnO-based dilute magnetic semiconductors

The electronic structures and magnetic properties of ZnO semiconductors doped with Cu, Co, C, Al and S are studied by first-principles calculation. The electronic transfer among Zn, O and doped atoms, and the differences of the number of electron between spin-up and spin-down, Δs, Δp, Δd for s, p and d orbits of these atoms, are analyzed in detail. It is found that, the ferromagnetic ground state is stabilized by its half-metallic electronic structure, and the strong local magnetic moments in Zn1−xCoxO, Zn1−xCuxO and ZnO1-xCx (x = 5.55%) DMSs originate mainly from the strong hybridizations between Cu-3d and O-2p, Co-3d and O-2p, Zn-3d and C-2p electrons. It is considered that the requirements to give rise to the ferromagnetism in the DMSs are the strong local magnetic moment and the electron transfer. The magnetic coupling in Zn1-xCoxO, Zn1-xCuxO and ZnO1-xCx is also considered to be a RKKY interaction.