Origin of Magnetism from Native Point Defects in ZnO.

Based on the first-principle calculations by using the Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA) method in connection with the local density approximation (LDA), we study theoretically the electronic and magnetic properties of different point defects in ZnO, which are Zinc interstitials (Zn), Zinc antisites (Zn), Oxygen interstitials (O) and Oxygen antisites (O) defects in ZnO. The supercell calculations were also performed using the full potential local-orbital (FPLO) band structure scheme. This work presents detailed information about total and local density of states at some concentrations of these defects; the stability of the ferromagnetic state compared with the spin-glass state is investigated by comparing calculating their total energy. The results show on one hand that Zn and Zn produce a shallow donor bellow the bottom of the conduction band (CB), while O and O produces the shallow acceptors above the top of the valence band (VB), and moment magnetic; on other hand that the ferromagnetic state is more stable than the spin-glass in Oxygen interstitials (O) and vice versa for oxygen antisites (O) of native point defects in ZnO. The other native point defects (Zn, Zn, V, and V) have a zero magnetic moment. The results show that the Curie temperature increases with the concentration of interstitial oxygen. [ABSTRACT FROM AUTHOR]