Non-ferromagnetic behavior in Ag–N codoped ZnO: First-principle calculations

We employ density-functional theory within the generalized-gradient approximation to study the structural and electronic properties of Ag–N codoped ZnO. The calculations show a strong tendency towards formation of the nearest-neighbor AgZn–NO pairs shown to be in the spin polarized state with a total magnetic moment of 2.02 μB. Compared with the isolated Ag or N doped ZnO, it is found that Ag–N codoping can obviously enhance the local magnetic moment of Ag and N atoms due to strong p–d hybridization. However, Ag–N codoping system shows non-ferromagnetic behavior, which is other than Cu–N codoping system, where robust ferromagnetism is confirmed by both experimental and theoretical research. It is demonstrated that the atomic relaxation is responsible for diminishing the magnetic moments of Ag–N codoped ZnO. We therefore suggest that Ag–N codoped ZnO is unsuitable for spintronics applications.