An ab-initio study of (Mn,Al) doped ZnO including strong correlation effects

(Mn,Al)-codoped ZnO has been investigated by means of first-principles calculations using density-functional theory within the generalized-gradient approximation plus on-site Coulomb interaction (GGA+U) to take into the strong correlations on the Mn site. It is found that for several Al–Mn distances, the system shows always an antiferromagnetic behavior. This is explained by the fact that even with the correct electronic structure described with the GGA+U scheme, the extra electron brought by Al is localized in the host conduction band, and therefore does not modify the occupation of the Mn atoms, suggesting that the antiferromagnetic interaction is still dominant.