Figure 3: Calculations of the spin-density (green) of a $\text{Zn}$ vacancy ($V\text{Zn}$) in $\text{ZnO}$ in the triplet state ($S=1$) in standard density-functional theory (DFT) (left) and after a correction (CONL) (right) show how uncorrected DFT predicts too delocalized spins. Consequently, the defect-defect wave function overlap and the resulting ferromagnetic coupling are strongly overestimated [68].