Study

We investigated the electronic and magnetic properties for O or Zn defect of (Cu, N) or (Cu, F)-co-doped ZnO with the concentration of 2.77 %- 8.33 % by using the first-principles calculations. The ferromagnetic coupling of Cu atoms in (Cu, N)-codoped ZnO can be attributed to the hole-mediated double-exchange through the strong 2p-3d coupling between Cu and neighboring O (or N) atoms. The ferromagnetism in Cu-doped ZnO is controllable by changing the carrier density. The Cu magnetic moment in low Cu concentration (2.77%) is increased by the N-doping, while for the F-doping it decreases. For two Cu atoms of Zn0.9445Cu0.0555O with O vacancy, the antiferromagnetic state is more energetically favorable than the ferromagnetic state