Materials Design for the Low-Resistivity in p-Type ZnO and Transparent Ferromagnet With Transition Metal Atom Doped ZnO: Prediction vs. Experiment

We propose a new valence control method of codoping with doping Ga (or In, Al) donor and N acceptor at the same time for the fabrication of a low-resistivity p-type ZnO based upon the ab initio calculation. We compare our predicted materials design to fabricate a low resistivity p-type ZnO with the recent successful codoping. Based upon the success in the valence control of ZnO, we propose a materials design to fabricate the ferromagnetic Mn-doped p-type ZnO upon codoping. It is shown that the anti-ferromagnetic state is more stable than the ferromagnetic ones due to the anti-ferromagnetic super-exchange interaction, if we have no mobile holes. Upon codoping with the mobile holes, it is shown that the ferromagnetic state becomes more stable than the anti-ferromagnetic ones due to the ferromagnetic double-exchange interaction. However, it is shown that the anti-ferromagnetic state is more stable upon electron doping due to the anti-ferromagnetic super-exchange interaction. We calculate the chemical trends of the magnetic state in V-, Cr-, Fe-, Co-, and Ni-doped (25 at%) in ZnO, and predict that all of these materials show the ferromagnetic ground states without electron and hole doping.