Half-Metallic Ferromagnetism in Cu-Doped ZnO Nanostructures from First-Principle Prediction

Ab initio calculations based on density functional theory are performed to study the magnetic properties and electronic structures of Cu-doped ZnO graphite-like sheet and nanotube. It is found that Cu dopant introduces appreciable magnetism into the ZnO nanostructures we address. The possible electronic mechanism is given in terms of the strong hybridization between O 2p and Cu 3d states that leads to the large bonding-antibonding splitting of down-spin e (g) states. Moreover, half-metallic characters in the Cu-doped ZnO nanostructures seem to be promising for spintronic applications, e.g., a high tunnel magnetoresistance (TMR) or spin injection. Examining the optical dielectric functions for the two modified systems, we conclude that the main emission of ZnO graphite-like sheet is almost unaffected by a low concentration of Cu impurity. The results may provide a reference for modifying the material property and designing spintronic devices.