Vacancy-induced magnetism in ZnO thin films and nanowires

摘要: Extensive calculations based on density functional theory have been carried out to understand the origin of magnetism in undoped ZnO thin films as found recent experiments. The observed is confirmed be due Zn, instead O, vacancy. main source magnetic moment, however, arises from unpaired 2p electrons at O sites surrounding Zn vacancy with each nearest-neighbor atom carrying a moment ranging 0.490 0.740 B. Moreover, study vacancy-vacancy interactions indicates that ground state, moments induced by vacancies prefer ferromagnetically couple antiferromagnetic state lying 44 meV higher energy. Since this larger than thermal energy room temperature, ferromagnetic can stable against fluctuations. Calculations and discussions are also extended nanowires surface volume ratio. Here, lead too. present theoretical not only demonstrates samples even without transition-metal doping but suggests introducing natural an effective way fabricate nanostructures. In addition, mediated nanostructures may certain advantages over doped systems biomedical applications.