Origination of electron magnetic chiral dichroism in cobalt-doped ZnO dilute magnetic semiconductors

Electron magnetic chiral dichroism (EMCD) relates the microstructure of a single nanostructure with the magnetic property, indicating that the ferromagnetism observed in cobalt-doped ZnO dilute magnetic semiconductor is intrinsic. First-principles calculations were carried out and the electronic states contributing to the spin imbalance are identified. An exact model is developed, allowing one to visualize the origination of dichroism to be the difference of transition intensity from spin-polarized 2p states to Co-3d states in cobalt-doped ZnO nanostructures.