Co decoration and charge injection on the electronic structure and magnetic properties of ZnO monolayer: A first-principles study

Inducing and manipulating the magnetism in ZnO monolayer is crucial for both fundamental study and practical applications. Herein, the effects of Co adatoms and charge injection on the electronic and magnetic properties of ZnO monolayer are studied by the first-principles calculations. The results reveal that the most stable configuration for Co1/ZnO monolayer is the one that Co is located on the top of O atom. As the numbers of Co atoms increase, the arrangement of Co atoms on the monolayer may change from linear to plane structure, and finally convert to tetrahedral structure. Furthermore, Con/ZnO monolayers (n = 1, 2, 3, 4) have superior electron behavior in comparison with pristine ZnO monolayer. With an increase in the Co cluster size, the work functions of Con/ZnO monolayers are decreased gradually. The characteristics of Con/ZnO monolayers change from semiconducting to semi-metallic state, but remain magnetic behavior. Moreover, the total magnetic moments of Con/ZnO monolayers are increased from 3.548 µB to 6.521 µB with increasing the Co content. Besides, the changes of Co-3d states are responsible for the tunable the magnetic moment in Co1/ZnO monolayer by the charge injection. These results are helpful to improve the understandings of electronic and magnetic behavior of Con/ZnO monolayers and broaden the valuable potential for the design of spintronic nano-devices.