Intrinsic magnetic properties of ZnO nanoislands: Insight from first-principles study

•Magnetic properties of ZnO nanoislands with zigzag edges and a triangular form are investigated.•Monolayer ZnO nanoislands with O-terminated edges exhibit magnetic properties.•Charge transfer is introduced to elucidate the magnetic properties.•Multi-layer ZnO nanoislands exhibit magnetic features when their layers are odd.

First-principles calculations have been employed to investigate magnetic and electronic properties of monolayer and multi-layer ZnO nanoislands which are hexagonal BN (h-BN) prototype structures with zigzag edges and a triangular form. Two types of the zigzag edges, that is, O-terminated and Zn-terminated ones are considered. It has been found that monolayer ZnO nanoislands with the O-terminated edges exhibit magnetic properties, regardless of the nanoislands size. However, the nanoislands with Zn-terminated edges are semiconductors, and the magnetic properties are observed just for some specific sizes. Charge transfer according to Bader charge analysis is introduced to elucidate the magnetic properties of the monolayer ZnO nanoislands. Besides, multi-layer ZnO nanoislands exhibit magnetic features when their layers are odd, while those of even layers are nonmagnetic.