Magnetism in oxygen-functionalized hexagonal boron nitride nanosheet on copper substrate

Wide-bandgap hexagonal boron nitride (h-BN) nanosheets, white graphene, can be uniformly grown on conducting Cu foils with high quality. Here, we show that h-BN monolayers on Cu substrates exhibit ferromagnetic, antiferromagnetic, or ferrimagnetic properties with ozone (O₃) molecules or oxygen-hydrogen (O-H₂) groups bonded on its B atoms, depending on the adsorption density and configuration of these functional groups. The magnetisms in the O₃- and O-H₂-functionalized h-BN sheets originate from unpaired electrons in the ozone molecule and electrons transferred from the H₂ molecule to the O atom, respectively. The Cu substrate plays an essential role in stabilizing the chemisorption of O₃ or O-H₂ on the h-BN sheets. Magnetic composite structures composed of Cu, h-BN, and oxygen provide a feasible route to facilitate the design of two-dimensional h-BN-based spin devices.