Spin-polarized bandgap of graphene induced by alternative chemisorption with MgO (111) substrate

Using First-principle calculations, the substrate effect of O-terminated (3×3) MgO (111) on graphene was investigated for spintronics application. It was found that the graphene could be turned into a spin-polarized semiconductor due to alternative sp3 chemisorption with the substrate. The majority spin channel has an insulating band gap of 2eV, while the minority spin channel has a semiconducting band gap of 0.3eV. These results imply that the graphene with a tailored pattern of chemisorption could be highly efficient for introducing a totally spin-polarized current and controlling its on/off switching.