Tuning electronic and magnetic properties of graphene by surface modification

We have demonstrated that the electronic and magnetic properties of graphene sheet can be delicately tuned by surface modification. Applying an external electric field to a fully hydrogenated graphene sheet can unload hydrogen atoms on one side, while keeping the hydrogen atoms on the other side, thus forming a half-hydrogenated graphene sheet, where the unpaired electrons in the unsaturated C sites give rise to magnetic moments, coupled through extended $p-p$ interactions. Furthermore, the electronic structure of the resulting half-hydrogenated graphene sheet can be further tuned by introducing F atoms on the other side, making a nonmagnetic semiconductor with a direct band gap.