Abstract
We propose that addition of hydrogen atoms at zigzag edges of nanographite and nanotubes may be a way to produce magnetic nanographite and magnetic nanotubes. When a carbon atom at the zigzag edge is terminated by two hydrogen atoms, the zigzag edge of the n-electron network is modified and behaves like the Klein edge. Thus difference in numbers between starred carbons and unstarred ones appears in nanographite and in a nanotube with a normal zigzag edge and a zigzag edge made of di-hydrogenated carbons. Our first-principles band-structure calculation of graphene ribbon prepared by this method shows existence of a spin-polarized flat band at the Fermi level. The result coincides with a conclusion of the Hubbard model on the graphene ribbon, where the Lieb theorem predicted existence of ferrimagnetism.
