Magnetism and structure at a vacancy in graphene
  The electronic structure, bonding and magnetism in graphene containing vacancies are studied using density-functional methods. The single-vacancy graphene ground state is spin polarized and structurally flat. The unpolarized state is non planar only for finite segments. Systems containing periodic arrays of vacancies displays magnetic transitions and metal-insulator transitions. 
M. W. C. Dharma-wardana, Marek Z. Zgierski (NRC Canada)