First-Principles Calculations of Hydrogen and Hydrogen-Vacancy Pairs in Graphene

Abstract

We study mono-hydrogen and hydrogen-vacancy pair in graphene by using first-principles calculations. In the most stable structure of mono-hydrogen, the hydrogen atom is bonded to one of the carbon atoms in the graphene sheet. The energy of the most stable spin-polarized state is 80 meV lower than that of the nonmagnetic state. We also study the hydrogen mono-vacancy pair. The dissociation energy of this pair into mono-vacancy and mono-hydrogen in graphene is positive (3.0eV). Therefore, when hydrogen diffuses, this complex is expected to be formed and this pair is nonmagnetic.