Ab initio studies of isolated hydrogen vacancies in graphane

• Various isolated H vacancies on graphane are investigated within the framework of DFT.
• The half-metallic and magnetic moments are obtained.
• Effects of charge states on the vacancies are studied.
• A half-metallic to metallic transition is noted.
• The induced magnetic moment is reduced due to both negative and positive charge doping.

We present a density functional study of various hydrogen vacancies located on a single hexagonal ring of graphane (fully hydrogenated graphene) considering the effects of charge states and the position of the Fermi level. We find that uncharged vacancies that lead to a carbon sublattice balance are energetically favorable and are wide band gap systems just like pristine graphane. Vacancies that do create a sublattice imbalance introduce spin polarized states into the band gap, and exhibit a half-metallic behavior with a magnetic moment of 1.00 μB per vacancy. The results show the possibility of using vacancies in graphane for novel spin-based applications. When charging such vacancy configurations, the deep donor (+1/0) and deep acceptor (0/−1) transition levels within the band gap are noted. We also note a half-metallic to metallic transition and a significant reduction of the induced magnetic moment due to both negative and positive charge doping.