Density Functional Investigations of Defect-Induced Mid-Gap States in Graphane

We have carried out ab initio electronic structure calculations on graphane (hydrogenated graphene) having single and double vacancy defects. Our analysis of the density of states reveals that such vacancies induce the mid-gap states and modify the band gap. The induced states are due to the unpaired electrons on carbon atoms surrounding the vacancy. Interestingly, the placement and the number of such states is found to be sensitive to the distance between the vacancies. It turns out that such vacancies also induce a local magnetic moment.