Effect of the Dehydrogenation of Graphane on Its Mechanical and Electronic Properties

Abstract

The effect of the desorption of hydrogen on the mechanical characteristics and electronic structure of the armchair conformation of graphane is studied in the context of the nonorthogonal tight-binding model. It is shown that the mechanical stiffness and the Poisson ratio nonmonotonically depend on the hydrogen content and take minimum values at a hydrogen vacancy content of ~50% and ~30%, respectively. As hydrogen is desorbed, the characteristic peaks of the phonon density of states are rapidly reduced. In the initial stage of desorption, local energy levels are formed in the band gap. As the number of hydrogen vacancies is increased, these levels form an impurity band, in which the Fermi level is located.