Wave packet dynamics in hydrogenated graphene at low hydrogen coverages.

The dynamics of an electron's wave packet on hydrogenated graphene at low hydrogen coverages has been simulated using the tight-binding model. It is found that the bonding between the hydrogen and carbon atoms induces an impurity electron state at an energy of ≈ 0.14 eV above the Dirac crossing energy ED, at which the impurity's scattering of electrons is resonantly enhanced. The asymmetry found in the energy-dependent transmission is explained by the Fano resonance, which has never been mentioned before. The impurity state having positive energy bias and the asymmetrical electron transmission can be used to explain the asymmetrical transporting behaviors measured in the experiment. By comparing the numerical simulations for an ordered sample with those for a disordered one, we conclude that the interference plays an important role in the electron's localization on the hydrogenated graphene.