Low-energy resonant scattering from hydrogen impurities in graphene

Abstract

We study the electronic transport properties of graphene with covalently bonded hydrogen impurities. Our measurements reveal low-energy resonant scattering processes within the transport for each charge carrier type. The observed resonances exhibit a strong energy dependence and are accompanied by a sharp increase in the scattering cross section. The ability to observe the scattering resonances was found to depend on the amount of disorder introduced into the graphene through the bonding of hydrogen. The results are shown to be in agreement with a theory regarding low-energy resonant scattering off a short-range impurity in graphene that takes into account both intravalley and intervalley scattering. Theory dictates that the observed resonances are the result of the formation of quasibound states of the Dirac fermions in graphene due to a divergence in one or more of the scattering lengths for the short-range hydrogen impurity potential. We anticipate our experimental results to have implications in graphene valley physics as well as graphene chemical modification, scattering, and localization theories.