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Abstract
| The interest in understanding the interaction between graphene and atoms that are adsorbed on its
surface (adatoms) spans a wide range of research fields and applications, for example, to
controllably change the properties of graphene in electronic devices or to detect those changes in
graphene-based sensors. We present a density functional theory study of the interaction between
graphene and Hg adatoms. Binding energy, electronic structure and electric field gradient (EFG)
were calculated for various high-symmetry atomic configurations, from isolated adatoms to a
continuous Hg monolayer. Hg as isolated adatom was found to be the most stable configuration,
with a binding energy of 188 meV. Whereas isolated adatoms have a minor effect on the electronic
structure of graphene (small acceptor effect), Hg monolayer configurations induce a metallic state,
with the Fermi level moving well above the Dirac point (donor behavior). Based on the EFG
calculated for the various configurations, we discuss how hyperfine techniques (perturbed angular
correlation spectroscopy, in particular) can be used to experimentally study Hg adsorption on
graphene. |