Hydrogen adatoms on graphene: The role of hybridization and lattice distortion

Abstract

By performing a detailed study of hydrogen adsorbates on graphene using density functional theory (DFT), we propose a general tight-binding (TB) formalism for a simultaneous treatment of multiple impurities of arbitrary species. To elucidate the details of the hydrogen-graphene bonding, we systematically examine the effects of hybridization and deformation on the band structure and the spectral function. An enhanced understanding of the binding mechanisms leads to a TB model whose predicted spectral function compares favorably with the DFT calculations on the scale of the supercell, as well as the individual adsorbates and carbon atoms. The computational load of our model scales with the number of impurities, not their separation, making it especially useful for experimentally relevant clustered impurity configurations that are too computationally expensive for DFT. The formalism described here allows for the treatment of Anderson impurities and impurities that bind to multiple carbon atoms.