Energy of bonding an adsorbed atom with a single-layer graphene

The change in the local density of states δρ _g of a single-sheet graphene due to adsorption of a single atom has been calculated in the framework of the M model proposed earlier. The dependence of the local density of states δρ _g on the position of the adatom energy level ɛ _a with respect to the Dirac point and other parameters of the problem has been analyzed. It has been shown that the largest changes in the local density of states δρ _g are caused by adatoms with the ɛ _a levels lying in the vicinity of the Dirac point, so that the minimum density of states of graphene remains equal to zero. An analytical expression has been derived for the energy of bonding W _ads of the adatom with graphene. The obtained estimates of the bonding energy W _ads in the weak and strong adatom-substrate bonding regimes are presented. Atoms of alkali metals and halogens have been considered as specific adsorbates.