Effects of silver adatoms on the electronic structure of silicene

This paper presents the adsorption of Ag adatoms on silicene surface using first-principles plane wave calculations within density functional theory. It is obtained that silver adatoms form strong bonds with the silicene yielding significant binding energies. The bare silicene, which is a nonmagnetic semimetal, becomes either nonmagnetic metal or semiconductor depending on the number of adsorbed silver atoms. Because of the charge transfer from adatoms to silicene, bonding and antibonding π bands crossing linearly at the Fermi level shift 0.35 eV below the Fermi level for both single and trimer Ag adsorption. Ag dimer adsorbed silicene becomes a narrow gap semiconductor with E _g = 0.112 eV.