Site dependent metal adsorption on (3 × 3) h-BN monolayer: Stability, magnetic and optical properties

Cu, Pd and Au metal adatom adsorption on different adsorption sites of graphene analog h-BN monolayer is presented. The results demonstrate that the atop N (AN) being the most favorable site for Cu while atop B (AB) for Pd/Au; as well as occurrence of chemisorption is also found in these sites. A general model has been proposed which essentially indicate electronegativity (χ) to be the governing reason regarding the choice of adsorption sites on h-BN sheet in a way such that the adatoms with χ < 2.04 are the most stable on AN site while adatoms with χ lying in the range 2.04–3.04 are the most stable on AB site. A detail study regarding magnetic properties reveal 100% spin polarization at Fermi level i.e. half metallic characteristics and 1μB/supercell magnetic moment in case of Cu and Au adatom adsorption at the most favorable sites. For Cu adsorbed h-BN system, the half metallic characteristics and strong chemical bonds arise from good hybridization at 0 eV between the outermost 2p orbital of nitrogen and the outermost 4s orbital of copper and at −1.49 eV between Cu 3d and 4s orbital with N 2p orbital. A thorough optical study on the above mentioned systems exhibits evolution/disappearance of different hump/shoulder peaks in the calculated absorption coefficient vs. energy plot which may be useful for experimental identification of the adsorbed systems.