Engineering magnetism and electronic properties of silicene by changing adsorption coverage

Electronic and magnetic properties of silicene functionalized by H, C, and F atoms at different coverages are studied based on density functional theory. For H and F adatoms, the most stable adsorption sites are top sites. The situation is different for C adatom, and its most preferable adsorption site is valley site. Among the three kinds of adatoms, the magnetism can always be induced by H adsorption, while spin polarization is triggered only in silicene with low C concentration. The F adsorption mainly changes sites of Fermi level. The various band structures of metal, spin gapless semiconductor, and semiconductor can be obtained.