  Band gap tuning and dielectric properties of small organic ligands adsorbed
on tin monolayers (stanene) have been investigated using first-principles
calculations. Charge density analysis using density-functional theory shows
that the ligands are chemisorbed on stanene and some of the groups can open a
band gap in the originally metallic statene. Furthermore many-body GW
calculations demonstrate that the dielectric properties of bare and ligand
adsorbed stanene have a large anisotropy. Our findings of a finite gap opens a
path for rational theoretical design of functionalized two-dimensional stanene.
