Tuning electronic and optical properties of bismuth monolayers by molecular adsorption

Abstract We perform first-principles calculations of the electronic and dielectric properties of bismuthene functionalized with small ligands. Molecular dynamics simulations show that adsorption of these ligands are stable at 300K. We show by calculating the Z 2 topological invariant that all functionalized structures have topological insulating (TI) behavior with a sizable energy band gap. All functional groups induce an electronic change enough to drastically modify the structural and electronic structure of bismuthene. Furthermore, our findings indicate that the dielectric properties exhibit a large anisotropy with the main absorption peak in the visible region.