Molecule-Adsorbed Topological Insulator and Metal Surfaces: A Comparative First-Principles Study

We compare electronic structure characteristics of three different kinds of benzene-Adsorbed (111) surfaces: That of Bi₂Te₃, a prototypical topological insulator, that of Au, a prototypical inert metal, and that of Pt, a prototypical catalytic metal. Using first-principles calculations based on dispersion-corrected density functional theory, we show that benzene is chemisorbed on Pt, but physisorbed on Au and Bi₂Te₃. The adsorption on Bi₂Te₃ is particularly weak, consistent with a minimal perturbation of the electronic structure at the surface of the topological insulator, revealed by a detailed analysis of the interaction of the molecular orbitals with the topological surface states.