Abstract:
The precise placement of organic molecules on substrates offers an expansive range of opportunities in the fields of materials science, electronics, catalysis, and nanotechnology. To realize these opportunities, an understanding of the adsorption site of the molecules and the corresponding electronic properties is a prerequisite. It is also an avenue for exploring the emergent physics of the molecule–substrate interaction, a must as any application needs a substrate. Here, we discuss iron phthalocyanine (FePc) molecules on the Bi2Se3 topological insulator surface using scanning tunneling microscopy (STM) and spectroscopy (STS). Submolecular-resolution STM images provide the atomic-scale registry of the adsorption site of FePc. Site-specific STS measurements on FePc underline the contribution of the local electronic environment offered by these sites. In the vicinity of the Fermi energy, STS data show that the Dirac point of Bi2Se3 remains unchanged after FePc adsorption. Density functional theory calculations support our results.