Real-space structural characterization of benzene monolayer on graphite (0001) surface investigated by low-temperature scanning tunneling microscopy

[Display omitted] •Nanoscale adsorbed structure of benzene on graphite was imaged in real space.•Observed superstructure was commensurate to the substrate.•Split of the STM image is suggestive of the hybridization of the HOMO with substrate. Real-space structural characterization of benzene (C6H6) adsorbed on the graphite (0001) surface was investigated at the nanoscale. Scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED) were used to assign a well-ordered 7×7R19.1° structure at around monolayer coverages. The STM image clarified the flat-lying adsorption of benzene with its molecular plane parallel to the surface. At a sample bias around the adsorption-induced highest occupied molecular orbital (HOMO) level, the STM image showed an elongated protrusion separated by a single nodal depression; this is because the degeneracy of the HOMO is lifted by the interaction with the substrate.