Complex superstructure patterns near defect sites of carbon nanotubes and graphite

Atomic resolution scanning tunneling microscope (STM) images of native and artificially created defect sites on graphite and carbon nanotubes were compared. The presence of position-dependent coexisting superstructure patterns was identified on all of the investigated samples. The results indicate that superstructure patterns are mainly determined by the available scattered states of the system rather than the detailed structure of the defect site. We propose an interference model, which can explain the presence of coexisting superstructures both on graphite and carbon nanotubes. The model predicts reduced corrugation amplitude for the case of graphite as compared to carbon nanotubes due to the wave-vector averaging on the Fermi circle.