Determination of α and β site defects on graphite using C60-adsorbed STM tips

Scanning tunneling microscope images of graphite surfaces obtained using C-60-adsorbed STM tips revealed electron scattering patterns generated by localized defects. For the case where the localized defects are most likely to be single point vacancies, we show that it is possible to distinguish between localized defects at alpha and beta sites, the two inequivalent sites on a graphite lattice. By modeling the graphite with a bilayered carbon cluster using the tight-binding approach, excellent agreement is established between experimentally obtained images and theoretical calculations of electron scattering at alpha and beta site defects. (C) 1998 Elsevier Science B.V. All rights reserved.