THREEFOLD ELECTRON-SCATTERING ON GRAPHITE OBSERVED WITH C-60-ADSORBEDSTM TIPS

The scanning tunneling microscope (STM) has been used to observe three fold symmetric electron scattering from point defects on a graphite su rface. These theoretically predicted electronic perturbations could no t be observed with a bare metal tip but could only be imaged when a fu llerene (C-60) molecule was adsorbed onto the tunneling region (apex) of an STM tip. Functionalizing an STM tip with an appropriate molecula r adsorbate alters the density of states near the Fermi level of the t ip and changes its imaging characteristics.