Long-Range Electronic Perturbations Caused by Defects Using Scanning Tunneling Microscopy

Science  05 May 1989:
Vol. 244, Issue 4904, pp. 559-562
DOI: 10.1126/science.244.4904.559


Real-space observations of long-range electronic perturbations caused by defects have been made with scanning tunneling microscopy. The defects are isolated adsorbed molecules on the surface of graphite. These defects perturb the charge density, giving periodic oscillations similar to Friedel oscillations. The oscillations have a wavelength √3 times that of the graphite lattice, and the symmetry of the oscillations reflects the nature of the defect.