INVESTIGATION OF NONCRYSTALLINE SURFACES BY SCANNING-TUNNELING-MICROSCOPY

Scanning tunneling microscopy offers the possibility to investigate th e local surface structure of non-crystalline samples. Images of an ico sahedral quasicrystal prove the quasiperiodic order of the bulk to ext end up to the surface. The surface of metallic glasses appears to be r elatively flat on a lateral length scale of several hundred Angstrom. Locally it consists of small protrusions with diameters of only a few Angstrom. Although these protrusions can be identified as images of si ngle atoms in some cases,it has so far not been possible to resolve th e complete and densely packed non-periodic array of surface atoms - ne ither on the quasicrystal nor on the metallic glasses.