Low-temperature scanning tunneling microscope

A scanning tunneling microscope operating at cryogenic temperatures is described. Results from topographic and spectroscopic measurements are presented for surfaces of NbN and graphite at a temperature of 6.5 K. A unique feature of this system is the very low spatial drift and the resulting high positional stability. The topographic data on NbN display a grainy structure. No indications for a superconductive energy gap are found from the tunnel spectroscopy. In the ordered graphite structure, domains are found separated by dislocations. © 1987.