APPLICATIONS OF A HIGH-STABILITY SCANNING TUNNELING MICROSCOPE

We have constructed a scanning tunneling microscope which is quite insensitive to vibrations and has a low thermal drift. Low thermal drift is obtained by using a compensating structure for the z-axis (perpendicular to the sample surface) of the scan unit and by utilizing symmetry in the x- and y-directions. To get a low sensitivity to vibrations, we made the scanning unit compact and rigid. A very light tip holder construction allows a high scan speed. We studied different surfaces of Ag single crystals and compared the results with a study of the same surfaces from the inside by a method based on the use of focused conduction electrons. A terrace surface model, introduced to explain the focusing results, has been confirmed for the Ag(001) surface. A description of tip preparation and tip shape is given.