Atomic resolution imaging and force versus distance measurements on KBr (001) using low temperature scanning force microscopy

Atomic scale dynamic scanning force microscopy images and force versus distance measurements at low temperatures on a cleaved KBr (0 0 1) single crystal are reported. Two distinct forms of atomically resolved contrast were observed. In one case, a nanotip was formed through a tip change. In this case, a strong corrugation of 0.07 nm was measured. It was possible to reverse this tip change intentionally. In the second case, the observed contrast was only 0.025 nm. The force-distance measurements are well modelled with a van der Waals force in the distance range of 0.5-15 nm. The residual forces at smaller tip-sample distances show a maximum attraction of 0.3 nN and decay within 0.2 nm. (C) 2002 Elsevier Science B.V. All rights reserved.