Comparison between Atomic Force Microscopic Images of Ionic Crystal Surfaces in Air and in Dry Argon

Abstract
We have observed cleavage surfaces of ionic crystals in air and in dry argon using atomic force microscopy (AFM). AFM images from cleavage surfaces of NaCl, KCl, LiF, CaF2 and BaF2 clearly exhibit atomically resolved images consisting of anions and cations for both conditions. The AFM image reveals that the force between tip and surface in dry argon is stronger than that in air.