Atomic scale force mapping with the atomic force microscope

The ability to recognize differences between atoms in topographically similar positions has been a long-standing goal in Atomic Force Microscopy especially in a biological context. Mapping of forces (often attractive) at very small (less than 5 A) tip-sample separations is one plausible way to achieve this. We have measured these types of forces above crystalline surfaces in water. Atomic resolution on attractive forces is demonstrated on the cleavage planes of calcite and muscovite mica. Atomic scale variations in the force between the tip and sample as a function of lateral position are observed on calcite.