Atomic resolution imaging using the electric double layer technique: friction vs. height contrast mechanisms

Abstract

Atomic resolution images of the mineral astrophyllite have been obtained using the electric double layer technique [Sokolov, I.Yu., Henderson, G.S., Wicks, F.J., Applied Physics Letters 70 (1997) 17] and when immersed in water. Both friction and height images were recorded simultaneously. We find that when scanning in water, the primary contribution to the image contrast comes from the friction force, in agreement with previously published studies. However, when scanning in the presence of an electric double layer (EDL), the image contrast is primarily the result of vertical force. These results remain valid over a large range of load forces.