Anisotropic surface coupling while sliding on dolomite and calcite crystals

Abstract

High-resolution friction force microscopy has been performed on the (104) surfaces of dolomite and calcite in deionized water. The two rows of oxygen atoms alternating in a zigzag way on top of both surfaces are resolved with similar contrast while scanning along the [421] direction. Along the [010] direction, only one row is resolved, provided that the normal loading is large enough. The direction-dependent interaction between the probing tip and surface atoms is explained by numeric calculations based on the Prandtl-Tomlinson model.