FLUCTUATION IN 2-DIMENSIONAL STICK-SLIP PHENOMENON OBSERVED WITH 2-DIMENSIONAL FRICTIONAL FORCE MICROSCOPE

We used an atomic force microscope combined with a lateral force micro scope (AFM/LFM) as a two-dimensional frictional force microscope (2D-F FM) to investigate the two-dimensional behavior of the atomic-scale fr iction between the cleaved surface of MoS2 and the Si3N4 tip apex of t he microcantilever based on the two-dimensional stick-slip model. As a result, for the scan direction along the row of the stick-points, we found the unstable state where the tip apex shows fluctuation between two adjacent rows of stick-points. On the other hand, near the row of the stick-points, we also found the stable state where the tip apex ta kes a straight walk on a row of the stick-points without fluctuation.