CONTACT AND NONCONTACT MODE IMAGING BY ATOMIC-FORCE MICROSCOPY

An atomic force microscope (AFM) with an optical interferometer method works as an atomic-scale corrugation microscope, while an atomic forc e/lateral force microscope (AFM/LFM) with an optical lever deflection method works as a two-dimensional frictional force microscope (2D-FFM) with an atomic resolution. Using an ultrahigh-vacuum AFM with an opti cal interferometer method, we demonstrated true atomic resolution imag ing of the cleaved InP(110) surface in non-contact mode. Then, using a 2D-FFM in air, we studied the two-dimensional nature of friction by m easuring the atomic-scale friction of a Si3N4 tip in contact with clea ved sample surfaces such as MoS2, graphite and NaF(100). As a result, we confirmed the existence of the two-dimensionally discrete friction with a lattice periodicity. Besides, using a two-dimensional stick-sli p model, we managed to explain the tip trajectory quantitatively induc ed by the two-dimensionally discrete friction with a lattice periodici ty.