Novel Three-Dimensional Positioner and Scanner for the STM Using Shear Deformation of Piezoceramic Plates

A new type of coarse and fine positioner of an STM tip has been developed. The x y-walker has three pairs of composite legs which are made of thickness expansion and thickness shear piezoelectric plates. While one of each pair of legs shrinks, the other leg expands and shear deforms giving rise to one-step displacement. The same type of z-walker is placed on the x y-walker. The position of the tip is finely controlled by shear deformation of the expanded legs. Two pieces of thickness shear piezo plates and a thickness expansion one are stacked for a rigid scanner. Atomic resolution of the STM unit has been confirmed on an air-cleaved MoS2 surface.