Length and angle measurements using regular crystalline lattice as reference

In this article, we report on the length and angle measurement methods using a regular crystalline lattice as the reference and a scanning tunneling microscope (STM) as a detector. (1) The feasibility of a comparative length measurement in the range of >5 μm using a regular crystalline lattice as the reference scale and a dual tunneling unit–STM (DTU–STM) as a detector is discussed. In order to reduce the thermal deformation effect, the DTU–STM was made with ultra-low thermal expansion material and a temperature control cell was used. A 5-μm-long atomic image of a highly oriented pyrolytic graphite (HOPG) crystal along the fast scanning axis was obtained using the DTU–STM in the temperature control cell. (2) An unit-angle measurement with nanoradian resolution by referring atomic structure (=crystalline axes) on crystalline surface is proposed. Design and a operation method of a unit-angle measuring machine using the HOPG crystalline surface and the STM is discussed.