Compact Coarse Approach Mechanism for a Scanning Probe Microscope

Abstract

We report a compact design for a coarse approach mechanism, the so-called `walker', for a lowtemperature ultra-high-vacuum scanning probe microscope. We adapted the slip-stick principle with three actuators driven by the time sequential scheme suggested by Pan et al. The shear piezo-stack was replaced by three rectangular pieces of a piezoelectric (PZT) actuator to reduce the walker volume. Three slip-stick actuators were used rather than six actuators in the original design. By using polished sapphire and rough alumina plates, we implemented perfect sticking and a sliding interface. Our design minimizes usage of glue or epoxy, where attachment strength would be deteriorated by repeated temperature cycling. By using te on material, we reduced the frictional force of sliding parts. Without a metallic spring, elastic motion was provided by the te on material against the holding force. A moving velocity of 18 m/s and a step distance of 0.3 m were measured at room temperature.