A compact inertial nanopositioner operating at cryogenic temperatures.

The article focuses on the design, construction, and characterization of a compact inertial nanopositioner operating down to cryogenic temperatures (~2 K) and its integration into a fully automated Point Contact Andreev Reflection (PCAR) spectroscopy apparatus. The nanopositioner employs a slip-stick mechanism driven by a piezoelectric stack and is controlled via custom electronics based on an Adafruit Feather M4 Express microcontroller, enabling precise, computer-interfaced positioning with sub-micrometer step sizes over a range of up to ~4 mm. Characterization at room and low temperatures demonstrated stable, reproducible motion, with step sizes decreasing by a factor of about 10 at 2.5 K compared to room temperature. The nanopositioner’s performance was validated through PCAR measurements on superconducting niobium films, showing reliable formation and control of ballistic contacts and temperature-dependent superconducting gap behavior consistent with BCS theory. The device’s small footprint and versatility make it suitable for integration into low-temperature scanning probe microscopes and other research or industrial applications requiring precise nanoscale positioning.