Investigating electronic structure with a novel cryogenic electron tunneling microscope.

We report on the development and initial testing of a low-cost cryogenic z-axis tunneling microscope (cryo-ZTM) designed to increase access to nanoscale electronic measurements in undergraduate laboratories. This instrument operates at both room and liquid nitrogen temperatures (77 K), allowing for direct investigation of low-temperature phenomena such as high-temperature superconductivity. We have collected I-V and I-z tunneling spectroscopy data across both temperature ranges on calibration samples including highly oriented pyrolytic graphite (HOPG), gold, and highly doped silicon. These data demonstrated reliable operation that aligned well with theoretical expectations. This instrument’s construction uses many off-the-shelf components, supporting our goal of democratizing advanced experimental tools in condensed matter physics education.