Methods, devices and systems for scanning tunneling microscopy control system design

A system for interacting with structures on a sample, the system comprising:

• a scanning tunneling microscope having a tip;
• a positioning system configured to precisely control movement of the tip of the scanning tunneling microscope relative to the sample;
• and
• a control unit in communication with the scanning tunneling microscope and the positioning system, wherein the control unit is configured to:
• receive data characterizing a tunneling current between a tip of the scanning tunneling microscope and a sample;
• estimate, in real-time, a work function associated with the scanning tunneling microscope;
• and
• adjust a position of the tip relative to the sample based on the estimated work function.