Simulation and Analysis of Methods for Scanning Tunneling Microscopy Feedback Control.

A scanning tunneling microscope (STM) requires precise control of the tip-sample distance to maintain a constant set-point tunneling current. Typically, the tip-sample distance is controlled through the use of a control algorithm. The control algorithm takes in the measured tunneling current and returns a correction to the tip-sample distance in order to achieve and maintain the set-point value for tunneling current.