Scanning Tunneling Potentiometry/Spectroscopy (STP/STS)

Abstract
We constructed a scanning tunneling potentiometry/spectroscopy (STP/STS) system which, for the first time, enables us to simultaneously obtain potential and differential conductance images at various tunneling voltages in addition to the usual topographic image. We applied this STP/STS system to the investigation of a granular surface of a variable carbon resistor. As a result, we found that potential drops at the grain boundary, some grains are conductive while others are resistive, and the grain boundaries are highly resistive in several places.