Stability, resolution, and tip–tip imaging by a dual-probe scanning tunneling microscope

Abstract

A scanning tunneling microscope (STM) comprised of two mechanically and electrically independent probes is described. This dual-probe STM is capable of atomic resolution imaging with either tip. The two probes have five combined degrees of freedom, which allow them to be positioned together at the same surface location without alterations in tip shape. The positioning capabilities of the microscope are demonstrated by obtaining images with each tip of a unique location on a graphite surface. Stable tip–tip imaging is demonstrated by directly recording the tunneling current between probe tips and the sample.