Scanning Tunneling Microscopy

Introduction

Scanning Tunneling Microscopy (STM) has become one of the most useful tools in the field of surface science. For their invention of this technique, Gerhard Binning and Heinrich Rohrer were awarded the 1986 Nobel Prize for Physics. An STM images the details of a surface at atomic resolution with the aid of an extremely sharp metal tip, terminating with a single atom, which exchanges electrons with the surface by quantum mechanical tunneling. The purpose of this experiment is to familiarize yourselves with the STM technique, and to image several different samples. 

Equipment

· IBM Burleigh Instructional Scanning Tunneling Microscope

· HOPG samples (possibly Au, TaS₂, LC, MoS₂ and YBCO samples)

· Manual, Scanning probe book

· Computer with STM control software

Procedure

Read through the included manual before attempting to operate any of the equipment. Critical to the successful imaging of samples is the preparation of the metal tip. Some samples are provided, others you will prepare yourselves. Familiarize yourselves with the equipment, and attempt to image as many samples as possible. You should be able to determine lattice spacings, and in some cases observe charge density waves and domain structures.

References

R. Serway, Physics for Scientists and Engineers, with Modern Physics, 3^rd ed., Saunders, Philadelphia (1990).

Burleigh Instructional Scanning Tunneling Microscope Operating Manual and Quick Start Procedures, Burleigh, New York (1994).

R. E. Thorne, "Charge Density Wave Conductors," Physics Today 49, 42 (May 1996).

X. L. Wu and C. M. Lieber, "The Hexagonal Domain-Like Charge Density Wave Phase of TaS₂ Determined by Scanning Tunneling Microscopy," Science 243, 1703 (1989).