High-stability bimorph scanning tunneling microscope

Abstract

A novel scanning tunneling microscope (STM) is described which is constructed almost entirely of aluminum and uses bimorph piezoelectric disks as the x,y,z drive elements. The design uses a simple, rugged tripod configuration for the fine motion drive arms. Coarse motion of the sample, which is mounted on an aluminum holder, is achieved by pushing or pulling, with a piezoelectric louse. Differential thermal expansion effects are avoided by design, to first order, and the resulting drift is ≤0.5 Å/min after only a short warm-up period. It is easy to build and operate, and has good immunity to mechanical vibrations. The frequency response is flat to 5 kHz. The x,y,z drive sensitivity is 8 Å/V and the range is ≥12000 Å. Some preliminary experimental results are presented, including atomic resolution images in air, of graphite and NbSe2.