High field excitation: scanning tunnelling microscopy and spectroscopy (STM and STS)

Abstract

Abstract Just as APFIM (see previous chapter) arose out of its parent technique FIM, so Scanning Tunnelling Spectroscopy (STS) has arisen out of Scanning Tunnelling Microscopy (STM). The similarities in origin go further, because while both FIM and STM are surface topographical imaging techniques, i.e. are concerned principally with effects due to surface structure, APFIM and STS provide information about the chemical nature of the surface, either by atomic compositional analysis or by surface state spectroscopic analysis. Again, in the same way that it was necessary in Chapter 21 to describe FIM in order to describe APFIM, so here it will be necessary to go into the details of the STM technique in order to be clear about the associated spectroscopic technique. There the similarities end, however, because although APFIM is now a well established technique, both STM and STS, the latter in particular, are relatively new. The inventors of STM were Binnig and Rohrer,1 who received the Nobel Prize for their contribution to physics.