 | It is possible to map the surfaces of conducting solids at the atomic level using an instrument called the scanning tunneling microscope (STM). The STM allows the observation and manipulation of adsorbate molecules and chemical reactions on the atomic scale. This is accomplished by manipulating and monitoring a small amount of current passing through the extremely small STM tip (single-atom tungsten nanotip). The current is amplified and used to measure the size of the gap between the nanotip and the atoms on the surface. The chapter-opening image is an example of the resolution achieved using the STM technology.
Scientists discovered a new method for confining electrons to artifical structures at the nanometer lengthscale. Surface state electrons on Cu(111) were confined to closed structures (corrals) defined by barriers built from Fe adatoms. The barriers were assembled by individually positioning Fe adatoms using the tip of a low temperature scanning tunneling microscope (STM). A circular corral of radius 71.3 Angstrom was constructed in this way out of 48 Fe adatoms.1 1www.sljus.lu.se/stm/NonTech.html |