Field ion microscopy and scanning tunneling microscopy similarities and differences

Both the field ion microscope and the scanning tunneling microscope are high resolution microscopy capable of imaging surface atoms with atomic resolution. Both use a tip and electron tunneling to form an image. Similarities and differences of these two instruments are briefly described here from the point of view of a field ion microscopist. In general STM is less restrictive, therefore it promises to have a wider application. There are, however, some capabilities unique to field ion microscopy which makes it particularly suited for many applications. Some of these experiments relevant for comparing with STM are briefly described.