Study of Metal Surfaces by Scanning Tunneling Microscopy

STM has successfully revealed the structure of semiconductor and graphite surfaces with atomic resolution. Metals, on the other hand, have not been studied by many groups, perhaps because atomic imaging of metal surfaces generally requires higher lateral and vertical resolution. In this talk we will discuss the reconstructions of various metal surfaces (Au, Ni,...). The geometrical structure of clean and chemisorbed surfaces will be compared to their electronic structures. It has been found that the tunneling tip influences not only the resolution and the symmetry of an STM scan but also the measured electronic structure. We will also discuss the gap distance dependence of a specific electronic state in metal-vacuum-metal tunneling.