Direct observation of standing wave formation at surface steps using scanning tunneling spectroscopy

Using scanning tunneling microscopy and spectroscopy, we have observed the formation of standing waves by the scattering of surface state electrons at steps and defects on the Au(111) surface. From the periods, peak positions, and intensities of the standing waves, the energy dispersion of the surface states, the scattering phase shifts as a function of energy and crystallographic direction, and coherence lengths could be determined. © 1993 The American Physical Society.