Field emission interferometry with the scanning tunneling microscope

A scanning tunneling microscope, operated in the near field emission regime, is used to obtain the phases of very low energy electrons reflected from a sample surface. A simple theoretical model shows that the spectrum of the electron standing waves, formed in the vacuum gap between the tip probe and the sample, is directly related to the complex amplitudes of the reflected electron waves. The surface sensitivity of the interferometric spectra is demonstrated in the analysis of different reconstructions of the Pb/Si(111) system. (C) 1999 Elsevier Science B.V. All rights reserved.