We explore the possibility of using a double-tip scanning tunneling microscope to probe the single-electron Green function of a sample surface, and describe a few important applications: (1) probing constant energy surfaces in k space by ballistic transport; (2) measuring scattering phase shifts of defects; (3) observing the transition from ballistic to diffusive transport to localization; and (4) measuring inelastic mean free paths.

• Received 18 July 1994

DOI:https://doi.org/10.1103/PhysRevB.51.5502