The search for residual resistivity dipoles by scanning tunneling potentiometry

Abstract

A review is given of the application of scanning tunneling potentiometry (STP) to the study of potential variations due to scattering from localized centers. Landauer has theoretically investigated such scattering in the ballistic regime where the electronic mean free path exceeds the size of the scattering centers. Landauer's analysis predicts the formation of a residual resistivity dipole (RRD) in the electrochemical potential. The dipole moment of the RRD is larger than that expected from conventional diffusive scattering theory. We have applied STP to search for RRDs in the vicinity of surface voids in thin bismuth films. Although these experiments were carried out at room temperature ballistic, transport effect became apparent, but diffusive scattering (phonon scattering) still accounted for a significant part of the observed dipoles. This review also includes a discussion of scattering from other types of defects such as grain boundaries and misfit dislocations.