Electron waves through quantum point contacts

Abstract

This paper reviews the authors work on the experimental and theoretical analyses of the angular distribution of electrons injected through a single quantum point contact. They observed double peaks in the distribution with the point contact quantized in two modes. The authors calculation of the distribution using a Fraunhofer diffraction approximation through a quantized single slit agreed well with results. In this calculation they use a Green's function in weak magnetic fields and constructed mirror images there. They also investigated the possibility of observing interference in the angular distribution between the first and second modes, and found that the interference terms of the angular distribution were cancelled due to system symmetry. Another possible way to observe interference is due to electron waves through double point contacts. To measure this interference, the authors developed submicron air bridges to make double point contacts with independently controlled widths. The authors measured the controlled additivity of the conductance for four point contacts.