Coherent electron flow from a double slit with slit widths in the quantum conductanceregime

Abstract

We report on a theoretical study of the quantum interference behaviour of electron flowfrom a double-slit device made from a semiconductor two-dimensional electrongas (2DEG) system with the slit widths in the quantum conductance regime.The device consists of a double slit and a single slit in a configuration where thesingle slit is placed on the source side of the double slit. The wavefunctions ofelectrons passing through the double-slit structure are calculated on the basis of ascattering matrix method. It is found that including a single slit between thedouble slit and the source contact in the device is essential for the observation ofinterference fringes of electron flow in a double-slit experiment with a 2DEG.When only the lowest mode is open for conduction in the individual slits, theinterference patterns of electron flow from the double slit resemble the resultsof a conventional Young’s double-slit experiment well. When several modes areopen for conduction in the individual slits, the interference patterns of electronflow from the double slit are dominated by the interference of electrons flowingthrough the highest index open modes in the slits. As a result of the existenceof multiple-lobe structures in electron flow from these high index open modes,these interference patterns, in general, show rather complex structures. We alsodiscuss the characteristics of interference patterns in the near- and far-field regimesand the dependence of the fringe spacing on the slit distance in the double slit.