Ballistic electron transmission in out-of-plane crossed wire junctions

Abstract

We have performed quantum-mechanical and classical simulations of ballistic electron transport in three-dimensional waveguide structures. The considered geometries are cross junctions of two out-of-plane waveguides, in which the coupling between the waveguides takes place in the third direction, perpendicular to the orthogonal waveguide axes. We find that the transmission coefficients in the single-mode regime are strongly affected by quantum-mechanical interferences of scattering due to directional conversions during the transmission. A large modulation of straight-through transmission is achieved by varying the aspect ratio of the cross section of the waveguides. The transmission into the side leads is found to disappear over a wide range of sample parameters. The magnetic-field dependence of the transport is also examined within the classical limit.