Quantum and Classical Ballistic Transport in Constricted Two-Dimensional Electron Gases

Abstract

An experimental and theoretical study of transport in constricted geometries in the two-dimensional electron gas in high mobility GaAs-AlGaAs heterostructures is described. A discussion is given of the influence of boundary scattering on the quantum interference corrections to the classical Drude conductivity in a quasi-ballistic regime, where the transport is ballistic over the channel width, but diffusive over its length. Additionally, results are presented of a recent study of fully ballistic transport through quantum point contacts of variable width defined in the two dimensional electron gas. The zero field conductance of the point contacts is found to be quantized at integer multiples of 2e 2/h, and the injection of ballistic electrons in the two dimensional electron gas is demonstrated in a transverse electron focussing experiment.