Aspects of One Dimensional Transport Effects in Gallium Arsenide Heterojunction Structures

A brief account is presented on aspects of recent work on one dimensional transport in GaAs-A1GaAs heterojunctions. Application of high resolution electron beam lithography allows the fabrication of a number of structures which illustrate ballistic transport, quantum interference and related effects. The physical origin of the quantisation of the 1D ballistic resistance is discussed as is the current saturation when the applied voltage exceeds the Fermi energy. The “locking” of the plateaux of quantised resistance when resistors are in parallel configuration is described. Results are presented on Aharonov-Bohm oscillations in singly-connected structures when a strong magnetic field forces the current to flow in edge states and a discussion is given on the quenching of the Hall effect and transport in a 1D superlattice.