Coherent Electron Focussing in a Two-Dimensional Electron Gas

Abstract

PACS. 72.20M- Galvanomagnetic and other magnetotransport effects. PACS. 73.40L- Semiconductor-to-semiconductor contacts, p-n junctions and heterojunctions. Abstract.- The fIrst experimental realization of ballistic point contacts in a two-dimensional electron gas for the study of transverse electron focussing by a magnetic field is reported. Multiple peaks associated with skipping orbits of electrons reflected specularly by the channel boundary are observed. At low temperatures fine structure in the focussing spectra is seen. Introduction.- Classical and quantum-mechanical transport in two-dimensional electron gases (2DEG) is mostly studied in the diffusive regime, i.e. on length scales large compared to the transport mean free path l. Due to the recent availability of high-mobility GaAs-AIGaAs heterostructures, l can be as large as 10µm. With micro-fabrication technology it is now becoming feasible to make structures for the study of electron transport which are