Electron flow. Computer model representing the flow of electron particles through a two- dimensional electron gas (2DEG). The gas" is composed of many free electrons, which can move around in only one plane. The 2DEG possesses an electric potential. Irregularities in this potential produce a "bumpy" surface. The model shows the paths taken by electrons released one at a time into the gas. The negatively-charged electrons were deflected by the bumps in the gas, producing an intricate branching pattern. The electron flow was modelled by Professor Eric Heller, Harvard University, Cambridge, Massachusetts, USA."