ELECTRON-ELECTRON-SCATTERING-INDUCED SIZE EFFECTS IN A 2-DIMENSIONAL WIRE

The differential resistance of wires defined in the two-dimensional el ectron gas in an (Al,Ga)As heterostructure is observed to first increa se and then decrease with increasing current. It is demonstrated that this behavior results from the interplay of an enhanced electron-elect ron-scattering rate (due to current heating of the electron gas), and the partly diffusive nature of boundary scattering in the wire. The da ta are identified as an experimental observation of the Knudsen maximu m and the Poiseuille flow regime in electron transport, and confirm an analogy between electron and gas flow that has been anticipated since the 1950s.