Magneto-transport spectroscopy on a quantum wire

One-dimensional structures are expected to show unique electronic transport behavior as a consequence of the Coulomb interaction between carriers. A considerable number of theoretical predictions remain largely untested by experiment due to a lack of a suitable one-dimensional wire. Using a new crystal growth technique a unique tube-like structure with a cross section of 25 nm × 25 nm has been created in a semiconductor. The mean free path of the electrons exceeds 10 μm - more than 400 times the confinement dimension. The energy spacing between one-dimensional modes far exceed any random potential fluctuations and is more than 10 times larger than previously achieved by other techniques. The conductance plateaus of these wires deviate significantly from the expected universal values suggesting the relevance of electron - electron interactions.