2D-1D coupling in cleaved edge overgrowth

We study the scattering properties of an interface between a one-dimensiona l (1D) wire and a two-dimensional (2D) electron gas. Experiments were condu cted in the highly controlled geometry provided by molecular bean epitaxy o vergrowth onto the cleaved edge of a high quality GaAs/AlGaAs quantum well. Such structures allow for the creation of variable length 1D-2D coupling s ections. We find ballistic 1D electron transport through these interaction regions with a mean foe path as long as 6 mu m. Our results explain the ori gin of the puzzling nonuniversal conductance quantization observed previous ly in such 1D wires.