2D-1D coupling in cleaved edge overgrowth

We study the scattering properties of an interface between a one-dimensional (1D) wire and a two-dimensional (2D) electron gas. Experiments were conducted in the highly controlled geometry provided by molecular bean epitaxy overgrowth onto the cleaved edge of a high quality GaAs/AlGaAs quantum well. Such structures allow for the creation of variable length 1D-2D coupling sections. 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 origin of the puzzling nonuniversal conductance quantization observed previously in such 1D wires.