Multi-Terminal Ballistic Transport in One-Dimensional Wires

In contrast to theoretical predictions of the Luttinger model, recent experiments have shown non-universal conductance quantization in one-dimensional wires that are fabricated using the cleaved edge overgrowth technique. In one of the papers, it was speculated that the origin of the reduced conductance lies in the interface between the one-dimensional wire and the two dimensional electron gas regions, which serve as ohmic contacts and thermal reservoirs. Here we report the results of a systematic study of such 2D-1D interfaces. By embedding a 2D-1D interaction region of controllable length inside an otherwise isolated wire, we were able to study the properties of the coupling between these two subsystems. Our results show that 2D-1D interface is in fact the origin of the non-universal conductance.