Transport in cleaved-edge overgrowth wires

We report the results of 3 terminal measurements on a one-dimensional (1D) wire. By utilizing cleaved-edge overgrowth, we were able to vary the coupling between a 1D conductor and an adjacent two-dimensional electron gas (2DEG) strip attached to the central part of the wire. We study the 1D-2DEG coupling by controlling the width of the 2DEG strip. Ballistic transport along the wire persists for interaction regions as long as View the MathML source. Thus, with our shortest interaction region (narrowest strip) of View the MathML source, the wire remains almost undisturbed by the presence of the nearby 2DEG allowing a true 3 terminal measurement on a clean wire. Our observations also explain the origin of the non-universal conductance quantization of such 1D wires.