Coherently aligned, multiatomic step arrays on GaAs(331) substrates generate a periodic array of conductive quantum wires in a two-dimensional (2D) electron gas. A small number of wires is selected by superimposing a constriction with independent side-gate control. By tuning the gate-voltage window, wires can be selected one by one. The resulting oscillatory current transmission provides a new functionality by switching between spatially separated electron channels. The wires are coupled by a small number of 2D electrons resulting in orders of magnitude reduced conductance perpendicular to the step edges.

• Received 31 August 1998

DOI:https://doi.org/10.1103/PhysRevLett.83.156