Side gating in δ-doped quantum wires

We have used a side gating technique to vary the width of narrow wires made from δ-doped GaAs. The wires show pronounced quantum interference effects which can be used to determine the wire width and electron phase coherence length as a function of gate voltage. At zero gate bias the depletion from the etched surfaces is very small because of the high electron density and the electrical width of the wires is therefore only slightly smaller than the physical width.