Single-electron acoustic charge transport on shallow-etched channels in a perpendicular magnetic field

The effect of a perpendicular magnetic field on the quantized current induced by a surface acoustic wave in a quasi-one-dimensional channel is studied. The channel was defined in a GaAs heterostructure by a shallow-etching technique. The quantized current in this constriction displayed superior precision (±{}60 ppm) and robustness to dc bias relative to that observed previously in Schottky-gate-defined channels. In a perpendicular magnetic field commensurability oscillations were observed in the interval of current between quantized plateaus. The phase of the oscillations changes when a plateau is approached, which leads to an oscillatory change in the slope of the plateaus.