Quantized electron transport by interference-induced quantum dots of two cross-travelling surface acoustic waves

Abstract

In traditional approaches of obtaining quantized acoustoelectric current, a narrow channel is fabricated to form quantum dots, which hold a fixed number of electrons at a certain depth. We propose a natural way of forming quantum dots without the narrow channel, by the interference of two surface acoustic waves (SAWs) propagating across each other. A wide transportation area is defined by the usual (but widely separated) split-gate structure with another independent gate in between. This design can increase the quantized current by one to two orders of magnitude. The three-gate structure also allows separate control of the barrier height and the side-gate pinch-off voltage, thus avoids current leakage through the area beneath the side gates.