Classical dynamics of electrons in quantized-acoustoelectric-current devices - art. no. 165418

We present a numerical study of the classical dynamics of interacting spinl ess electrons in quantized-acoustoelectric-current devices. In these device s, a surface acoustic wave (SAW) captures electrons from a two-dimensional electron gas (2DEG) and transports a fraction of them through a narrow depl eted constriction. If the same number of electrons are transported in each cycle, a quantized current will result. In our model, each SAW minimum capt ures similar to 30 electrons as the SAW maximum behind it passes through th e 2DEG chemical potential. It then moves toward the center of the constrict ion losing on average one electron every 3 ps as it becomes smaller. For te mperatures below similar to1.7 K the electrons form a crystal, which heats up to this temperature through the equipartition of excess potential energy produced by the loss of electrons. Thermal excitation out of the minima th en results in variations in the number of electrons transported. At tempera tures above similar to1.7 K the electrons are in a more liquidlike state an d evaporative cooling occurs. The dependence of acoustoelectric current on the constriction potential and the temperature are found to be in good agre ement with experiment.