Electron population control of a highly isolated quantum dot using surface-acoustic waves

We demonstrate a method to control the electron population of a highly isolated quantum dot using a surface-acoustic-wave (SAW) pulse. A gate-defined quantum dot in a GaAs/AlGaAs heterostructure is tuned into a nonequilibrium charge state with a strong barrier potential, where an empty (or occupied) dot level is placed below (or above) the Fermi energy of the reservoirs. When a SAW pulse is launched through the dot from an interdigitated transducer, the perturbation of the barrier potential and the dot potential accelerates charge equilibration process. The resulting single-electron population (or depopulation) event is monitored by a nearby quantum point contact.