Measurement of Coulomb-energy-dependent tunnelling rates in surface-acoustic-wave-defined dynamic quantum dots

We present measurements of the escape rate of electrons from dynamic quantum dots (QDs), generated in surface-acoustic-wave minima, as the dynamic QD passes a tunnel barrier. The tunnelling time for this interaction is View the MathML source. A rate-equation formulation is used to extract the tunnelling rates, which are strongly dependent on the number of electrons in the dynamic QD, and can be changed by over an order of magnitude by varying the tunnel-barrier gate voltage. We compare this dependence to a saddle-point-potential model for non-interacting electrons, to obtain the addition energies of the dynamic QD, which are found to be of a comparable order of magnitude to those measured in static few-electron QDs.