Single-electron transfer between double quantum dots defined by surface acoustic waves

We investigate single-electron transport through two parallel channels driven by surface acoustic waves (SAWs). The number of electrons injected into each channel per SAW potential minimum can be controlled down to one. We can transfer the injected electrons (a single electron per SAW minimum) into the other channel using the gate voltage to tilt the channel potentials at the tunnelling barrier. Our expectation was to observe Rabi oscillations due to coherent tunnelling, but the experimental results indicate that the electron transfer is classical.