Sound-driven single-electron transfer in a tunable beam-splitter setup
Surface acoustic waves (SAWs) strongly modulate the shallow electric potential in piezoelectric materials. In semiconductor heterostructures such as GaAs/AlGaAs, SAWs can thus be employed to transfer individual electrons between distant quantum dots. This transfer mechanism makes SAW technologies a promising candidate to convey quantum information through a circuit of quantum logic gates. Here we present two essential building blocks of such a SAW-driven quantum circuit. First, we implement a triggered single-electron source enabling synchronisation of SAW-driven transport along parallel paths. Then, we couple a pair of transport channels via a tunnel barrier to partition a flying electron arbitrarily into the two paths. All of the presented single-shot experiments are performed with a transfer efficiency exceeding 99 %. Our results open up the way to perform quantum logic operations on the fly and show that a SAW-driven integrated circuit is feasible with single electrons on a large scale.