In-flight distribution of an electron within a surface acoustic wave

Edlbauer, H. and Wang, J. and Ota, S. and Richard, A. and Jadot, B. and Mortemousque, P.-A. and Okazaki, Y. and Nakamura, S. and Kodera, T. and Kaneko, N.-H. and Ludwig, A. and Wieck, A.D. and Urdampilleta, M. and Meunier, T. and Bäuerle, C. and Takada, S.

Volume: 119 Pages:
DOI: 10.1063/5.0062491
Published: 2021

Surface acoustic waves (SAWs) have large potential to realize quantum-optics-like experiments with single flying electrons employing their spin or charge degree of freedom. For such quantum applications, highly efficient trapping of the electron in a specific moving quantum dot (QD) of a SAW train plays a key role. Probabilistic transport over multiple moving minima would cause uncertainty in synchronization that is detrimental for coherence of entangled flying electrons and in-flight quantum operations. It is thus of central importance to identify the device parameters enabling electron transport within a single SAW minimum. A detailed experimental investigation of this aspect is so far missing. Here, we fill this gap by demonstrating time-of-flight measurements for a single electron that is transported via a SAW train between distant stationary QDs. Our measurements reveal the in-flight distribution of the electron within the moving acousto-electric quantum dots of the SAW train. Increasing the acousto-electric amplitude, we observe the threshold necessary to confine the flying electron at a specific, deliberately chosen SAW minimum. Investigating the effect of a barrier along the transport channel, we also benchmark the robustness of SAW-driven electron transport against stationary potential variations. Our results pave the way for highly controlled transport of electron qubits in a SAW-driven platform for quantum experiments. © 2021 Author(s).

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