Lars R. Schreiber

Conveyor-mode single-electron shuttling in Si/SiGe

L. R. Schreiber,1 I. Seidler,1 T. Struck,1 R. Xue,1 N. Focke,1 V. Langrock,1 J. A. Krzywda, 2 , Ł. Cywiński2, and H. Bluhm1

1 JARA-FIT Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany

2 Institute of Physics, Polish Academy of Sciences, Warsaw, Poland

To achieve a scalable quantum computing architecture, a coherent mid-range link between qubit registers has been suggested to solve the wiring fan-out problem [1]. Shuttling the qubit carrying electrons between registers is a natural choice for high-fidelity coherent links provided the overhead of control signals stays moderate.

Here, we demonstrate shuttling of a single electron by a propagating wave-potential in an electrostatically defined 420 nm long Si/SiGe quantum-channel [2]. This conveyor-mode shuttling approach requires only four sinusoidal control signals independent from its length. We present the simulation-based optimization of the device geometry aiming at miminimzing the effect of potential disorder from charged defects at the Si/oxide interface [3]. The tuning of the signal parameters is straightforward and we observe a high single-electron shuttling fidelity of 99.42 % including a reversal of direction [2]. By detecting the single electron trajectory, we collect information about the remaining potential disorder within the quantum-channel. Finally, we discuss spin-dephasing mechanisms expected during conveyor-mode shuttling in Si/SiGe and the perspective for spin-coherent shuttling with a transfer fidelity of at least 99.9 % across a distance of 10 µm [3].

[1] L. M.  K. Vandersypen et al., npj Quantum Inf. 3, 1 (2017).

[2] I. Seilder et al., npj Quantum Inf. 8:100 (2022).

[3] V. Langrock et al., arXiv:2202.11793 (2022).