Conveyor-mode single-electron shuttling in Si/SiGe for a scalable quantum computing architecture

Small spin-qubit registers defined by single electrons confined in Si/SiGe quantum dots operate successfully and connecting these could permit scalable quantum computation. Shuttling the qubit between registers is a natural choice for high-fidelity coherent links [1]. Electron shuttling by Landau-Zener transitions across a series of tunnel-coupled quantum dots was shown [2], but required invidually tuned voltages.

We demonstrate proof-of-principle of shuttling a single electron by a gate induced propagating wave-potential in Si/SiGe termed conveyor mode [3] shuttling. Independent from its length only four sinusoidal control signals and low tuning effort is required. We transfer a single electron over 420 nm and observe a high single-electron shuttling fidelity of 99.42±0.02 % including a reversal of direction. Measuring the sensor response while transferring the electron enables us to detect the electron motion. Our shuttler can be readily embedded in industrial fabrication of Si/SiGe qubit chips and paves the way to solving the signal-fanout problem for a fully scalable semiconductor quantum-computing architecture.

[1] L. M. K. Vandersypen et al., npj Quantum Inf. 3, 34 (2017).

[2] A.R. Mills et al., Nat. Commun. 10, 1063 (2019).

[3] P. Huang et al., Phys. Rev. B 88, 075301 (2013).