PRX Quantum (Mar 2021)

Spin Readout of a CMOS Quantum Dot by Gate Reflectometry and Spin-Dependent Tunneling

  • Virginia N. Ciriano-Tejel,
  • Michael A. Fogarty,
  • Simon Schaal,
  • Louis Hutin,
  • Benoit Bertrand,
  • Lisa Ibberson,
  • M. Fernando Gonzalez-Zalba,
  • Jing Li,
  • Yann-Michel Niquet,
  • Maud Vinet,
  • John J.L. Morton

DOI
https://doi.org/10.1103/PRXQuantum.2.010353
Journal volume & issue
Vol. 2, no. 1
p. 010353

Abstract

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Silicon spin qubits are promising candidates for realizing large-scale quantum processors, benefitting from a magnetically quiet host material and the prospects of leveraging the mature silicon device fabrication industry. We report the measurement of an electron spin in a singly occupied gate-defined quantum dot, fabricated using CMOS-compatible processes at the 300-mm wafer scale. For readout, we employ spin-dependent tunneling combined with a low-footprint single-lead quantum-dot charge sensor, measured using rf gate reflectometry. We demonstrate spin readout in two devices using this technique, obtaining valley splittings in the range 0.5–0.7 meV using excited-state spectroscopy, and measure a maximum electron-spin relaxation time (T_{1}) of 9±3 s at 1 T. These long lifetimes indicate the silicon-nanowire geometry and fabrication processes employed here show a great deal of promise for qubit devices, while the spin-readout method demonstrated here is well suited to a variety of scalable architectures.