Single-spin qubits in isotopically enriched silicon at low magnetic field

Ruichen Zhao, Tuomo Tanttu, Kuan Yen Tan, Bas Hensen, Kok Wai Chan, Jason Hwang, Ross Leon, Chi Herng Yang, Will Gilbert, Fay Hudson, Kohei Itoh, Andrey Kiselev, Thaddeus Ladd, Andrea Morello, Arne Laucht, Andrew Dzurak

Research output: Contribution to journalArticleScientificpeer-review

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Single-electron spin qubits employ magnetic fields on the order of 1 Tesla or above to enable quantum state readout via spin-dependent-tunnelling. This requires demanding microwave engineering for coherent spin resonance control, which limits the prospects for large scale multi-qubit systems. Alternatively, singlet-triplet readout enables high-fidelity spin-state measurements in much lower magnetic fields, without the need for reservoirs. Here, we demonstrate low-field operation of metal-oxide-silicon quantum dot qubits by combining coherent single-spin control with high-fidelity, single-shot, Pauli-spin-blockade-based ST readout. We discover that the qubits decohere faster at low magnetic fields with T"Rabi=18.6 μs and T2*=1.4 μs at 150 mT. Their coherence is limited by spin flips of residual 29Si nuclei in the isotopically enriched 28Si host material, which occur more frequently at lower fields. Our finding indicates that new trade-offs will be required to ensure the frequency stabilization of spin qubits, and highlights the importance of isotopic enrichment of device substrates for the realization of a scalable silicon-based quantum processor.
Original languageEnglish
Article number5500
JournalNature Communications
Issue number1
Publication statusPublished - 3 Dec 2019
MoE publication typeA1 Journal article-refereed


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