Single-spin qubits in isotopically enriched silicon at low magnetic field.
R Zhao, T Tanttu, K Y Tan, B Hensen, K W Chan, J C C Hwang, R C C Leon, C H Yang, W Gilbert, F E Hudson, K M Itoh, A A Kiselev, T D Ladd, A Morello, A Laucht, A S Dzurak
Author Information
R Zhao: Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia. ruichen77@gmail.com.
T Tanttu: Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia.
K Y Tan: QCD Labs, QTF Centre of Excellence, Department of Applied Physics, Aalto University, 00076, Aalto, Finland. ORCID
B Hensen: Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia.
K W Chan: Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia. ORCID
J C C Hwang: Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia. ORCID
R C C Leon: Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia.
C H Yang: Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia. ORCID
W Gilbert: Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia.
F E Hudson: Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia. ORCID
K M Itoh: School of Fundamental Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, 223-8522, Japan.
A A Kiselev: HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA, 90265, USA.
T D Ladd: HRL Laboratories, LLC, 3011 Malibu Canyon Road, Malibu, CA, 90265, USA.
A Morello: Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia. ORCID
A Laucht: Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia. ORCID
A S Dzurak: Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia. a.dzurak@unsw.edu.au. ORCID
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 [Formula: see text] μs and [Formula: see text] μs at 150 mT. Their coherence is limited by spin flips of residual Si nuclei in the isotopically enriched Si 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.
