1
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Tranter A, Kranz L, Sutherland S, Keizer JG, Gorman SK, Buchler BC, Simmons MY. Machine Learning-Assisted Precision Manufacturing of Atom Qubits in Silicon. ACS NANO 2024; 18. [PMID: 39018335 PMCID: PMC11295186 DOI: 10.1021/acsnano.4c00080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 06/10/2024] [Accepted: 06/13/2024] [Indexed: 07/19/2024]
Abstract
Donor-based qubits in silicon, manufactured using scanning tunneling microscope (STM) lithography, provide a promising route to realizing full-scale quantum computing architectures. This is due to the precision of donor placement, long coherence times, and scalability of the silicon material platform. The properties of multiatom quantum dot qubits, however, depend on the exact number and location of the donor atoms within the quantum dots. In this work, we develop machine learning techniques that allow accurate and real-time prediction of the donor number at the qubit site during STM patterning. Machine learning image recognition is used to determine the probability distribution of donor numbers at the qubit site directly from STM images during device manufacturing. Models in excess of 90% accuracy are found to be consistently achieved by mitigating overfitting through reduced model complexity, image preprocessing, data augmentation, and examination of the intermediate layers of the convolutional neural networks. The results presented in this paper constitute an important milestone in automating the manufacture of atom-based qubits for computation and sensing applications.
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Affiliation(s)
- Aaron
D. Tranter
- Centre
of Excellence for Quantum Computation and Communication Technology,
Department of Quantum Science and Technology, Research School of Physics, The Australian National University, Acton 2601, Australia
| | - Ludwik Kranz
- Centre
of Excellence for Quantum Computation and Communication Technology,
School of Physics, UNSW Sydney, Kensington 2052, New South Wales, Australia
- Silicon
Quantum Computing Pty Ltd, UNSW Sydney, Kensington 2052, New South Wales, Australia
| | - Sam Sutherland
- Centre
of Excellence for Quantum Computation and Communication Technology,
School of Physics, UNSW Sydney, Kensington 2052, New South Wales, Australia
- Silicon
Quantum Computing Pty Ltd, UNSW Sydney, Kensington 2052, New South Wales, Australia
| | - Joris G. Keizer
- Centre
of Excellence for Quantum Computation and Communication Technology,
School of Physics, UNSW Sydney, Kensington 2052, New South Wales, Australia
- Silicon
Quantum Computing Pty Ltd, UNSW Sydney, Kensington 2052, New South Wales, Australia
| | - Samuel K. Gorman
- Centre
of Excellence for Quantum Computation and Communication Technology,
School of Physics, UNSW Sydney, Kensington 2052, New South Wales, Australia
- Silicon
Quantum Computing Pty Ltd, UNSW Sydney, Kensington 2052, New South Wales, Australia
| | - Benjamin C. Buchler
- Centre
of Excellence for Quantum Computation and Communication Technology,
Department of Quantum Science and Technology, Research School of Physics, The Australian National University, Acton 2601, Australia
| | - Michelle Y. Simmons
- Centre
of Excellence for Quantum Computation and Communication Technology,
School of Physics, UNSW Sydney, Kensington 2052, New South Wales, Australia
- Silicon
Quantum Computing Pty Ltd, UNSW Sydney, Kensington 2052, New South Wales, Australia
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2
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Delord T, Monge R, Meriles CA. Correlated Spectroscopy of Electric Noise with Color Center Clusters. NANO LETTERS 2024; 24:6474-6479. [PMID: 38767585 PMCID: PMC11157654 DOI: 10.1021/acs.nanolett.4c00222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 05/11/2024] [Accepted: 05/13/2024] [Indexed: 05/22/2024]
Abstract
Experimental noise often contains information about the interactions of a system with its environment, but establishing a relation between the measured time fluctuations and the underlying physical observables is rarely apparent. Here, we leverage a multidimensional and multisensor analysis of spectral diffusion to investigate the dynamics of trapped carriers near subdiffraction clusters of nitrogen-vacancy (NV) centers in diamond. We establish statistical correlations in the spectral fluctuations we measure as we recursively probe the cluster optical resonances, which we then exploit to reveal proximal traps. Further, we deterministically induce Stark shifts in the cluster spectrum, ultimately allowing us to pinpoint the relative three-dimensional positions of interacting NVs as well as the location and charge sign of surrounding traps. Our results can be generalized to other color centers and provide opportunities for the characterization of photocarrier dynamics in semiconductors and the manipulation of nanoscale spin-qubit clusters connected via electric fields.
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Affiliation(s)
- Tom Delord
- Department
of Physics, CUNY-City College of New York, New York, New York 10031, United States
| | - Richard Monge
- Department
of Physics, CUNY-City College of New York, New York, New York 10031, United States
| | - Carlos A. Meriles
- Department
of Physics, CUNY-City College of New York, New York, New York 10031, United States
- CUNY-Graduate
Center, New York, New York 10016, United States
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3
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Kang JH, Yoon T, Lee C, Lim S, Ryu H. Design of high-performance entangling logic in silicon quantum dot systems with Bayesian optimization. Sci Rep 2024; 14:10080. [PMID: 38698015 PMCID: PMC11066012 DOI: 10.1038/s41598-024-60478-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 04/23/2024] [Indexed: 05/05/2024] Open
Abstract
Device engineering based on computer-aided simulations is essential to make silicon (Si) quantum bits (qubits) be competitive to commercial platforms based on superconductors and trapped ions. Combining device simulations with the Bayesian optimization (BO), here we propose a systematic design approach that is quite useful to procure fast and precise entangling operations of qubits encoded to electron spins in electrode-driven Si quantum dot (QD) systems. For a target problem of the controlled-X (CNOT) logic operation, we employ BO with the Gaussian process regression to evolve design factors of a Si double QD system to the ones that are optimal in terms of speed and fidelity of a CNOT logic driven by a single microwave pulse. The design framework not only clearly contributes to cost-efficient securing of solutions that enhance performance of the target quantum operation, but can be extended to implement more complicated logics with Si QD structures in experimentally unprecedented ways.
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Affiliation(s)
- Ji-Hoon Kang
- Division of National Supercomputing, Korea Institute of Science and Technology Information, Daejeon, 34141, Republic of Korea
| | - Taehyun Yoon
- Artificial Intelligence Graduate School, Ulsan National Institute of Science and Technology, Ulsan, 44919, Republic of Korea
| | - Chanhui Lee
- Department of Artificial Intelligence, Korea University, Seoul, 02841, Republic of Korea
| | - Sungbin Lim
- Department of Statistics, Korea University, Seoul, 02841, Republic of Korea.
| | - Hoon Ryu
- Division of National Supercomputing, Korea Institute of Science and Technology Information, Daejeon, 34141, Republic of Korea.
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4
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Reiner J, Chung Y, Misha SH, Lehner C, Moehle C, Poulos D, Monir S, Charde KJ, Macha P, Kranz L, Thorvaldson I, Thorgrimsson B, Keith D, Hsueh YL, Rahman R, Gorman SK, Keizer JG, Simmons MY. High-fidelity initialization and control of electron and nuclear spins in a four-qubit register. NATURE NANOTECHNOLOGY 2024; 19:605-611. [PMID: 38326467 PMCID: PMC11106007 DOI: 10.1038/s41565-023-01596-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 12/20/2023] [Indexed: 02/09/2024]
Abstract
Single electron spins bound to multi-phosphorus nuclear spin registers in silicon have demonstrated fast (0.8 ns) two-qubitSWAP gates and long spin relaxation times (~30 s). In these spin registers, when the donors are ionized, the nuclear spins remain weakly coupled to their environment, allowing exceptionally long coherence times. When the electron is present, the hyperfine interaction allows coupling of the spin and charge degrees of freedom for fast qubit operation and control. Here we demonstrate the use of the hyperfine interaction to enact electric dipole spin resonance to realize high-fidelity ( F = 10 0 - 6 + 0 %) initialization of all the nuclear spins within a four-qubit nuclear spin register. By controllably initializing the nuclear spins to⇓ ⇓ ⇓ , we achieve single-electron qubit gate fidelities of F = 99.78 ± 0.07% (Clifford gate fidelities of 99.58 ± 0.14%), above the fault-tolerant threshold for the surface code with a coherence time ofT 2 * = 12 μ s .
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Affiliation(s)
- J Reiner
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales, Australia
- Silicon Quantum Computing Pty Ltd., University of New South Wales, Sydney, New South Wales, Australia
| | - Y Chung
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales, Australia
- Silicon Quantum Computing Pty Ltd., University of New South Wales, Sydney, New South Wales, Australia
| | - S H Misha
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales, Australia
- Silicon Quantum Computing Pty Ltd., University of New South Wales, Sydney, New South Wales, Australia
| | - C Lehner
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales, Australia
- Silicon Quantum Computing Pty Ltd., University of New South Wales, Sydney, New South Wales, Australia
| | - C Moehle
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales, Australia
- Silicon Quantum Computing Pty Ltd., University of New South Wales, Sydney, New South Wales, Australia
| | - D Poulos
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales, Australia
- Silicon Quantum Computing Pty Ltd., University of New South Wales, Sydney, New South Wales, Australia
| | - S Monir
- Silicon Quantum Computing Pty Ltd., University of New South Wales, Sydney, New South Wales, Australia
- School of Physics, University of New South Wales, Sydney, New South Wales, Australia
| | - K J Charde
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales, Australia
- Silicon Quantum Computing Pty Ltd., University of New South Wales, Sydney, New South Wales, Australia
| | - P Macha
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales, Australia
- Silicon Quantum Computing Pty Ltd., University of New South Wales, Sydney, New South Wales, Australia
| | - L Kranz
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales, Australia
- Silicon Quantum Computing Pty Ltd., University of New South Wales, Sydney, New South Wales, Australia
| | - I Thorvaldson
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales, Australia
- Silicon Quantum Computing Pty Ltd., University of New South Wales, Sydney, New South Wales, Australia
| | - B Thorgrimsson
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales, Australia
- Silicon Quantum Computing Pty Ltd., University of New South Wales, Sydney, New South Wales, Australia
| | - D Keith
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales, Australia
- Silicon Quantum Computing Pty Ltd., University of New South Wales, Sydney, New South Wales, Australia
| | - Y L Hsueh
- Silicon Quantum Computing Pty Ltd., University of New South Wales, Sydney, New South Wales, Australia
- School of Physics, University of New South Wales, Sydney, New South Wales, Australia
| | - R Rahman
- Silicon Quantum Computing Pty Ltd., University of New South Wales, Sydney, New South Wales, Australia
- School of Physics, University of New South Wales, Sydney, New South Wales, Australia
| | - S K Gorman
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales, Australia
- Silicon Quantum Computing Pty Ltd., University of New South Wales, Sydney, New South Wales, Australia
| | - J G Keizer
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales, Australia
- Silicon Quantum Computing Pty Ltd., University of New South Wales, Sydney, New South Wales, Australia
| | - M Y Simmons
- Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales, Australia.
- Silicon Quantum Computing Pty Ltd., University of New South Wales, Sydney, New South Wales, Australia.
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5
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Kot P, Ismail M, Drost R, Siebrecht J, Huang H, Ast CR. Electric control of spin transitions at the atomic scale. Nat Commun 2023; 14:6612. [PMID: 37857623 PMCID: PMC10587172 DOI: 10.1038/s41467-023-42287-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 10/05/2023] [Indexed: 10/21/2023] Open
Abstract
Electric control of spins has been a longstanding goal in the field of solid state physics due to the potential for increased efficiency in information processing. This efficiency can be optimized by transferring spintronics to the atomic scale. We present electric control of spin resonance transitions in single TiH molecules by employing electron spin resonance scanning tunneling microscopy (ESR-STM). We find strong bias voltage dependent shifts in the ESR signal of about ten times its line width. We attribute this to the electric field in the tunnel junction, which induces a displacement of the spin system changing the g-factor and the effective magnetic field of the tip. We demonstrate direct electric control of the spin transitions in coupled TiH dimers. Our findings open up new avenues for fast coherent control of coupled spin systems and expands on the understanding of spin electric coupling.
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Affiliation(s)
- Piotr Kot
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569, Stuttgart, Germany
| | - Maneesha Ismail
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569, Stuttgart, Germany
| | - Robert Drost
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569, Stuttgart, Germany
| | - Janis Siebrecht
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569, Stuttgart, Germany
| | - Haonan Huang
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569, Stuttgart, Germany
| | - Christian R Ast
- Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569, Stuttgart, Germany.
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6
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Schneider E, England J. Isotopically Enriched Layers for Quantum Computers Formed by 28Si Implantation and Layer Exchange. ACS APPLIED MATERIALS & INTERFACES 2023; 15:21609-21617. [PMID: 37075328 PMCID: PMC10165600 DOI: 10.1021/acsami.3c01112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
28Si enrichment is crucial for production of group IV semiconductor-based quantum computers. Cryogenically cooled, monocrystalline 28Si is a spin-free, vacuum-like environment where qubits are protected from sources of decoherence that cause loss of quantum information. Currently, 28Si enrichment techniques rely on deposition of centrifuged SiF4 gas, the source of which is not widely available, or bespoke ion implantation methods. Previously, conventional ion implantation into naturalSi substrates has produced heavily oxidized 28Si layers. Here we report on a novel enrichment process involving ion implantation of 28Si into Al films deposited on native-oxide free Si substrates followed by layer exchange crystallization. We measured continuous, oxygen-free epitaxial 28Si enriched to 99.7%. Increases in isotopic enrichment are possible, and improvements in crystal quality, aluminum content, and thickness uniformity are required before the process can be considered viable. TRIDYN models, used to model 30 keV 28Si implants into Al to understand the observed post-implant layers and to investigate the implanted layer exchange process window over different energy and vacuum conditions, showed that the implanted layer exchange process is insensitive to implantation energy and would increase in efficiency with oxygen concentrations in the implanter end-station by reducing sputtering. Required implant fluences are an order of magnitude lower than those required for enrichment by direct 28Si implants into Si and can be chosen to control the final thickness of the enriched layer. We show that implanted layer exchange could potentially produce quantum grade 28Si using conventional semiconductor foundry equipment within production-worthy time scales.
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Affiliation(s)
- Ella Schneider
- Surrey Ion Beam Centre, Advanced Technology Institute, University of Surrey, Guildford GU2 7XH, United Kingdom
| | - Jonathan England
- Surrey Ion Beam Centre, Advanced Technology Institute, University of Surrey, Guildford GU2 7XH, United Kingdom
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7
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Savytskyy R, Botzem T, Fernandez de Fuentes I, Joecker B, Pla JJ, Hudson FE, Itoh KM, Jakob AM, Johnson BC, Jamieson DN, Dzurak AS, Morello A. An electrically driven single-atom "flip-flop" qubit. SCIENCE ADVANCES 2023; 9:eadd9408. [PMID: 36763660 PMCID: PMC9916988 DOI: 10.1126/sciadv.add9408] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 01/09/2023] [Indexed: 06/18/2023]
Abstract
The spins of atoms and atom-like systems are among the most coherent objects in which to store quantum information. However, the need to address them using oscillating magnetic fields hinders their integration with quantum electronic devices. Here, we circumvent this hurdle by operating a single-atom "flip-flop" qubit in silicon, where quantum information is encoded in the electron-nuclear states of a phosphorus donor. The qubit is controlled using local electric fields at microwave frequencies, produced within a metal-oxide-semiconductor device. The electrical drive is mediated by the modulation of the electron-nuclear hyperfine coupling, a method that can be extended to many other atomic and molecular systems and to the hyperpolarization of nuclear spin ensembles. These results pave the way to the construction of solid-state quantum processors where dense arrays of atoms can be controlled using only local electric fields.
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Affiliation(s)
- Rostyslav Savytskyy
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Tim Botzem
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | | | - Benjamin Joecker
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Jarryd J. Pla
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Fay E. Hudson
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Kohei M. Itoh
- School of Fundamental Science and Technology, Keio University, Kohoku-ku, Yokohama, Japan
| | - Alexander M. Jakob
- School of Physics, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Brett C. Johnson
- School of Physics, University of Melbourne, Melbourne, VIC 3010, Australia
| | - David N. Jamieson
- School of Physics, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Andrew S. Dzurak
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Andrea Morello
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW 2052, Australia
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8
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Gilbert W, Tanttu T, Lim WH, Feng M, Huang JY, Cifuentes JD, Serrano S, Mai PY, Leon RCC, Escott CC, Itoh KM, Abrosimov NV, Pohl HJ, Thewalt MLW, Hudson FE, Morello A, Laucht A, Yang CH, Saraiva A, Dzurak AS. On-demand electrical control of spin qubits. NATURE NANOTECHNOLOGY 2023; 18:131-136. [PMID: 36635331 DOI: 10.1038/s41565-022-01280-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 10/24/2022] [Indexed: 06/17/2023]
Abstract
Once called a 'classically non-describable two-valuedness' by Pauli, the electron spin forms a qubit that is naturally robust to electric fluctuations. Paradoxically, a common control strategy is the integration of micromagnets to enhance the coupling between spins and electric fields, which, in turn, hampers noise immunity and adds architectural complexity. Here we exploit a switchable interaction between spins and orbital motion of electrons in silicon quantum dots, without a micromagnet. The weak effects of relativistic spin-orbit interaction in silicon are enhanced, leading to a speed up in Rabi frequency by a factor of up to 650 by controlling the energy quantization of electrons in the nanostructure. Fast electrical control is demonstrated in multiple devices and electronic configurations. Using the electrical drive, we achieve a coherence time T2,Hahn ≈ 50 μs, fast single-qubit gates with Tπ/2 = 3 ns and gate fidelities of 99.93%, probed by randomized benchmarking. High-performance all-electrical control improves the prospects for scalable silicon quantum computing.
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Affiliation(s)
- Will Gilbert
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia.
- Diraq, Sydney, New South Wales, Australia.
| | - Tuomo Tanttu
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - Wee Han Lim
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - MengKe Feng
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Jonathan Y Huang
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Jesus D Cifuentes
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Santiago Serrano
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Philip Y Mai
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Ross C C Leon
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Christopher C Escott
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - Kohei M Itoh
- School of Fundamental Science and Technology, Keio University, Yokohama, Japan
| | | | | | - Michael L W Thewalt
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Fay E Hudson
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - Andrea Morello
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Arne Laucht
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - Chih Hwan Yang
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - Andre Saraiva
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia.
- Diraq, Sydney, New South Wales, Australia.
| | - Andrew S Dzurak
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia.
- Diraq, Sydney, New South Wales, Australia.
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9
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Johnson BC, Stuiber M, Creedon DL, Bose M, Berhane A, Willems van Beveren LH, Rubanov S, Cole JH, Mourik V, Hamilton AR, Duty TL, McCallum JC. Silicon-Aluminum Phase-Transformation-Induced Superconducting Rings. NANO LETTERS 2023; 23:17-24. [PMID: 36573935 DOI: 10.1021/acs.nanolett.2c02814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The development of devices that exhibit both superconducting and semiconducting properties is an important endeavor for emerging quantum technologies. We investigate superconducting nanowires fabricated on a silicon-on-insulator (SOI) platform. Aluminum from deposited contact electrodes is found to interdiffuse with Si along the entire length of the nanowire, over micrometer length scales and at temperatures well below the Al-Si eutectic. The phase-transformed material is conformal with the predefined device patterns. The superconducting properties of a transformed mesoscopic ring formed on a SOI platform are investigated. Low-temperature magnetoresistance oscillations, quantized in units of the fluxoid, h/2e, are observed.
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Affiliation(s)
- Brett C Johnson
- School of Science, RMIT University, Melbourne, Victoria3001, Australia
| | - Michael Stuiber
- Melbourne Centre for Nanofabrication, Clayton, Victoria3168, Australia
| | - Daniel L Creedon
- School of Physics, University of Melbourne, Parkville, Victoria3010, Australia
| | - Manjith Bose
- School of Physics, University of Melbourne, Parkville, Victoria3010, Australia
| | - Amanuel Berhane
- School of Physics, University of New South Wales, Sydney, New South Wales1466, Australia
| | | | - Sergey Rubanov
- Ian Holmes Imaging Centre, Bio21 Institute, University of Melbourne, Parkville, Victoria3010, Australia
| | - Jared H Cole
- School of Science, RMIT University, Melbourne, Victoria3001, Australia
| | - Vincent Mourik
- School of Physics, University of New South Wales, Sydney, New South Wales1466, Australia
| | - Alexander R Hamilton
- School of Physics, University of New South Wales, Sydney, New South Wales1466, Australia
| | - Timothy L Duty
- School of Physics, University of New South Wales, Sydney, New South Wales1466, Australia
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10
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Šimėnas M, O'Sullivan J, Kennedy OW, Lin S, Fearn S, Zollitsch CW, Dold G, Schmitt T, Schüffelgen P, Liu RB, Morton JJL. Near-Surface ^{125}Te^{+} Spins with Millisecond Coherence Lifetime. PHYSICAL REVIEW LETTERS 2022; 129:117701. [PMID: 36154421 DOI: 10.1103/physrevlett.129.117701] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 03/11/2022] [Accepted: 07/20/2022] [Indexed: 06/16/2023]
Abstract
Impurity spins in crystal matrices are promising components in quantum technologies, particularly if they can maintain their spin properties when close to surfaces and material interfaces. Here, we investigate an attractive candidate for microwave-domain applications, the spins of group-VI ^{125}Te^{+} donors implanted into natural Si at depths as shallow as 20 nm. We show that surface band bending can be used to ionize such near-surface Te to spin-active Te^{+} state, and that optical illumination can be used further to control the Te donor charge state. We examine spin activation yield, spin linewidth, and relaxation (T_{1}) and coherence times (T_{2}) and show how a zero-field 3.5 GHz "clock transition" extends spin coherence times to over 1 ms, which is about an order of magnitude longer than other near-surface spin systems.
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Affiliation(s)
- Mantas Šimėnas
- London Centre for Nanotechnology, UCL, 17-19 Gordon Street, London WC1H 0AH, United Kingdom
| | - James O'Sullivan
- London Centre for Nanotechnology, UCL, 17-19 Gordon Street, London WC1H 0AH, United Kingdom
| | - Oscar W Kennedy
- London Centre for Nanotechnology, UCL, 17-19 Gordon Street, London WC1H 0AH, United Kingdom
| | - Sen Lin
- Department of Physics, Centre for Quantum Coherence and The Hong Kong Institute of Quantum Information Science and Technology, The Chinese University of Hong Kong, Hong Kong, China
| | - Sarah Fearn
- Department of Materials, Imperial College London, London SW7 2BX, United Kingdom
| | - Christoph W Zollitsch
- London Centre for Nanotechnology, UCL, 17-19 Gordon Street, London WC1H 0AH, United Kingdom
| | - Gavin Dold
- London Centre for Nanotechnology, UCL, 17-19 Gordon Street, London WC1H 0AH, United Kingdom
| | - Tobias Schmitt
- Institute for Semiconductor Nanoelectronics, Peter Grünberg Institute 9, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
| | - Peter Schüffelgen
- Institute for Semiconductor Nanoelectronics, Peter Grünberg Institute 9, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
| | - Ren-Bao Liu
- Department of Physics, Centre for Quantum Coherence and The Hong Kong Institute of Quantum Information Science and Technology, The Chinese University of Hong Kong, Hong Kong, China
| | - John J L Morton
- London Centre for Nanotechnology, UCL, 17-19 Gordon Street, London WC1H 0AH, United Kingdom
- Department of Electrical and Electronic Engineering, UCL, Malet Place, London WC1E 7JE, United Kingdom
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11
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Tremblay MA, Delfosse N, Beverland ME. Constant-Overhead Quantum Error Correction with Thin Planar Connectivity. PHYSICAL REVIEW LETTERS 2022; 129:050504. [PMID: 35960553 DOI: 10.1103/physrevlett.129.050504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 06/15/2022] [Indexed: 06/15/2023]
Abstract
Quantum low density parity check (LDPC) codes may provide a path to build low-overhead fault-tolerant quantum computers. However, as general LDPC codes lack geometric constraints, naïve layouts couple many distant qubits with crossing connections which could be hard to build in hardware and could result in performance-degrading crosstalk. We propose a 2D layout for quantum LDPC codes by decomposing their Tanner graphs into a small number of planar layers. Each layer contains long-range connections which do not cross. For any Calderbank-Shor-Steane code with a degree-δ Tanner graph, we design stabilizer measurement circuits with depth at most (2δ+2) using at most ⌈δ/2⌉ layers. We observe a circuit-noise threshold of 0.28% for a positive-rate code family using 49 physical qubits per logical qubit. For a physical error rate of 10^{-4}, this family reaches a logical error rate of 10^{-15} using fourteen times fewer physical qubits than the surface code.
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Affiliation(s)
- Maxime A Tremblay
- Institut quantique & Département de physique, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Nicolas Delfosse
- Microsoft Quantum & Microsoft Research, Redmond, Washington 98052, USA
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12
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Cujia KS, Herb K, Zopes J, Abendroth JM, Degen CL. Parallel detection and spatial mapping of large nuclear spin clusters. Nat Commun 2022; 13:1260. [PMID: 35273190 PMCID: PMC8913684 DOI: 10.1038/s41467-022-28935-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 12/08/2021] [Indexed: 11/09/2022] Open
Abstract
Nuclear magnetic resonance imaging (MRI) at the atomic scale offers exciting prospects for determining the structure and function of individual molecules and proteins. Quantum defects in diamond have recently emerged as a promising platform towards reaching this goal, and allowed for the detection and localization of single nuclear spins under ambient conditions. Here, we present an efficient strategy for extending imaging to large nuclear spin clusters, fulfilling an important requirement towards a single-molecule MRI technique. Our method combines the concepts of weak quantum measurements, phase encoding and simulated annealing to detect three-dimensional positions from many nuclei in parallel. Detection is spatially selective, allowing us to probe nuclei at a chosen target radius while avoiding interference from strongly-coupled proximal nuclei. We demonstrate our strategy by imaging clusters containing more than 20 carbon-13 nuclear spins within a radius of 2.4 nm from single, near-surface nitrogen-vacancy centers at room temperature. The radius extrapolates to 5-6 nm for 1H. Beside taking an important step in nanoscale MRI, our experiment also provides an efficient tool for the characterization of large nuclear spin registers in the context of quantum simulators and quantum network nodes.
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Affiliation(s)
- K S Cujia
- Department of Physics, ETH Zurich, Otto Stern Weg 1, 8093, Zurich, Switzerland. .,IT'IS Foundation, Zeughausstrasse 43, 8004, Zurich, Switzerland.
| | - K Herb
- Department of Physics, ETH Zurich, Otto Stern Weg 1, 8093, Zurich, Switzerland.
| | - J Zopes
- Department of Physics, ETH Zurich, Otto Stern Weg 1, 8093, Zurich, Switzerland. .,Ansys Switzerland GmbH, Technoparkstrasse 1, 8005, Zurich, Switzerland.
| | - J M Abendroth
- Department of Physics, ETH Zurich, Otto Stern Weg 1, 8093, Zurich, Switzerland.
| | - C L Degen
- Department of Physics, ETH Zurich, Otto Stern Weg 1, 8093, Zurich, Switzerland. .,Quantum Center, ETH Zurich, 8093, Zurich, Switzerland.
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13
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Alfieri A, Anantharaman SB, Zhang H, Jariwala D. Nanomaterials for Quantum Information Science and Engineering. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022:e2109621. [PMID: 35139247 DOI: 10.1002/adma.202109621] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 02/04/2022] [Indexed: 06/14/2023]
Abstract
Quantum information science and engineering (QISE)-which entails the use of quantum mechanical states for information processing, communications, and sensing-and the area of nanoscience and nanotechnology have dominated condensed matter physics and materials science research in the 21st century. Solid-state devices for QISE have, to this point, predominantly been designed with bulk materials as their constituents. This review considers how nanomaterials (i.e., materials with intrinsic quantum confinement) may offer inherent advantages over conventional materials for QISE. The materials challenges for specific types of qubits, along with how emerging nanomaterials may overcome these challenges, are identified. Challenges for and progress toward nanomaterials-based quantum devices are condidered. The overall aim of the review is to help close the gap between the nanotechnology and quantum information communities and inspire research that will lead to next-generation quantum devices for scalable and practical quantum applications.
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Affiliation(s)
- Adam Alfieri
- Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Surendra B Anantharaman
- Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Huiqin Zhang
- Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Deep Jariwala
- Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
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14
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Precision tomography of a three-qubit donor quantum processor in silicon. Nature 2022; 601:348-353. [PMID: 35046601 DOI: 10.1038/s41586-021-04292-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 11/29/2021] [Indexed: 11/08/2022]
Abstract
Nuclear spins were among the first physical platforms to be considered for quantum information processing1,2, because of their exceptional quantum coherence3 and atomic-scale footprint. However, their full potential for quantum computing has not yet been realized, owing to the lack of methods with which to link nuclear qubits within a scalable device combined with multi-qubit operations with sufficient fidelity to sustain fault-tolerant quantum computation. Here we demonstrate universal quantum logic operations using a pair of ion-implanted 31P donor nuclei in a silicon nanoelectronic device. A nuclear two-qubit controlled-Z gate is obtained by imparting a geometric phase to a shared electron spin4, and used to prepare entangled Bell states with fidelities up to 94.2(2.7)%. The quantum operations are precisely characterized using gate set tomography (GST)5, yielding one-qubit average gate fidelities up to 99.95(2)%, two-qubit average gate fidelity of 99.37(11)% and two-qubit preparation/measurement fidelities of 98.95(4)%. These three metrics indicate that nuclear spins in silicon are approaching the performance demanded in fault-tolerant quantum processors6. We then demonstrate entanglement between the two nuclei and the shared electron by producing a Greenberger-Horne-Zeilinger three-qubit state with 92.5(1.0)% fidelity. Because electron spin qubits in semiconductors can be further coupled to other electrons7-9 or physically shuttled across different locations10,11, these results establish a viable route for scalable quantum information processing using donor nuclear and electron spins.
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15
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Jakob AM, Robson SG, Schmitt V, Mourik V, Posselt M, Spemann D, Johnson BC, Firgau HR, Mayes E, McCallum JC, Morello A, Jamieson DN. Deterministic Shallow Dopant Implantation in Silicon with Detection Confidence Upper-Bound to 99.85% by Ion-Solid Interactions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2103235. [PMID: 34632636 DOI: 10.1002/adma.202103235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 08/17/2021] [Indexed: 06/13/2023]
Abstract
Silicon chips containing arrays of single dopant atoms can be the material of choice for classical and quantum devices that exploit single donor spins. For example, group-V donors implanted in isotopically purified 28 Si crystals are attractive for large-scale quantum computers. Useful attributes include long nuclear and electron spin lifetimes of 31 P, hyperfine clock transitions in 209 Bi or electrically controllable 123 Sb nuclear spins. Promising architectures require the ability to fabricate arrays of individual near-surface dopant atoms with high yield. Here, an on-chip detector electrode system with 70 eV root-mean-square noise (≈20 electrons) is employed to demonstrate near-room-temperature implantation of single 14 keV 31 P+ ions. The physics model for the ion-solid interaction shows an unprecedented upper-bound single-ion-detection confidence of 99.85 ± 0.02% for near-surface implants. As a result, the practical controlled silicon doping yield is limited by materials engineering factors including surface gate oxides in which detected ions may stop. For a device with 6 nm gate oxide and 14 keV 31 P+ implants, a yield limit of 98.1% is demonstrated. Thinner gate oxides allow this limit to converge to the upper-bound. Deterministic single-ion implantation can therefore be a viable materials engineering strategy for scalable dopant architectures in silicon devices.
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Affiliation(s)
- Alexander M Jakob
- School of Physics, ARC Centre for Quantum Computation and Communication Technology, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Simon G Robson
- School of Physics, ARC Centre for Quantum Computation and Communication Technology, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Vivien Schmitt
- School of Electrical Engineering and Telecommunications, ARC Centre for Quantum Computation and Communication Technology, UNSW Sydney, Sydney, NSW, 2052, Australia
| | - Vincent Mourik
- School of Electrical Engineering and Telecommunications, ARC Centre for Quantum Computation and Communication Technology, UNSW Sydney, Sydney, NSW, 2052, Australia
| | - Matthias Posselt
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, 01328, Saxony, Germany
| | - Daniel Spemann
- School of Physics, ARC Centre for Quantum Computation and Communication Technology, University of Melbourne, Parkville, VIC, 3010, Australia
- Leibniz Institute of Surface Engineering (IOM), Leipzig, 04318, Saxony, Germany
| | - Brett C Johnson
- School of Physics, ARC Centre for Quantum Computation and Communication Technology, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Hannes R Firgau
- School of Electrical Engineering and Telecommunications, ARC Centre for Quantum Computation and Communication Technology, UNSW Sydney, Sydney, NSW, 2052, Australia
| | - Edwin Mayes
- RMIT Microscopy and Microanalysis Facility, RMIT University, Melbourne, VIC, 3001, Australia
| | - Jeffrey C McCallum
- School of Physics, ARC Centre for Quantum Computation and Communication Technology, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Andrea Morello
- School of Electrical Engineering and Telecommunications, ARC Centre for Quantum Computation and Communication Technology, UNSW Sydney, Sydney, NSW, 2052, Australia
| | - David N Jamieson
- School of Physics, ARC Centre for Quantum Computation and Communication Technology, University of Melbourne, Parkville, VIC, 3010, Australia
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16
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Germanium Quantum-Dot Array with Self-Aligned Electrodes for Quantum Electronic Devices. NANOMATERIALS 2021; 11:nano11102743. [PMID: 34685184 PMCID: PMC8541477 DOI: 10.3390/nano11102743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 10/12/2021] [Accepted: 10/13/2021] [Indexed: 11/20/2022]
Abstract
Semiconductor-based quantum registers require scalable quantum-dots (QDs) to be accurately located in close proximity to and independently addressable by external electrodes. Si-based QD qubits have been realized in various lithographically-defined Si/SiGe heterostructures and validated only for milli-Kelvin temperature operation. QD qubits have recently been explored in germanium (Ge) materials systems that are envisaged to operate at higher temperatures, relax lithographic-fabrication requirements, and scale up to large quantum systems. We report the unique scalability and tunability of Ge spherical-shaped QDs that are controllably located, closely coupled between each another, and self-aligned with control electrodes, using a coordinated combination of lithographic patterning and self-assembled growth. The core experimental design is based on the thermal oxidation of poly-SiGe spacer islands located at each sidewall corner or included-angle location of Si3N4/Si-ridges with specially designed fanout structures. Multiple Ge QDs with good tunability in QD sizes and self-aligned electrodes were controllably achieved. Spherical-shaped Ge QDs are closely coupled to each other via coupling barriers of Si3N4 spacer layers/c-Si that are electrically tunable via self-aligned poly-Si or polycide electrodes. Our ability to place size-tunable spherical Ge QDs at any desired location, therefore, offers a large parameter space within which to design novel quantum electronic devices.
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17
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Zhang L, Yang X, Li S, Zhang J. Functionalized Silicon Electrodes Toward Electrostatic Catalysis. Front Chem 2021; 9:715647. [PMID: 34386481 PMCID: PMC8353247 DOI: 10.3389/fchem.2021.715647] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 06/22/2021] [Indexed: 11/13/2022] Open
Abstract
Oriented external electric fields are now emerging as "smart effectors" of chemical changes. The key challenges in experimentally studying electrostatic catalysis are (i) controlling the orientation of fields along the reaction axis and (ii) finely adjusting the magnitudes of electrostatic stimuli. Surface models provide a versatile platform for addressing the direction of electric fields with respect to reactants and balancing the trade-off between the solubility of charged species and the intensity of electric fields. In this mini-review, we present the recent advances that have been investigated of the electrostatic effect on the chemical reaction on the monolayer-functionalized silicon surfaces. We mainly focus on elucidating the mediator/catalysis role of static electric fields induced from either solid/liquid electric double layers at electrode/electrolyte interfaces or space charges in the semiconductors, indicating the electrostatic aspects is of great significance in the semiconductor electrochemistry, redox electroactivity, and chemical bonding. Herein, the functionalization of silicon surfaces allows scientists to explore electrostatic catalysis from nanoscale to mesoscale; most importantly, it provides glimpses of the wide-ranging potentials of oriented electric fields for switching on/off the macroscale synthetic organic electrochemistry and living radical polymerization.
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Affiliation(s)
- Long Zhang
- Institute of Quantum and Sustainable Technology (IQST), School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, China.,Foshan (Southern China) Institute for New Materials, Foshan, China
| | - Xiaohua Yang
- Institute of Quantum and Sustainable Technology (IQST), School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, China
| | - Shun Li
- Institute of Quantum and Sustainable Technology (IQST), School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, China
| | - JianMing Zhang
- Institute of Quantum and Sustainable Technology (IQST), School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, China
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18
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Harpak N, Davidi G, Granot E, Patolsky F. Diversely Doped Uniform Silicon Nanotube Axial Heterostructures Enabled by "Dopant Reflection". LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:1247-1254. [PMID: 33417463 DOI: 10.1021/acs.langmuir.0c03249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Here, we propose a novel method for the synthesis of extremely uniform, diversely doped silicon nanotube heterostructures. The method, comprising a simple two-step synthesis, exploits the use of a Ge nanowire sacrificial core upon which a multidoping axial pattern can be easily obtained, that is enclosed in an intrinsic Si shell. The Ge-Si core-shell structure is then heated to 750 °C, allowing the migration of dopant elements from the Ge core directly into the Si shell. Removal of the Ge core, via either wet or dry etch, does not impair the crystallinity of the Si shell nor its electrical characteristics, allowing for the formation of a multidoped axially patterned, conformal, and uniform Si nanotube. The precise dopant patterning allows for the extension of Si nanotube applications, which were unattainable because of the inability to precisely control the parameters and uniformity of the nanotubes while doping the structure simultaneously.
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Affiliation(s)
- Nimrod Harpak
- School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Guy Davidi
- School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Eran Granot
- School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Fernando Patolsky
- School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
- Department of Materials Science and Engineering, the Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
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19
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Ma Dzik MT, Laucht A, Hudson FE, Jakob AM, Johnson BC, Jamieson DN, Itoh KM, Dzurak AS, Morello A. Conditional quantum operation of two exchange-coupled single-donor spin qubits in a MOS-compatible silicon device. Nat Commun 2021; 12:181. [PMID: 33420013 PMCID: PMC7794236 DOI: 10.1038/s41467-020-20424-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 12/02/2020] [Indexed: 11/09/2022] Open
Abstract
Silicon nanoelectronic devices can host single-qubit quantum logic operations with fidelity better than 99.9%. For the spins of an electron bound to a single-donor atom, introduced in the silicon by ion implantation, the quantum information can be stored for nearly 1 second. However, manufacturing a scalable quantum processor with this method is considered challenging, because of the exponential sensitivity of the exchange interaction that mediates the coupling between the qubits. Here we demonstrate the conditional, coherent control of an electron spin qubit in an exchange-coupled pair of 31P donors implanted in silicon. The coupling strength, J = 32.06 ± 0.06 MHz, is measured spectroscopically with high precision. Since the coupling is weaker than the electron-nuclear hyperfine coupling A ≈ 90 MHz which detunes the two electrons, a native two-qubit controlled-rotation gate can be obtained via a simple electron spin resonance pulse. This scheme is insensitive to the precise value of J, which makes it suitable for the scale-up of donor-based quantum computers in silicon that exploit the metal-oxide-semiconductor fabrication protocols commonly used in the classical electronics industry.
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Affiliation(s)
- Mateusz T Ma Dzik
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW, 2052, Australia
| | - Arne Laucht
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW, 2052, Australia
| | - Fay E Hudson
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW, 2052, Australia
| | - Alexander M Jakob
- Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Brett C Johnson
- Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - David N Jamieson
- Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Kohei M Itoh
- School of Fundamental Science and Technology, Keio University, 3-14-1, Hiyoshi, 223-8522, Japan
| | - Andrew S Dzurak
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW, 2052, Australia
| | - Andrea Morello
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, NSW, 2052, Australia.
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20
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Bello F, Kongsuwan N, Donegan JF, Hess O. Controlled Cavity-Free, Single-Photon Emission and Bipartite Entanglement of Near-Field-Excited Quantum Emitters. NANO LETTERS 2020; 20:5830-5836. [PMID: 32574498 DOI: 10.1021/acs.nanolett.0c01705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We report theoretical statistics of 1- and 2-qubit (bipartite) systems, namely, photon antibunching and entanglement, of near-field excited quantum emitters. The sub-diffraction focusing of a plasmonic waveguide is shown to generate enough power over a sufficiently small region (<50 × 50 nm2) to strongly drive quantum emitters. This enables ultrafast (10-14 s) single-photon emission as well as creates entangled states between two emitters when performing a controlled-NOT operation. A comparative analysis of silicon and near-zero index materials demonstrates advantages and uncovers challenges of embedding quantum emitters for single-photon emission and for bipartite entanglement. The use of a movable plasmonic waveguide, in lieu of stationary nanostructures, allows high-speed rasterization between sets of qubits and enables spatially flexible data storage and quantum information processing. Furthermore, the sub-diffraction focusing of the waveguide is shown to achieve cavity-free dynamic entanglement. This greatly reduces fabrication constraints and increases the speed and scalability of nanophotonic quantum devices.
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Affiliation(s)
- Frank Bello
- School of Physics and CRANN Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Nuttawut Kongsuwan
- Blackett Laboratory, Department of Physics, Imperial College London, London SW7 2AZ, U.K
- Quantum Technology Foundation (Thailand), 98 Soi Ari, Bangkok 10110, Thailand
- Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400, Thailand
| | - John F Donegan
- School of Physics and CRANN Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Ortwin Hess
- School of Physics and CRANN Institute, Trinity College Dublin, Dublin 2, Ireland
- Blackett Laboratory, Department of Physics, Imperial College London, London SW7 2AZ, U.K
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21
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Giménez-Santamarina S, Cardona-Serra S, Clemente-Juan JM, Gaita-Ariño A, Coronado E. Exploiting clock transitions for the chemical design of resilient molecular spin qubits. Chem Sci 2020; 11:10718-10728. [PMID: 34094324 PMCID: PMC8162297 DOI: 10.1039/d0sc01187h] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Molecular spin qubits are chemical nanoobjects with promising applications that are so far hampered by the rapid loss of quantum information, a process known as decoherence. A strategy to improve this situation involves employing so-called Clock Transitions (CTs), which arise at anticrossings between spin energy levels. At CTs, the spin states are protected from magnetic noise and present an enhanced quantum coherence. Unfortunately, these optimal points are intrinsically hard to control since their transition energy cannot be tuned by an external magnetic field; moreover, their resilience towards geometric distortions has not yet been analyzed. Here we employ a python-based computational tool for the systematic theoretical analysis and chemical optimization of CTs. We compare three relevant case studies with increasingly complex ground states. First, we start with vanadium(iv)-based spin qubits, where the avoided crossings are controlled by hyperfine interaction and find that these S = 1/2 systems are very promising, in particular in the case of vanadyl complexes in an L-band pulsed EPR setup. Second, we proceed with a study of the effect of symmetry distortions in a holmium polyoxotungstate of formula [Ho(W5O18)2]9- where CTs had already been experimentally demonstrated. Here we determine the relative importance of the different structural distortions that causes the anticrossings. Third, we study the most complicated case, a polyoxopalladate cube [HoPd12(AsPh)8O32]5- which presents an unusually rich ground spin multiplet. This system allows us to find uniquely favorable CTs that could nevertheless be accessible with standard pulsed EPR equipment (X-band or Q-band) after a suitable chemical distortion to break the perfect cubic symmetry. Since anticrossings and CTs constitute a rich source of physical phenomena in very different kinds of quantum systems, the generalization of this study is expected to have impact not only in molecular spin science but also in other related fields such as molecular photophysics and photochemistry.
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Affiliation(s)
| | - Salvador Cardona-Serra
- ICMol, Universitat de València C/Catedrático José Beltrán no 2 46980 Paterna Valencia Spain
| | - Juan M Clemente-Juan
- ICMol, Universitat de València C/Catedrático José Beltrán no 2 46980 Paterna Valencia Spain
| | - Alejandro Gaita-Ariño
- ICMol, Universitat de València C/Catedrático José Beltrán no 2 46980 Paterna Valencia Spain
| | - Eugenio Coronado
- ICMol, Universitat de València C/Catedrático José Beltrán no 2 46980 Paterna Valencia Spain
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22
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Asaad S, Mourik V, Joecker B, Johnson MAI, Baczewski AD, Firgau HR, Mądzik MT, Schmitt V, Pla JJ, Hudson FE, Itoh KM, McCallum JC, Dzurak AS, Laucht A, Morello A. Coherent electrical control of a single high-spin nucleus in silicon. Nature 2020; 579:205-209. [PMID: 32161384 DOI: 10.1038/s41586-020-2057-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 01/30/2020] [Indexed: 11/09/2022]
Abstract
Nuclear spins are highly coherent quantum objects. In large ensembles, their control and detection via magnetic resonance is widely exploited, for example, in chemistry, medicine, materials science and mining. Nuclear spins also featured in early proposals for solid-state quantum computers1 and demonstrations of quantum search2 and factoring3 algorithms. Scaling up such concepts requires controlling individual nuclei, which can be detected when coupled to an electron4-6. However, the need to address the nuclei via oscillating magnetic fields complicates their integration in multi-spin nanoscale devices, because the field cannot be localized or screened. Control via electric fields would resolve this problem, but previous methods7-9 relied on transducing electric signals into magnetic fields via the electron-nuclear hyperfine interaction, which severely affects nuclear coherence. Here we demonstrate the coherent quantum control of a single 123Sb (spin-7/2) nucleus using localized electric fields produced within a silicon nanoelectronic device. The method exploits an idea proposed in 196110 but not previously realized experimentally with a single nucleus. Our results are quantitatively supported by a microscopic theoretical model that reveals how the purely electrical modulation of the nuclear electric quadrupole interaction results in coherent nuclear spin transitions that are uniquely addressable owing to lattice strain. The spin dephasing time, 0.1 seconds, is orders of magnitude longer than those obtained by methods that require a coupled electron spin to achieve electrical driving. These results show that high-spin quadrupolar nuclei could be deployed as chaotic models, strain sensors and hybrid spin-mechanical quantum systems using all-electrical controls. Integrating electrically controllable nuclei with quantum dots11,12 could pave the way to scalable, nuclear- and electron-spin-based quantum computers in silicon that operate without the need for oscillating magnetic fields.
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Affiliation(s)
- Serwan Asaad
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Vincent Mourik
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Benjamin Joecker
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Mark A I Johnson
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Andrew D Baczewski
- Center for Computing Research, Sandia National Laboratories, Albuquerque, NM, USA
| | - Hannes R Firgau
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Mateusz T Mądzik
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Vivien Schmitt
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Jarryd J Pla
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Fay E Hudson
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Kohei M Itoh
- School of Fundamental Science and Technology, Keio University, Yokohama, Japan
| | - Jeffrey C McCallum
- Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Melbourne, Victoria, Australia
| | - Andrew S Dzurak
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Arne Laucht
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia
| | - Andrea Morello
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia.
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23
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Hensen B, Wei Huang W, Yang CH, Wai Chan K, Yoneda J, Tanttu T, Hudson FE, Laucht A, Itoh KM, Ladd TD, Morello A, Dzurak AS. A silicon quantum-dot-coupled nuclear spin qubit. NATURE NANOTECHNOLOGY 2020; 15:13-17. [PMID: 31819245 DOI: 10.1038/s41565-019-0587-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 11/05/2019] [Indexed: 06/10/2023]
Abstract
Single nuclear spins in the solid state are a potential future platform for quantum computing1-3, because they possess long coherence times4-6 and offer excellent controllability7. Measurements can be performed via localized electrons, such as those in single atom dopants8,9 or crystal defects10-12. However, establishing long-range interactions between multiple dopants or defects is challenging13,14. Conversely, in lithographically defined quantum dots, tunable interdot electron tunnelling allows direct coupling of electron spin-based qubits in neighbouring dots15-20. Moreover, the compatibility with semiconductor fabrication techniques21 may allow for scaling to large numbers of qubits in the future. Unfortunately, hyperfine interactions are typically too weak to address single nuclei. Here we show that for electrons in silicon metal-oxide-semiconductor quantum dots the hyperfine interaction is sufficient to initialize, read out and control single 29Si nuclear spins. This approach combines the long coherence times of nuclear spins with the flexibility and scalability of quantum dot systems. We demonstrate high-fidelity projective readout and control of the nuclear spin qubit, as well as entanglement between the nuclear and electron spins. Crucially, we find that both the nuclear spin and electron spin retain their coherence while moving the electron between quantum dots. Hence we envision long-range nuclear-nuclear entanglement via electron shuttling3. Our results establish nuclear spins in quantum dots as a powerful new resource for quantum processing.
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Affiliation(s)
- Bas Hensen
- Center for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
- Delft University of Technology, Delft, The Netherlands
| | - Wister Wei Huang
- Center for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Chih-Hwan Yang
- Center for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Kok Wai Chan
- Center for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Jun Yoneda
- Center for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Tuomo Tanttu
- Center for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Fay E Hudson
- Center for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Arne Laucht
- Center for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Kohei M Itoh
- School of Fundamental Science and Technology, Keio University, Yokohama, Japan
| | | | - Andrea Morello
- Center for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Andrew S Dzurak
- Center for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia.
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24
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Huang TL, Peng KP, Chen CL, Lin HC, George T, Li PW. Tunable diameter and spacing of double Ge quantum dots using highly-controllable spacers and selective oxidation of SiGe. Sci Rep 2019; 9:11303. [PMID: 31383902 PMCID: PMC6683190 DOI: 10.1038/s41598-019-47806-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 07/24/2019] [Indexed: 11/30/2022] Open
Abstract
We report the novel tunability of the diameters and spacings of paired Ge double quantum dots (DQDs) using nano-spacer technology in combination with selective oxidation of Si0.85Ge0.15 at high temperature. Pairs of spherical-shaped Ge QDs were formed by the selective oxidation of poly-SiGe spacer islands at each sidewall corner of the nano-patterned Si3N4/poly-Si ridges. The diameters of the Ge spherical QDs are essentially determined by geometrical conditions (height, width, and length) of the nano-patterned spacer islands of poly-SiGe, which are tunable by adjusting the process times of deposition and etch back for poly-SiGe spacer layers in combination with the exposure dose of electron-beam lithography. Most importantly, the separations between the Ge DQDs are controllable by adjusting the widths of the poly-Si/Si3N4 ridges and the thermal oxidation times. Our self-organization and self-alignment approach achieved high symmetry within the Ge DQDs in terms of the individual QD diameters as well as the coupling barriers between the QDs and external electrodes in close proximity.
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25
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Groot-Berning K, Kornher T, Jacob G, Stopp F, Dawkins ST, Kolesov R, Wrachtrup J, Singer K, Schmidt-Kaler F. Deterministic Single-Ion Implantation of Rare-Earth Ions for Nanometer-Resolution Color-Center Generation. PHYSICAL REVIEW LETTERS 2019; 123:106802. [PMID: 31573288 DOI: 10.1103/physrevlett.123.106802] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Indexed: 05/24/2023]
Abstract
Single dopant atoms or dopant-related defect centers in a solid state matrix are of particular importance among the physical systems proposed for quantum computing and communication, due to their potential to realize a scalable architecture compatible with electronic and photonic integrated circuits. Here, using a deterministic source of single laser-cooled Pr^{+} ions, we present the fabrication of arrays of praseodymium color centers in yttrium-aluminum-garnet substrates. The beam of single Pr^{+} ions is extracted from a Paul trap and focused down to 30(9) nm. Using a confocal microscope, we determine a conversion yield into active color centers of up to 50% and realize a placement precision of 34 nm.
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Affiliation(s)
- Karin Groot-Berning
- QUANTUM, Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - Thomas Kornher
- Physikalisches Institut, Universität Stuttgart, 70569 Stuttgart, Germany
| | - Georg Jacob
- QUANTUM, Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - Felix Stopp
- QUANTUM, Institut für Physik, Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany
| | - Samuel T Dawkins
- Experimentalphysik I, Institut für Physik, Universität Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Roman Kolesov
- Physikalisches Institut, Universität Stuttgart, 70569 Stuttgart, Germany
| | - Jörg Wrachtrup
- Physikalisches Institut, Universität Stuttgart, 70569 Stuttgart, Germany
| | - Kilian Singer
- Experimentalphysik I, Institut für Physik, Universität Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
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26
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Atzori M, Sessoli R. The Second Quantum Revolution: Role and Challenges of Molecular Chemistry. J Am Chem Soc 2019; 141:11339-11352. [PMID: 31287678 DOI: 10.1021/jacs.9b00984] [Citation(s) in RCA: 199] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Implementation of modern Quantum Technologies might benefit from the remarkable quantum properties shown by molecular spin systems. In this Perspective, we highlight the role that molecular chemistry can have in the current second quantum revolution, i.e., the use of quantum physics principles to create new quantum technologies, in this specific case by means of molecular components. Herein, we briefly review the current status of the field by identifying the key advances recently made by the molecular chemistry community, such as for example the design of molecular spin qubits with long spin coherence and the realization of multiqubit architectures for quantum gates implementation. With a critical eye to the current state-of-the-art, we also highlight the main challenges needed for the further advancement of the field toward quantum technologies development.
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Affiliation(s)
- Matteo Atzori
- Laboratoire National des Champs Magnétiques Intenses, UPR 3228-CNRS , F-38042 Grenoble , France
| | - Roberta Sessoli
- Dipartimento di Chimica "Ugo Schiff" & INSTM RU , Università degli Studi di Firenze , I-50019 Sesto Fiorentino , Italy
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27
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Park DK, Park S, Jee H, Lee S. Electron spin relaxations of phosphorus donors in bulk silicon under large electric field. Sci Rep 2019; 9:2951. [PMID: 30814605 PMCID: PMC6393552 DOI: 10.1038/s41598-019-39613-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 01/21/2019] [Indexed: 11/09/2022] Open
Abstract
Modulation of donor electron wavefunction via electric fields is vital to quantum computing architectures based on donor spins in silicon. For practical and scalable applications, the donor-based qubits must retain sufficiently long coherence times in any realistic experimental conditions. Here, we present pulsed electron spin resonance studies on the longitudinal (T1) and transverse (T2) relaxation times of phosphorus donors in bulk silicon with various electric field strengths up to near avalanche breakdown in high magnetic fields of about 1.2 T and low temperatures of about 8 K. We find that the T1 relaxation time is significantly reduced under large electric fields due to electric current, and T2 is affected as the T1 process can dominate decoherence. Furthermore, we show that the magnetoresistance effect in silicon can be exploited as a means to combat the reduction in the coherence times. While qubit coherence times must be much longer than quantum gate times, electrically accelerated T1 can be found useful when qubit state initialization relies on thermal equilibration.
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Affiliation(s)
- Daniel K Park
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Korea. .,School of Electrical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Korea.
| | - Sejun Park
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Korea
| | - Hyejung Jee
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Korea.,Department of Physics, Imperial College London, London, SW7 2BW, United Kingdom
| | - Soonchil Lee
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Korea.
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28
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Abstract
This study alleviates the low operating temperature constraint of Si qubits. A qubit is a key element for quantum sensors, memories, and computers. Electron spin in Si is a promising qubit, as it allows both long coherence times and potential compatibility with current silicon technology. Si qubits have been implemented using gate-defined quantum dots or shallow impurities. However, operation of Si qubits has been restricted to milli-Kelvin temperatures, thus limiting the application of the quantum technology. In this study, we addressed a single deep impurity, having strong electron confinement of up to 0.3 eV, using single-electron tunnelling transport. We also achieved qubit operation at 5–10 K through a spin-blockade effect based on the tunnelling transport via two impurities. The deep impurity was implemented by tunnel field-effect transistors (TFETs) instead of conventional FETs. With further improvement in fabrication and controllability, this work presents the possibility of operating silicon spin qubits at elevated temperatures.
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29
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Zhang X, Li HO, Cao G, Xiao M, Guo GC, Guo GP. Semiconductor quantum computation. Natl Sci Rev 2019; 6:32-54. [PMID: 34691830 PMCID: PMC8291422 DOI: 10.1093/nsr/nwy153] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 11/05/2018] [Accepted: 12/18/2018] [Indexed: 11/12/2022] Open
Abstract
Semiconductors, a significant type of material in the information era, are becoming more and more powerful in the field of quantum information. In recent decades, semiconductor quantum computation was investigated thoroughly across the world and developed with a dramatically fast speed. The research varied from initialization, control and readout of qubits, to the architecture of fault-tolerant quantum computing. Here, we first introduce the basic ideas for quantum computing, and then discuss the developments of single- and two-qubit gate control in semiconductors. Up to now, the qubit initialization, control and readout can be realized with relatively high fidelity and a programmable two-qubit quantum processor has even been demonstrated. However, to further improve the qubit quality and scale it up, there are still some challenges to resolve such as the improvement of the readout method, material development and scalable designs. We discuss these issues and introduce the forefronts of progress. Finally, considering the positive trend of the research on semiconductor quantum devices and recent theoretical work on the applications of quantum computation, we anticipate that semiconductor quantum computation may develop fast and will have a huge impact on our lives in the near future.
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Affiliation(s)
- Xin Zhang
- Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Hai-Ou Li
- Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Gang Cao
- Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Ming Xiao
- Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Guang-Can Guo
- Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Guo-Ping Guo
- Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
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30
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Abadillo-Uriel JC, Koiller B, Calderón MJ. Two-dimensional semiconductors pave the way towards dopant-based quantum computing. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2018; 9:2668-2673. [PMID: 30416918 PMCID: PMC6204835 DOI: 10.3762/bjnano.9.249] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 09/26/2018] [Indexed: 05/26/2023]
Abstract
Since the proposal in 1998 to build a quantum computer using dopants in silicon as qubits, much progress has been made in the nanofabrication of semiconductors and the control of charge and spins in single dopants. However, an important problem remains unsolved, namely the control over exchange interactions and tunneling between two donors, which presents a peculiar oscillatory behavior as the dopants relative positions vary at the scale of the lattice parameter. Such behavior is due to the valley degeneracy in the conduction band of silicon, and does not occur when the conduction-band edge is at k = 0. We investigate the possibility of circumventing this problem by using two-dimensional (2D) materials as hosts. Dopants in 2D systems are more tightly bound and potentially easier to position and manipulate. Moreover, many of them present the conduction band minimum at k = 0, thus no exchange or tunnel coupling oscillations. Considering the properties of currently available 2D semiconductor materials, we access the feasibility of such a proposal in terms of quantum manipulability of isolated dopants (for single qubit operations) and dopant pairs (for two-qubit operations). Our results indicate that a wide variety of 2D materials may perform at least as well as, and possibly better, than the currently studied bulk host materials for donor qubits.
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Affiliation(s)
- José Carlos Abadillo-Uriel
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
| | - Belita Koiller
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, RJ 21941-972, Brazil
| | - María José Calderón
- Materials Science Factory, Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain
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31
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Atzori M, Chiesa A, Morra E, Chiesa M, Sorace L, Carretta S, Sessoli R. A two-qubit molecular architecture for electron-mediated nuclear quantum simulation. Chem Sci 2018; 9:6183-6192. [PMID: 30090305 PMCID: PMC6062844 DOI: 10.1039/c8sc01695j] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 06/13/2018] [Indexed: 01/02/2023] Open
Abstract
A molecular architecture where two vanadyl-based qubits are linked together is herein described and investigated as a platform for quantum simulation.
A switchable interaction between pairs of highly coherent qubits is a crucial ingredient for the physical realization of quantum information processing. One promising route to enable quantum logic operations involves the use of nuclear spins as protected elementary units of information, qubits. Here we propose a simple way to use fast electronic spin excitations to switch the effective interaction between nuclear spin qubits and the realization of a two-qubit molecular architecture based on highly coherent vanadyl moieties to implement quantum logic operations. Controlled generation of entanglement between qubits is possible here through chemically tuned magnetic coupling between electronic spins, which is clearly evidenced by the splitting of the vanadium(iv) hyperfine lines in the continuous-wave electron paramagnetic resonance spectrum. The system has been further characterized by pulsed electron paramagnetic resonance spectroscopy, evidencing remarkably long coherence times. The experimentally derived spin Hamiltonian parameters have been used to simulate the system dynamics under the sequence of pulses required to implement quantum gates in a realistic description that includes also the harmful effect of decoherence. This demonstrates the possibility of using this molecular complex to implement a control-Z (CZ) gate and simple quantum simulations. Indeed, we also propose a proof-of-principle experiment based on the simulation of the quantum tunneling of the magnetization in a S = 1 spin system.
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Affiliation(s)
- Matteo Atzori
- Dipartimento di Chimica "Ugo Schiff" & INSTM , Università Degli Studi di Firenze , I-50019 Sesto Fiorentino , Italy . ;
| | - Alessandro Chiesa
- Dipartimento di Scienze Matematiche , Fisiche e Informatiche , Università di Parma , I-43124 Parma , Italy . .,Institute for Advanced Simulation , Forschungszentrum Jülich , D-52425 Jülich , Germany
| | - Elena Morra
- Dipartimento di Chimica & NIS Centre , Università di Torino , Via P. Giuria 7 , I-10125 Torino , Italy
| | - Mario Chiesa
- Dipartimento di Chimica & NIS Centre , Università di Torino , Via P. Giuria 7 , I-10125 Torino , Italy
| | - Lorenzo Sorace
- Dipartimento di Chimica "Ugo Schiff" & INSTM , Università Degli Studi di Firenze , I-50019 Sesto Fiorentino , Italy . ;
| | - Stefano Carretta
- Dipartimento di Scienze Matematiche , Fisiche e Informatiche , Università di Parma , I-43124 Parma , Italy .
| | - Roberta Sessoli
- Dipartimento di Chimica "Ugo Schiff" & INSTM , Università Degli Studi di Firenze , I-50019 Sesto Fiorentino , Italy . ;
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32
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Affiliation(s)
- Andrea Morello
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, Australia.
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33
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Veldhorst M, Eenink HGJ, Yang CH, Dzurak AS. Silicon CMOS architecture for a spin-based quantum computer. Nat Commun 2017; 8:1766. [PMID: 29242497 PMCID: PMC5730618 DOI: 10.1038/s41467-017-01905-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 10/24/2017] [Indexed: 12/02/2022] Open
Abstract
Recent advances in quantum error correction codes for fault-tolerant quantum computing and physical realizations of high-fidelity qubits in multiple platforms give promise for the construction of a quantum computer based on millions of interacting qubits. However, the classical-quantum interface remains a nascent field of exploration. Here, we propose an architecture for a silicon-based quantum computer processor based on complementary metal-oxide-semiconductor (CMOS) technology. We show how a transistor-based control circuit together with charge-storage electrodes can be used to operate a dense and scalable two-dimensional qubit system. The qubits are defined by the spin state of a single electron confined in quantum dots, coupled via exchange interactions, controlled using a microwave cavity, and measured via gate-based dispersive readout. We implement a spin qubit surface code, showing the prospects for universal quantum computation. We discuss the challenges and focus areas that need to be addressed, providing a path for large-scale quantum computing. Realisation of large-scale quantum computation requires both error correction capability and a large number of qubits. Here, the authors propose to use a CMOS-compatible architecture featuring a spin qubit surface code and individual qubit control via floating memory gate electrodes.
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Affiliation(s)
- M Veldhorst
- Qutech and Kavli Institute of Nanoscience, TU Delft, 2600, GA Delft, The Netherlands. .,Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia.
| | - H G J Eenink
- Qutech and Kavli Institute of Nanoscience, TU Delft, 2600, GA Delft, The Netherlands.,Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The 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, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - A S Dzurak
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia.
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34
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Harvey-Collard P, Jacobson NT, Rudolph M, Dominguez J, Ten Eyck GA, Wendt JR, Pluym T, Gamble JK, Lilly MP, Pioro-Ladrière M, Carroll MS. Coherent coupling between a quantum dot and a donor in silicon. Nat Commun 2017; 8:1029. [PMID: 29044099 PMCID: PMC5715091 DOI: 10.1038/s41467-017-01113-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 08/18/2017] [Indexed: 11/30/2022] Open
Abstract
Individual donors in silicon chips are used as quantum bits with extremely low error rates. However, physical realizations have been limited to one donor because their atomic size causes fabrication challenges. Quantum dot qubits, in contrast, are highly adjustable using electrical gate voltages. This adjustability could be leveraged to deterministically couple donors to quantum dots in arrays of qubits. In this work, we demonstrate the coherent interaction of a 31P donor electron with the electron of a metal-oxide-semiconductor quantum dot. We form a logical qubit encoded in the spin singlet and triplet states of the two-electron system. We show that the donor nuclear spin drives coherent rotations between the electronic qubit states through the contact hyperfine interaction. This provides every key element for compact two-electron spin qubits requiring only a single dot and no additional magnetic field gradients, as well as a means to interact with the nuclear spin qubit. In silicon, quantum information can be stored in donors or quantum dots, each with its advantages and limitations—particularly in terms of fabrication. Here the authors coherently couple a phosphorous donor’s electron spin to a quantum dot, encoding information in the hybrid two-electron system’s state.
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Affiliation(s)
- Patrick Harvey-Collard
- Département de Physique et Institut Quantique, Université de Sherbrooke, Sherbrooke, QC, Canada, J1K 2R1. .,Sandia National Laboratories, Albuquerque, NM, 87185, USA.
| | - N Tobias Jacobson
- Center for Computing Research, Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | - Martin Rudolph
- Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | | | | | - Joel R Wendt
- Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | - Tammy Pluym
- Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | - John King Gamble
- Center for Computing Research, Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | - Michael P Lilly
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM, 87185, USA
| | - Michel Pioro-Ladrière
- Département de Physique et Institut Quantique, Université de Sherbrooke, Sherbrooke, QC, Canada, J1K 2R1.,Quantum Information Science Program, Canadian Institute for Advanced Research, Toronto, ON, Canada, M5G 1Z8
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35
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Nguyen T, Hill CD, Hollenberg LCL, James MR. Fan-out Estimation in Spin-based Quantum Computer Scale-up. Sci Rep 2017; 7:13386. [PMID: 29042570 PMCID: PMC5645404 DOI: 10.1038/s41598-017-13308-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 09/21/2017] [Indexed: 11/26/2022] Open
Abstract
Solid-state spin-based qubits offer good prospects for scaling based on their long coherence times and nexus to large-scale electronic scale-up technologies. However, high-threshold quantum error correction requires a two-dimensional qubit array operating in parallel, posing significant challenges in fabrication and control. While architectures incorporating distributed quantum control meet this challenge head-on, most designs rely on individual control and readout of all qubits with high gate densities. We analysed the fan-out routing overhead of a dedicated control line architecture, basing the analysis on a generalised solid-state spin qubit platform parameterised to encompass Coulomb confined (e.g. donor based spin qubits) or electrostatically confined (e.g. quantum dot based spin qubits) implementations. The spatial scalability under this model is estimated using standard electronic routing methods and present-day fabrication constraints. Based on reasonable assumptions for qubit control and readout we estimate 102–105 physical qubits, depending on the quantum interconnect implementation, can be integrated and fanned-out independently. Assuming relatively long control-free interconnects the scalability can be extended. Ultimately, the universal quantum computation may necessitate a much higher number of integrated qubits, indicating that higher dimensional electronics fabrication and/or multiplexed distributed control and readout schemes may be the preferredstrategy for large-scale implementation.
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Affiliation(s)
- Thien Nguyen
- Research School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia.
| | - Charles D Hill
- ARC Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Victoria, 3010, Australia
| | - Lloyd C L Hollenberg
- ARC Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Victoria, 3010, Australia
| | - Matthew R James
- ARC Centre for Quantum Computation and Communication Technology, Research School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
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36
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Sigillito AJ, Tyryshkin AM, Schenkel T, Houck AA, Lyon SA. All-electric control of donor nuclear spin qubits in silicon. NATURE NANOTECHNOLOGY 2017; 12:958-962. [PMID: 28805818 DOI: 10.1038/nnano.2017.154] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 07/03/2017] [Indexed: 06/07/2023]
Abstract
The electronic and nuclear spin degrees of freedom of donor impurities in silicon form ultra-coherent two-level systems that are potentially useful for applications in quantum information and are intrinsically compatible with industrial semiconductor processing. However, because of their smaller gyromagnetic ratios, nuclear spins are more difficult to manipulate than electron spins and are often considered too slow for quantum information processing. Moreover, although alternating current magnetic fields are the most natural choice to drive spin transitions and implement quantum gates, they are difficult to confine spatially to the level of a single donor, thus requiring alternative approaches. In recent years, schemes for all-electrical control of donor spin qubits have been proposed but no experimental demonstrations have been reported yet. Here, we demonstrate a scalable all-electric method for controlling neutral 31P and 75As donor nuclear spins in silicon. Using coplanar photonic bandgap resonators, we drive Rabi oscillations on nuclear spins exclusively using electric fields by employing the donor-bound electron as a quantum transducer, much in the spirit of recent works with single-molecule magnets. The electric field confinement leads to major advantages such as low power requirements, higher qubit densities and faster gate times. Additionally, this approach makes it possible to drive nuclear spin qubits either at their resonance frequency or at its first subharmonic, thus reducing device bandwidth requirements. Double quantum transitions can be driven as well, providing easy access to the full computational manifold of our system and making it convenient to implement nuclear spin-based qudits using 75As donors.
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Affiliation(s)
- Anthony J Sigillito
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Alexei M Tyryshkin
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Thomas Schenkel
- Accelerator Technology and Applied Physics Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Andrew A Houck
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Stephen A Lyon
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
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Morse KJ, Abraham RJS, DeAbreu A, Bowness C, Richards TS, Riemann H, Abrosimov NV, Becker P, Pohl HJ, Thewalt MLW, Simmons S. A photonic platform for donor spin qubits in silicon. SCIENCE ADVANCES 2017; 3:e1700930. [PMID: 28782032 PMCID: PMC5529058 DOI: 10.1126/sciadv.1700930] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 06/19/2017] [Indexed: 05/25/2023]
Abstract
Donor spins in silicon are highly competitive qubits for upcoming quantum technologies, offering complementary metal-oxide semiconductor compatibility, coherence (T2) times of minutes to hours, and simultaneous initialization, manipulation, and readout fidelities near ~99.9%. This allows for many quantum error correction protocols, which will be essential for scale-up. However, a proven method of reliably coupling spatially separated donor qubits has yet to be identified. We present a scalable silicon-based platform using the unique optical properties of "deep" chalcogen donors. For the prototypical 77Se+ donor, we measure lower bounds on the transition dipole moment and excited-state lifetime, enabling access to the strong coupling limit of cavity quantum electrodynamics using known silicon photonic resonator technology and integrated silicon photonics. We also report relatively strong photon emission from this same transition. These results unlock clear pathways for silicon-based quantum computing, spin-to-photon conversion, photonic memories, integrated single-photon sources, and all-optical switches.
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Affiliation(s)
- Kevin J. Morse
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Rohan J. S. Abraham
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Adam DeAbreu
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Camille Bowness
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Timothy S. Richards
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Helge Riemann
- Leibniz-Institut für Kristallzüchtung, 12489 Berlin, Germany
| | | | - Peter Becker
- Physikalisch-Technische Bundesanstalt (PTB) Braunschweig, 38116 Braunschweig, Germany
| | | | - Michael L. W. Thewalt
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Stephanie Simmons
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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