1
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Belli M, Fanciulli M. Electron Spin-Lattice Relaxation of Substitutional Nitrogen in Silicon: The Role of Disorder and Motional Effects. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 14:21. [PMID: 38202475 PMCID: PMC10780458 DOI: 10.3390/nano14010021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 12/11/2023] [Accepted: 12/16/2023] [Indexed: 01/12/2024]
Abstract
In a previous investigation, the authors proposed nitrogen as a possible candidate for exploiting the donor spin in silicon quantum devices. This system is characterized by a ground state deeper than the other group V impurities in silicon, offering less stringent requirements on the device temperature necessary to access the unionized state. The nitrogen donor is slightly displaced from the substitutional site, and upon heating, the system undergoes a motional transition. In the present article, we show the results from our investigation on the spin-relaxation times in natSi and 28Si substrates and discuss the motional effects on relaxation. The stretched exponential relaxation observed is interpreted as a distribution of spin-lattice relaxation times, whose origin is also discussed. This information greatly contributes to the assessment of a nitrogen-doped silicon system as a potential candidate for quantum devices working at temperatures higher than those required for other group V donors in silicon.
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Affiliation(s)
- Matteo Belli
- CNR-IMM, Unità di Agrate Brianza, Via C. Olivetti, 2, 20864 Agrate Brianza, Italy
| | - Marco Fanciulli
- Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, Via R. Cozzi 55, 20125 Milano, Italy
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2
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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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3
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Murzakhanov FF, Mamin GV, Orlinskii SB, Gerstmann U, Schmidt WG, Biktagirov T, Aharonovich I, Gottscholl A, Sperlich A, Dyakonov V, Soltamov VA. Electron-Nuclear Coherent Coupling and Nuclear Spin Readout through Optically Polarized V B- Spin States in hBN. NANO LETTERS 2022; 22:2718-2724. [PMID: 35357842 DOI: 10.1021/acs.nanolett.1c04610] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Coherent coupling of defect spins with surrounding nuclei along with the endowment to read out the latter are basic requirements for an application in quantum technologies. We show that negatively charged boron vacancies (VB-) in hexagonal boron nitride (hBN) meet these prerequisites. We demonstrate Hahn-echo coherence of the VB- spin with a characteristic decay time Tcoh = 15 μs, close to the theoretically predicted limit of 18 μs for defects in hBN. Elongation of the coherence time up to 36 μs is demonstrated by means of the Carr-Purcell-Meiboom-Gill decoupling technique. Modulation of the Hahn-echo decay is shown to be induced by coherent coupling of the VB- spin with the three nearest 14N nuclei via a nuclear quadrupole interaction of 2.11 MHz. DFT calculation confirms that the electron-nuclear coupling is confined to the defective layer and stays almost unchanged with a transition from the bulk to the single layer.
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Affiliation(s)
| | | | | | - Uwe Gerstmann
- Theoretische Materialphysik, Universität Paderborn, 33098 Paderborn, Germany
| | - Wolf Gero Schmidt
- Theoretische Materialphysik, Universität Paderborn, 33098 Paderborn, Germany
| | - Timur Biktagirov
- Theoretische Materialphysik, Universität Paderborn, 33098 Paderborn, Germany
| | - Igor Aharonovich
- School of Mathematical and Physical Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
- ARC Centre of Excellence for Transformative Meta-Optical Systems (TMOS), University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Andreas Gottscholl
- Experimental Physics 6 and Würzburg-Dresden Cluster of Excellence ct.qmat, Julius Maximilian University of Würzburg, 97074 Würzburg, Germany
| | - Andreas Sperlich
- Experimental Physics 6 and Würzburg-Dresden Cluster of Excellence ct.qmat, Julius Maximilian University of Würzburg, 97074 Würzburg, Germany
| | - Vladimir Dyakonov
- Experimental Physics 6 and Würzburg-Dresden Cluster of Excellence ct.qmat, Julius Maximilian University of Würzburg, 97074 Würzburg, Germany
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4
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Arutyunov N, Krause-Rehberg R, Elsayed M, Emtsev V, Abrosimov N, Oganesyan G, Kozlovski V. Microstructure of bismuth centers in silicon before and after irradiation with 15 MeV protons. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:245702. [PMID: 33626521 DOI: 10.1088/1361-648x/abe96f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 02/24/2021] [Indexed: 06/12/2023]
Abstract
A decrease of two-gamma annihilation rate of a positron in a strong spin-orbit field of the annihilation site of bismuth impurity center209Bi (J= 9/2) in silicon with natural isotope composition was revealed (Jis the nuclear spin). This decrease was observed along with increasing occupancy of Bi donor states (binding energyE{Bi} ≈ 69 meV). Atoms of29Si (J= 1/2) isotope are involved in spin interactions of positron with Bi impurity centers. The growth of occupancy of Bi donor states inhibits two-gamma annihilation rate. The estimated cross-section of positron trapping by the Bi impurity center isσ+≈ (1.23-1.5) × 10-13 cm2. Together with this surprisingly large value, the integral rate of two-gamma annihilation in a hypothetical polyelectron system of the Bi impurity center is by a factor of just Δ ∼ 2.18 higher compared to the magnitude ≈2.09 × 109 s-1known for elemental isolated polyelectron, (e-e+e-). Possible formation of the positron-containing exciton-like states, (e+)D0X(D= Bi, P) is also discussed. Irradiation of material with 15 MeV protons results in decreasing the factor Δ by ∼11% due to forming the radiation complex in which Bi atom is in an open volume ambient it. Such complex is suggested to haveD3dsymmetry and be the deep donor. Low-temperature measurements of both the positron annihilation rate and Hall effect have been applied for studying the isochronal annealing of these point radiation defects which were found to be thermally stable up to ∼370 °C; they can be annealed at ∼430 °C - 470 °C. According to available data ofab initiocluster calculations, the complex of Bi atom with a simulated vacancy hasD3dsymmetry with the energy gain ∼0.92 eV, thus indicating qualitative agreement between experimental and theoretical data.
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Affiliation(s)
- Nikolay Arutyunov
- Martin Luther University Halle, Department of Physics, 06120, Halle, Germany
- Ioffe Physico-Technical Institute, 194021, St. Petersburg, Russia
| | | | - Mohamed Elsayed
- Martin Luther University Halle, Department of Physics, 06120, Halle, Germany
- Minia University, Department of Physics, Faculty of Science, 61519, Minia, Egypt
| | - Vadim Emtsev
- Ioffe Physico-Technical Institute, 194021, St. Petersburg, Russia
| | - Nikolay Abrosimov
- Leibniz-lnstitut für Kristallzüchtung (IKZ), D-12489, Berlin, Germany
| | - Gagik Oganesyan
- Ioffe Physico-Technical Institute, 194021, St. Petersburg, Russia
| | - Vitalii Kozlovski
- St. Petersburg State Polytechnical University, 195251, St. Petersburg, Russia
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5
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Ranjan V, O'Sullivan J, Albertinale E, Albanese B, Chanelière T, Schenkel T, Vion D, Esteve D, Flurin E, Morton JJL, Bertet P. Multimode Storage of Quantum Microwave Fields in Electron Spins over 100 ms. PHYSICAL REVIEW LETTERS 2020; 125:210505. [PMID: 33274991 DOI: 10.1103/physrevlett.125.210505] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 10/19/2020] [Indexed: 06/12/2023]
Abstract
We report long coherence times (up to 300 ms) for near-surface bismuth donor electron spins in silicon coupled to a superconducting microresonator, biased at a clock transition. This enables us to demonstrate the partial absorption of a train of weak microwave fields in the spin ensemble, their storage for 100 ms, and their retrieval, using a Hahn-echo-like protocol. Phase coherence and quantum statistics are preserved in the storage.
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Affiliation(s)
- V Ranjan
- Université Paris-Saclay, CEA, CNRS, SPEC, 91191 Gif-sur-Yvette Cedex, France
| | - J O'Sullivan
- London Centre for Nanotechnology, University College London, London WC1H 0AH, United Kingdom
| | - E Albertinale
- Université Paris-Saclay, CEA, CNRS, SPEC, 91191 Gif-sur-Yvette Cedex, France
| | - B Albanese
- Université Paris-Saclay, CEA, CNRS, SPEC, 91191 Gif-sur-Yvette Cedex, France
| | - T Chanelière
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France
| | - T Schenkel
- Accelerator Technology and Applied Physics Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - D Vion
- Université Paris-Saclay, CEA, CNRS, SPEC, 91191 Gif-sur-Yvette Cedex, France
| | - D Esteve
- Université Paris-Saclay, CEA, CNRS, SPEC, 91191 Gif-sur-Yvette Cedex, France
| | - E Flurin
- Université Paris-Saclay, CEA, CNRS, SPEC, 91191 Gif-sur-Yvette Cedex, France
| | - J J L Morton
- London Centre for Nanotechnology, University College London, London WC1H 0AH, United Kingdom
| | - P Bertet
- Université Paris-Saclay, CEA, CNRS, SPEC, 91191 Gif-sur-Yvette Cedex, France
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6
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Jiang Z, Soghomonian V, Heremans JJ. Dynamic Nuclear Spin Polarization Induced by the Edelstein Effect at Bi(111) Surfaces. PHYSICAL REVIEW LETTERS 2020; 125:106802. [PMID: 32955340 DOI: 10.1103/physrevlett.125.106802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Revised: 07/07/2020] [Accepted: 08/11/2020] [Indexed: 06/11/2023]
Abstract
Nuclear spin polarization induced by hyperfine interaction and mainly the Edelstein effect due to strong spin-orbit interaction, is investigated by quantum transport in Bi(111) thin film samples. The Bi(111) films are deposited on mica by van der Waals epitaxial growth. The Bi(111) films show micrometer-sized triangular islands with 0.39 nm step height, corresponding to the Bi(111) bilayer height. At low temperatures a high current density is applied to generate a nonequilibrium carrier spin polarization by mainly the Edelstein effect at the Bi(111) surface, which then induces dynamic nuclear polarization by hyperfine interaction. Comparative quantum magnetotransport antilocalization measurements indicate a suppression of antilocalization by the in-plane Overhauser field from the nuclear polarization and allow a quantification of the Overhauser field. Hence nuclear polarization was both achieved and quantified by a purely electronic transport-based approach.
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Affiliation(s)
- Zijian Jiang
- Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, USA
| | - V Soghomonian
- Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, USA
| | - J J Heremans
- Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, USA
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7
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Wang P, Chen C, Peng X, Wrachtrup J, Liu RB. Characterization of Arbitrary-Order Correlations in Quantum Baths by Weak Measurement. PHYSICAL REVIEW LETTERS 2019; 123:050603. [PMID: 31491311 DOI: 10.1103/physrevlett.123.050603] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Indexed: 06/10/2023]
Abstract
Correlations of fluctuations are the driving forces behind the dynamics and thermodynamics in quantum many-body systems. For qubits embedded in a quantum bath, the correlations in the bath are key to understanding and combating decoherence-a critical issue in quantum information technology. However, there is no systematic method for characterizing the many-body correlations in quantum baths beyond the second order or the Gaussian approximation. Here we present a scheme to characterize the correlations in a quantum bath to arbitrary order. The scheme employs a weak measurement of the bath via the projective measurement of a central system. The bath correlations, including both the "classical" and the "quantum" parts, can be reconstructed from the correlations of the measurement outputs. The possibility of full characterization of many-body correlations in a quantum bath forms the basis for optimizing quantum control against decoherence in realistic environments, for studying the quantum characteristics of baths, and for the quantum sensing of correlated clusters in quantum baths.
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Affiliation(s)
- Ping Wang
- Department of Physics, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Chong Chen
- Department of Physics, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Xinhua Peng
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
- CAS Key Laboratory of Microscale Magnetic Resonance and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Jörg Wrachtrup
- 3rd Institute of Physics, Research Center SCoPE and IQST, University of Stuttgart, 70569 Stuttgart, Germany
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
| | - Ren-Bao Liu
- Department of Physics, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
- The Hong Kong Institute of Quantum Information Science and Technology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
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8
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Probst S, Ranjan V, Ansel Q, Heeres R, Albanese B, Albertinale E, Vion D, Esteve D, Glaser SJ, Sugny D, Bertet P. Shaped pulses for transient compensation in quantum-limited electron spin resonance spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 303:42-47. [PMID: 31003062 DOI: 10.1016/j.jmr.2019.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 06/09/2023]
Abstract
In high sensitivity inductive electron spin resonance spectroscopy, superconducting microwave resonators with large quality factors are employed. While they enhance the sensitivity, they also distort considerably the shape of the applied rectangular microwave control pulses, which limits the degree of control over the spin ensemble. Here, we employ shaped microwave pulses compensating the signal distortion to drive the spins faster than the resonator bandwidth. This translates into a shorter echo, with enhanced signal-to-noise ratio. The shaped pulses are also useful to minimize the dead-time of our spectrometer, which allows to reduce the wait time between successive drive pulses.
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Affiliation(s)
- Sebastian Probst
- Quantronics Group, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191, Gif-sur-Yvette Cedex, France
| | - Vishal Ranjan
- Quantronics Group, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191, Gif-sur-Yvette Cedex, France
| | - Quentin Ansel
- Université de Bourgogne Franche-Comté, Laboratoire Interdisciplinaire Carnot de Bourgogne, CNRS UMR 6303, 21078 Dijon Cedex, France
| | - Reinier Heeres
- Quantronics Group, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191, Gif-sur-Yvette Cedex, France
| | - Bartolo Albanese
- Quantronics Group, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191, Gif-sur-Yvette Cedex, France
| | - Emanuele Albertinale
- Quantronics Group, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191, Gif-sur-Yvette Cedex, France
| | - Denis Vion
- Quantronics Group, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191, Gif-sur-Yvette Cedex, France
| | - Daniel Esteve
- Quantronics Group, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191, Gif-sur-Yvette Cedex, France
| | - Steffen J Glaser
- Department of Chemistry, Technische Universität München, Lichtenbergstraße 4, D-85747 Garching, Germany; Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, D-80799 Munchen, Germany
| | - Dominique Sugny
- Université de Bourgogne Franche-Comté, Laboratoire Interdisciplinaire Carnot de Bourgogne, CNRS UMR 6303, 21078 Dijon Cedex, France
| | - Patrice Bertet
- Quantronics Group, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191, Gif-sur-Yvette Cedex, France.
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9
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Ortu A, Tiranov A, Welinski S, Fröwis F, Gisin N, Ferrier A, Goldner P, Afzelius M. Simultaneous coherence enhancement of optical and microwave transitions in solid-state electronic spins. NATURE MATERIALS 2018; 17:671-675. [PMID: 30042512 DOI: 10.1038/s41563-018-0138-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 06/22/2018] [Indexed: 06/08/2023]
Abstract
Solid-state electronic spins are extensively studied in quantum information science, as their large magnetic moments offer fast operations for computing1 and communication2-4, and high sensitivity for sensing5. However, electronic spins are more sensitive to magnetic noise, but engineering of their spectroscopic properties, for example, using clock transitions and isotopic engineering, can yield remarkable spin coherence times, as for electronic spins in GaAs6, donors in silicon7-11 and vacancy centres in diamond12,13. Here we demonstrate simultaneously induced clock transitions for both microwave and optical domains in an isotopically purified 171Yb3+:Y2SiO5 crystal, reaching coherence times of greater than 100 μs and 1 ms in the optical and microwave domains, respectively. This effect is due to the highly anisotropic hyperfine interaction, which makes each electronic-nuclear state an entangled Bell state. Our results underline the potential of 171Yb3+:Y2SiO5 for quantum processing applications relying on both optical and spin manipulation, such as optical quantum memories4,14, microwave-to-optical quantum transducers15,16, and single-spin detection17, while they should also be observable in a range of different materials with anisotropic hyperfine interactions.
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Affiliation(s)
- Antonio Ortu
- Groupe de Physique Appliquée, Université de Genève, Genève, Switzerland
| | - Alexey Tiranov
- Groupe de Physique Appliquée, Université de Genève, Genève, Switzerland
| | - Sacha Welinski
- Chimie ParisTech, PSL University, CNRS, Institut de Recherche de Chimie Paris, Paris, France
| | - Florian Fröwis
- Groupe de Physique Appliquée, Université de Genève, Genève, Switzerland
| | - Nicolas Gisin
- Groupe de Physique Appliquée, Université de Genève, Genève, Switzerland
| | - Alban Ferrier
- Chimie ParisTech, PSL University, CNRS, Institut de Recherche de Chimie Paris, Paris, France
- Faculté des Sciences et Ingénierie, Sorbonne Université, Paris, France
| | - Philippe Goldner
- Chimie ParisTech, PSL University, CNRS, Institut de Recherche de Chimie Paris, Paris, France
| | - Mikael Afzelius
- Groupe de Physique Appliquée, Université de Genève, Genève, Switzerland.
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10
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Hudak BM, Song J, Sims H, Troparevsky MC, Humble TS, Pantelides ST, Snijders PC, Lupini AR. Directed Atom-by-Atom Assembly of Dopants in Silicon. ACS NANO 2018; 12:5873-5879. [PMID: 29750507 DOI: 10.1021/acsnano.8b02001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The ability to controllably position single atoms inside materials is key for the ultimate fabrication of devices with functionalities governed by atomic-scale properties. Single bismuth dopant atoms in silicon provide an ideal case study in view of proposals for single-dopant quantum bits. However, bismuth is the least soluble pnictogen in silicon, meaning that the dopant atoms tend to migrate out of position during sample growth. Here, we demonstrate epitaxial growth of thin silicon films doped with bismuth. We use atomic-resolution aberration-corrected imaging to view the as-grown dopant distribution and then to controllably position single dopants inside the film. Atomic-scale quantum-mechanical calculations corroborate the experimental findings. These results indicate that the scanning transmission electron microscope is of particular interest for assembling functional materials atom-by-atom because it offers both real-time monitoring and atom manipulation. We envision electron-beam manipulation of atoms inside materials as an achievable route to controllable assembly of structures of individual dopants.
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Affiliation(s)
- Bethany M Hudak
- Materials Sciences and Technology Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 United States
- The Institute for Functional Imaging of Materials , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 United States
| | - Jiaming Song
- Materials Sciences and Technology Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 United States
| | - Hunter Sims
- Materials Sciences and Technology Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 United States
- Department of Physics and Astronomy , Vanderbilt University , Nashville , Tennessee 37235 United States
| | - M Claudia Troparevsky
- Materials Sciences and Technology Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 United States
| | - Travis S Humble
- Computational Sciences and Engineering Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 United States
| | - Sokrates T Pantelides
- Materials Sciences and Technology Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 United States
- Department of Physics and Astronomy , Vanderbilt University , Nashville , Tennessee 37235 United States
| | - Paul C Snijders
- Materials Sciences and Technology Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 United States
- Department of Physics and Astronomy , The University of Tennessee , Knoxville , Tennessee 37996 United States
| | - Andrew R Lupini
- Materials Sciences and Technology Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 United States
- The Institute for Functional Imaging of Materials , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 United States
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11
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Morton JJL, Bertet P. Storing quantum information in spins and high-sensitivity ESR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 287:128-139. [PMID: 29413326 DOI: 10.1016/j.jmr.2017.11.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 11/21/2017] [Accepted: 11/22/2017] [Indexed: 06/08/2023]
Abstract
Quantum information, encoded within the states of quantum systems, represents a novel and rich form of information which has inspired new types of computers and communications systems. Many diverse electron spin systems have been studied with a view to storing quantum information, including molecular radicals, point defects and impurities in inorganic systems, and quantum dots in semiconductor devices. In these systems, spin coherence times can exceed seconds, single spins can be addressed through electrical and optical methods, and new spin systems with advantageous properties continue to be identified. Spin ensembles strongly coupled to microwave resonators can, in principle, be used to store the coherent states of single microwave photons, enabling so-called microwave quantum memories. We discuss key requirements in realising such memories, including considerations for superconducting resonators whose frequency can be tuned onto resonance with the spins. Finally, progress towards microwave quantum memories and other developments in the field of superconducting quantum devices are being used to push the limits of sensitivity of inductively-detected electron spin resonance. The state-of-the-art currently stands at around 65 spins per Hz, with prospects to scale down to even fewer spins.
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Affiliation(s)
- John J L Morton
- London Centre for Nanotechnology, UCL, London WC1H 0AH, United Kingdom; Dept. of Electronic and Electrical Engineering, UCL, London WC1E 7JE, United Kingdom.
| | - Patrice Bertet
- Quantronics Group, SPEC, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
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12
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Mostafa A, Medraj M. Binary Phase Diagrams and Thermodynamic Properties of Silicon and Essential Doping Elements (Al, As, B, Bi, Ga, In, N, P, Sb and Tl). MATERIALS (BASEL, SWITZERLAND) 2017; 10:E676. [PMID: 28773034 PMCID: PMC5554057 DOI: 10.3390/ma10060676] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 06/13/2017] [Accepted: 06/13/2017] [Indexed: 11/20/2022]
Abstract
Fabrication of solar and electronic silicon wafers involves direct contact between solid, liquid and gas phases at near equilibrium conditions. Understanding of the phase diagrams and thermochemical properties of the Si-dopant binary systems is essential for providing processing conditions and for understanding the phase formation and transformation. In this work, ten Si-based binary phase diagrams, including Si with group IIIA elements (Al, B, Ga, In and Tl) and with group VA elements (As, Bi, N, P and Sb), have been reviewed. Each of these systems has been critically discussed on both aspects of phase diagram and thermodynamic properties. The available experimental data and thermodynamic parameters in the literature have been summarized and assessed thoroughly to provide consistent understanding of each system. Some systems were re-calculated to obtain a combination of the best evaluated phase diagram and a set of optimized thermodynamic parameters. As doping levels of solar and electronic silicon are of high technological importance, diffusion data has been presented to serve as a useful reference on the properties, behavior and quantities of metal impurities in silicon. This paper is meant to bridge the theoretical understanding of phase diagrams with the research and development of solar-grade silicon production, relying on the available information in the literature and our own analysis.
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Affiliation(s)
- Ahmad Mostafa
- Mechanical and Materials Engineering Department, Khalifa University of Science and Technology, Masdar Institute, Masdar City 54224, UAE.
| | - Mamoun Medraj
- Mechanical and Materials Engineering Department, Khalifa University of Science and Technology, Masdar Institute, Masdar City 54224, UAE.
- Mechanical Engineering Department, Concordia University, 1515 Rue Sainte Catherine west, Montreal, QC H3G 2W1, Canada.
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Murata K, Kirkham C, Shimomura M, Nitta K, Uruga T, Terada Y, Nittoh KI, Bowler DR, Miki K. Dopant activation mechanism of Bi wire-δ-doping into Si crystal, investigated with wavelength dispersive fluorescence x-ray absorption fine structure and density functional theory. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:155001. [PMID: 28218893 DOI: 10.1088/1361-648x/aa6180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We successfully characterized the local structures of Bi atoms in a wire-δ-doped layer (1/8 ML) in a Si crystal, using wavelength dispersive fluorescence x-ray absorption fine structure at the beamline BL37XU, in SPring-8, with the help of density functional theory calculations. It was found that the burial of Bi nanolines on the Si(0 0 1) surface, via growth of Si capping layer at 400 °C by molecular beam epitaxy, reduced the Bi-Si bond length from [Formula: see text] to [Formula: see text] Å. We infer that following epitaxial growth the Bi-Bi dimers of the nanoline are broken, and the Bi atoms are located at substitutional sites within the Si crystal, leading to the shorter Bi-Si bond lengths.
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Affiliation(s)
- Koichi Murata
- National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba, 305-0044, Japan. Faculty of Pure and Applied Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba, 305-8573, Japan
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14
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Yang W, Ma WL, Liu RB. Quantum many-body theory for electron spin decoherence in nanoscale nuclear spin baths. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:016001. [PMID: 27811398 DOI: 10.1088/0034-4885/80/1/016001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Decoherence of electron spins in nanoscale systems is important to quantum technologies such as quantum information processing and magnetometry. It is also an ideal model problem for studying the crossover between quantum and classical phenomena. At low temperatures or in light-element materials where the spin-orbit coupling is weak, the phonon scattering in nanostructures is less important and the fluctuations of nuclear spins become the dominant decoherence mechanism for electron spins. Since the 1950s, semi-classical noise theories have been developed for understanding electron spin decoherence. In spin-based solid-state quantum technologies, the relevant systems are in the nanometer scale and nuclear spin baths are quantum objects which require a quantum description. Recently, quantum pictures have been established to understand the decoherence and quantum many-body theories have been developed to quantitatively describe this phenomenon. Anomalous quantum effects have been predicted and some have been experimentally confirmed. A systematically truncated cluster-correlation expansion theory has been developed to account for the many-body correlations in nanoscale nuclear spin baths that are built up during electron spin decoherence. The theory has successfully predicted and explained a number of experimental results in a wide range of physical systems. In this review, we will cover this recent progress. The limitations of the present quantum many-body theories and possible directions for future development will also be discussed.
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Affiliation(s)
- Wen Yang
- Beijing Computational Science Research Center, Beijing 100193, People's Republic of China
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15
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Quantum decoherence dynamics of divacancy spins in silicon carbide. Nat Commun 2016; 7:12935. [PMID: 27679936 PMCID: PMC5056425 DOI: 10.1038/ncomms12935] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 08/17/2016] [Indexed: 11/08/2022] Open
Abstract
Long coherence times are key to the performance of quantum bits (qubits). Here, we experimentally and theoretically show that the Hahn-echo coherence time of electron spins associated with divacancy defects in 4H-SiC reaches 1.3 ms, one of the longest Hahn-echo coherence times of an electron spin in a naturally isotopic crystal. Using a first-principles microscopic quantum-bath model, we find that two factors determine the unusually robust coherence. First, in the presence of moderate magnetic fields (30 mT and above), the 29Si and 13C paramagnetic nuclear spin baths are decoupled. In addition, because SiC is a binary crystal, homo-nuclear spin pairs are both diluted and forbidden from forming strongly coupled, nearest-neighbour spin pairs. Longer neighbour distances result in fewer nuclear spin flip-flops, a less fluctuating intra-crystalline magnetic environment, and thus a longer coherence time. Our results point to polyatomic crystals as promising hosts for coherent qubits in the solid state.
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Abstract
Spontaneous emission of radiation is one of the fundamental mechanisms by which an excited quantum system returns to equilibrium. For spins, however, spontaneous emission is generally negligible compared to other non-radiative relaxation processes because of the weak coupling between the magnetic dipole and the electromagnetic field. In 1946, Purcell realized that the rate of spontaneous emission can be greatly enhanced by placing the quantum system in a resonant cavity. This effect has since been used extensively to control the lifetime of atoms and semiconducting heterostructures coupled to microwave or optical cavities, and is essential for the realization of high-efficiency single-photon sources. Here we report the application of this idea to spins in solids. By coupling donor spins in silicon to a superconducting microwave cavity with a high quality factor and a small mode volume, we reach the regime in which spontaneous emission constitutes the dominant mechanism of spin relaxation. The relaxation rate is increased by three orders of magnitude as the spins are tuned to the cavity resonance, demonstrating that energy relaxation can be controlled on demand. Our results provide a general way to initialize spin systems into their ground state and therefore have applications in magnetic resonance and quantum information processing. They also demonstrate that the coupling between the magnetic dipole of a spin and the electromagnetic field can be enhanced up to the point at which quantum fluctuations have a marked effect on the spin dynamics; as such, they represent an important step towards the coherent magnetic coupling of individual spins to microwave photons.
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House MG, Xiao M, Guo G, Li H, Cao G, Rosenthal MM, Jiang H. Detection and measurement of spin-dependent dynamics in random telegraph signals. PHYSICAL REVIEW LETTERS 2013; 111:126803. [PMID: 24093289 DOI: 10.1103/physrevlett.111.126803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Indexed: 06/02/2023]
Abstract
A quantum point contact was used to observe single-electron fluctuations of a quantum dot in a GaAs heterostructure. The resulting random telegraph signals (RTS) contain statistical information about the electron spin state if the tunneling dynamics are spin dependent. We develop a statistical method to extract information about spin-dependent dynamics from RTS and use it to demonstrate that these dynamics can be studied in the thermal energy regime. The tunneling rates of each spin state are independently measured in a finite external magnetic field. We confirm previous findings of a decrease in overall tunneling rates for the spin excited state compared to the ground state as an external magnetic field is increased.
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Affiliation(s)
- M G House
- Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, California 90095, USA
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18
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Wolfowicz G, Tyryshkin AM, George RE, Riemann H, Abrosimov NV, Becker P, Pohl HJ, Thewalt MLW, Lyon SA, Morton JJL. Atomic clock transitions in silicon-based spin qubits. NATURE NANOTECHNOLOGY 2013; 8:561-564. [PMID: 23793304 DOI: 10.1038/nnano.2013.117] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 05/22/2013] [Indexed: 06/02/2023]
Abstract
A major challenge in using spins in the solid state for quantum technologies is protecting them from sources of decoherence. This is particularly important in nanodevices where the proximity of material interfaces, and their associated defects, can play a limiting role. Spin decoherence can be addressed to varying degrees by improving material purity or isotopic composition, for example, or active error correction methods such as dynamic decoupling (or even combinations of the two). However, a powerful method applied to trapped ions in the context of atomic clocks is the use of particular spin transitions that are inherently robust to external perturbations. Here, we show that such 'clock transitions' can be observed for electron spins in the solid state, in particular using bismuth donors in silicon. This leads to dramatic enhancements in the electron spin coherence time, exceeding seconds. We find that electron spin qubits based on clock transitions become less sensitive to the local magnetic environment, including the presence of (29)Si nuclear spins as found in natural silicon. We expect the use of such clock transitions will be of additional significance for donor spins in nanodevices, mitigating the effects of magnetic or electric field noise arising from nearby interfaces and gates.
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Affiliation(s)
- Gary Wolfowicz
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK.
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19
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Makarov VI, Khmelinskii I. Exchange resonance in MDM nanolayer systems: experiment and theory. J Chem Phys 2013; 138:074705. [PMID: 23445028 DOI: 10.1063/1.4791556] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Exchange resonance spectra of three sandwich devices containing nanolayers of Cr, Mn, Co, Ni, and Eu were recorded at 77 K. We found that these spectra are significantly different from those obtained earlier for Fe-SiO2-Au three-layer nanosandwich device. Detailed theoretical approach was developed to analyze the recorded spectra, g-factor values, and relaxation properties of the spin-polarized states in the nanolayers. We found that the g-factor values and spin-lattice relaxation rates may be adequately described by the spin-orbit scattering mechanism. Electric charge density fluctuations may also contribute to spin-lattice relaxation in nanolayers. Second-order effects in the relaxation mechanism were also briefly considered.
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Affiliation(s)
- Vladimir I Makarov
- Department of Physics, University of Puerto Rico, Rio Piedras, P.O. Box 23343, San Juan, Puerto Rico
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20
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Morley GW, Lueders P, Mohammady MH, Balian SJ, Aeppli G, Kay CWM, Witzel WM, Jeschke G, Monteiro TS. Quantum control of hybrid nuclear-electronic qubits. NATURE MATERIALS 2013. [PMID: 23202370 DOI: 10.1038/nmat3499] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Pulsed magnetic resonance allows the quantum state of electronic and nuclear spins to be controlled on the timescale of nanoseconds and microseconds respectively. The time required to flip dilute spins is orders of magnitude shorter than their coherence times, leading to several schemes for quantum information processing with spin qubits. Instead, we investigate 'hybrid nuclear-electronic' qubits consisting of near 50:50 superpositions of the electronic and nuclear spin states. Using bismuth-doped silicon, we demonstrate quantum control over these states in 32 ns, which is orders of magnitude faster than previous experiments using pure nuclear states. The coherence times of up to 4 ms are five orders of magnitude longer than the manipulation times, and are limited only by naturally occurring (29)Si nuclear spin impurities. We find a quantitative agreement between our experiments and an analytical theory for the resonance positions, as well as their relative intensities and Rabi oscillation frequencies. These results bring spins in a solid material a step closer to research on ion-trap qubits.
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Affiliation(s)
- Gavin W Morley
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK.
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21
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Zhao N, Wrachtrup J. Quantum information: Best of both worlds. NATURE MATERIALS 2013; 12:97-98. [PMID: 23340470 DOI: 10.1038/nmat3531] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
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22
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Lo CC, Weis CD, van Tol J, Bokor J, Schenkel T. All-electrical nuclear spin polarization of donors in silicon. PHYSICAL REVIEW LETTERS 2013; 110:057601. [PMID: 23414045 DOI: 10.1103/physrevlett.110.057601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Indexed: 06/01/2023]
Abstract
We demonstrate an all-electrical donor nuclear spin polarization method in silicon by exploiting the tunable interaction of donor bound electrons with a two-dimensional electron gas, and achieve over two orders of magnitude nuclear hyperpolarization at T=5 K and B=12 T with an in-plane magnetic field. We also show an intricate dependence of nuclear polarization effects on the orientation of the magnetic field, and both hyperpolarization and antipolarization can be controllably achieved in the quantum Hall regime. Our results demonstrate that donor nuclear spin qubits can be initialized through local gate control of electrical currents without the need for optical excitation, enabling the implementation of nuclear spin qubit initialization in dense multiqubit arrays.
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Affiliation(s)
- C C Lo
- Accelerator and Fusion Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
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23
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Wang XJ, Chesi S, Coish WA. Spin-echo dynamics of a heavy hole in a quantum dot. PHYSICAL REVIEW LETTERS 2012; 109:237601. [PMID: 23368266 DOI: 10.1103/physrevlett.109.237601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Indexed: 06/01/2023]
Abstract
We develop a theory for the spin-echo dynamics of a heavy hole in a quantum dot, accounting for both hyperfine- and electric-field-induced fluctuations. We show that a moderate applied magnetic field can drive this system to a motional-averaging regime, making the hyperfine interaction ineffective as a decoherence source. Furthermore, we show that decay of the spin-echo envelope is highly sensitive to the geometry. In particular, we find a specific choice of initialization and π-pulse axes which can be used to study intrinsic hyperfine-induced hole-spin dynamics, even in systems with substantial electric-field-induced dephasing. These results point the way to designed hole-spin qubits as a robust and long-lived alternative to electron spins.
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Affiliation(s)
- Xiaoya Judy Wang
- Department of Physics, McGill University, Montreal, Quebec H3A 2T8, Canada
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24
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Balian SJ, Kunze MBA, Mohammady MH, Morley GW, Witzel WM, Kay CWM, Monteiro TS. Measuring central-spin interaction with a spin-bath by pulsed ENDOR: Towards suppression of spin diffusion decoherence. ACTA ACUST UNITED AC 2012; 86. [PMID: 23082071 DOI: 10.1103/physrevb.86.104428] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We present pulsed electron-nuclear double resonance (ENDOR) experiments which enable us to characterize the coupling between bismuth donor spin-qubits in Si and the surrounding spin-bath of (29)Si impurities which provides the dominant decoherence mechanism (nuclear spin diffusion) at low temperatures (< 16 K). Decoupling from the spin-bath is predicted and cluster correlation expansion simulations show near-complete suppression of spin diffusion, at optimal working points. The suppression takes the form of sharply peaked divergences of the spin diffusion coherence time, in contrast with previously identified broader regions of insensitivity to classical fluctuations. ENDOR data shows anisotropic contributions are comparatively weak, so the form of the divergences is independent of crystal orientation.
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Affiliation(s)
- S J Balian
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
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25
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Tyryshkin AM, Tojo S, Morton JJL, Riemann H, Abrosimov NV, Becker P, Pohl HJ, Schenkel T, Thewalt MLW, Itoh KM, Lyon SA. Electron spin coherence exceeding seconds in high-purity silicon. NATURE MATERIALS 2011; 11:143-7. [PMID: 22138791 DOI: 10.1038/nmat3182] [Citation(s) in RCA: 191] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 10/24/2011] [Indexed: 05/05/2023]
Abstract
Silicon is one of the most promising semiconductor materials for spin-based information processing devices. Its advanced fabrication technology facilitates the transition from individual devices to large-scale processors, and the availability of a (28)Si form with no magnetic nuclei overcomes a primary source of spin decoherence in many other materials. Nevertheless, the coherence lifetimes of electron spins in the solid state have typically remained several orders of magnitude lower than that achieved in isolated high-vacuum systems such as trapped ions. Here we examine electron spin coherence of donors in pure (28)Si material (residual (29)Si concentration <50 ppm) with donor densities of 10(14)-10(15) cm(-3). We elucidate three mechanisms for spin decoherence, active at different temperatures, and extract a coherence lifetime T(2) up to 2 s. In this regime, we find the electron spin is sensitive to interactions with other donor electron spins separated by ~200 nm. A magnetic field gradient suppresses such interactions, producing an extrapolated electron spin T(2) of 10 s at 1.8 K. These coherence lifetimes are without peer in the solid state and comparable to high-vacuum qubits, making electron spins of donors in silicon ideal components of quantum computers, or quantum memories for systems such as superconducting qubits.
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Affiliation(s)
- Alexei M Tyryshkin
- Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA
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26
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Abstract
Quantum computers hold the promise of massive performance enhancements across a range of applications, from cryptography and databases to revolutionary scientific simulation tools. Such computers would make use of the same quantum mechanical phenomena that pose limitations on the continued shrinking of conventional information processing devices. Many of the key requirements for quantum computing differ markedly from those of conventional computers. However, silicon, which plays a central part in conventional information processing, has many properties that make it a superb platform around which to build a quantum computer.
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Delgado F, Fernández-Rossier J. Inelastic electron tunneling spectroscopy of a single nuclear spin. PHYSICAL REVIEW LETTERS 2011; 107:076804. [PMID: 21902416 DOI: 10.1103/physrevlett.107.076804] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Indexed: 05/31/2023]
Abstract
Detection of a single nuclear spin constitutes an outstanding problem in different fields of physics such as quantum computing or magnetic imaging. Here we show that the energy levels of a single nuclear spin can be measured by means of inelastic electron tunneling spectroscopy (IETS). We consider two different systems, a magnetic adatom probed with scanning tunneling microscopy and a single Bi dopant in a silicon nanotransistor. We find that the hyperfine coupling opens new transport channels which can be resolved at experimentally accessible temperatures. Our simulations evince that IETS yields information about the occupations of the nuclear spin states, paving the way towards transport-detected single nuclear spin resonance.
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Affiliation(s)
- F Delgado
- Departamento de Física Aplicada, Universidad de Alicante, San Vicente del Raspeig, Spain
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28
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Dreher L, Hilker TA, Brandlmaier A, Goennenwein STB, Huebl H, Stutzmann M, Brandt MS. Electroelastic hyperfine tuning of phosphorus donors in silicon. PHYSICAL REVIEW LETTERS 2011; 106:037601. [PMID: 21405299 DOI: 10.1103/physrevlett.106.037601] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 11/08/2010] [Indexed: 05/30/2023]
Abstract
We demonstrate an electroelastic control of the hyperfine interaction between nuclear and electronic spins opening an alternative way to address and couple spin-based qubits. The hyperfine interaction is measured by electrically detected magnetic resonance in phosphorus-doped silicon epitaxial layers employing a hybrid structure consisting of a silicon-germanium virtual substrate and a piezoelectric actuator. By applying a voltage to the actuator, the hyperfine interaction is changed by up to 0.9 MHz, which would be enough to shift the phosphorus donor electron spin out of resonance by more than one linewidth in isotopically purified 28Si.
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Affiliation(s)
- L Dreher
- Walter Schottky Institut, Technische Universität München, Am Coulombwall 3, 85748 Garching, Germany.
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McCamey DR, Van Tol J, Morley GW, Boehme C. Electronic Spin Storage in an Electrically Readable Nuclear Spin Memory with a Lifetime >100 Seconds. Science 2010; 330:1652-6. [DOI: 10.1126/science.1197931] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- D. R. McCamey
- Department of Physics and Astronomy, University of Utah, Salt Lake City, UT, 84112, USA
| | - J. Van Tol
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - G. W. Morley
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1H 0AH, UK
| | - C. Boehme
- Department of Physics and Astronomy, University of Utah, Salt Lake City, UT, 84112, USA
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30
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Witzel WM, Carroll MS, Morello A, Cywiński L, Das Sarma S. Electron spin decoherence in isotope-enriched silicon. PHYSICAL REVIEW LETTERS 2010; 105:187602. [PMID: 21231138 DOI: 10.1103/physrevlett.105.187602] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Indexed: 05/30/2023]
Abstract
Silicon is promising for spin-based quantum computation because nuclear spins, a source of magnetic noise, may be eliminated through isotopic enrichment. Long spin decoherence times T2 have been measured in isotope-enriched silicon but come far short of the T2=2T1 limit. The effect of nuclear spins on T2 is well established. However, the effect of background electron spins from ever present residual phosphorus impurities in silicon can also produce significant decoherence. We study spin decoherence decay as a function of donor concentration, 29Si concentration, and temperature using cluster expansion techniques specifically adapted to the problem of a sparse dipolarly coupled electron spin bath. Our results agree with the existing experimental spin echo data in Si:P and establish the importance of background dopants as the ultimate decoherence mechanism in isotope-enriched silicon.
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Affiliation(s)
- Wayne M Witzel
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.
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31
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Wu H, George RE, Wesenberg JH, Mølmer K, Schuster DI, Schoelkopf RJ, Itoh KM, Ardavan A, Morton JJL, Briggs GAD. Storage of multiple coherent microwave excitations in an electron spin ensemble. PHYSICAL REVIEW LETTERS 2010; 105:140503. [PMID: 21230819 DOI: 10.1103/physrevlett.105.140503] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Indexed: 05/30/2023]
Abstract
Strong coupling between a microwave photon and electron spins, which could enable a long-lived quantum memory element for superconducting qubits, is possible using a large ensemble of spins. This represents an inefficient use of resources unless multiple photons, or qubits, can be orthogonally stored and retrieved. Here we employ holographic techniques to realize a coherent memory using a pulsed magnetic field gradient and demonstrate the storage and retrieval of up to 100 weak 10 GHz coherent excitations in collective states of an electron spin ensemble. We further show that such collective excitations in the electron spin can then be stored in nuclear spin states, which offer coherence times in excess of seconds.
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Affiliation(s)
- Hua Wu
- Department of Materials, Oxford University, Oxford OX1 3PH, United Kingdom
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32
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Morley GW, Warner M, Stoneham AM, Greenland PT, van Tol J, Kay CWM, Aeppli G. The initialization and manipulation of quantum information stored in silicon by bismuth dopants. NATURE MATERIALS 2010; 9:725-9. [PMID: 20711180 DOI: 10.1038/nmat2828] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Accepted: 07/06/2010] [Indexed: 05/05/2023]
Abstract
A prerequisite for exploiting spins for quantum data storage and processing is long spin coherence times. Phosphorus dopants in silicon (Si:P) have been favoured as hosts for such spins because of measured electron spin coherence times (T2) longer than any other electron spin in the solid state: 14 ms at 7 K with isotopically purified silicon. Heavier impurities such as bismuth in silicon (Si:Bi) could be used in conjunction with Si:P for quantum information proposals that require two separately addressable spin species. However, the question of whether the incorporation of the much less soluble Bi into Si leads to defect species that destroy coherence has not been addressed. Here we show that schemes involving Si:Bi are indeed feasible as the electron spin coherence time T2 is at least as long as for Si:P with non-isotopically purified silicon. We polarized the Si:Bi electrons and hyperpolarized the I=9/2 nuclear spin of (209)Bi, manipulating both with pulsed magnetic resonance. The larger nuclear spin means that a Si:Bi dopant provides a 20-dimensional Hilbert space rather than the four-dimensional Hilbert space of an I=1/2 Si:P dopant.
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Affiliation(s)
- Gavin W Morley
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK.
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33
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Mohammady MH, Morley GW, Monteiro TS. Bismuth qubits in silicon: the role of EPR cancellation resonances. PHYSICAL REVIEW LETTERS 2010; 105:067602. [PMID: 20868015 DOI: 10.1103/physrevlett.105.067602] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Indexed: 05/29/2023]
Abstract
We investigate electron paramagnetic resonance spectra of bismuth-doped silicon, at intermediate magnetic fields B≃0.1-0.6 T, theoretically and experimentally (with 9.7 GHz X-band spectra). We identify a previously unexplored regime of "cancellation resonances," where a component of the hyperfine coupling is resonant with the external field. We show that this regime has experimentally accessible consequences for quantum information applications, such as reduction of decoherence, fast manipulation of the coupled electron-nuclear qubits, and spectral line narrowing.
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Affiliation(s)
- M H Mohammady
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
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