1
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CMOS-based cryogenic control of silicon quantum circuits. Nature 2021; 593:205-210. [PMID: 33981049 DOI: 10.1038/s41586-021-03469-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 03/18/2021] [Indexed: 11/08/2022]
Abstract
The most promising quantum algorithms require quantum processors that host millions of quantum bits when targeting practical applications1. A key challenge towards large-scale quantum computation is the interconnect complexity. In current solid-state qubit implementations, an important interconnect bottleneck appears between the quantum chip in a dilution refrigerator and the room-temperature electronics. Advanced lithography supports the fabrication of both control electronics and qubits in silicon using technology compatible with complementary metal oxide semiconductors (CMOS)2. When the electronics are designed to operate at cryogenic temperatures, they can ultimately be integrated with the qubits on the same die or package, overcoming the 'wiring bottleneck'3-6. Here we report a cryogenic CMOS control chip operating at 3 kelvin, which outputs tailored microwave bursts to drive silicon quantum bits cooled to 20 millikelvin. We first benchmark the control chip and find an electrical performance consistent with qubit operations of 99.99 per cent fidelity, assuming ideal qubits. Next, we use it to coherently control actual qubits encoded in the spin of single electrons confined in silicon quantum dots7-9 and find that the cryogenic control chip achieves the same fidelity as commercial instruments at room temperature. Furthermore, we demonstrate the capabilities of the control chip by programming a number of benchmarking protocols, as well as the Deutsch-Josza algorithm10, on a two-qubit quantum processor. These results open up the way towards a fully integrated, scalable silicon-based quantum computer.
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2
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Takeda K, Noiri A, Yoneda J, Nakajima T, Tarucha S. Resonantly Driven Singlet-Triplet Spin Qubit in Silicon. PHYSICAL REVIEW LETTERS 2020; 124:117701. [PMID: 32242710 DOI: 10.1103/physrevlett.124.117701] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 12/12/2019] [Accepted: 02/20/2020] [Indexed: 06/11/2023]
Abstract
We report implementation of a resonantly driven singlet-triplet spin qubit in silicon. The qubit is defined by the two-electron antiparallel spin states and universal quantum control is provided through a resonant drive of the exchange interaction at the qubit frequency. The qubit exhibits long T_{2}^{*} exceeding 1 μs that is limited by dephasing due to the ^{29}Si nuclei rather than charge noise thanks to the symmetric operation and a large micromagnet Zeeman field gradient. The randomized benchmarking shows 99.6% single gate fidelity which is the highest reported for singlet-triplet qubits.
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Affiliation(s)
- K Takeda
- Center for Emergent Matter Science (CEMS), RIKEN, Wako-shi, Saitama 351-0198, Japan
| | - A Noiri
- Center for Emergent Matter Science (CEMS), RIKEN, Wako-shi, Saitama 351-0198, Japan
| | - J Yoneda
- Center for Emergent Matter Science (CEMS), RIKEN, Wako-shi, Saitama 351-0198, Japan
| | - T Nakajima
- Center for Emergent Matter Science (CEMS), RIKEN, Wako-shi, Saitama 351-0198, Japan
| | - S Tarucha
- Center for Emergent Matter Science (CEMS), RIKEN, Wako-shi, Saitama 351-0198, Japan
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3
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Leon RCC, Yang CH, Hwang JCC, Lemyre JC, Tanttu T, Huang W, Chan KW, Tan KY, Hudson FE, Itoh KM, Morello A, Laucht A, Pioro-Ladrière M, Saraiva A, Dzurak AS. Coherent spin control of s-, p-, d- and f-electrons in a silicon quantum dot. Nat Commun 2020; 11:797. [PMID: 32047151 PMCID: PMC7012832 DOI: 10.1038/s41467-019-14053-w] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 12/11/2019] [Indexed: 11/09/2022] Open
Abstract
Once the periodic properties of elements were unveiled, chemical behaviour could be understood in terms of the valence of atoms. Ideally, this rationale would extend to quantum dots, and quantum computation could be performed by merely controlling the outer-shell electrons of dot-based qubits. Imperfections in semiconductor materials disrupt this analogy, so real devices seldom display a systematic many-electron arrangement. We demonstrate here an electrostatically confined quantum dot that reveals a well defined shell structure. We observe four shells (31 electrons) with multiplicities given by spin and valley degrees of freedom. Various fillings containing a single valence electron-namely 1, 5, 13 and 25 electrons-are found to be potential qubits. An integrated micromagnet allows us to perform electrically-driven spin resonance (EDSR), leading to faster Rabi rotations and higher fidelity single qubit gates at higher shell states. We investigate the impact of orbital excitations on single qubits as a function of the dot deformation and exploit it for faster qubit control.
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Affiliation(s)
- R C C Leon
- 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
| | - J C C Hwang
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
- Research and Prototype Foundry, The University of Sydney, Sydney, NSW, 2006, Australia
| | - J Camirand Lemyre
- Institut Quantique et Département de Physique, Université de Sherbrooke, Sherbrooke, Québec, J1K 2R1, Canada
| | - T Tanttu
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - W Huang
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - K W Chan
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - K Y Tan
- QCD Labs COMP Centre of Excellence, Department of Applied Physics, Aalto University, 00076, Aalto, Finland
| | - F E Hudson
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - K M Itoh
- School of Fundamental Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohokuku, Yokohama, 223-8522, Japan
| | - A Morello
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - A Laucht
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - M Pioro-Ladrière
- Institut Quantique et Département de Physique, Université de Sherbrooke, Sherbrooke, Québec, J1K 2R1, Canada
- Quantum Information Science Program, Canadian Institute for Advanced Research, Toronto, ON, M5G 1Z8, Canada
| | - A Saraiva
- 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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4
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Chen JS, Li M, Cotlet M. Nanoscale Photoinduced Charge Transfer with Individual Quantum Dots: Tunability through Synthesis, Interface Design, and Interaction with Charge Traps. ACS OMEGA 2019; 4:9102-9112. [PMID: 31459998 PMCID: PMC6648770 DOI: 10.1021/acsomega.9b00803] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 05/03/2019] [Indexed: 05/29/2023]
Abstract
Semiconducting colloidal quantum dots (QDs) provide an excellent platform for nanoscale charge-transfer studies. Because of their size-dependent optoelectronic properties, which can be tuned via chemical synthesis and of their versatility in surface ligand exchange, QDs can be coupled with various types of acceptors to create hybrids with controlled type (electron or hole), direction, and rate of charge flow, depending on the foreseen application, either solar harvesting, light emitting, or biosensing. This perspective highlights several examples of QD-based hybrids with controllable (tunable) rate of charge transfer obtained by various approaches, including by changing the QD core size and shell thickness by colloidal synthesis, by the insertion of molecular linkers or dielectric spacers between donor and acceptor components. We also show that subjecting QDs to external factors such as electric fields and alternate optical excitation energy is another approach to bias the internal charge transfer between charges photogenerated in the QD core and QD's surface charge traps. The perspective also provides the reader with various examples of how single nanoparticle spectroscopic studies can help in understanding and quantifying nanoscale charge transfer with QDs.
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Affiliation(s)
- Jia-Shiang Chen
- Center
for Functional Nanomaterials, Brookhaven
National Laboratory, Upton, New York 11973, United States
- Department
of Materials Science and Chemical Engineering, Stony Brook University, Stony
Brook, New York 11794, United States
| | - Mingxing Li
- Center
for Functional Nanomaterials, Brookhaven
National Laboratory, Upton, New York 11973, United States
| | - Mircea Cotlet
- Center
for Functional Nanomaterials, Brookhaven
National Laboratory, Upton, New York 11973, United States
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5
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Mills AR, Zajac DM, Gullans MJ, Schupp FJ, Hazard TM, Petta JR. Shuttling a single charge across a one-dimensional array of silicon quantum dots. Nat Commun 2019; 10:1063. [PMID: 30837460 PMCID: PMC6401174 DOI: 10.1038/s41467-019-08970-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 02/08/2019] [Indexed: 11/09/2022] Open
Abstract
Significant advances have been made towards fault-tolerant operation of silicon spin qubits, with single qubit fidelities exceeding 99.9%, several demonstrations of two-qubit gates based on exchange coupling, and the achievement of coherent single spin-photon coupling. Coupling arbitrary pairs of spatially separated qubits in a quantum register poses a significant challenge as most qubit systems are constrained to two dimensions with nearest neighbor connectivity. For spins in silicon, new methods for quantum state transfer should be developed to achieve connectivity beyond nearest-neighbor exchange. Here we demonstrate shuttling of a single electron across a linear array of nine series-coupled silicon quantum dots in ~50 ns via a series of pairwise interdot charge transfers. By constructing more complex pulse sequences we perform parallel shuttling of two and three electrons at a time through the array. These experiments demonstrate a scalable approach to physically transporting single electrons across large silicon quantum dot arrays.
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Affiliation(s)
- A R Mills
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - D M Zajac
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - M J Gullans
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - F J Schupp
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - T M Hazard
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - J R Petta
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA.
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6
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van der Heijden J, Kobayashi T, House MG, Salfi J, Barraud S, Laviéville R, Simmons MY, Rogge S. Readout and control of the spin-orbit states of two coupled acceptor atoms in a silicon transistor. SCIENCE ADVANCES 2018; 4:eaat9199. [PMID: 30539142 PMCID: PMC6286166 DOI: 10.1126/sciadv.aat9199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 11/07/2018] [Indexed: 06/09/2023]
Abstract
Coupling spin qubits to electric fields is attractive to simplify qubit manipulation and couple qubits over long distances. Electron spins in silicon offer long lifetimes, but their weak spin-orbit interaction makes electrical coupling challenging. Hole spins bound to acceptor dopants, spin-orbit-coupled J = 3/2 systems similar to Si vacancies in SiC and single Co dopants, are an electrically active spin system in silicon. However, J = 3/2 systems are much less studied than S = 1/2 electrons, and spin readout has not yet been demonstrated for acceptors in silicon. Here, we study acceptor hole spin dynamics by dispersive readout of single-hole tunneling between two coupled acceptors in a nanowire transistor. We identify m J = ±1/2 and m J = ±3/2 levels, and we use a magnetic field to overcome the initial heavy-light hole splitting and to tune the J = 3/2 energy spectrum. We find regimes of spin-like (+3/2 to -3/2) and charge-like (±1/2 to ±3/2) relaxations, separated by a regime of enhanced relaxation induced by mixing of light and heavy holes. The demonstrated control over the energy level ordering and hybridization are new tools in the J = 3/2 system that are crucial to optimize single-atom spin lifetime and electrical coupling.
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Affiliation(s)
- Joost van der Heijden
- School of Physics and Australian Centre of Excellence for Quantum Computation and Communication Technology, UNSW, Sydney, Australia
| | - Takashi Kobayashi
- School of Physics and Australian Centre of Excellence for Quantum Computation and Communication Technology, UNSW, Sydney, Australia
| | - Matthew G. House
- School of Physics and Australian Centre of Excellence for Quantum Computation and Communication Technology, UNSW, Sydney, Australia
| | - Joe Salfi
- School of Physics and Australian Centre of Excellence for Quantum Computation and Communication Technology, UNSW, Sydney, Australia
| | - Sylvain Barraud
- University of Grenoble Alpes and CEA, LETI, MINATEC, 38000 Grenoble, France
| | - Romain Laviéville
- University of Grenoble Alpes and CEA, LETI, MINATEC, 38000 Grenoble, France
| | - Michelle Y. Simmons
- School of Physics and Australian Centre of Excellence for Quantum Computation and Communication Technology, UNSW, Sydney, Australia
| | - Sven Rogge
- School of Physics and Australian Centre of Excellence for Quantum Computation and Communication Technology, UNSW, Sydney, Australia
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7
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Zhao X, Hu X. Toward high-fidelity coherent electron spin transport in a GaAs double quantum dot. Sci Rep 2018; 8:13968. [PMID: 30228299 PMCID: PMC6143546 DOI: 10.1038/s41598-018-31879-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 08/14/2018] [Indexed: 11/18/2022] Open
Abstract
In this paper, we investigate how to achieve high-fidelity electron spin transport in a GaAs double quantum dot. Our study examines fidelity loss in spin transport from multiple perspectives. We first study incoherent fidelity loss due to hyperfine and spin-orbit interaction. We calculate fidelity loss due to the random Overhauser field from hyperfine interaction, and spin relaxation rate due to spin-orbit interaction in a wide range of experimental parameters with a focus on the occurrence of spin hot spots. A safe parameter regime is identified in order to avoid these spin hot spots. We then analyze systematic errors due to non-adiabatic transitions in the Landau-Zener process of sweeping the interdot detuning, and propose a scheme to take advantage of possible Landau-Zener-Stückelberg interference to achieve high-fidelity spin transport at a higher speed. At last, we study another systematic error caused by the correction to the electron g-factor from the double dot potential, which can lead to a notable phase error. In all, our results should provide a useful guidance for future experiments on coherent electron spin transport.
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Affiliation(s)
- Xinyu Zhao
- Department of Physics, University at Buffalo, SUNY, Buffalo, New York, 14260-1500, USA
| | - Xuedong Hu
- Department of Physics, University at Buffalo, SUNY, Buffalo, New York, 14260-1500, USA.
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8
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Watson TF, Philips SGJ, Kawakami E, Ward DR, Scarlino P, Veldhorst M, Savage DE, Lagally MG, Friesen M, Coppersmith SN, Eriksson MA, Vandersypen LMK. A programmable two-qubit quantum processor in silicon. Nature 2018; 555:633-637. [PMID: 29443962 DOI: 10.1038/nature25766] [Citation(s) in RCA: 433] [Impact Index Per Article: 72.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 01/16/2018] [Indexed: 12/18/2022]
Abstract
Now that it is possible to achieve measurement and control fidelities for individual quantum bits (qubits) above the threshold for fault tolerance, attention is moving towards the difficult task of scaling up the number of physical qubits to the large numbers that are needed for fault-tolerant quantum computing. In this context, quantum-dot-based spin qubits could have substantial advantages over other types of qubit owing to their potential for all-electrical operation and ability to be integrated at high density onto an industrial platform. Initialization, readout and single- and two-qubit gates have been demonstrated in various quantum-dot-based qubit representations. However, as seen with small-scale demonstrations of quantum computers using other types of qubit, combining these elements leads to challenges related to qubit crosstalk, state leakage, calibration and control hardware. Here we overcome these challenges by using carefully designed control techniques to demonstrate a programmable two-qubit quantum processor in a silicon device that can perform the Deutsch-Josza algorithm and the Grover search algorithm-canonical examples of quantum algorithms that outperform their classical analogues. We characterize the entanglement in our processor by using quantum-state tomography of Bell states, measuring state fidelities of 85-89 per cent and concurrences of 73-82 per cent. These results pave the way for larger-scale quantum computers that use spins confined to quantum dots.
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Affiliation(s)
- T F Watson
- QuTech and the Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands
| | - S G J Philips
- QuTech and the Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands
| | - E Kawakami
- QuTech and the Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands
| | - D R Ward
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - P Scarlino
- QuTech and the Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands
| | - M Veldhorst
- QuTech and the Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands
| | - D E Savage
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - M G Lagally
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Mark Friesen
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - S N Coppersmith
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - M A Eriksson
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - L M K Vandersypen
- QuTech and the Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands
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9
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Fujita T, Stano P, Allison G, Morimoto K, Sato Y, Larsson M, Park JH, Ludwig A, Wieck AD, Oiwa A, Tarucha S. Signatures of Hyperfine, Spin-Orbit, and Decoherence Effects in a Pauli Spin Blockade. PHYSICAL REVIEW LETTERS 2016; 117:206802. [PMID: 27886503 DOI: 10.1103/physrevlett.117.206802] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Indexed: 06/06/2023]
Abstract
We detect in real time interdot tunneling events in a weakly coupled two-electron double quantum dot in GaAs. At finite magnetic fields, we observe two characteristic tunneling times T_{d} and T_{b}, belonging to, respectively, a direct and a blocked (spin-flip-assisted) tunneling. The latter corresponds to the lifting of a Pauli spin blockade, and the tunneling times ratio η=T_{b}/T_{d} characterizes the blockade efficiency. We find pronounced changes in the behavior of η upon increasing the magnetic field, with η increasing, saturating, and increasing again. We explain this behavior as due to the crossover of the dominant blockade-lifting mechanism from the hyperfine to spin-orbit interactions and due to a change in the contribution of the charge decoherence.
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Affiliation(s)
- T Fujita
- Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - P Stano
- Center for Emergent Matter Science (CEMS), RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
- Institute of Physics, Slovak Academy of Sciences, 845 11 Bratislava, Slovakia
| | - G Allison
- Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Center for Emergent Matter Science (CEMS), RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - K Morimoto
- Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Y Sato
- Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - M Larsson
- Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - J-H Park
- Center for Emergent Matter Science (CEMS), RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - A Ludwig
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, Gebäude NB, D-44780 Bochum, Germany
| | - A D Wieck
- Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, Gebäude NB, D-44780 Bochum, Germany
| | - A Oiwa
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - S Tarucha
- Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
- Center for Emergent Matter Science (CEMS), RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
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10
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Baart TA, Shafiei M, Fujita T, Reichl C, Wegscheider W, Vandersypen LMK. Single-spin CCD. NATURE NANOTECHNOLOGY 2016; 11:330-334. [PMID: 26727201 DOI: 10.1038/nnano.2015.291] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 11/11/2015] [Indexed: 06/05/2023]
Abstract
Spin-based electronics or spintronics relies on the ability to store, transport and manipulate electron spin polarization with great precision. In its ultimate limit, information is stored in the spin state of a single electron, at which point quantum information processing also becomes a possibility. Here, we demonstrate the manipulation, transport and readout of individual electron spins in a linear array of three semiconductor quantum dots. First, we demonstrate single-shot readout of three spins with fidelities of 97% on average, using an approach analogous to the operation of a charge-coupled device (CCD). Next, we perform site-selective control of the three spins, thereby writing the content of each pixel of this 'single-spin charge-coupled device'. Finally, we show that shuttling an electron back and forth in the array hundreds of times, covering a cumulative distance of 80 μm, has negligible influence on its spin projection. Extrapolating these results to the case of much larger arrays points at a diverse range of potential applications, from quantum information to imaging and sensing.
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Affiliation(s)
- T A Baart
- QuTech and Kavli Institute of Nanoscience, TU Delft, GA Delft 2600, The Netherlands
| | - M Shafiei
- QuTech and Kavli Institute of Nanoscience, TU Delft, GA Delft 2600, The Netherlands
| | - T Fujita
- QuTech and Kavli Institute of Nanoscience, TU Delft, GA Delft 2600, The Netherlands
| | - C Reichl
- Solid State Physics Laboratory, ETH Zürich, Zürich 8093, Switzerland
| | - W Wegscheider
- Solid State Physics Laboratory, ETH Zürich, Zürich 8093, Switzerland
| | - L M K Vandersypen
- QuTech and Kavli Institute of Nanoscience, TU Delft, GA Delft 2600, The Netherlands
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11
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Scarlino P, Kawakami E, Stano P, Shafiei M, Reichl C, Wegscheider W, Vandersypen LMK. Spin-relaxation anisotropy in a GaAs quantum dot. PHYSICAL REVIEW LETTERS 2014; 113:256802. [PMID: 25554903 DOI: 10.1103/physrevlett.113.256802] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Indexed: 06/04/2023]
Abstract
We report that the electron spin-relaxation time T_{1} in a GaAs quantum dot with a spin-1/2 ground state has a 180° periodicity in the orientation of the in-plane magnetic field. This periodicity has been predicted for circular dots as being due to the interplay of Rashba and Dresselhaus spin orbit contributions. Different from this prediction, we find that the extrema in the T_{1} do not occur when the magnetic field is along the [110] and [11[over ¯]0] crystallographic directions. This deviation is attributed to an elliptical dot confining potential. The T_{1} varies by more than 1 order of magnitude when rotating a 3 T field, reaching about 80 ms for the optimal angle. We infer from the data that in our device the signs of the Rashba and Dresselhaus constants are opposite.
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Affiliation(s)
- P Scarlino
- Kavli Institute of Nanoscience, TU Delft, Lorentzweg 1, 2628 CJ Delft, Netherlands
| | - E Kawakami
- Kavli Institute of Nanoscience, TU Delft, Lorentzweg 1, 2628 CJ Delft, Netherlands
| | - P Stano
- RIKEN Center for Emergent Matter Science, Wako-shi, Saitama 351-0198, Japan and Institute of Physics, Slovak Academy of Sciences, Dubravska cesta 9, 84511 Bratislava, Slovakia
| | - M Shafiei
- Kavli Institute of Nanoscience, TU Delft, Lorentzweg 1, 2628 CJ Delft, Netherlands
| | - C Reichl
- Solid State Physics Laboratory, ETH Zurich, Schafmattstrasse 16, 8093 Zurich, Switzerland
| | - W Wegscheider
- Solid State Physics Laboratory, ETH Zurich, Schafmattstrasse 16, 8093 Zurich, Switzerland
| | - L M K Vandersypen
- Kavli Institute of Nanoscience, TU Delft, Lorentzweg 1, 2628 CJ Delft, Netherlands
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