1
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Tran KX, Bracker AS, Yakes MK, Grim JQ, Carter SG. Enhanced Spin Coherence of a Self-Assembled Quantum Dot Molecule at the Optimal Electrical Bias. PHYSICAL REVIEW LETTERS 2022; 129:027403. [PMID: 35867431 DOI: 10.1103/physrevlett.129.027403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
A pair of coupled dots with one electron in each dot can provide improvements in spin coherence, particularly at an electrical bias called the "sweet spot," but few measurements have been performed on self-assembled dots in this regime. Here, we directly measure the T_{2}^{*} coherence time of the singlet-triplet states in this system as a function of bias and magnetic field, obtaining a maximum T_{2}^{*} of 60 ns, more than an order of magnitude higher than an electron spin in a single quantum dot. Our results uncover two main dephasing mechanisms: electrical noise away from the sweet spot, and a magnetic field dependent interaction with nuclear spins due to a difference in g factors.
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Affiliation(s)
- Kha X Tran
- Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375, USA
| | - Allan S Bracker
- Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375, USA
| | - Michael K Yakes
- Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375, USA
| | - Joel Q Grim
- Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375, USA
| | - Samuel G Carter
- Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, D.C. 20375, USA
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2
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Nikandish R, Blokhina E, Leipold D, Staszewski RB. Semiconductor Quantum Computing: Toward a CMOS quantum computer on chip. IEEE NANOTECHNOLOGY MAGAZINE 2021. [DOI: 10.1109/mnano.2021.3113216] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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3
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Zhang T, Liu H, Gao F, Xu G, Wang K, Zhang X, Cao G, Wang T, Zhang J, Hu X, Li HO, Guo GP. Anisotropic g-Factor and Spin-Orbit Field in a Germanium Hut Wire Double Quantum Dot. NANO LETTERS 2021; 21:3835-3842. [PMID: 33914549 DOI: 10.1021/acs.nanolett.1c00263] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Holes in nanowires have drawn significant attention in recent years because of the strong spin-orbit interaction, which plays an important role in constructing Majorana zero modes and manipulating spin-orbit qubits. Here, from the strongly anisotropic leakage current in the spin blockade regime for a double dot, we extract the full g-tensor and find that the spin-orbit field is in plane with an azimuthal angle of 59° to the axis of the nanowire. The direction of the spin-orbit field indicates a strong spin-orbit interaction along the nanowire, which may have originated from the interface inversion asymmetry in Ge hut wires. We also demonstrate two different spin relaxation mechanisms for the holes in the Ge hut wire double dot: spin-flip co-tunneling to the leads, and spin-orbit interaction within the double dot. These results help establish feasibility of a Ge-based quantum processor.
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Affiliation(s)
- Ting Zhang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - He Liu
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Fei Gao
- Institute of Physics and CAS Center for Excellence in Topological Quantum Computation, Chinese Academy of Sciences, Beijing 100190, China
| | - Gang Xu
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ke Wang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xin Zhang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Gang Cao
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ting Wang
- Institute of Physics and CAS Center for Excellence in Topological Quantum Computation, Chinese Academy of Sciences, Beijing 100190, China
| | - Jianjun Zhang
- Institute of Physics and CAS Center for Excellence in Topological Quantum Computation, Chinese Academy of Sciences, Beijing 100190, China
| | - Xuedong Hu
- Department of Physics, University at Buffalo, SUNY, Buffalo, New York 14260, United States
| | - Hai-Ou Li
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Guo-Ping Guo
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Origin Quantum Computing Company Limited, Hefei, Anhui 230026, China
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4
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Wu H, Xu H, Shi Y, Yuan T, Meng T, Zhang Y, Xie W, Li X, Li Y, Fan L. Recent Advance in Carbon Dots: From Properties to Applications. CHINESE J CHEM 2021. [DOI: 10.1002/cjoc.202000609] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Hao Wu
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University Beijing 100875 China
| | - Huimin Xu
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University Beijing 100875 China
| | - Yuxin Shi
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University Beijing 100875 China
| | - Ting Yuan
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University Beijing 100875 China
| | - Ting Meng
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University Beijing 100875 China
| | - Yang Zhang
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University Beijing 100875 China
| | - Wenjing Xie
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University Beijing 100875 China
| | - Xiaohong Li
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University Beijing 100875 China
| | - Yunchao Li
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University Beijing 100875 China
| | - Louzhen Fan
- College of Chemistry, Key Laboratory of Theoretical & Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University Beijing 100875 China
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5
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de Leon NP, Itoh KM, Kim D, Mehta KK, Northup TE, Paik H, Palmer BS, Samarth N, Sangtawesin S, Steuerman DW. Materials challenges and opportunities for quantum computing hardware. Science 2021; 372:372/6539/eabb2823. [PMID: 33859004 DOI: 10.1126/science.abb2823] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Quantum computing hardware technologies have advanced during the past two decades, with the goal of building systems that can solve problems that are intractable on classical computers. The ability to realize large-scale systems depends on major advances in materials science, materials engineering, and new fabrication techniques. We identify key materials challenges that currently limit progress in five quantum computing hardware platforms, propose how to tackle these problems, and discuss some new areas for exploration. Addressing these materials challenges will require scientists and engineers to work together to create new, interdisciplinary approaches beyond the current boundaries of the quantum computing field.
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Affiliation(s)
- Nathalie P de Leon
- Department of Electrical Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Kohei M Itoh
- School of Fundamental Science and Technology, Keio University, Yokohama 223-8522, Japan
| | - Dohun Kim
- Department of Physics and Astronomy and Institute of Applied Physics, Seoul National University, Seoul 08826, Korea
| | - Karan K Mehta
- Department of Physics, Institute for Quantum Electronics, ETH Zürich, 8092 Zürich, Switzerland
| | - Tracy E Northup
- Institut für Experimentalphysik, Universität Innsbruck, 6020 Innsbruck, Austria
| | - Hanhee Paik
- IBM Quantum, IBM T. J. Watson Research Center, Yorktown Heights, NY 10598, USA.
| | - B S Palmer
- Laboratory for Physical Sciences, University of Maryland, College Park, MD 20740, USA.,Quantum Materials Center, University of Maryland, College Park, MD 20742, USA
| | - N Samarth
- Department of Physics, The Pennsylvania State University, University Park, PA 16802, USA
| | - Sorawis Sangtawesin
- School of Physics and Center of Excellence in Advanced Functional Materials, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - D W Steuerman
- Kavli Foundation, 5715 Mesmer Avenue, Los Angeles, CA 90230, USA
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6
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Metal-Organic Frameworks as a Platform for CO2 Capture and Chemical Processes: Adsorption, Membrane Separation, Catalytic-Conversion, and Electrochemical Reduction of CO2. Catalysts 2020. [DOI: 10.3390/catal10111293] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The continuous rise in the atmospheric concentration of carbon dioxide gas (CO2) is of significant global concern. Several methodologies and technologies are proposed and applied by the industries to mitigate the emissions of CO2 into the atmosphere. This review article offers a large number of studies that aim to capture, convert, or reduce CO2 by using a superb porous class of materials (metal-organic frameworks, MOFs), aiming to tackle this worldwide issue. MOFs possess several remarkable features ranging from high surface area and porosity to functionality and morphology. As a result of these unique features, MOFs were selected as the main class of porous material in this review article. MOFs act as an ideal candidate for the CO2 capture process. The main approaches for capturing CO2 are pre-combustion capture, post-combustion capture, and oxy-fuel combustion capture. The applications of MOFs in the carbon capture processes were extensively overviewed. In addition, the applications of MOFs in the adsorption, membrane separation, catalytic conversion, and electrochemical reduction processes of CO2 were also studied in order to provide new practical and efficient techniques for CO2 mitigation.
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7
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Milster S, Grünbaum T, Bange S, Kurrmann S, Kraus H, Stoltzfus DM, Leung AE, Darwish TA, Burn PL, Boehme C, Lupton JM. Perdeuterated Conjugated Polymers for Ultralow-Frequency Magnetic Resonance of OLEDs. Angew Chem Int Ed Engl 2020; 59:9388-9392. [PMID: 32167645 PMCID: PMC7317727 DOI: 10.1002/anie.202002477] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Indexed: 11/07/2022]
Abstract
The formation of excitons in OLEDs is spin dependent and can be controlled by electron-paramagnetic resonance, affecting device resistance and electroluminescence yield. We explore electrically detected magnetic resonance in the regime of very low magnetic fields (<1 mT). A pronounced feature emerges at zero field in addition to the conventional spin- 1 / 2 Zeeman resonance for which the Larmor frequency matches that of the incident radiation. By comparing a conventional π-conjugated polymer as the active material to a perdeuterated analogue, we demonstrate the interplay between the zero-field feature and local hyperfine fields. The zero-field peak results from a quasistatic magnetic-field effect of the RF radiation for periods comparable to the carrier-pair lifetime. Zeeman resonances are resolved down to 3.2 MHz, approximately twice the Larmor frequency of an electron in Earth's field. However, since reducing hyperfine fields sharpens the Zeeman peak at the cost of an increased zero-field peak, we suggest that this result may constitute a fundamental low-field limit of magnetic resonance in carrier-pair-based systems. OLEDs offer an alternative solid-state platform to investigate the radical-pair mechanism of magnetic-field effects in photochemical reactions, allowing models of biological magnetoreception to be tested by measuring spin decoherence directly in the time domain by pulsed experiments.
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Affiliation(s)
- Sebastian Milster
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, 93053, Regensburg, Germany
| | - Tobias Grünbaum
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, 93053, Regensburg, Germany
| | - Sebastian Bange
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, 93053, Regensburg, Germany
| | - Simon Kurrmann
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, 93053, Regensburg, Germany
| | - Hermann Kraus
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, 93053, Regensburg, Germany
| | - Dani M Stoltzfus
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Anna E Leung
- National Deuteration Facility, Australian Nuclear Science and Technology Organization (ANSTO), Locked Bag 2001, Kirrawee DC, NSW, 2232, Australia
| | - Tamim A Darwish
- National Deuteration Facility, Australian Nuclear Science and Technology Organization (ANSTO), Locked Bag 2001, Kirrawee DC, NSW, 2232, Australia
| | - Paul L Burn
- Centre for Organic Photonics & Electronics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Christoph Boehme
- Department of Physics and Astronomy, University of Utah, 115 South 1400 East, Salt Lake City, UT, 84112, USA
| | - John M Lupton
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, 93053, Regensburg, Germany
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8
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Milster S, Grünbaum T, Bange S, Kurrmann S, Kraus H, Stoltzfus DM, Leung AE, Darwish TA, Burn PL, Boehme C, Lupton JM. Perdeuterated Conjugated Polymers for Ultralow‐Frequency Magnetic Resonance of OLEDs. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202002477] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Sebastian Milster
- Institut für Experimentelle und Angewandte PhysikUniversität Regensburg Universitätsstrasse 31 93053 Regensburg Germany
| | - Tobias Grünbaum
- Institut für Experimentelle und Angewandte PhysikUniversität Regensburg Universitätsstrasse 31 93053 Regensburg Germany
| | - Sebastian Bange
- Institut für Experimentelle und Angewandte PhysikUniversität Regensburg Universitätsstrasse 31 93053 Regensburg Germany
| | - Simon Kurrmann
- Institut für Experimentelle und Angewandte PhysikUniversität Regensburg Universitätsstrasse 31 93053 Regensburg Germany
| | - Hermann Kraus
- Institut für Experimentelle und Angewandte PhysikUniversität Regensburg Universitätsstrasse 31 93053 Regensburg Germany
| | - Dani M. Stoltzfus
- Centre for Organic Photonics & ElectronicsSchool of Chemistry and Molecular BiosciencesThe University of Queensland Brisbane Queensland 4072 Australia
| | - Anna E. Leung
- National Deuteration FacilityAustralian Nuclear Science and Technology Organization (ANSTO) Locked Bag 2001 Kirrawee DC NSW 2232 Australia
| | - Tamim A. Darwish
- National Deuteration FacilityAustralian Nuclear Science and Technology Organization (ANSTO) Locked Bag 2001 Kirrawee DC NSW 2232 Australia
| | - Paul L. Burn
- Centre for Organic Photonics & ElectronicsSchool of Chemistry and Molecular BiosciencesThe University of Queensland Brisbane Queensland 4072 Australia
| | - Christoph Boehme
- Department of Physics and AstronomyUniversity of Utah 115 South 1400 East Salt Lake City UT 84112 USA
| | - John M. Lupton
- Institut für Experimentelle und Angewandte PhysikUniversität Regensburg Universitätsstrasse 31 93053 Regensburg Germany
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9
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Dehollain JP, Mukhopadhyay U, Michal VP, Wang Y, Wunsch B, Reichl C, Wegscheider W, Rudner MS, Demler E, Vandersypen LMK. Nagaoka ferromagnetism observed in a quantum dot plaquette. Nature 2020; 579:528-533. [PMID: 32123352 DOI: 10.1038/s41586-020-2051-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 01/08/2020] [Indexed: 11/09/2022]
Abstract
Engineered, highly controllable quantum systems are promising simulators of emergent physics beyond the simulation capabilities of classical computers1. An important problem in many-body physics is itinerant magnetism, which originates purely from long-range interactions of free electrons and whose existence in real systems has been debated for decades2,3. Here we use a quantum simulator consisting of a four-electron-site square plaquette of quantum dots4 to demonstrate Nagaoka ferromagnetism5. This form of itinerant magnetism has been rigorously studied theoretically6-9 but has remained unattainable in experiments. We load the plaquette with three electrons and demonstrate the predicted emergence of spontaneous ferromagnetic correlations through pairwise measurements of spin. We find that the ferromagnetic ground state is remarkably robust to engineered disorder in the on-site potentials and we can induce a transition to the low-spin state by changing the plaquette topology to an open chain. This demonstration of Nagaoka ferromagnetism highlights that quantum simulators can be used to study physical phenomena that have not yet been observed in any experimental system. The work also constitutes an important step towards large-scale quantum dot simulators of correlated electron systems.
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Affiliation(s)
- J P Dehollain
- QuTech, TU Delft, Delft, The Netherlands.,Kavli Institute of Nanoscience, TU Delft, Delft, The Netherlands.,School of Mathematical and Physical Sciences, University of Technology Sydney, Sydney, New South Wales, Australia
| | - U Mukhopadhyay
- QuTech, TU Delft, Delft, The Netherlands.,Kavli Institute of Nanoscience, TU Delft, Delft, The Netherlands
| | - V P Michal
- QuTech, TU Delft, Delft, The Netherlands.,Kavli Institute of Nanoscience, TU Delft, Delft, The Netherlands
| | - Y Wang
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - B Wunsch
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - C Reichl
- Solid State Physics Laboratory, ETH Zürich, Zürich, Switzerland
| | - W Wegscheider
- Solid State Physics Laboratory, ETH Zürich, Zürich, Switzerland
| | - M S Rudner
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark.,Niels Bohr International Academy, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - E Demler
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - L M K Vandersypen
- QuTech, TU Delft, Delft, The Netherlands. .,Kavli Institute of Nanoscience, TU Delft, Delft, The Netherlands.
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10
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Bugu S, Ozaydin F, Ferrus T, Kodera T. Preparing Multipartite Entangled Spin Qubits via Pauli Spin Blockade. Sci Rep 2020; 10:3481. [PMID: 32103078 PMCID: PMC7044317 DOI: 10.1038/s41598-020-60299-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 02/07/2020] [Indexed: 11/27/2022] Open
Abstract
Preparing large-scale multi-partite entangled states of quantum bits in each physical form such as photons, atoms or electrons for each specific application area is a fundamental issue in quantum science and technologies. Here, we propose a setup based on Pauli spin blockade (PSB) for the preparation of large-scale W states of electrons in a double quantum dot (DQD). Within the proposed scheme, two W states of n and m electrons respectively can be fused by allowing each W state to transfer a single electron to each quantum dot. The presence or absence of PSB then determines whether the two states have fused or not, leading to the creation of a W state of n + m - 2 electrons in the successful case. Contrary to previous works based on quantum dots or nitrogen-vacancy centers in diamond, our proposal does not require any photon assistance. Therefore the 'complex' integration and tuning of an optical cavity is not a necessary prerequisite. We also show how to improve the success rate in our setup. Because requirements are based on currently available technology and well-known sensing techniques, our scheme can directly contribute to the advances in quantum technologies and, in particular in solid state systems.
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Affiliation(s)
- Sinan Bugu
- Department of Electrical and Electronic Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8552, Japan.
| | - Fatih Ozaydin
- Institute for International Strategy, Tokyo International University, 1-13-1 Matoba-kita, Kawagoe, Saitama, 350-1197, Japan
- Department of Information Technologies, Isik University, Sile, Istanbul, 34980, Turkey
| | - Thierry Ferrus
- Hitachi Cambridge Laboratory, J. J. Thomson Avenue, CB3 0HE, Cambridge, United Kingdom
| | - Tetsuo Kodera
- Department of Electrical and Electronic Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8552, Japan
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11
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Abstract
Spin qubits and superconducting qubits are among the promising candidates for realizing a solid state quantum computer. For the implementation of a hybrid architecture which can profit from the advantages of either approach, a coherent link is necessary that integrates and controllably couples both qubit types on the same chip over a distance that is several orders of magnitude longer than the physical size of the spin qubit. We realize such a link with a frequency-tunable high impedance SQUID array resonator. The spin qubit is a resonant exchange qubit hosted in a GaAs triple quantum dot. It can be operated at zero magnetic field, allowing it to coexist with superconducting qubits on the same chip. We spectroscopically observe coherent interaction between the resonant exchange qubit and a transmon qubit in both resonant and dispersive regimes, where the interaction is mediated either by real or virtual resonator photons. Different qubit platforms each have their own advantages and disadvantages. By engineering couplings between them it may be possible to create a more capable hybrid device. Here the authors demonstrate coherent coupling between a semiconductor spin qubit and a superconducting transmon.
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12
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de Bruijckere J, Gehring P, Palacios-Corella M, Clemente-León M, Coronado E, Paaske J, Hedegård P, van der Zant HSJ. Ground-State Spin Blockade in a Single-Molecule Junction. PHYSICAL REVIEW LETTERS 2019; 122:197701. [PMID: 31144938 DOI: 10.1103/physrevlett.122.197701] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 02/21/2019] [Indexed: 05/19/2023]
Abstract
It is known that the quantum mechanical ground state of a nanoscale junction has a significant impact on its electrical transport properties. This becomes particularly important in transistors consisting of a single molecule. Because of strong electron-electron interactions and the possibility of accessing ground states with high spins, these systems are eligible hosts of a current-blockade phenomenon called a ground-state spin blockade. This effect arises from the inability of a charge carrier to account for the spin difference required to enter the junction, as that process would violate the spin selection rules. Here, we present a direct experimental demonstration of a ground-state spin blockade in a high-spin single-molecule transistor. The measured transport characteristics of this device exhibit a complete suppression of resonant transport due to a ground-state spin difference of 3/2 between subsequent charge states. Strikingly, the blockade can be reversibly lifted by driving the system through a magnetic ground-state transition in one charge state, using the tunability offered by both magnetic and electric fields.
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Affiliation(s)
- J de Bruijckere
- Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands
| | - P Gehring
- Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands
| | - M Palacios-Corella
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, Catedrático José Beltrán 2, Paterna, 46980, Spain
| | - M Clemente-León
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, Catedrático José Beltrán 2, Paterna, 46980, Spain
| | - E Coronado
- Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, Catedrático José Beltrán 2, Paterna, 46980, Spain
| | - J Paaske
- Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - P Hedegård
- Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - H S J van der Zant
- Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands
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13
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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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14
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Nilsson M, Boström FV, Lehmann S, Dick KA, Leijnse M, Thelander C. Tuning the Two-Electron Hybridization and Spin States in Parallel-Coupled InAs Quantum Dots. PHYSICAL REVIEW LETTERS 2018; 121:156802. [PMID: 30362807 DOI: 10.1103/physrevlett.121.156802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Indexed: 05/27/2023]
Abstract
We study spin transport in the one- and two-electron regimes of parallel-coupled double quantum dots (DQDs). The DQDs are formed in InAs nanowires by a combination of crystal-phase engineering and electrostatic gating, with an interdot tunnel coupling (t) tunable by one order of magnitude. Large single-particle energy separations (up to 10 meV) and |g^{*}| factors (∼10) enable detailed studies of the B-field-induced transition from a singlet-to-triplet ground state as a function of t. In particular, we investigate how the magnitude of the spin-orbit-induced singlet-triplet anticrossing depends on t. For cases of strong coupling, we find values of 230 μeV for the anticrossing using excited-state spectroscopy. Experimental results are reproduced by calculations based on rate equations and a DQD model including a single orbital in each dot.
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Affiliation(s)
- Malin Nilsson
- Division of Solid State Physics and NanoLund, Lund University, Box 118, S-221 00 Lund, Sweden
| | - Florinda Viñas Boström
- Division of Solid State Physics and NanoLund, Lund University, Box 118, S-221 00 Lund, Sweden
| | - Sebastian Lehmann
- Division of Solid State Physics and NanoLund, Lund University, Box 118, S-221 00 Lund, Sweden
| | - Kimberly A Dick
- Division of Solid State Physics and NanoLund, Lund University, Box 118, S-221 00 Lund, Sweden
- Center for Analysis and Synthesis, Lund University, Box 124, S-221 00 Lund, Sweden
| | - Martin Leijnse
- Division of Solid State Physics and NanoLund, Lund University, Box 118, S-221 00 Lund, Sweden
| | - Claes Thelander
- Division of Solid State Physics and NanoLund, Lund University, Box 118, S-221 00 Lund, Sweden
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15
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Wang JY, Huang GY, Huang S, Xue J, Pan D, Zhao J, Xu H. Anisotropic Pauli Spin-Blockade Effect and Spin-Orbit Interaction Field in an InAs Nanowire Double Quantum Dot. NANO LETTERS 2018; 18:4741-4747. [PMID: 29987931 DOI: 10.1021/acs.nanolett.8b01153] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We report on experimental detection of the spin-orbit interaction field in an InAs nanowire double quantum dot device. In the spin blockade regime, leakage current through the double quantum dot is measured and is used to extract the effects of spin-orbit interaction and hyperfine interaction on spin state mixing. At finite magnetic fields, the leakage current arising from the hyperfine interaction can be suppressed, and the spin-orbit interaction dominates spin state mixing. We observe dependence of the leakage current on the applied magnetic field direction and determine the direction of the spin-orbit interaction field. We show that the spin-orbit field lies in a direction perpendicular to the nanowire axis but with a pronounced off-substrate-plane angle. The results are expected to have an important implication in employing InAs nanowires to construct spin-orbit qubits and topological quantum devices.
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Affiliation(s)
- Ji-Yin Wang
- Beijing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices, and Department of Electronics , Peking University , Beijing 100871 , China
| | - Guang-Yao Huang
- Beijing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices, and Department of Electronics , Peking University , Beijing 100871 , China
| | - Shaoyun Huang
- Beijing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices, and Department of Electronics , Peking University , Beijing 100871 , China
| | - Jianhong Xue
- Beijing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices, and Department of Electronics , Peking University , Beijing 100871 , China
| | - Dong Pan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors , Chinese Academy of Sciences , Beijing 100083 , China
| | - Jianhua Zhao
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors , Chinese Academy of Sciences , Beijing 100083 , China
| | - Hongqi Xu
- Beijing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices, and Department of Electronics , Peking University , Beijing 100871 , China
- Division of Solid State Physics , Lund University , Box 118, S-22100 Lund , Sweden
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16
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Hofmann A, Maisi VF, Krähenmann T, Reichl C, Wegscheider W, Ensslin K, Ihn T. Anisotropy and Suppression of Spin-Orbit Interaction in a GaAs Double Quantum Dot. PHYSICAL REVIEW LETTERS 2017; 119:176807. [PMID: 29219432 DOI: 10.1103/physrevlett.119.176807] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Indexed: 06/07/2023]
Abstract
The spin-flip tunneling rates are measured in GaAs-based double quantum dots by time-resolved charge detection. Such processes occur in the Pauli spin blockade regime with two electrons occupying the double quantum dot. Ways are presented for tuning the spin-flip tunneling rate, which on the one hand gives access to measuring the Rashba and Dresselhaus spin-orbit coefficients. On the other hand, they make it possible to turn on and off the effect of spin-orbit interaction with a high on/off ratio. The tuning is accomplished by choosing the alignment of the tunneling direction with respect to the crystallographic axes, as well as by choosing the orientation of the external magnetic field with respect to the spin-orbit magnetic field. Spin lifetimes of 10 s are achieved at a tunneling rate close to 1 kHz.
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Affiliation(s)
- A Hofmann
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - V F Maisi
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - T Krähenmann
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - C Reichl
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - W Wegscheider
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - K Ensslin
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - T Ihn
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
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17
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Szańkowski P, Ramon G, Krzywda J, Kwiatkowski D, Cywiński Ł. Environmental noise spectroscopy with qubits subjected to dynamical decoupling. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:333001. [PMID: 28569239 DOI: 10.1088/1361-648x/aa7648] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A qubit subjected to pure dephasing due to classical Gaussian noise can be turned into a spectrometer of this noise by utilizing its readout under properly chosen dynamical decoupling (DD) sequences to reconstruct the power spectral density of the noise. We review the theory behind this DD-based noise spectroscopy technique, paying special attention to issues that arise when the environmental noise is non-Gaussian and/or it has truly quantum properties. While we focus on the theoretical basis of the method, we connect the discussed concepts with specific experiments, and provide an overview of environmental noise models relevant for solid-state based qubits, including quantum-dot based spin qubits, superconducting qubits, and NV centers in diamond.
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Affiliation(s)
- P Szańkowski
- Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668 Warsaw, Poland
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18
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Jamali S, Joshi G, Malissa H, Lupton JM, Boehme C. Monolithic OLED-Microwire Devices for Ultrastrong Magnetic Resonant Excitation. NANO LETTERS 2017; 17:4648-4653. [PMID: 28665134 DOI: 10.1021/acs.nanolett.7b01135] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Organic light-emitting diodes (OLEDs) make highly sensitive probes to test magnetic resonance phenomena under unconventional conditions since spin precession controls singlet-triplet transitions of electron-hole pairs, which in turn give rise to distinct recombination currents in conductivity. Electron paramagnetic resonance can therefore be detected in the absence of spin polarization. We exploit this characteristic to explore the exotic regime of ultrastrong light-matter coupling, where the Rabi frequency of a charge carrier spin is of the order of the transition frequency of the two-level system. To reach this domain, we have to lower the Zeeman splitting of the spin states, defined by the static magnetic field B0, and raise the strength of the oscillatory driving field of the resonance, B1. This is achieved by shrinking the OLED and bringing the source of resonant radio frequency (RF) radiation as close as possible to the organic semiconductor in a monolithic device structure, which incorporates an OLED fabricated directly on top of an RF microwire within one monolithic thin-film device structure. With an RF driving power in the milliwatt range applied to the microwire, the regime of bleaching and inversion of the magnetic resonance signal is reached due to the onset of the spin-Dicke effect. In this example of ultrastrong light-matter coupling, the individual resonant spin transitions of electron-hole pairs become indistinguishable with respect to the driving field, and superradiance of the magnetic dipole transitions sets in.
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Affiliation(s)
- Shirin Jamali
- Department of Physics and Astronomy, University of Utah , 115 S, 1400 E, Salt Lake City, Utah 84112, United States
| | - Gajadhar Joshi
- Department of Physics and Astronomy, University of Utah , 115 S, 1400 E, Salt Lake City, Utah 84112, United States
| | - Hans Malissa
- Department of Physics and Astronomy, University of Utah , 115 S, 1400 E, Salt Lake City, Utah 84112, United States
| | - John M Lupton
- Department of Physics and Astronomy, University of Utah , 115 S, 1400 E, Salt Lake City, Utah 84112, United States
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg , Universitätsstrasse 31, 93040 Regensburg, Germany
| | - Christoph Boehme
- Department of Physics and Astronomy, University of Utah , 115 S, 1400 E, Salt Lake City, Utah 84112, United States
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19
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Osika EN, Chacón A, Lewenstein M, Szafran B. Spin-valley dynamics of electrically driven ambipolar carbon-nanotube quantum dots. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:285301. [PMID: 28594639 DOI: 10.1088/1361-648x/aa720e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
An ambipolar n-p double quantum dot defined by potential variation along a semiconducting carbon-nanotube is considered. We focus on the (1e,1h) charge configuration with a single excess electron of the conduction band confined in the n-type dot and a single missing electron in the valence band state of the p-type dot for which lifting of the Pauli blockade of the current was observed in the electric-dipole spin resonance (Laird et al 2013 Nat. Nanotechnol. 8 565). The dynamics of the system driven by periodic electric field is studied with the Floquet theory and the time-dependent configuration interaction method with the single-electron spin-valley-orbitals determined for atomistic tight-binding Hamiltonian. We find that the transitions lifting the Pauli blockade are strongly influenced by coupling to a vacuum state with an empty n dot and a fully filled p dot. The coupling shifts the transition energies and strongly modifies the effective g factors for axial magnetic field. The coupling is modulated by the bias between the dots but it appears effective for surprisingly large energy splitting between the (1e,1h) ground state and the vacuum (0e, 0h) state. Multiphoton transitions and high harmonic generation effects are also discussed.
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Affiliation(s)
- E N Osika
- AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Kraków, Poland
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20
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Many-body Tunneling and Nonequilibrium Dynamics of Doublons in Strongly Correlated Quantum Dots. Sci Rep 2017; 7:2486. [PMID: 28559583 PMCID: PMC5449409 DOI: 10.1038/s41598-017-02728-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 04/13/2017] [Indexed: 12/03/2022] Open
Abstract
Quantum tunneling dominates coherent transport at low temperatures in many systems of great interest. In this work we report a many–body tunneling (MBT), by nonperturbatively solving the Anderson multi-impurity model, and identify it a fundamental tunneling process on top of the well–acknowledged sequential tunneling and cotunneling. We show that the MBT involves the dynamics of doublons in strongly correlated systems. Proportional to the numbers of dynamical doublons, the MBT can dominate the off–resonant transport in the strongly correlated regime. A T3/2–dependence of the MBT current on temperature is uncovered and can be identified as a fingerprint of the MBT in experiments. We also prove that the MBT can support the coherent long–range tunneling of doublons, which is well consistent with recent experiments on ultracold atoms. As a fundamental physical process, the MBT is expected to play important roles in general quantum systems.
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21
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Pei T, Pályi A, Mergenthaler M, Ares N, Mavalankar A, Warner JH, Briggs GAD, Laird EA. Hyperfine and Spin-Orbit Coupling Effects on Decay of Spin-Valley States in a Carbon Nanotube. PHYSICAL REVIEW LETTERS 2017; 118:177701. [PMID: 28498696 DOI: 10.1103/physrevlett.118.177701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Indexed: 06/07/2023]
Abstract
The decay of spin-valley states is studied in a suspended carbon nanotube double quantum dot via the leakage current in Pauli blockade and via dephasing and decoherence of a qubit. From the magnetic field dependence of the leakage current, hyperfine and spin-orbit contributions to relaxation from blocked to unblocked states are identified and explained quantitatively by means of a simple model. The observed qubit dephasing rate is consistent with the hyperfine coupling strength extracted from this model and inconsistent with dephasing from charge noise. However, the qubit coherence time, although longer than previously achieved, is probably still limited by charge noise in the device.
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Affiliation(s)
- T Pei
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
| | - A Pályi
- Department of Physics and MTA-BME Condensed Matter Research Group, Budapest University of Technology and Economics, 1111 Budapest, Hungary
| | - M Mergenthaler
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
| | - N Ares
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
| | - A Mavalankar
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
| | - J H Warner
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
| | - G A D Briggs
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
| | - E A Laird
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
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22
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Gaudenzi R, Misiorny M, Burzurí E, Wegewijs MR, van der Zant HSJ. Transport mirages in single-molecule devices. J Chem Phys 2017. [DOI: 10.1063/1.4975767] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- R. Gaudenzi
- Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands
| | - M. Misiorny
- Department of Microtechnology and Nanoscience MC2, Chalmers University of Technology, 412 96 Göteborg, Sweden
- Faculty of Physics, Adam Mickiewicz University, 61-614 Poznań, Poland
| | - E. Burzurí
- Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands
| | - M. R. Wegewijs
- Peter Grünberg Institut, Forschungszentrum Jülich, 52425 Jülich, Germany
- JARA-FIT, 52056 Aachen, Germany
- Institute for Theory of Statistical Physics, RWTH Aachen, 52056 Aachen, Germany
| | - H. S. J. van der Zant
- Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands
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23
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Moore JN, Hayakawa J, Mano T, Noda T, Yusa G. Optically Imaged Striped Domains of Nonequilibrium Electronic and Nuclear Spins in a Fractional Quantum Hall Liquid. PHYSICAL REVIEW LETTERS 2017; 118:076802. [PMID: 28256890 DOI: 10.1103/physrevlett.118.076802] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Indexed: 06/06/2023]
Abstract
Using photoluminescence microscopy enhanced by magnetic resonance, we visualize in real space both electron and nuclear polarization occurring in nonequilibrium fraction quantum Hall (FQH) liquids. We observe stripelike domain regions comprising FQH excited states which discretely form when the FQH liquid is excited by a source-drain current. These regions are deformable and give rise to bidirectionally polarized nuclear spins as spin-resolved electrons flow across their boundaries.
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Affiliation(s)
- John N Moore
- Department of Physics, Tohoku University, Sendai 980-8578, Japan
| | | | - Takaaki Mano
- National Institute for Materials Science, Tsukuba, Ibaraki 305-0047, Japan
| | - Takeshi Noda
- National Institute for Materials Science, Tsukuba, Ibaraki 305-0047, Japan
| | - Go Yusa
- Department of Physics, Tohoku University, Sendai 980-8578, Japan
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24
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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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25
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Takeda K, Kamioka J, Otsuka T, Yoneda J, Nakajima T, Delbecq MR, Amaha S, Allison G, Kodera T, Oda S, Tarucha S. A fault-tolerant addressable spin qubit in a natural silicon quantum dot. SCIENCE ADVANCES 2016; 2:e1600694. [PMID: 27536725 PMCID: PMC4982751 DOI: 10.1126/sciadv.1600694] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 07/12/2016] [Indexed: 05/18/2023]
Abstract
Fault-tolerant quantum computing requires high-fidelity qubits. This has been achieved in various solid-state systems, including isotopically purified silicon, but is yet to be accomplished in industry-standard natural (unpurified) silicon, mainly as a result of the dephasing caused by residual nuclear spins. This high fidelity can be achieved by speeding up the qubit operation and/or prolonging the dephasing time, that is, increasing the Rabi oscillation quality factor Q (the Rabi oscillation decay time divided by the π rotation time). In isotopically purified silicon quantum dots, only the second approach has been used, leaving the qubit operation slow. We apply the first approach to demonstrate an addressable fault-tolerant qubit using a natural silicon double quantum dot with a micromagnet that is optimally designed for fast spin control. This optimized design allows access to Rabi frequencies up to 35 MHz, which is two orders of magnitude greater than that achieved in previous studies. We find the optimum Q = 140 in such high-frequency range at a Rabi frequency of 10 MHz. This leads to a qubit fidelity of 99.6% measured via randomized benchmarking, which is the highest reported for natural silicon qubits and comparable to that obtained in isotopically purified silicon quantum dot-based qubits. This result can inspire contributions to quantum computing from industrial communities.
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Affiliation(s)
- Kenta Takeda
- RIKEN, Center for Emergent Matter Science, Wako-shi, Saitama 351-0198, Japan
- Corresponding author.
| | - Jun Kamioka
- Department of Physical Electronics and Quantum Nanoelectronics Research Center, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan
| | - Tomohiro Otsuka
- RIKEN, Center for Emergent Matter Science, Wako-shi, Saitama 351-0198, Japan
| | - Jun Yoneda
- RIKEN, Center for Emergent Matter Science, Wako-shi, Saitama 351-0198, Japan
| | - Takashi Nakajima
- RIKEN, Center for Emergent Matter Science, Wako-shi, Saitama 351-0198, Japan
| | - Matthieu R. Delbecq
- RIKEN, Center for Emergent Matter Science, Wako-shi, Saitama 351-0198, Japan
| | - Shinichi Amaha
- RIKEN, Center for Emergent Matter Science, Wako-shi, Saitama 351-0198, Japan
| | - Giles Allison
- RIKEN, Center for Emergent Matter Science, Wako-shi, Saitama 351-0198, Japan
| | - Tetsuo Kodera
- Department of Physical Electronics and Quantum Nanoelectronics Research Center, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan
| | - Shunri Oda
- Department of Physical Electronics and Quantum Nanoelectronics Research Center, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan
| | - Seigo Tarucha
- RIKEN, Center for Emergent Matter Science, Wako-shi, Saitama 351-0198, Japan
- Department of Applied Physics, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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26
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Bechtold A, Li F, Müller K, Simmet T, Ardelt PL, Finley JJ, Sinitsyn NA. Quantum Effects in Higher-Order Correlators of a Quantum-Dot Spin Qubit. PHYSICAL REVIEW LETTERS 2016; 117:027402. [PMID: 27447523 DOI: 10.1103/physrevlett.117.027402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Indexed: 06/06/2023]
Abstract
We measure time correlators of a spin qubit in an optically active quantum dot beyond the second order. Such higher-order correlators are shown to be directly sensitive to pure quantum effects that cannot be explained within the classical framework. They allow direct determination of ensemble and quantum dephasing times, T_{2}^{*} and T_{2}, using only repeated projective measurements and without the need for coherent spin control. Our method enables studies of purely quantum behavior in solid state systems, including tests of the Leggett-Garg type of inequalities that rule out local hidden variable interpretation of the quantum-dot spin dynamics.
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Affiliation(s)
- A Bechtold
- Walter Schottky Institut and Physik Department, Technische Universität München, 85748 Garching, Germany
| | - F Li
- Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 USA
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - K Müller
- Walter Schottky Institut and Physik Department, Technische Universität München, 85748 Garching, Germany
- E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305, USA
| | - T Simmet
- Walter Schottky Institut and Physik Department, Technische Universität München, 85748 Garching, Germany
| | - P-L Ardelt
- Walter Schottky Institut and Physik Department, Technische Universität München, 85748 Garching, Germany
| | - J J Finley
- Walter Schottky Institut and Physik Department, Technische Universität München, 85748 Garching, Germany
| | - N A Sinitsyn
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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27
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Perron JK, Stewart MD, Zimmerman NM. A new regime of Pauli-spin blockade. JOURNAL OF APPLIED PHYSICS 2016; 119:134307. [PMID: 29353918 PMCID: PMC5774638 DOI: 10.1063/1.4945393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Pauli-spin blockade (PSB) is a transport phenomenon in double quantum dots that allows for a type of spin to charge conversion often used to probe fundamental physics such as spin relaxation and singlet-triplet coupling. In this paper, we theoretically explore Pauli-spin blockade as a function of magnetic field B applied parallel to the substrate. In the well-studied low magnetic field regime, where PSB occurs in the forward (1, 1) → (0, 2) tunneling direction, we highlight some aspects of PSB that are not discussed in detail in existing literature, including the change in size of both bias triangles measured in the forward and reverse biasing directions as a function of B. At higher fields, we predict a crossover to "reverse PSB" in which current is blockaded in the reverse direction due to the occupation of a spin singlet as opposed to the traditional triplet blockade that occurs at low fields. The onset of reverse PSB coincides with the development of a tail like feature in the measured bias triangles and occurs when the Zeeman energy of the polarized triplet equals the exchange energy in the (0, 2) charge configuration. In Si quantum dots, these fields are experimentally accessible; thus, this work suggests a way to observe a crossover in magnetic field to qualitatively different behavior.
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Affiliation(s)
- Justin K Perron
- Department of Physics, California State University San Marcos, California 92096, USA
- Joint Quantum Institute, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - M D Stewart
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Neil M Zimmerman
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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Maisi VF, Hofmann A, Röösli M, Basset J, Reichl C, Wegscheider W, Ihn T, Ensslin K. Spin-Orbit Coupling at the Level of a Single Electron. PHYSICAL REVIEW LETTERS 2016; 116:136803. [PMID: 27081997 DOI: 10.1103/physrevlett.116.136803] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Indexed: 06/05/2023]
Abstract
We utilize electron counting techniques to distinguish a spin-conserving fast tunneling process and a slower process involving spin flips in AlGaAs/GaAs-based double quantum dots. By studying the dependence of the rates on the interdot tunnel coupling of the two dots, we find that as many as 4% of the tunneling events occur with a spin flip related to spin-orbit coupling in GaAs. Our measurement has a fidelity of 99% in terms of resolving whether a tunneling event occurred with a spin flip or not.
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Affiliation(s)
- V F Maisi
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - A Hofmann
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - M Röösli
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - J Basset
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - C Reichl
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - W Wegscheider
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - T Ihn
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | - K Ensslin
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
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29
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Voisin B, Maurand R, Barraud S, Vinet M, Jehl X, Sanquer M, Renard J, De Franceschi S. Electrical Control of g-Factor in a Few-Hole Silicon Nanowire MOSFET. NANO LETTERS 2016; 16:88-92. [PMID: 26599868 DOI: 10.1021/acs.nanolett.5b02920] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Hole spins in silicon represent a promising yet barely explored direction for solid-state quantum computation, possibly combining long spin coherence, resulting from a reduced hyperfine interaction, and fast electrically driven qubit manipulation. Here we show that a silicon-nanowire field-effect transistor based on state-of-the-art silicon-on-insulator technology can be operated as a few-hole quantum dot. A detailed magnetotransport study of the first accessible hole reveals a g-factor with unexpectedly strong anisotropy and gate dependence. We infer that these two characteristics could enable an electrically driven g-tensor-modulation spin resonance with Rabi frequencies exceeding several hundred mega-Hertz.
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Affiliation(s)
- B Voisin
- Univ. Grenoble Alpes, INAC-SPSMS , F-38000 Grenoble, France
- CEA, INAC-SPSMS , F-38000 Grenoble, France
| | - R Maurand
- Univ. Grenoble Alpes, INAC-SPSMS , F-38000 Grenoble, France
- CEA, INAC-SPSMS , F-38000 Grenoble, France
| | - S Barraud
- CEA, LETI , MINATEC Campus, 17 rue des Martyrs, 38054 Grenoble, France
| | - M Vinet
- CEA, LETI , MINATEC Campus, 17 rue des Martyrs, 38054 Grenoble, France
| | - X Jehl
- Univ. Grenoble Alpes, INAC-SPSMS , F-38000 Grenoble, France
- CEA, INAC-SPSMS , F-38000 Grenoble, France
| | - M Sanquer
- Univ. Grenoble Alpes, INAC-SPSMS , F-38000 Grenoble, France
- CEA, INAC-SPSMS , F-38000 Grenoble, France
| | - J Renard
- Univ. Grenoble Alpes, INAC-SPSMS , F-38000 Grenoble, France
- CEA, INAC-SPSMS , F-38000 Grenoble, France
| | - S De Franceschi
- Univ. Grenoble Alpes, INAC-SPSMS , F-38000 Grenoble, France
- CEA, INAC-SPSMS , F-38000 Grenoble, France
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30
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Kondo Y, Amaha S, Ono K, Kono K, Tarucha S. Critical Behavior of Alternately Pumped Nuclear Spins in Quantum Dots. PHYSICAL REVIEW LETTERS 2015; 115:186803. [PMID: 26565487 DOI: 10.1103/physrevlett.115.186803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Indexed: 06/05/2023]
Abstract
Nuclear spins in a spin-blocked quantum dot can be pumped and eventually polarized in either of two opposite directions that are selected by applying two different source-drain voltages. Applying a square pulse train as the source-drain voltage can continuously switch the pumping direction alternately. We propose and demonstrate a critical behavior in the polarization after alternate pumping, where the final polarization is sensitive to the initial polarization and pulse conditions. This sensitivity leads to stochastic behavior in the final polarization under nominally the same pumping conditions.
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Affiliation(s)
- Y Kondo
- Center of Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - S Amaha
- Center of Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - K Ono
- Center of Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Low Temperature Physics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - K Kono
- Center of Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Low Temperature Physics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - S Tarucha
- Center of Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Department of Applied Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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31
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Imanaka D, Sharmin S, Hashisaka M, Muraki K, Fujisawa T. Exchange-Induced Spin Blockade in a Two-Electron Double Quantum Dot. PHYSICAL REVIEW LETTERS 2015; 115:176802. [PMID: 26551135 DOI: 10.1103/physrevlett.115.176802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Indexed: 06/05/2023]
Abstract
We have experimentally identified the exchange-induced spin blockade in a GaAs double quantum dot. The transport is suppressed only when the eigenstates are well-defined singlet and triplet states, and thus sensitive to dynamic nuclear-spin polarization that causes singlet-triplet mixing. This gives rise to unusual current spectra, such as a sharp current dip and an asymmetric current profile near the triplet resonance of a double quantum dot. Numerical simulations suggest that the current dip is a signature of identical nuclear-spin polarization in the two dots, which is attractive for coherent spin manipulations in a material with nuclear spins.
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Affiliation(s)
- D Imanaka
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro 152-8551, Japan
| | - S Sharmin
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro 152-8551, Japan
| | - M Hashisaka
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro 152-8551, Japan
| | - K Muraki
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi 243-0198, Japan
| | - T Fujisawa
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro 152-8551, Japan
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Betz AC, Wacquez R, Vinet M, Jehl X, Saraiva AL, Sanquer M, Ferguson AJ, Gonzalez-Zalba MF. Dispersively Detected Pauli Spin-Blockade in a Silicon Nanowire Field-Effect Transistor. NANO LETTERS 2015; 15:4622-4627. [PMID: 26047255 DOI: 10.1021/acs.nanolett.5b01306] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report the dispersive readout of the spin state of a double quantum dot formed at the corner states of a silicon nanowire field-effect transistor. Two face-to-face top-gate electrodes allow us to independently tune the charge occupation of the quantum dot system down to the few-electron limit. We measure the charge stability of the double quantum dot in DC transport as well as dispersively via in situ gate-based radio frequency reflectometry, where one top-gate electrode is connected to a resonator. The latter removes the need for external charge sensors in quantum computing architectures and provides a compact way to readout the dispersive shift caused by changes in the quantum capacitance during inter-dot charge transitions. Here, we observe Pauli spin-blockade in the high-frequency response of the circuit at finite magnetic fields between singlet and triplet states. The blockade is lifted at higher magnetic fields when intra-dot triplet states become the ground state configuration. A line shape analysis of the dispersive phase shift reveals furthermore an intra-dot valley-orbit splitting Δvo of 145 μeV. Our results open up the possibility to operate compact complementary metal-oxide semiconductor (CMOS) technology as a singlet-triplet qubit and make split-gate silicon nanowire architectures an ideal candidate for the study of spin dynamics.
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Affiliation(s)
- A C Betz
- †Hitachi Cambridge Laboratory, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - R Wacquez
- ‡CEA/LETI-MINATEC, CEA-Grenoble, 17 rue des Martyrs, F-38054 Grenoble, France
| | - M Vinet
- ‡CEA/LETI-MINATEC, CEA-Grenoble, 17 rue des Martyrs, F-38054 Grenoble, France
| | - X Jehl
- §SPSMS, UMR-E CEA/UJF-Grenoble 1, INAC, 17 rue des Martyrs, 38054 Grenoble, France
| | - A L Saraiva
- ∥Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, Brazil
| | - M Sanquer
- §SPSMS, UMR-E CEA/UJF-Grenoble 1, INAC, 17 rue des Martyrs, 38054 Grenoble, France
| | - A J Ferguson
- ⊥Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - M F Gonzalez-Zalba
- †Hitachi Cambridge Laboratory, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
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Hoehne F, Dreher L, Franke DP, Stutzmann M, Vlasenko LS, Itoh KM, Brandt MS. Submillisecond hyperpolarization of nuclear spins in silicon. PHYSICAL REVIEW LETTERS 2015; 114:117602. [PMID: 25839308 DOI: 10.1103/physrevlett.114.117602] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Indexed: 06/04/2023]
Abstract
In this Letter, we devise a fast and effective nuclear spin hyperpolarization scheme, which is, in principle, magnetic field independent. We use this scheme to experimentally demonstrate polarizations of up to 66% for phosphorus donor nuclear spins in bulk silicon, which are created within less than 100 μs in a magnetic field of 0.35 T at a temperature of 5 K. The polarization scheme is based on a spin-dependent recombination process via weakly coupled spin pairs, for which the recombination time constant strongly depends on the relative orientation of the two spins. We further use this scheme to measure the nuclear spin relaxation time and find a value of ∼100 ms under illumination, in good agreement with the value calculated for nuclear spin flips induced by repeated ionization and deionization processes.
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Affiliation(s)
- Felix Hoehne
- Walter Schottky Institut, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
| | - Lukas Dreher
- Walter Schottky Institut, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
| | - David P Franke
- Walter Schottky Institut, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
| | - Martin Stutzmann
- Walter Schottky Institut, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
| | - Leonid S Vlasenko
- A. F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
| | - Kohei M Itoh
- School of Fundamental Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohuku-ku, Yokohama 223-8522, Japan
| | - Martin S Brandt
- Walter Schottky Institut, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
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Buddhiraju S, Muralidharan B. Role of dual nuclear baths on spin blockade leakage current bistabilities. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:485302. [PMID: 25374371 DOI: 10.1088/0953-8984/26/48/485302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Spin-blockaded electronic transport across a double quantum dot (DQD) system represents an important advancement in the area of spin-based quantum information. The basic mechanism underlying the blockade is the formation of a blocking triplet state. The bistability of the leakage current as a function of the applied magnetic field in this regime is believed to arise from the effect of nuclear Overhauser fields on spin-flip transitions between the blocking triplet and the conducting singlet states. The objective of this paper is to present the nuances of considering a two bath model on the experimentally observed current bistability by employing a self consistent simulation of the nuclear spin dynamics coupled with the electronic transport of the DQD set up. In doing so, we first discuss the important subtleties involved in the microscopic derivation of the hyperfine mediated spin flip rates. We then give insights as to how the differences between the two nuclear baths and the resulting difference Overhauser field affect the two-electron states of the DQD and their connection with the experimentally observed current hysteresis curve.
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Affiliation(s)
- Siddharth Buddhiraju
- Department of Electrical Engineering, Center of Excellence in Nanoelectronics, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India
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35
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Hao X, Ruskov R, Xiao M, Tahan C, Jiang H. Electron spin resonance and spin–valley physics in a silicon double quantum dot. Nat Commun 2014; 5:3860. [DOI: 10.1038/ncomms4860] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 04/11/2014] [Indexed: 11/09/2022] Open
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36
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Sánchez R, Granger G, Gaudreau L, Kam A, Pioro-Ladrière M, Studenikin SA, Zawadzki P, Sachrajda AS, Platero G. Long-range spin transfer in triple quantum dots. PHYSICAL REVIEW LETTERS 2014; 112:176803. [PMID: 24836266 DOI: 10.1103/physrevlett.112.176803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Indexed: 06/03/2023]
Abstract
Tunneling in a quantum coherent structure is not restricted to only nearest neighbors. Hopping between distant sites is possible via the virtual occupation of otherwise avoided intermediate states. Here we report the observation of long-range transitions in the transport through three quantum dots coupled in series. A single electron is delocalized between the left and right quantum dots, while the center one remains always empty. Superpositions are formed, and both charge and spin are exchanged between the outermost dots. The delocalized electron acts as a quantum bus transferring the spin state from one end to the other. Spin selection is enabled by spin correlations. The process is detected via the observation of narrow resonances which are insensitive to Pauli spin blockade.
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Affiliation(s)
- R Sánchez
- Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain
| | - G Granger
- National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario K1A 0R6, Canada
| | - L Gaudreau
- National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario K1A 0R6, Canada and Département de physique, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - A Kam
- National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario K1A 0R6, Canada
| | - M Pioro-Ladrière
- Département de physique, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - S A Studenikin
- National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario K1A 0R6, Canada
| | - P Zawadzki
- National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario K1A 0R6, Canada
| | - A S Sachrajda
- National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario K1A 0R6, Canada
| | - G Platero
- Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain
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37
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Schuetz MJA, Kessler EM, Vandersypen LMK, Cirac JI, Giedke G. Steady-state entanglement in the nuclear spin dynamics of a double quantum dot. PHYSICAL REVIEW LETTERS 2013; 111:246802. [PMID: 24483686 DOI: 10.1103/physrevlett.111.246802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2013] [Indexed: 06/03/2023]
Abstract
We propose a scheme for the deterministic generation of steady-state entanglement between the two nuclear spin ensembles in an electrically defined double quantum dot. Because of quantum interference in the collective coupling to the electronic degrees of freedom, the nuclear system is actively driven into a two-mode squeezedlike target state. The entanglement buildup is accompanied by a self-polarization of the nuclear spins towards large Overhauser field gradients. Moreover, the feedback between the electronic and nuclear dynamics leads to multistability and criticality in the steady-state solutions.
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Affiliation(s)
- M J A Schuetz
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany
| | - E M Kessler
- Physics Department, Harvard University, Cambridge, Massachusetts 02318, USA and ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA
| | - L M K Vandersypen
- Kavli Institute of NanoScience, TU Delft, P.O. Box 5046, 2600 GA Delft, The Netherlands
| | - J I Cirac
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany
| | - G Giedke
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching, Germany
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De Greve K, Press D, McMahon PL, Yamamoto Y. Ultrafast optical control of individual quantum dot spin qubits. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2013; 76:092501. [PMID: 24006335 DOI: 10.1088/0034-4885/76/9/092501] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Single spins in semiconductor quantum dots form a promising platform for solid-state quantum information processing. The spin-up and spin-down states of a single electron or hole, trapped inside a quantum dot, can represent a single qubit with a reasonably long decoherence time. The spin qubit can be optically coupled to excited (charged exciton) states that are also trapped in the quantum dot, which provides a mechanism to quickly initialize, manipulate and measure the spin state with optical pulses, and to interface between a stationary matter qubit and a 'flying' photonic qubit for quantum communication and distributed quantum information processing. The interaction of the spin qubit with light may be enhanced by placing the quantum dot inside a monolithic microcavity. An entire system, consisting of a two-dimensional array of quantum dots and a planar microcavity, may plausibly be constructed by modern semiconductor nano-fabrication technology and could offer a path toward chip-sized scalable quantum repeaters and quantum computers. This article reviews the recent experimental developments in optical control of single quantum dot spins for quantum information processing. We highlight demonstrations of a complete set of all-optical single-qubit operations on a single quantum dot spin: initialization, an arbitrary SU(2) gate, and measurement. We review the decoherence and dephasing mechanisms due to hyperfine interaction with the nuclear-spin bath, and show how the single-qubit operations can be combined to perform spin echo sequences that extend the qubit decoherence from a few nanoseconds to several microseconds, more than 5 orders of magnitude longer than the single-qubit gate time. Two-qubit coupling is discussed, both within a single chip by means of exchange coupling of nearby spins and optically induced geometric phases, as well as over longer-distances. Long-distance spin-spin entanglement can be generated if each spin can emit a photon that is entangled with the spin, and these photons are then interfered. We review recent work demonstrating entanglement between a stationary spin qubit and a flying photonic qubit. These experiments utilize the polarization- and frequency-dependent spontaneous emission from the lowest charged exciton state to single spin Zeeman sublevels.
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Leijnse M, Flensberg K. Coupling spin qubits via superconductors. PHYSICAL REVIEW LETTERS 2013; 111:060501. [PMID: 23971543 DOI: 10.1103/physrevlett.111.060501] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Indexed: 06/02/2023]
Abstract
We show how superconductors can be used to couple, initialize, and read out spatially separated spin qubits. When two single-electron quantum dots are tunnel coupled to the same superconductor, the singlet component of the two-electron state partially leaks into the superconductor via crossed Andreev reflection. This induces a gate-controlled singlet-triplet splitting which, with an appropriate superconductor geometry, remains large for dot separations within the superconducting coherence length. Furthermore, we show that when two double-dot singlet-triplet qubits are tunnel coupled to a superconductor with finite charging energy, crossed Andreev reflection enables a strong two-qubit coupling over distances much larger than the coherence length.
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Affiliation(s)
- Martin Leijnse
- Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
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40
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Chekhovich EA, Makhonin MN, Tartakovskii AI, Yacoby A, Bluhm H, Nowack KC, Vandersypen LMK. Nuclear spin effects in semiconductor quantum dots. NATURE MATERIALS 2013; 12:494-504. [PMID: 23695746 DOI: 10.1038/nmat3652] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 04/12/2013] [Indexed: 06/02/2023]
Abstract
The interaction of an electronic spin with its nuclear environment, an issue known as the central spin problem, has been the subject of considerable attention due to its relevance for spin-based quantum computation using semiconductor quantum dots. Independent control of the nuclear spin bath using nuclear magnetic resonance techniques and dynamic nuclear polarization using the central spin itself offer unique possibilities for manipulating the nuclear bath with significant consequences for the coherence and controlled manipulation of the central spin. Here we review some of the recent optical and transport experiments that have explored this central spin problem using semiconductor quantum dots. We focus on the interaction between 10(4)-10(6) nuclear spins and a spin of a single electron or valence-band hole. We also review the experimental techniques as well as the key theoretical ideas and the implications for quantum information science.
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Affiliation(s)
- E A Chekhovich
- Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
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Srinivasa V, Nowack KC, Shafiei M, Vandersypen LMK, Taylor JM. Simultaneous spin-charge relaxation in double quantum dots. PHYSICAL REVIEW LETTERS 2013; 110:196803. [PMID: 23705734 DOI: 10.1103/physrevlett.110.196803] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Indexed: 06/02/2023]
Abstract
We investigate phonon-induced spin and charge relaxation mediated by spin-orbit and hyperfine interactions for a single electron confined within a double quantum dot. A simple toy model incorporating both direct decay to the ground state of the double dot and indirect decay via an intermediate excited state yields an electron spin relaxation rate that varies nonmonotonically with the detuning between the dots. We confirm this model with experiments performed on a GaAs double dot, demonstrating that the relaxation rate exhibits the expected detuning dependence and can be electrically tuned over several orders of magnitude. Our analysis suggests that spin-orbit mediated relaxation via phonons serves as the dominant mechanism through which the double-dot electron spin-flip rate varies with detuning.
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Affiliation(s)
- V Srinivasa
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA.
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Petersen G, Hoffmann EA, Schuh D, Wegscheider W, Giedke G, Ludwig S. Large nuclear spin polarization in gate-defined quantum dots using a single-domain nanomagnet. PHYSICAL REVIEW LETTERS 2013; 110:177602. [PMID: 23679779 DOI: 10.1103/physrevlett.110.177602] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 03/13/2013] [Indexed: 06/02/2023]
Abstract
The electron-nuclei (hyperfine) interaction is central to spin qubits in solid state systems. It can be a severe decoherence source but also allows dynamic access to the nuclear spin states. We study a double quantum dot exposed to an on-chip single-domain nanomagnet and show that its inhomogeneous magnetic field crucially modifies the complex nuclear spin dynamics such that the Overhauser field tends to compensate external magnetic fields. This turns out to be beneficial for polarizing the nuclear spin ensemble. We reach a nuclear spin polarization of ≃50%, unrivaled in lateral dots, and explain our manipulation technique using a comprehensive rate equation model.
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Affiliation(s)
- Gunnar Petersen
- Center for Nanoscience and Fakultät für Physik, Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539 München, Germany
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Busl M, Granger G, Gaudreau L, Sánchez R, Kam A, Pioro-Ladrière M, Studenikin SA, Zawadzki P, Wasilewski ZR, Sachrajda AS, Platero G. Bipolar spin blockade and coherent state superpositions in a triple quantum dot. NATURE NANOTECHNOLOGY 2013; 8:261-265. [PMID: 23416792 DOI: 10.1038/nnano.2013.7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 01/10/2013] [Indexed: 06/01/2023]
Abstract
Spin qubits based on interacting spins in double quantum dots have been demonstrated successfully. Readout of the qubit state involves a conversion of spin to charge information, which is universally achieved by taking advantage of a spin blockade phenomenon resulting from Pauli's exclusion principle. The archetypal spin blockade transport signature in double quantum dots takes the form of a rectified current. At present, more complex spin qubit circuits including triple quantum dots are being developed. Here we show, both experimentally and theoretically, that in a linear triple quantum dot circuit the spin blockade becomes bipolar with current strongly suppressed in both bias directions and also that a new quantum coherent mechanism becomes relevant. In this mechanism, charge is transferred non-intuitively via coherent states from one end of the linear triple dot circuit to the other, without involving the centre site. Our results have implications for future complex nanospintronic circuits.
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Affiliation(s)
- M Busl
- Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid, Spain
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44
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Pribiag VS, Nadj-Perge S, Frolov SM, van den Berg JWG, van Weperen I, Plissard SR, Bakkers EPAM, Kouwenhoven LP. Electrical control of single hole spins in nanowire quantum dots. NATURE NANOTECHNOLOGY 2013; 8:170-174. [PMID: 23416794 DOI: 10.1038/nnano.2013.5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 01/09/2013] [Indexed: 06/01/2023]
Abstract
The development of viable quantum computation devices will require the ability to preserve the coherence of quantum bits (qubits). Single electron spins in semiconductor quantum dots are a versatile platform for quantum information processing, but controlling decoherence remains a considerable challenge. Hole spins in III-V semiconductors have unique properties, such as a strong spin-orbit interaction and weak coupling to nuclear spins, and therefore, have the potential for enhanced spin control and longer coherence times. A weaker hyperfine interaction has previously been reported in self-assembled quantum dots using quantum optics techniques, but the development of hole-spin-based electronic devices in conventional III-V heterostructures has been limited by fabrication challenges. Here, we show that gate-tunable hole quantum dots can be formed in InSb nanowires and used to demonstrate Pauli spin blockade and electrical control of single hole spins. The devices are fully tunable between hole and electron quantum dots, which allows the hyperfine interaction strengths, g-factors and spin blockade anisotropies to be compared directly in the two regimes.
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Affiliation(s)
- V S Pribiag
- Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands.
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45
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van Heck B, Burrello M, Yacoby A, Akhmerov AR. Topological blockade and measurement of topological charge. PHYSICAL REVIEW LETTERS 2013; 110:086803. [PMID: 23473185 DOI: 10.1103/physrevlett.110.086803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Indexed: 06/01/2023]
Abstract
The fractionally charged quasiparticles appearing in the 5/2 fractional quantum Hall plateau are predicted to have an extra nonlocal degree of freedom, known as topological charge. We show how this topological charge can block the tunneling of these particles, and how such topological blockade can be used to read out their topological charge. We argue that the short time scale required for this measurement is favorable for the detection of the non-Abelian anyonic statistics of the quasiparticles. We also show how topological blockade can be used to measure braiding statistics, and to couple a topological qubit with a conventional one.
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Affiliation(s)
- B van Heck
- Instituut-Lorentz, Universiteit Leiden, PO Box 9506, 2300 RA Leiden, The Netherlands
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46
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Kristinsdóttir LH, Karlström O, Bjerlin J, Cremon JC, Schlagheck P, Wacker A, Reimann SM. Total current blockade in an ultracold dipolar quantum wire. PHYSICAL REVIEW LETTERS 2013; 110:085303. [PMID: 23473160 DOI: 10.1103/physrevlett.110.085303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 12/06/2012] [Indexed: 06/01/2023]
Abstract
Cold-atom systems offer a great potential for the future design of new mesoscopic quantum systems with properties that are fundamentally different from semiconductor nanostructures. Here, we investigate the quantum-gas analogue of a quantum wire and find a new scenario for the quantum transport: Attractive interactions may lead to a complete suppression of current in the low-bias range, a total current blockade. We demonstrate this effect for the example of ultracold quantum gases with dipolar interactions.
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Affiliation(s)
- L H Kristinsdóttir
- Mathematical Physics and Nanometer Structure Consortium, nmC@LU, Lund University, Box 118, 22100 Lund, Sweden
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47
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Rudner MS, Levitov LS. Self-sustaining dynamical nuclear polarization oscillations in quantum dots. PHYSICAL REVIEW LETTERS 2013; 110:086601. [PMID: 23473181 DOI: 10.1103/physrevlett.110.086601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Indexed: 06/01/2023]
Abstract
Early experiments on spin-blockaded double quantum dots revealed robust, large-amplitude current oscillations in the presence of a static (dc) source-drain bias. Despite experimental evidence implicating dynamical nuclear polarization, the mechanism has remained a mystery. Here we introduce a minimal albeit realistic model of coupled electron and nuclear spin dynamics which supports self-sustained oscillations. Our mechanism relies on a nuclear spin analog of the tunneling magnetoresistance phenomenon (spin-dependent tunneling rates in the presence of an inhomogeneous Overhauser field) and nuclear spin diffusion, which governs dynamics of the spatial profile of nuclear polarization. The proposed framework naturally explains the differences in phenomenology between vertical and lateral quantum dot structures as well as the extremely long oscillation periods.
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Affiliation(s)
- M S Rudner
- The Niels Bohr International Academy, Blegdamsvej 17, DK-2100 Copenhagen, Denmark
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48
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van den Berg JWG, Nadj-Perge S, Pribiag VS, Plissard SR, Bakkers EPAM, Frolov SM, Kouwenhoven LP. Fast spin-orbit qubit in an indium antimonide nanowire. PHYSICAL REVIEW LETTERS 2013; 110:066806. [PMID: 23432291 DOI: 10.1103/physrevlett.110.066806] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2012] [Indexed: 05/22/2023]
Abstract
Because of the strong spin-orbit interaction in indium antimonide, orbital motion and spin are no longer separated. This enables fast manipulation of qubit states by means of microwave electric fields. We report Rabi oscillation frequencies exceeding 100 MHz for spin-orbit qubits in InSb nanowires. Individual qubits can be selectively addressed due to intrinsic differences in their g factors. Based on Ramsey fringe measurements, we extract a coherence time T(2)(*)=8±1 ns at a driving frequency of 18.65 GHz. Applying a Hahn echo sequence extends this coherence time to 34 ns.
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Affiliation(s)
- J W G van den Berg
- Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands
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49
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Fink T, Bluhm H. Noise spectroscopy using correlations of single-shot qubit readout. PHYSICAL REVIEW LETTERS 2013; 110:010403. [PMID: 23383763 DOI: 10.1103/physrevlett.110.010403] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Indexed: 06/01/2023]
Abstract
A better understanding of the noise causing qubit decoherence is crucial for improving qubit performance. The noise spectrum affecting the qubit may be extracted by measuring dephasing under the application of pulse sequences but requires accurate qubit control and sufficiently long relaxation times, which are not always available. Here, we describe an alternative method to extract the spectrum from correlations of single-shot measurement outcomes of successive free induction decays. This method only requires qubit initialization and readout with a moderate fidelity and also allows independent tuning of both the overall sensitivity and the frequency region over which it is sensitive. Thus, it is possible to maintain a good detection contrast over a very wide frequency range. We discuss using our method for measuring both 1/f noise and the fluctuation spectrum of the nuclear bath of GaAs spin qubits.
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Affiliation(s)
- T Fink
- 2nd Institute of Physics C, RWTH Aachen University, D-52074 Aachen, Germany and JARA-Fundamentals of Future Information Technology, D-52425 Jülich, Germany
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50
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Frolov SM, Danon J, Nadj-Perge S, Zuo K, van Tilburg JWW, Pribiag VS, van den Berg JWG, Bakkers EPAM, Kouwenhoven LP. Suppression of Zeeman gradients by nuclear polarization in double quantum dots. PHYSICAL REVIEW LETTERS 2012; 109:236805. [PMID: 23368241 DOI: 10.1103/physrevlett.109.236805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Indexed: 06/01/2023]
Abstract
We use electric dipole spin resonance to measure dynamic nuclear polarization in InAs nanowire quantum dots. The resonance shifts in frequency when the system transitions between metastable high and low current states, indicating the presence of nuclear polarization. We propose that the low and the high current states correspond to different total Zeeman energy gradients between the two quantum dots. In the low current state, dynamic nuclear polarization efficiently compensates the Zeeman gradient due to the g-factor mismatch, resulting in a suppressed total Zeeman gradient. We present a theoretical model of electron-nuclear feedback that demonstrates a fixed point in nuclear polarization for nearly equal Zeeman splittings in the two dots and predicts a narrowed hyperfine gradient distribution.
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Affiliation(s)
- S M Frolov
- Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft, The Netherlands
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