1
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Shibata K, Yoshida M, Hirakawa K, Otsuka T, Bisri SZ, Iwasa Y. Single PbS colloidal quantum dot transistors. Nat Commun 2023; 14:7486. [PMID: 37980351 PMCID: PMC10657373 DOI: 10.1038/s41467-023-43343-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 11/07/2023] [Indexed: 11/20/2023] Open
Abstract
Colloidal quantum dots are sub-10 nm semiconductors treated with liquid processes, rendering them attractive candidates for single-electron transistors operating at high temperatures. However, there have been few reports on single-electron transistors using colloidal quantum dots due to the difficulty in fabrication. In this work, we fabricated single-electron transistors using single oleic acid-capped PbS quantum dot coupled to nanogap metal electrodes and measured single-electron tunneling. We observed dot size-dependent carrier transport, orbital-dependent electron charging energy and conductance, electric field modulation of the electron confinement potential, and the Kondo effect, which provide nanoscopic insights into carrier transport through single colloidal quantum dots. Moreover, the large charging energy in small quantum dots enables single-electron transistor operation even at room temperature. These findings, as well as the commercial availability and high stability, make PbS quantum dots promising for the development of quantum information and optoelectronic devices, particularly room-temperature single-electron transistors with excellent optical properties.
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Affiliation(s)
- Kenji Shibata
- Department of Electrical and Electronic Engineering, Tohoku Institute of Technology, 35-1 Yagiyama, Kasumi-cho, Taihaku-ku, Sendai, 982-8577, Japan.
| | - Masaki Yoshida
- Department of Electrical and Electronic Engineering, Tohoku Institute of Technology, 35-1 Yagiyama, Kasumi-cho, Taihaku-ku, Sendai, 982-8577, Japan
| | - Kazuhiko Hirakawa
- Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan
- Institute for Nano Quantum Information Electronics, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan
| | - Tomohiro Otsuka
- Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
- WPI Advanced Institute for Materials Research, Tohoku University, Sendai, 980-8577, Japan
- Department of Electronic Engineering, Tohoku University, Aoba 6-6-05, Aramaki, Aoba-Ku, Sendai, 980-8579, Japan
- Center for Science and Innovation in Spintronics, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
- Quantum Functional System Research Group, RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Satria Zulkarnaen Bisri
- Emergent Device Research Team, RIKEN Center for Emergent Matter Science, 2-1 Hirosawa Wako, Saitama, 351-0198, Japan
- Department of Applied Physics and Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei-shi, Tokyo, 184-8588, Japan
| | - Yoshihiro Iwasa
- Emergent Device Research Team, RIKEN Center for Emergent Matter Science, 2-1 Hirosawa Wako, Saitama, 351-0198, Japan
- Department of Applied Physics and Quantum-Phase Electronics Center, University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
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2
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Gilbert W, Tanttu T, Lim WH, Feng M, Huang JY, Cifuentes JD, Serrano S, Mai PY, Leon RCC, Escott CC, Itoh KM, Abrosimov NV, Pohl HJ, Thewalt MLW, Hudson FE, Morello A, Laucht A, Yang CH, Saraiva A, Dzurak AS. On-demand electrical control of spin qubits. NATURE NANOTECHNOLOGY 2023; 18:131-136. [PMID: 36635331 DOI: 10.1038/s41565-022-01280-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 10/24/2022] [Indexed: 06/17/2023]
Abstract
Once called a 'classically non-describable two-valuedness' by Pauli, the electron spin forms a qubit that is naturally robust to electric fluctuations. Paradoxically, a common control strategy is the integration of micromagnets to enhance the coupling between spins and electric fields, which, in turn, hampers noise immunity and adds architectural complexity. Here we exploit a switchable interaction between spins and orbital motion of electrons in silicon quantum dots, without a micromagnet. The weak effects of relativistic spin-orbit interaction in silicon are enhanced, leading to a speed up in Rabi frequency by a factor of up to 650 by controlling the energy quantization of electrons in the nanostructure. Fast electrical control is demonstrated in multiple devices and electronic configurations. Using the electrical drive, we achieve a coherence time T2,Hahn ≈ 50 μs, fast single-qubit gates with Tπ/2 = 3 ns and gate fidelities of 99.93%, probed by randomized benchmarking. High-performance all-electrical control improves the prospects for scalable silicon quantum computing.
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Affiliation(s)
- Will Gilbert
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia.
- Diraq, Sydney, New South Wales, Australia.
| | - Tuomo Tanttu
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - Wee Han Lim
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - MengKe Feng
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Jonathan Y Huang
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Jesus D Cifuentes
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Santiago Serrano
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Philip Y Mai
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Ross C C Leon
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Christopher C Escott
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - Kohei M Itoh
- School of Fundamental Science and Technology, Keio University, Yokohama, Japan
| | | | | | - Michael L W Thewalt
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Fay E Hudson
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - Andrea Morello
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
| | - Arne Laucht
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - Chih Hwan Yang
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia
- Diraq, Sydney, New South Wales, Australia
| | - Andre Saraiva
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia.
- Diraq, Sydney, New South Wales, Australia.
| | - Andrew S Dzurak
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales, Australia.
- Diraq, Sydney, New South Wales, Australia.
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3
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A silicon singlet-triplet qubit driven by spin-valley coupling. Nat Commun 2022; 13:641. [PMID: 35110561 PMCID: PMC8810768 DOI: 10.1038/s41467-022-28302-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 12/22/2021] [Indexed: 11/25/2022] Open
Abstract
Spin–orbit effects, inherent to electrons confined in quantum dots at a silicon heterointerface, provide a means to control electron spin qubits without the added complexity of on-chip, nanofabricated micromagnets or nearby coplanar striplines. Here, we demonstrate a singlet–triplet qubit operating mode that can drive qubit evolution at frequencies in excess of 200 MHz. This approach offers a means to electrically turn on and off fast control, while providing high logic gate orthogonality and long qubit dephasing times. We utilize this operational mode for dynamical decoupling experiments to probe the charge noise power spectrum in a silicon metal-oxide-semiconductor double quantum dot. In addition, we assess qubit frequency drift over longer timescales to capture low-frequency noise. We present the charge noise power spectral density up to 3 MHz, which exhibits a 1/fα dependence consistent with α ~ 0.7, over 9 orders of magnitude in noise frequency. Spin-orbit coupling in gate-defined quantum dots in silicon metal-oxide semiconductors provides a promising route for electrical control of spin qubits. Here, the authors demonstrate that intervalley spin–orbit interaction enables fast singlet–triplet qubit rotations in this platform, at frequencies exceeding 200MHz.
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4
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Zhang X, Hu RZ, Li HO, Jing FM, Zhou Y, Ma RL, Ni M, Luo G, Cao G, Wang GL, Hu X, Jiang HW, Guo GC, Guo GP. Giant Anisotropy of Spin Relaxation and Spin-Valley Mixing in a Silicon Quantum Dot. PHYSICAL REVIEW LETTERS 2020; 124:257701. [PMID: 32639759 DOI: 10.1103/physrevlett.124.257701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 04/20/2020] [Accepted: 05/19/2020] [Indexed: 06/11/2023]
Abstract
In silicon quantum dots (QDs), at a certain magnetic field commonly referred to as the "hot spot," the electron spin relaxation rate (T_{1}^{-1}) can be drastically enhanced due to strong spin-valley mixing. Here, we experimentally find that with a valley splitting of 78.2±1.6 μeV, this hot spot in spin relaxation can be suppressed by more than 2 orders of magnitude when the in-plane magnetic field is oriented at an optimal angle, about 9° from the [100] sample plane. This directional anisotropy exhibits a sinusoidal modulation with a 180° periodicity. We explain the magnitude and phase of this modulation using a model that accounts for both spin-valley mixing and intravalley spin-orbit mixing. The generality of this phenomenon is also confirmed by tuning the electric field and the valley splitting up to 268.5±0.7 μeV.
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Affiliation(s)
- 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
| | - Rui-Zi Hu
- 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
| | - 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
| | - Fang-Ming Jing
- 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
| | - Yuan Zhou
- 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
| | - Rong-Long Ma
- 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
| | - Ming Ni
- 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 Luo
- 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
| | - Gui-Lei Wang
- Key Laboratory of Microelectronics Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
| | - Xuedong Hu
- Department of Physics, University at Buffalo, SUNY, Buffalo, New York 14260, USA
| | - Hong-Wen Jiang
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
| | - Guang-Can 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
| | - 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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5
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Leon RCC, Yang CH, Hwang JCC, Lemyre JC, Tanttu T, Huang W, Chan KW, Tan KY, Hudson FE, Itoh KM, Morello A, Laucht A, Pioro-Ladrière M, Saraiva A, Dzurak AS. Coherent spin control of s-, p-, d- and f-electrons in a silicon quantum dot. Nat Commun 2020; 11:797. [PMID: 32047151 PMCID: PMC7012832 DOI: 10.1038/s41467-019-14053-w] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 12/11/2019] [Indexed: 11/09/2022] Open
Abstract
Once the periodic properties of elements were unveiled, chemical behaviour could be understood in terms of the valence of atoms. Ideally, this rationale would extend to quantum dots, and quantum computation could be performed by merely controlling the outer-shell electrons of dot-based qubits. Imperfections in semiconductor materials disrupt this analogy, so real devices seldom display a systematic many-electron arrangement. We demonstrate here an electrostatically confined quantum dot that reveals a well defined shell structure. We observe four shells (31 electrons) with multiplicities given by spin and valley degrees of freedom. Various fillings containing a single valence electron-namely 1, 5, 13 and 25 electrons-are found to be potential qubits. An integrated micromagnet allows us to perform electrically-driven spin resonance (EDSR), leading to faster Rabi rotations and higher fidelity single qubit gates at higher shell states. We investigate the impact of orbital excitations on single qubits as a function of the dot deformation and exploit it for faster qubit control.
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Affiliation(s)
- R C C Leon
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia.
| | - C H Yang
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - J C C Hwang
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
- Research and Prototype Foundry, The University of Sydney, Sydney, NSW, 2006, Australia
| | - J Camirand Lemyre
- Institut Quantique et Département de Physique, Université de Sherbrooke, Sherbrooke, Québec, J1K 2R1, Canada
| | - T Tanttu
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - W Huang
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - K W Chan
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - K Y Tan
- QCD Labs COMP Centre of Excellence, Department of Applied Physics, Aalto University, 00076, Aalto, Finland
| | - F E Hudson
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - K M Itoh
- School of Fundamental Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohokuku, Yokohama, 223-8522, Japan
| | - A Morello
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - A Laucht
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - M Pioro-Ladrière
- Institut Quantique et Département de Physique, Université de Sherbrooke, Sherbrooke, Québec, J1K 2R1, Canada
- Quantum Information Science Program, Canadian Institute for Advanced Research, Toronto, ON, M5G 1Z8, Canada
| | - A Saraiva
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia.
| | - A S Dzurak
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, NSW, 2052, Australia.
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6
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Harvey-Collard P, Jacobson NT, Bureau-Oxton C, Jock RM, Srinivasa V, Mounce AM, Ward DR, Anderson JM, Manginell RP, Wendt JR, Pluym T, Lilly MP, Luhman DR, Pioro-Ladrière M, Carroll MS. Spin-orbit Interactions for Singlet-Triplet Qubits in Silicon. PHYSICAL REVIEW LETTERS 2019; 122:217702. [PMID: 31283344 DOI: 10.1103/physrevlett.122.217702] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 02/25/2019] [Indexed: 06/09/2023]
Abstract
Spin-orbit coupling is relatively weak for electrons in bulk silicon, but enhanced interactions are reported in nanostructures such as the quantum dots used for spin qubits. These interactions have been attributed to various dissimilar interface effects, including disorder or broken crystal symmetries. In this Letter, we use a double-quantum-dot qubit to probe these interactions by comparing the spins of separated singlet-triplet electron pairs. We observe both intravalley and intervalley mechanisms, each dominant for [110] and [100] magnetic field orientations, respectively, that are consistent with a broken crystal symmetry model. We also observe a third spin-flip mechanism caused by tunneling between the quantum dots. This improved understanding is important for qubit uniformity, spin control and decoherence, and two-qubit gates.
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Affiliation(s)
- Patrick Harvey-Collard
- Département de physique et Institut quantique, Université de Sherbrooke, Sherbrooke (Québec) J1K 2R1, Canada
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - N Tobias Jacobson
- Center for Computing Research, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Chloé Bureau-Oxton
- Département de physique et Institut quantique, Université de Sherbrooke, Sherbrooke (Québec) J1K 2R1, Canada
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Ryan M Jock
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Vanita Srinivasa
- Center for Computing Research, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Andrew M Mounce
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Daniel R Ward
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - John M Anderson
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | | | - Joel R Wendt
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Tammy Pluym
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Michael P Lilly
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Dwight R Luhman
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Michel Pioro-Ladrière
- Département de physique et Institut quantique, Université de Sherbrooke, Sherbrooke (Québec) J1K 2R1, Canada
- Quantum Information Science Program, Canadian Institute for Advanced Research, Toronto (Ontario) M5G 1Z8, Canada
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7
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Abstract
This study alleviates the low operating temperature constraint of Si qubits. A qubit is a key element for quantum sensors, memories, and computers. Electron spin in Si is a promising qubit, as it allows both long coherence times and potential compatibility with current silicon technology. Si qubits have been implemented using gate-defined quantum dots or shallow impurities. However, operation of Si qubits has been restricted to milli-Kelvin temperatures, thus limiting the application of the quantum technology. In this study, we addressed a single deep impurity, having strong electron confinement of up to 0.3 eV, using single-electron tunnelling transport. We also achieved qubit operation at 5–10 K through a spin-blockade effect based on the tunnelling transport via two impurities. The deep impurity was implemented by tunnel field-effect transistors (TFETs) instead of conventional FETs. With further improvement in fabrication and controllability, this work presents the possibility of operating silicon spin qubits at elevated temperatures.
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8
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Zhang X, Li HO, Cao G, Xiao M, Guo GC, Guo GP. Semiconductor quantum computation. Natl Sci Rev 2019; 6:32-54. [PMID: 34691830 PMCID: PMC8291422 DOI: 10.1093/nsr/nwy153] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 11/05/2018] [Accepted: 12/18/2018] [Indexed: 11/12/2022] Open
Abstract
Semiconductors, a significant type of material in the information era, are becoming more and more powerful in the field of quantum information. In recent decades, semiconductor quantum computation was investigated thoroughly across the world and developed with a dramatically fast speed. The research varied from initialization, control and readout of qubits, to the architecture of fault-tolerant quantum computing. Here, we first introduce the basic ideas for quantum computing, and then discuss the developments of single- and two-qubit gate control in semiconductors. Up to now, the qubit initialization, control and readout can be realized with relatively high fidelity and a programmable two-qubit quantum processor has even been demonstrated. However, to further improve the qubit quality and scale it up, there are still some challenges to resolve such as the improvement of the readout method, material development and scalable designs. We discuss these issues and introduce the forefronts of progress. Finally, considering the positive trend of the research on semiconductor quantum devices and recent theoretical work on the applications of quantum computation, we anticipate that semiconductor quantum computation may develop fast and will have a huge impact on our lives in the near future.
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Affiliation(s)
- Xin Zhang
- Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Hai-Ou Li
- Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Gang Cao
- Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Ming Xiao
- Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Guang-Can Guo
- Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Guo-Ping Guo
- Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei 230026, China
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9
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Shim YP, Ruskov R, Hurst HM, Tahan C. Induced quantum dot probe for material characterization. APPLIED PHYSICS LETTERS 2019; 114:10.1063/1.5053756. [PMID: 38618628 PMCID: PMC11010771 DOI: 10.1063/1.5053756] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
We propose a non-destructive means of characterizing a semiconductor wafer via measuring parameters of an induced quantum dot on the material system of interest with a separate probe chip that can also house the measurement circuitry. We show that a single wire can create the dot, determine if an electron is present, and be used to measure critical device parameters. Adding more wires enables more complicated (potentially multi-dot) systems and measurements. As one application for this concept we consider silicon metal-oxide-semiconductor (MOS) and silicon/silicon-germanium quantum dot qubits relevant to quantum computing and show how to measure low-lying excited states (so-called "valley" states). This approach provides an alternative method for characterization of parameters that are critical for various semiconductor-based quantum dot devices without fabricating such devices.
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Affiliation(s)
- Yun-Pil Shim
- Laboratory for Physical Sciences, College Park, Maryland 20740, USA
- Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Rusko Ruskov
- Laboratory for Physical Sciences, College Park, Maryland 20740, USA
- Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Hilary M. Hurst
- Laboratory for Physical Sciences, College Park, Maryland 20740, USA
| | - Charles Tahan
- Laboratory for Physical Sciences, College Park, Maryland 20740, USA
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10
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Cota E, Ulloa SE. Spin-orbit interaction and controlled singlet-triplet dynamics in silicon double quantum dots. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:295301. [PMID: 29873301 DOI: 10.1088/1361-648x/aacabc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We undertake a theoretical study of the role of spin orbit interactions in a silicon double quantum dot. We propose that an accurate estimate of the strength of this interaction can be obtained through the study of the return probability of the double occupation singlet state in a magnetic field, as the system is gated dynamically across the relevant states in the low energy two-electron manifold. Landau-Zener type of processes involving appropriate control of voltage pulses across neighboring avoided crossings in the energy spectrum of the system are utilized to explore the system dynamics. Our description takes into account Zeeman splitting, intervalley mixing and spin-orbit interaction present in the structure. Using a density matrix equation of motion approach, we carry out numerical calculations for the return probability of the double occupation singlet state. The analysis in terms of Landau-Zener theory allows the determination of the spin-orbit coupling strength for different Zeeman splitting regimes.
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Affiliation(s)
- Ernesto Cota
- Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Apartado Postal 14, Ensenada, Baja California 22800, Mexico
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11
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Russ M, Burkard G. Three-electron spin qubits. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:393001. [PMID: 28562367 DOI: 10.1088/1361-648x/aa761f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The goal of this article is to review the progress of three-electron spin qubits from their inception to the state of the art. We direct the main focus towards the exchange-only qubit (Bacon et al 2000 Phys. Rev. Lett. 85 1758-61, DiVincenzo et al 2000 Nature 408 339) and its derived versions, e.g. the resonant exchange (RX) qubit, but we also discuss other qubit implementations using three electron spins. For each three-spin qubit we describe the qubit model, the envisioned physical realization, the implementations of single-qubit operations, as well as the read-out and initialization schemes. Two-qubit gates and decoherence properties are discussed for the RX qubit and the exchange-only qubit, thereby completing the list of requirements for quantum computation for a viable candidate qubit implementation. We start by describing the full system of three electrons in a triple quantum dot, then discuss the charge-stability diagram, restricting ourselves to the relevant subsystem, introduce the qubit states, and discuss important transitions to other charge states (Russ et al 2016 Phys. Rev. B 94 165411). Introducing the various qubit implementations, we begin with the exchange-only qubit (DiVincenzo et al 2000 Nature 408 339, Laird et al 2010 Phys. Rev. B 82 075403), followed by the RX qubit (Medford et al 2013 Phys. Rev. Lett. 111 050501, Taylor et al 2013 Phys. Rev. Lett. 111 050502), the spin-charge qubit (Kyriakidis and Burkard 2007 Phys. Rev. B 75 115324), and the hybrid qubit (Shi et al 2012 Phys. Rev. Lett. 108 140503, Koh et al 2012 Phys. Rev. Lett. 109 250503, Cao et al 2016 Phys. Rev. Lett. 116 086801, Thorgrimsson et al 2016 arXiv:1611.04945). The main focus will be on the exchange-only qubit and its modification, the RX qubit, whose single-qubit operations are realized by driving the qubit at its resonant frequency in the microwave range similar to electron spin resonance. Two different types of two-qubit operations are presented for the exchange-only qubits which can be divided into short-ranged and long-ranged interactions. Both of these interaction types are expected to be necessary in a large-scale quantum computer. The short-ranged interactions use the exchange coupling by placing qubits next to each other and applying exchange-pulses (DiVincenzo et al 2000 Nature 408 339, Fong and Wandzura 2011 Quantum Inf. Comput. 11 1003, Setiawan et al 2014 Phys. Rev. B 89 085314, Zeuch et al 2014 Phys. Rev. B 90 045306, Doherty and Wardrop 2013 Phys. Rev. Lett. 111 050503, Shim and Tahan 2016 Phys. Rev. B 93 121410), while the long-ranged interactions use the photons of a superconducting microwave cavity as a mediator in order to couple two qubits over long distances (Russ and Burkard 2015 Phys. Rev. B 92 205412, Srinivasa et al 2016 Phys. Rev. B 94 205421). The nature of the three-electron qubit states each having the same total spin and total spin in z-direction (same Zeeman energy) provides a natural protection against several sources of noise (DiVincenzo et al 2000 Nature 408 339, Taylor et al 2013 Phys. Rev. Lett. 111 050502, Kempe et al 2001 Phys. Rev. A 63 042307, Russ and Burkard 2015 Phys. Rev. B 91 235411). The price to pay for this advantage is an increase in gate complexity. We also take into account the decoherence of the qubit through the influence of magnetic noise (Ladd 2012 Phys. Rev. B 86 125408, Mehl and DiVincenzo 2013 Phys. Rev. B 87 195309, Hung et al 2014 Phys. Rev. B 90 045308), in particular dephasing due to the presence of nuclear spins, as well as dephasing due to charge noise (Medford et al 2013 Phys. Rev. Lett. 111 050501, Taylor et al 2013 Phys. Rev. Lett. 111 050502, Shim and Tahan 2016 Phys. Rev. B 93 121410, Russ and Burkard 2015 Phys. Rev. B 91 235411, Fei et al 2015 Phys. Rev. B 91 205434), fluctuations of the energy levels on each dot due to noisy gate voltages or the environment. Several techniques are discussed which partly decouple the qubit from magnetic noise (Setiawan et al 2014 Phys. Rev. B 89 085314, West and Fong 2012 New J. Phys. 14 083002, Rohling and Burkard 2016 Phys. Rev. B 93 205434) while for charge noise it is shown that it is favorable to operate the qubit on the so-called '(double) sweet spots' (Taylor et al 2013 Phys. Rev. Lett. 111 050502, Shim and Tahan 2016 Phys. Rev. B 93 121410, Russ and Burkard 2015 Phys. Rev. B 91 235411, Fei et al 2015 Phys. Rev. B 91 205434, Malinowski et al 2017 arXiv: 1704.01298), which are least susceptible to noise, thus providing a longer lifetime of the qubit.
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Affiliation(s)
- Maximilian Russ
- Department of Physics, University of Konstanz, D-78457 Konstanz, Germany
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Zimmerman NM, Huang P, Culcer D. Valley Phase and Voltage Control of Coherent Manipulation in Si Quantum Dots. NANO LETTERS 2017; 17:4461-4465. [PMID: 28657758 DOI: 10.1021/acs.nanolett.7b01677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
With any roughness at the interface of an indirect-bandgap semiconducting dot, the phase of the valley-orbit coupling can take on a random value. This random value, in double quantum dots, causes a large change in the exchange splitting. We demonstrate a simple analytical method to calculate the phase, and thus the exchange splitting and singlet-triplet qubit frequency, for an arbitrary interface. We then show that, with lateral control of the position of a quantum dot using a gate voltage, the valley-orbit phase can be controlled over a wide range, so that variations in the exchange splitting can be controlled for individual devices. Finally, we suggest experiments to measure the valley phase and the concomitant gate voltage control.
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Affiliation(s)
- Neil M Zimmerman
- Quantum Measurement Division, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
| | - Peihao Huang
- Quantum Measurement Division, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States
- Joint Quantum Institute, University of Maryland and National Institute of Standards and Technology , Gaithersburg, Maryland 20742, United States
| | - Dimitrie Culcer
- School of Physics and Australian Research Council Centre of Excellence in Low-Energy Electronics Technologies, UNSW Node, The University of New South Wales , Sydney 2052, Australia
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13
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Schoenfield JS, Freeman BM, Jiang H. Coherent manipulation of valley states at multiple charge configurations of a silicon quantum dot device. Nat Commun 2017; 8:64. [PMID: 28680042 PMCID: PMC5498670 DOI: 10.1038/s41467-017-00073-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 05/31/2017] [Indexed: 11/09/2022] Open
Abstract
Qubits based on silicon quantum dots are emerging as leading candidates for the solid-state implementation of quantum information processing. In silicon, valley states represent a degree of freedom in addition to spin and charge. Characterizing and controlling valley states is critical for the encoding and read-out of electrons-in-silicon-based qubits. Here, we report the coherent manipulation of a qubit, which is based on the two valley states of an electron confined in a silicon quantum dot. We carry out valley qubit operations at multiple charge configurations of the double quantum dot device. The dependence of coherent oscillations on pulse excitation level and duration allows us to map out the energy dispersion as a function of detuning as well as the phase coherence time of the valley qubit. The coherent manipulation also provides a method of measuring valley splittings that are too small to probe with conventional methods. Silicon quantum dots provide a promising platform for quantum computing based on manipulation of electron degrees of freedom in a well-characterized environment. Here, the authors demonstrate coherent control of electron valley states, yielding an accurate determination of the valley splitting.
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Affiliation(s)
- Joshua S Schoenfield
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California, 90095, USA
| | - Blake M Freeman
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California, 90095, USA
| | - HongWen Jiang
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California, 90095, USA.
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Hou W, Wang Y, Wei J, Yan Y. Manipulation of Pauli spin blockade in double quantum dot systems. J Chem Phys 2017; 146:224304. [PMID: 29166066 DOI: 10.1063/1.4985146] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Pauli spin blockade (PSB) is a significant physical effect in double quantum dot (DQD) systems. In this paper, we start from the fundamental quantum model of the DQD with the electron-electron interaction being considered and then systematically study the PSB effect in DQD by using a recently developed nonperturbative method, the hierarchical equations of motion approach. By checking the current-voltage and nonequilibrium spectral function features, the physical picture of the PSB is explicitly elucidated. Then, various kinds of manipulation of PSBs are discussed, including gate voltage, exchange interaction, and electron spin resonance. Three main characteristics beyond low-order perturbation theory are demonstrated in detail as follows: (1) the finite leakage current in the strongly correlated limit; (2) the enhancement and lifting of PSB by exchange interaction; and (3) the ON-and-OFF switch of PSB by real-time modulation.
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Affiliation(s)
- WenJie Hou
- Department of Physics, Renmin University of China, Beijing 100872, China
| | - YuanDong Wang
- Department of Physics, Renmin University of China, Beijing 100872, China
| | - JianHua Wei
- Department of Physics, Renmin University of China, Beijing 100872, China
| | - YiJing Yan
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
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15
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Salfi J, Tong M, Rogge S, Culcer D. Quantum computing with acceptor spins in silicon. NANOTECHNOLOGY 2016; 27:244001. [PMID: 27171901 DOI: 10.1088/0957-4484/27/24/244001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The states of a boron acceptor near a Si/SiO2 interface, which bind two low-energy Kramers pairs, have exceptional properties for encoding quantum information and, with the aid of strain, both heavy hole and light hole-based spin qubits can be designed. Whereas a light-hole spin qubit was introduced recently (arXiv:1508.04259), here we present analytical and numerical results proving that a heavy-hole spin qubit can be reliably initialised, rotated and entangled by electrical means alone. This is due to strong Rashba-like spin-orbit interaction terms enabled by the interface inversion asymmetry. Single qubit rotations rely on electric-dipole spin resonance (EDSR), which is strongly enhanced by interface-induced spin-orbit terms. Entanglement can be accomplished by Coulomb exchange, coupling to a resonator, or spin-orbit induced dipole-dipole interactions. By analysing the qubit sensitivity to charge noise, we demonstrate that interface-induced spin-orbit terms are responsible for sweet spots in the dephasing time [Formula: see text] as a function of the top gate electric field, which are close to maxima in the EDSR strength, where the EDSR gate has high fidelity. We show that both qubits can be described using the same starting Hamiltonian, and by comparing their properties we show that the complex interplay of bulk and interface-induced spin-orbit terms allows a high degree of electrical control and makes acceptors potential candidates for scalable quantum computation in Si.
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Affiliation(s)
- Joe Salfi
- School of Physics, The University of New South Wales, Sydney 2052, Australia
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16
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Electron Paramagnetic Resonance of Single Magnetic Moment on a Surface. Sci Rep 2016; 6:25584. [PMID: 27156935 PMCID: PMC4860648 DOI: 10.1038/srep25584] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 04/20/2016] [Indexed: 11/09/2022] Open
Abstract
We address electron spin resonance of single magnetic moments in a tunnel junction using time-dependent electric fields and spin-polarized current. We show that the tunneling current directly depends on the local magnetic moment and that the frequency of the external electric field mixes with the characteristic Larmor frequency of the local spin. The importance of the spin-polarized current induced anisotropy fields acting on the local spin moment is, moreover, demonstrated. Our proposed model thus explains the absence of an electron spin resonance for a half integer spin, in contrast with the strong signal observed for an integer spin.
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Knapp TJ, Mohr RT, Li YS, Thorgrimsson B, Foote RH, Wu X, Ward DR, Savage DE, Lagally MG, Friesen M, Coppersmith SN, Eriksson MA. Characterization of a gate-defined double quantum dot in a Si/SiGe nanomembrane. NANOTECHNOLOGY 2016; 27:154002. [PMID: 26938505 DOI: 10.1088/0957-4484/27/15/154002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report the fabrication and characterization of a gate-defined double quantum dot formed in a Si/SiGe nanomembrane. In the past, all gate-defined quantum dots in Si/SiGe heterostructures were formed on top of strain-graded virtual substrates. The strain grading process necessarily introduces misfit dislocations into a heterostructure, and these defects introduce lateral strain inhomogeneities, mosaic tilt, and threading dislocations. The use of a SiGe nanomembrane as the virtual substrate enables the strain relaxation to be entirely elastic, eliminating the need for misfit dislocations. However, in this approach the formation of the heterostructure is more complicated, involving two separate epitaxial growth procedures separated by a wet-transfer process that results in a buried non-epitaxial interface 625 nm from the quantum dot. We demonstrate that in spite of this buried interface in close proximity to the device, a double quantum dot can be formed that is controllable enough to enable tuning of the inter-dot tunnel coupling, the identification of spin states, and the measurement of a singlet-to-triplet transition as a function of an applied magnetic field.
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Affiliation(s)
- T J Knapp
- Wisconsin Institute for Quantum Information, University of Wisconsin-Madison, 1150 University Avenue, Madison, WI 53706-1390, USA. Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, WI 53706-1390, USA
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18
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Cao G, Li HO, Yu GD, Wang BC, Chen BB, Song XX, Xiao M, Guo GC, Jiang HW, Hu X, Guo GP. Tunable Hybrid Qubit in a GaAs Double Quantum Dot. PHYSICAL REVIEW LETTERS 2016; 116:086801. [PMID: 26967435 DOI: 10.1103/physrevlett.116.086801] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Indexed: 06/05/2023]
Abstract
We experimentally demonstrate a tunable hybrid qubit in a five-electron GaAs double quantum dot. The qubit is encoded in the (1,4) charge regime of the double dot and can be manipulated completely electrically. More importantly, dot anharmonicity leads to quasiparallel energy levels and a new anticrossing, which help preserve quantum coherence of the qubit and yield a useful working point. We have performed Larmor precession and Ramsey fringe experiments near the new working point and find that the qubit decoherence time is significantly improved over a charge qubit. This work shows a new way to encode a semiconductor qubit that is controllable and coherent.
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Affiliation(s)
- Gang Cao
- Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Hai-Ou Li
- Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Guo-Dong Yu
- Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Bao-Chuan Wang
- Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Bao-Bao Chen
- Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiang-Xiang Song
- Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ming Xiao
- Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Guang-Can Guo
- Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Hong-Wen Jiang
- Department of Physics and Astronomy, University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Xuedong Hu
- Department of Physics, University at Buffalo, SUNY, Buffalo, New York 14260, USA
| | - Guo-Ping Guo
- Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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19
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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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20
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Eng K, Ladd TD, Smith A, Borselli MG, Kiselev AA, Fong BH, Holabird KS, Hazard TM, Huang B, Deelman PW, Milosavljevic I, Schmitz AE, Ross RS, Gyure MF, Hunter AT. Isotopically enhanced triple-quantum-dot qubit. SCIENCE ADVANCES 2015; 1:e1500214. [PMID: 26601186 PMCID: PMC4640653 DOI: 10.1126/sciadv.1500214] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 04/09/2015] [Indexed: 05/05/2023]
Abstract
Like modern microprocessors today, future processors of quantum information may be implemented using all-electrical control of silicon-based devices. A semiconductor spin qubit may be controlled without the use of magnetic fields by using three electrons in three tunnel-coupled quantum dots. Triple dots have previously been implemented in GaAs, but this material suffers from intrinsic nuclear magnetic noise. Reduction of this noise is possible by fabricating devices using isotopically purified silicon. We demonstrate universal coherent control of a triple-quantum-dot qubit implemented in an isotopically enhanced Si/SiGe heterostructure. Composite pulses are used to implement spin-echo type sequences, and differential charge sensing enables single-shot state readout. These experiments demonstrate sufficient control with sufficiently low noise to enable the long pulse sequences required for exchange-only two-qubit logic and randomized benchmarking.
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21
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Veldhorst M, Hwang JCC, Yang CH, Leenstra AW, de Ronde B, Dehollain JP, Muhonen JT, Hudson FE, Itoh KM, Morello A, Dzurak AS. An addressable quantum dot qubit with fault-tolerant control-fidelity. NATURE NANOTECHNOLOGY 2014; 9:981-985. [PMID: 25305743 DOI: 10.1038/nnano.2014.216] [Citation(s) in RCA: 202] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 08/28/2014] [Indexed: 06/04/2023]
Abstract
Exciting progress towards spin-based quantum computing has recently been made with qubits realized using nitrogen-vacancy centres in diamond and phosphorus atoms in silicon. For example, long coherence times were made possible by the presence of spin-free isotopes of carbon and silicon. However, despite promising single-atom nanotechnologies, there remain substantial challenges in coupling such qubits and addressing them individually. Conversely, lithographically defined quantum dots have an exchange coupling that can be precisely engineered, but strong coupling to noise has severely limited their dephasing times and control fidelities. Here, we combine the best aspects of both spin qubit schemes and demonstrate a gate-addressable quantum dot qubit in isotopically engineered silicon with a control fidelity of 99.6%, obtained via Clifford-based randomized benchmarking and consistent with that required for fault-tolerant quantum computing. This qubit has dephasing time T2* = 120 μs and coherence time T2 = 28 ms, both orders of magnitude larger than in other types of semiconductor qubit. By gate-voltage-tuning the electron g*-factor we can Stark shift the electron spin resonance frequency by more than 3,000 times the 2.4 kHz electron spin resonance linewidth, providing a direct route to large-scale arrays of addressable high-fidelity qubits that are compatible with existing manufacturing technologies.
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Affiliation(s)
- M Veldhorst
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - J C C Hwang
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - C H Yang
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - A W Leenstra
- University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - B de Ronde
- University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - J P Dehollain
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - J T Muhonen
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - F E Hudson
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - K M Itoh
- School of Fundamental Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
| | - A Morello
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - A S Dzurak
- Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
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22
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Rohling N, Russ M, Burkard G. Hybrid spin and valley quantum computing with singlet-triplet qubits. PHYSICAL REVIEW LETTERS 2014; 113:176801. [PMID: 25379928 DOI: 10.1103/physrevlett.113.176801] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Indexed: 06/04/2023]
Abstract
The valley degree of freedom in the electronic band structure of silicon, graphene, and other materials is often considered to be an obstacle for quantum computing (QC) based on electron spins in quantum dots. Here we show that control over the valley state opens new possibilities for quantum information processing. Combining qubits encoded in the singlet-triplet subspace of spin and valley states allows for universal QC using a universal two-qubit gate directly provided by the exchange interaction. We show how spin and valley qubits can be separated in order to allow for single-qubit rotations.
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Affiliation(s)
- Niklas Rohling
- Department of Physics, University of Konstanz, D-78457 Konstanz, Germany
| | - Maximilian Russ
- Department of Physics, University of Konstanz, D-78457 Konstanz, Germany
| | - Guido Burkard
- Department of Physics, University of Konstanz, D-78457 Konstanz, Germany
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23
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Kawakami E, Scarlino P, Ward DR, Braakman FR, Savage DE, Lagally MG, Friesen M, Coppersmith SN, Eriksson MA, Vandersypen LMK. Electrical control of a long-lived spin qubit in a Si/SiGe quantum dot. NATURE NANOTECHNOLOGY 2014; 9:666-670. [PMID: 25108810 DOI: 10.1038/nnano.2014.153] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 06/27/2014] [Indexed: 06/03/2023]
Abstract
Nanofabricated quantum bits permit large-scale integration but usually suffer from short coherence times due to interactions with their solid-state environment. The outstanding challenge is to engineer the environment so that it minimally affects the qubit, but still allows qubit control and scalability. Here, we demonstrate a long-lived single-electron spin qubit in a Si/SiGe quantum dot with all-electrical two-axis control. The spin is driven by resonant microwave electric fields in a transverse magnetic field gradient from a local micromagnet, and the spin state is read out in the single-shot mode. Electron spin resonance occurs at two closely spaced frequencies, which we attribute to two valley states. Thanks to the weak hyperfine coupling in silicon, a Ramsey decay timescale of 1 μs is observed, almost two orders of magnitude longer than the intrinsic timescales in GaAs quantum dots, whereas gate operation times are comparable to those reported in GaAs. The spin echo decay time is ~40 μs, both with one and four echo pulses, possibly limited by intervalley scattering. These advances strongly improve the prospects for quantum information processing based on quantum dots.
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Affiliation(s)
- E Kawakami
- 1] Kavli Institute of Nanoscience, TU Delft, Lorentzweg 1, 2628 CJ Delft, The Netherlands [2]
| | - P Scarlino
- 1] Kavli Institute of Nanoscience, TU Delft, Lorentzweg 1, 2628 CJ Delft, The Netherlands [2]
| | - D R Ward
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - F R Braakman
- 1] Kavli Institute of Nanoscience, TU Delft, Lorentzweg 1, 2628 CJ Delft, The Netherlands [2]
| | - D E Savage
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - M G Lagally
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Mark Friesen
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - S N Coppersmith
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - M A Eriksson
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - L M K Vandersypen
- Kavli Institute of Nanoscience, TU Delft, Lorentzweg 1, 2628 CJ Delft, The Netherlands
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