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Single-spin-qubit geometric gate in a silicon quantum dot

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Physical Review Applied 2024年第1期21卷 014044-014044页

作者： Rong-Long Ma Ao-Ran Li Chu Wang Zhen-Zhen Kong Wei-Zhu Liao Ming Ni Sheng-Kai Zhu Ning Chu Chengxian Zhang Di Liu Gang Cao Gui-Lei Wang Hai-Ou Li Guo-Ping Guo CAS Key Laboratory of Quantum Information University of Science and Technology of China Hefei Anhui 230026 China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei Anhui 230026 China Integrated Circuit Advanced Process R&D Center Institute of Microelectronics Chinese Academy of Sciences Beijing 100029 China School of Physical Science and Technology Guangxi University Nanning 530004 China Hefei National Laboratory University of Science and Technology of China Hefei 230088 China Beijing Superstring Academy of Memory Technology Beijing 100176 China Origin Quantum Computing Company Limited Hefei Anhui 230026 China

Preserving qubit coherence and maintaining high-fidelity qubit control under complex noise environment is an enduring challenge for scalable quantum computing. Here we demonstrate an addressable fault-tolerant single spin qubit with an average control fidelity of 99.12% via randomized benchmarking on a silicon quantum dot device with an integrated micromagnet. Its dephasing time T2∗ is 1.025μs, and can be enlarged to 264μs by using the Hahn-echo technique, reflecting strong low-frequency noise in our system. To break through the noise limitation, we introduce geometric quantum computing to obtain high control fidelity by exploiting its noise-resilient feature. However, the control fidelities of the geometric quantum gates are lower than 99%. According to our simulation, the noise-resilient feature of geometric quantum gates is masked by the heating effect. With further optimization to alleviate the heating effect, geometric quantum computing can be a potential approach to reproducibly achieving high-fidelity qubit control in a complex noise environment.

关键词： Geometric & topological phases Quantum gates Quantum information with solid state qubits Elemental semiconductors Quantum dots Single-electron transistors Electron dipole spin resonance Microwave techniques

Observation of magnetic droplets in magnetic tunnel junctions

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arXiv 2020年

作者： Shi, Kewen Cai, Wenlong Jiang, Sheng Zhu, Daoqian Cao, Kaihua Guo, Zongxia Wei, Jiaqi Du, Ao Li, Zhi Huang, Yan Yin, Jialiang Åkerman, Johan Zhao, Weisheng Fert Beijing Institute School of Integrated Circuit Science and Engineering Beijing Advanced Innovation Center for Big Data and Brain Computing Beihang University Beijing China Beihang-Goertek Joint Microelectronics Institute Qingdao Research Institute Beihang University Qingdao266000 China Department of Physics University of Gothenburg Gothenburg412 96 Sweden Department of Applied Physics School of Engineering Sciences KTH Royal Institute of Technology Electrum 229 KistaSE-16440 Sweden

Magnetic droplets, a class of highly non-linear magnetodynamical solitons, can be nucleated and stabilized in nanocontact spin-torque nano-oscillators where they greatly increase the microwave output power. Here, we experimentally demonstrate magnetic droplets in magnetic tunnel junctions (MTJs). The droplet nucleation is accompanied by a power increase of over 300 times compared to its ferromagnetic resonance modes. The nucleation and stabilization of droplets are ascribed to the double-CoFeB free layer structure in the all-perpendicular MTJ which provides a low Zhang-Li torque and a high pinning field. Our results enable better electrical sensitivity in the fundamental studies of droplets and show that the droplets can be utilized in MTJ-based applications. Copyright © 2020, The Authors. All rights reserved.

关键词： Spin dynamics

Scaling MOSFETs with Self-aligned Super-Steep-Retrograded Halo (3SRH)

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ECS Transactions 2011年第1期34卷

作者： Binneng Wu Weiping Xiao Huilong Zhu Qingqing Liang Hao Wu Haizhou Yin Zhijiong Luo Hongyu Yu Dapeng Chen Tianchun Ye Institute of Microelectronics Chinese Academy of Sciences No.3 BeiTuCheng West Rd. Beijing Beijing 100029 China Institute of Microelectronics Chinese Academy of Sciences School of Electrical & Electronic Engineering Nanyang Technological University Integrated Circuit Advanced Process Center Institute of Microelectronics Chinese Academy of Sciences

In order to take the advantages of the replacement gate process, improve the control of SCE, and enhance the performance of CMOSFETs, a novel method of self-aligned super-steep-retrograded halo (3SRH) implantation is designed and presented in this paper. With process and device simulations, it's demonstrated that 3SRH can be used to enhance MOSFET performance.

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Correcting on-chip distortion of control pulses with silicon spin qubits

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arXiv 2023年

作者： Ni, Ming Ma, Rong-Long Kong, Zhen-Zhen Chu, Ning Liao, Wei-Zhu Zhu, Sheng-Kai Wang, Chu Luo, Gang Liu, Di Cao, Gang Wang, Gui-Lei Li, Hai-Ou Guo, Guo-Ping Cas Key Laboratory of Quantum Information University of Science and Technology of China Anhui Hefei230026 China Cas Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Anhui Hefei230026 China Integrated Circuit Advanced Process R&d Center Institute of Microelectronics Chinese Academy of Sciences Beijing100029 China Hefei National Laboratory University of Science and Technology of China Hefei230088 China Beijing Superstring Academy of Memory Technology Beijing100176 China Origin Quantum Computing Company Limited Anhui Hefei230026 China

Pulse distortion, as one of the coherent error sources, hinders the characterization and control of qubits. In the semiconductor quantum dot system, the distortions on measurement pulses and control pulses disturb the experimental results, while no effective calibration procedure has yet been reported. Here, we demonstrate two different calibration methods to calibrate and correct the distortion using the two-qubit system as a detector. The two calibration methods have different correction accuracy and complexity. One is the coarse predistortion (CPD) method, with which the distortion is partly relieved. The other method is the all predistortion (APD) method, with which we measure the transfer function and significantly improve the exchange oscillation homogeneity. The two methods use the exchange oscillation homogeneity as the metric and are appropriate for any qubit that oscillates with a diabatic pulse. With the APD procedure, an arbitrary control waveform can be accurately delivered to the device, which is essential for characterizing qubits and improving gate fidelity. Copyright © 2023, The Authors. All rights reserved.

关键词： Qubits

Singlet-triplet-state readout in silicon-metal-oxide-semiconductor double quantum dots

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arXiv 2023年

作者： Ma, Rong-Long Zhu, Sheng-Kai Kong, Zhen-Zhen Sun, Tai-Ping Ni, Ming Zhou, Yu-Chen Zhou, Yuan Luo, Gang Cao, Gang Wang, Gui-Lei Li, Hai-Ou Guo, Guo-Ping CAS Key Laboratory of Quantum Information University of Science and Technology of China Anhui Hefei230026 China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Anhui Hefei230026 China Integrated Circuit Advanced Process R&D Center Institute of Microelectronics Chinese Academy of Sciences Beijing100029 China Hefei National Laboratory University of Science and Technology of China Hefei230088 China Beijing Superstring Academy of Memory Technology Beijing100176 China Origin Quantum Computing Company Limited Anhui Hefei230026 China

High-fidelity singlet-triplet state readout is essential for large-scale quantum computing. However, the widely used threshold method of comparing a mean value with the fixed threshold will limit the judgment accuracy, especially for the relaxed triplet state, under the restriction of relaxation time and signal-to-noise ratio. Here, we achieve an enhanced latching readout based on Pauli spin blockade in a Si-MOS double quantum dot device and demonstrate an average singlet-triplet state readout fidelity of 97.59% by the threshold method. We reveal the inherent deficiency of the threshold method for the relaxed triplet state classification and introduce machine learning as a relaxation-independent readout method to reduce the misjudgment. The readout fidelity for classifying the simulated single-shot traces can be improved to 99.67% by machine learning method, better than the threshold method of 97.54% which is consistent with the experimental result. This work indicates that machine learning method can be a strong potential candidate for alleviating the restrictions of stably achieving high-fidelity and high-accuracy singlet-triplet state readout in large-scale quantum computing. Copyright © 2023, The Authors. All rights reserved.

关键词： Semiconductor quantum dots

Ferroelectric hafnia as an intrinsic ionic conductor

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arXiv 2023年

作者： Zhao, Guo-Dong Liu, Xingen Xu, Zhongshan Ren, Wei Zhu, Xiaona Zhang, David Wei Yu, Shaofeng School of Microelectronics Fudan University Shanghai200433 China School of Mathematical Information Shaoxing University Shaoxing312000 China Physics Department Shanghai Key Laboratory of High Temperature Superconductors State Key Laboratory of Advanced Special Steel International Centre of Quantum and Molecular Structures Shanghai University Shanghai200444 China Jiashan Fudan Institute Jiashan314100 China National Integrated Circuit Innovation Center Shanghai201204 China

The intensively concerned hafnia-based ferroelectric (FE) material has been controversial over whether the origin of its observed ferroelectricity being structural or electrochemical. We revisit the rigorous application of modern theory of polarization on displacive FE-HfO2, and make clear the microscopic mechanism of ionic conductance intertwined with continuous nucleation-and-growth FE switching in HfO2 from first principles. Independent from the involvement of vacancies, active oxygen ions in FE-HfO2 can be collectively conducted along continuous FE uniaxialconnected-paths (UCPs) in a typical nucleation-and-growth manner. The ionic conductance should have a nonlinear electric-field dependence from the Merz’s law, which is consistent with the strongly correlated ionic conductance. Based on our established physical picture, some abnormal experimental observations of HfO2 may be explained beyond the pristine understanding of FE switching within double-well potentials. Copyright © 2023, The Authors. All rights reserved.

关键词： Nucleation

A Novel Tunnel Oxide Based Tunnel FET

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ECS Transactions 2011年第1期34卷

作者： Hefei Wang Zhijiong Luo Haizhou Yin Huilong Zhu Jia Liu Zhengyong Zhu Integrated Circuit Advanced Process Center Chinese Academy of Sciences 3 Beitucheng West Road Chaoyang District Beijing Beijing 100029 China Institute of Microelectronics Chinese Academy of Sciences Institute of Microelectronics Chinese Academy of Sciences No.3 BeiTuCheng West Rd. Beijing Beijing 100029 China Chinese Academy of Sciences

In this work, we propose a novel tunnel oxide based Tunnel FET. This novel Tunnel FET can achieve high drive currents, low SS, low off currents and many other superb device characteristics. From device simulation, this novel device can obtain drive currents 100x higher than that of a conventional Tunnel FET. This novel device also can realize SS as low as 30mV/dec. Moreover, this novel device has potential to significantly reduce off currents, and suppress the ambipolar behavior existing in conventional Tunnel FETs. In addition, the novel device can obtain the ability to scale down without performance degradation due to the unique scalability of tunnel oxide. These excellent device characteristics make the novel Tunnel FET an ideal device structure for future LSTP applications.

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A diverse set of two-qubit gates for spin qubits in semiconductor quantum dots

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arXiv 2024年

作者： Ni, Ming Ma, Rong-Long Kong, Zhen-Zhen Chu, Ning Zhu, Sheng-Kai Wang, Chu Li, Ao-Ran Liao, Wei-Zhu Cao, Gang Wang, Gui-Lei Guo, Guang-Can Hu, Xuedong Li, Hai-Ou Guo, Guo-Ping CAS Key Laboratory of Quantum Information University of Science and Technology of China Anhui Hefei230026 China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Anhui Hefei230026 China Integrated Circuit Advanced Process R&D Center Institute of Microelectronics Chinese Academy of Sciences Beijing100029 China Department of Physics University at Buffalo SUNY BuffaloNY14260 United States Beijing Superstring Academy of Memory Technology Beijing100176 China Hefei National Laboratory University of Science and Technology of China Hefei230088 China Origin Quantum Computing Company Limited Anhui Hefei230026 China

To realize large-scale quantum information processes, an ideal scheme for two-qubit operations should enable diverse operations with given hardware and physical interaction. However, for spin qubits in semiconductor quantum dots, the common two-qubit operations, including CPhase gates, SWAP gates, and CROT gates, are realized with distinct parameter regions and control waveforms, posing challenges for their simultaneous implementation. Here, taking advantage of the inherent Heisenberg interaction between spin qubits, we propose and verify a fast composite two-qubit gate scheme to extend the available two-qubit gate types as well as reduce the requirements for device properties. Apart from the formerly proposed CPhase (controlled-phase) gates and SWAP gates, theoretical results indicate that the iSWAP-family gate and Fermionic simulation (fSim) gate set are additionally available for spin qubits. Meanwhile, our gate scheme limits the parameter requirements of all essential two-qubit gates to a common J~∆EZ region, facilitate the simultaneous realization of them. Furthermore, we present the preliminary experimental demonstration of the composite gate scheme, observing excellent match between the measured and simulated results. With this versatile composite gate scheme, broad-spectrum two-qubit operations allow us to efficiently utilize the hardware and the underlying physics resources, helping accelerate and broaden the scope of the upcoming noise intermediate-scale quantum (NISQ) computing. Copyright © 2024, The Authors. All rights reserved.

关键词： Semiconductor quantum dots

Single spin qubit geometric gate in a silicon quantum dot

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arXiv 2023年

作者： Ma, Rong-Long Li, Ao-Ran Wang, Chu Kong, Zhen-Zhen Liao, Wei-Zhu Ni, Ming Zhu, Sheng-Kai Chu, Ning Zhang, Cheng-Xian Liu, Di Cao, Gang Wang, Gui-Lei Li, Hai-Ou Guo, Guo-Ping CAS Key Laboratory of Quantum Information University of Science and Technology of China Anhui Hefei230026 China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Anhui Hefei230026 China Integrated Circuit Advanced Process R&D Center Institute of Microelectronics Chinese Academy of Sciences Beijing100029 China School of Physical Science and Technology Guangxi University Nanning530004 China Hefei National Laboratory University of Science and Technology of China Hefei230088 China Beijing Superstring Academy of Memory Technology Beijing100176 China Origin Quantum Computing Company Limited Anhui Hefei230026 China

Preserving qubit coherence and maintaining high-fidelity qubit control under complex noise environment is an enduring challenge for scalable quantum computing. Here we demonstrate an addressable fault-tolerant single spin qubit with an average control fidelity of 99.12 % via randomized benchmarking on a silicon quantum dot device with an integrated micromagnet. Its dephasing time T2∗ is 1.025 µs, and can be enlarged to 264 µs by using the Hahn echo technique, reflecting strong low-frequency noise in our system. To break through the noise limitation, we introduce geometric quantum computing to obtain high control fidelity by exploiting its noise-resilient feature. However, the control fidelities of the geometric quantum gates are lower than 99 %. According to our simulation, the noise-resilient feature of geometric quantum gates is masked by the heating effect. With further optimization to alleviate the heating effect, geometric quantum computing can be a potential approach to reproducibly achieving high-fidelity qubit control in a complex noise environment. Copyright © 2023, The Authors. All rights reserved.

关键词： Qubits