Article
Nanoscience & Nanotechnology
Ella Schneider, Jonathan England
Summary: 28Si enrichment is crucial for quantum computers based on group IV semiconductors. A novel enrichment process involving ion implantation of 28Si into Al films deposited on native-oxide free Si substrates followed by layer exchange crystallization is reported. The process shows potential to produce quantum grade 28Si using conventional semiconductor foundry equipment within production-worthy time scales.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Physics, Applied
F. K. Unseld, M. Meyer, M. T. Madzik, F. Borsoi, S. L. de Snoo, S. V. Amitonov, A. Sammak, G. Scappucci, M. Veldhorst, L. M. K. Vandersypen
Summary: Semiconductor spin qubits have attracted attention as a potential platform for fault-tolerant quantum computing. In this study, researchers successfully created a tunnel-coupled 2x2 quantum dot array in a Si-28/SiGe heterostructure using high-quality materials and carefully designed gate patterns. By loading a single electron into each of the four quantum dots, the researchers were able to achieve the specific charge state (1,1,1,1). This work provides valuable information for the design of 2D quantum dot arrays and represents a significant step towards the operation of spin qubits in Si-28/SiGe quantum dots in two dimensions.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Ella B. Schneider, Jonathan England, Luke Antwis, Alex Royle, Roger Webb, Russell Gwilliam
Summary: The study explored the use of conventional ion implantation to create enriched Si-28 layers for quantum computers. Results showed that low energy, ultra-high vacuum implantation is crucial for achieving high Si-28 enrichment levels exceeding 99.9%. However, utilizing ultra-low energy implants may lead to excessive oxygen contamination and compromise the enrichment efficiency.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Jingwei Mu, Shaoyun Huang, Zhi-Hai Liu, Weijie Li, Ji-Yin Wang, Dong Pan, Guang-Yao Huang, Yuanjie Chen, Jianhua Zhao, H. Q. Xu
Summary: The research team successfully demonstrated a highly tunable linear quadruple QD system in a nanowire and obtained characteristic two-dimensional charge stability diagrams through electron transport measurements, providing important experimental evidence for studying multiple QD systems.
Article
Physics, Multidisciplinary
Ting Lin, Hai-Ou Li, Gang Cao, Guo-Ping Guo
Summary: In this work, we propose a mechanism for coupling a plane structure of four quantum dots with a resonator. We investigate the dependence of the quadruple coupling strength and qubit decoherence rate, and identify the optimal operating position for the hybrid system. Using the input-output theory, we predict the signatures in the resonator spectrum. Additionally, based on previous research, we demonstrate that the device described in this paper can achieve the strong coupling limit, allowing for system extension under existing technical conditions.
Article
Chemistry, Multidisciplinary
Marcel Meyer, Corentin Deprez, Timo R. van Abswoude, Ilja N. Meijer, Dingshan Liu, Chien-An Wang, Saurabh Karwal, Stefan Oosterhout, Francesco Borsoi, Amir Sammak, Nico W. Hendrickx, Giordano Scappucci, Menno Veldhorst
Summary: This article introduces a method of voltage adjustment using the gate voltage characteristics to achieve uniformity in the pinch-off voltages of quantum dots. The method is demonstrated to increase the stability of the quantum dots and offers new possibilities for scalable spin qubit arrays.
Article
Quantum Science & Technology
Weijie Li, Zhihai Liu, Jingwei Mu, Yi Luo, Dong Pan, Jianhua Zhao, H. Q. Xu
Summary: A serial triple quantum dot (TQD) integrated with a quantum dot (QD) charge sensor was successfully realized using a fine finger-gate technique applied to an InAs nanowire. The complex charge states and intriguing properties of the TQD were studied in the few-electron regime through direct transport measurements and charge-sensor detection measurements. The TQD's charge stability diagrams were measured by the charge sensor and were well reproduced by simultaneous direct transport measurements and simulations based on an effective capacitance network model. In addition, the TQD was demonstrated and discussed as a quantum cellular automaton.
ADVANCED QUANTUM TECHNOLOGIES
(2023)
Article
Physics, Applied
A. R. Mills, C. R. Guinn, M. M. Feldman, A. J. Sigillito, M. J. Gullans, M. T. Rakher, J. Kerckhoff, C. A. C. Jackson, J. R. Petta
Summary: In this study, the researchers demonstrate that by operating with low electron temperatures and employing high-bandwidth cryogenic amplifiers, single-qubit readout visibilities of >99% and average single-qubit control fidelities of >99.95% can be achieved in silicon spin qubits, indicating high overall operation fidelity.
PHYSICAL REVIEW APPLIED
(2022)
Article
Multidisciplinary Sciences
Andre Al-Haddad, Solene Oberli, Jesus Gonzalez-Vazquez, Maximilian Bucher, Gilles Doumy, Phay Ho, Jacek Krzywinski, Thomas J. Lane, Alberto Lutman, Agostino Marinelli, Timothy J. Maxwell, Stefan Moeller, Stephen T. Pratt, Dipanwita Ray, Ron Shepard, Stephen H. Southworth, Alvaro Vazquez-Mayagoitia, Peter Walter, Linda Young, Antonio Picon, Christoph Bostedt
Summary: This study demonstrates the ability to track ultrafast electron rearrangement and chemical bond breaking in real time at specific sites using X-ray photoelectron spectroscopy. By observing the chemical shifts of the carbon core-electron binding energy, the authors can investigate charge redistribution and dissociation processes.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Jaco J. Geuchies, Baldur Brynjarsson, Gianluca Grimaldi, Solrun Gudjonsdottir, Ward van der Stam, Wiel H. Evers, Arjan J. Houtepen
Summary: Research demonstrates that by electrochemically doping films of CdSe/CdS/ZnS QDs, quantitative control over the gain threshold can be achieved, opening up a new route for the creation of cheap, solution-processable, low-threshold QD lasers.
Article
Nanoscience & Nanotechnology
Pierre-Andre Mortemousque, Emmanuel Chanrion, Baptiste Jadot, Hanno Flentje, Arne Ludwig, Andreas D. Wieck, Matias Urdampilleta, Christopher Bauerle, Tristan Meunier
Summary: Controlling individual quantum objects organized in arrays is essential for scalable quantum information platforms. By integrating nearest-neighbour coupled semiconductor quantum dots in a 3 x 3 array with finely tuned virtual gate control, 2D coherent spin control has been achieved. Recent efforts in controlling electron spins in quantum dot arrays have led to the realization of quantum simulators and multielectron spin-coherent manipulations. However, demonstrating 2D scaling with a high connectivity of such implementations remains a challenge.
NATURE NANOTECHNOLOGY
(2021)
Article
Computer Science, Software Engineering
Zaman Amirzadeh, Mohammad Gholami
Summary: In this article, novel counters based on QCA technology are designed by introducing a new D flip-flop and modifying it to have set and reset abilities. The proposed counters are able to selectively count from different ranges, with improvements in terms of cell number, occupied area, delay, total energy, and average energy dissipation compared to previous designs. The proposed selective counter counting from 2 to 5 is a new contribution to the field. Simulation results validate the theoretical expectations.
CONCURRENCY AND COMPUTATION-PRACTICE & EXPERIENCE
(2022)
Article
Chemistry, Physical
Youngsang Park, Sung Yong Bae, Taewan Kim, Seongmin Park, Jae Taek Oh, Daekwon Shin, Mahnmin Choi, Hyojung Kim, Bora Kim, Doh C. Lee, Jung Hoon Song, Hyosung Choi, Sohee Jeong, Younghoon Kim
Summary: The power conversion efficiency of solution-processed thin-film solar cells has greatly improved in the past decade, but their operational stability remains a concern. This study presents a device architecture using Indium Arsenide colloidal quantum dots as the electron transporting layer, which enhances the stability and efficiency of the solar cells.
ADVANCED ENERGY MATERIALS
(2022)
Article
Multidisciplinary Sciences
David W. Kanaar, Utkan Gungordu, J. P. Kestner
Summary: In this study, a method for implementing spin state transfer in long chains of singly occupied quantum dots in a non-adiabatic manner is proposed. The interacting problem is broken down into simpler problems using Cartan decomposition, and smooth non-adiabatic pulses are designed using dynamical invariants, which can be implemented in devices with modest control bandwidth. The extensibility of the results to directed shuttling of spin states on two-dimensional lattices of quantum dots with fixed coupling is also discussed.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2022)
Article
Engineering, Environmental
P. Keerthana, Avijit Kumar Das, M. Bharath, Munmun Ghosh, Anitha Varghese
Summary: A fluorescent ratiometric nanosensor was developed using biomass-derived carbon quantum dots with surface modification for highly selective identification of cadmium ions.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2023)
Article
Multidisciplinary Sciences
F. Borjans, X. G. Croot, X. Mi, M. J. Gullans, J. R. Petta
Article
Physics, Applied
F. Borjans, X. Mi, J. R. Petta
Summary: The study demonstrates high-fidelity spin readout using a charge sensor within a triple quantum dot, achieving near-digital sensor response and over 450 power signal-to-noise ratio at an integration time of 1 μs. The approach enables measurement of spin relaxation time and achieves greater than 99% average single-shot spin readout fidelity for singlet-triplet qubit, combining minimal device overhead with flexible qubit operation in semiconductor quantum devices.
PHYSICAL REVIEW APPLIED
(2021)
Article
Nanoscience & Nanotechnology
Seong Woo Oh, Artem O. Denisov, Pengcheng Chen, Jason R. Petta
Summary: Silicon can be isotopically enriched for highly coherent semiconductor spin qubits, but the six-fold valley degeneracy in bulk Si may affect silicon quantum devices. A cryogen-free scanning gate microscope for Si/Si0.7Ge0.3 quantum devices at mK temperatures was developed, capable of forming and measuring quantum dots without compromising quantum control experiments. Vibration noise reduction techniques were implemented to achieve precise characterization of fully functioning Si/Si0.7Ge0.3 quantum devices.
Editorial Material
Physics, Applied
Anthony J. Sigillito, Jacob P. Covey, Johannes M. Fink, Karl Petersson, Stefan Preble
APPLIED PHYSICS LETTERS
(2022)
Article
Multidisciplinary Sciences
Adam R. Mills, Charles R. Guinn, Michael J. Gullans, Anthony J. Sigillito, Mayer M. Feldman, Erik Nielsen, Jason R. Petta
Summary: Silicon spin qubits have the potential to become the dominant technology in the development of intermediate-scale quantum processors. However, there are still shortcomings in achieving high-fidelity state preparation and readout, as well as single- and two-qubit gate operations.
Article
Chemistry, Multidisciplinary
Artem O. Denisov, Seong W. Oh, Gordian Fuchs, Adam R. Mills, Pengcheng Chen, Christopher R. Anderson, Mark F. Gyure, Arthur W. Barnard, Jason R. Petta
Summary: Researchers have successfully combined the spatial resolution of scanning probe microscopy with the speed of microwave measurements by coupling a metallic tip to a Si/SiGe double quantum dot. They were able to observe excited states with an energy of -65microelectronvolts, consistent with valley splittings in Si/SiGe.
Article
Physics, Nuclear
A. P. D. Ramirez, E. E. Peters, J. R. Vanhoy, S. F. Hicks, L. A. Alasagas, D. K. Alcorn-Dominguez, S. T. Block, S. T. Byrd, E. A. Chouinard, B. M. Combs, B. P. Crider, E. C. Derdyn, L. Downes, J. A. Erlanson, S. E. Evans, A. J. French, E. A. Garza, J. Girgis, T. D. Harrison, S. L. Henderson, T. J. Howard, D. T. Jackson, L. J. Kersting, A. Kumar, S. H. Liu, C. J. Lueck, E. M. Lyons, P. J. McDonough, M. T. McEllistrem, T. J. Morin, S. Mukhopadhyay, T. A. Nguyen, M. Nickel, S. Nigam, R. L. Pecha, J. Potter, F. M. Prados-Estevez, B. G. Rice, T. J. Ross, Z. C. Santonil, J. Schneiderjan, L. C. Sidwell, A. J. Sigillito, J. L. Steves, B. K. Thompson, D. W. Watts, Y. Xiao, S. W. Yates
Summary: Elastic and inelastic neutron scattering angular distributions were measured on natural carbon samples to confirm existing experimental data and evaluations, and guide improvements in resonance parameters if necessary. The results largely agree with existing values, but show some deviations in certain energy ranges. These data will aid in refining the description of carbon samples in neutron scattering.
Article
Physics, Applied
A. R. Mills, C. R. Guinn, M. M. Feldman, A. J. Sigillito, M. J. Gullans, M. T. Rakher, J. Kerckhoff, C. A. C. Jackson, J. R. Petta
Summary: In this study, the researchers demonstrate that by operating with low electron temperatures and employing high-bandwidth cryogenic amplifiers, single-qubit readout visibilities of >99% and average single-qubit control fidelities of >99.95% can be achieved in silicon spin qubits, indicating high overall operation fidelity.
PHYSICAL REVIEW APPLIED
(2022)
Review
Physics, Multidisciplinary
Guido Burkard, Thaddeus D. Ladd, Andrew Pan, John M. Nichol, Jason R. Petta
Summary: The spin degree of freedom of an electron or a nucleus is a basic property that provides a natural two-level system for quantum information processing. Semiconductor spin qubits have made significant advancements in terms of quantum state preparation, coherent control, and measurement. These qubits have the potential for scalable solid-state quantum information processing, thanks to their small size, high density, long coherence times, and existing industrial infrastructure.
REVIEWS OF MODERN PHYSICS
(2023)
Article
Quantum Science & Technology
Artem O. Denisov, Gordian Fuchs, Seong W. Oh, Jason R. Petta
Summary: We charge floating metallic gates on a Si/SiGe heterostructure using the tip of an AFM. The AFM tip acts as a movable cryogenic switch, allowing us to bias and lock the charge on the gate. This method enables us to reduce the size of the quantum dot floating-gate electrode and measure immeasurable values of leakage resistance.
Article
Quantum Science & Technology
Jonas Mielke, Jason R. Petta, Guido Burkard
Summary: Nuclear spins exhibit long coherence times and strong isolation from the environment, making them promising for quantum information applications. A method for nuclear spin readout by probing microwave resonator transmission is presented, demonstrating feasibility with current state-of-the-art devices. Optimal readout points with strong signal contrast and potential for coherent excitation exchange between a nuclear spin qubit and cavity photons are identified.
Article
Quantum Science & Technology
F. Borjans, X. Zhang, X. Mi, G. Cheng, N. Yao, C. A. C. Jackson, L. F. Edge, J. R. Petta
Summary: The study found that the valley degree of freedom in silicon quantum dots is crucial for spin qubits. Significant variations in valley splitting and intra- and intervalley tunnel couplings were observed using microwave spectroscopy. Strong interactions between different valley states on neighboring dots were attributed to local inhomogeneities in the silicon quantum well.
Review
Physics, Applied
Guido Burkard, Michael J. Gullans, Xiao Mi, Jason R. Petta
NATURE REVIEWS PHYSICS
(2020)
