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John, V. (author), Borsoi, F. (author), György, Zoltán (author), Wang, C.A. (author), Széchenyi, Gábor (author), van Riggelen, F. (author), Lawrie, W.I.L. (author), Hendrickx, N.W. (author), Sammak, A. (author), Scappucci, G. (author), Pályi, András (author), Veldhorst, M. (author)Electrically driven spin resonance is a powerful technique for controlling semiconductor spin qubits. However, it faces challenges in qubit addressability and off-resonance driving in larger systems. We demonstrate coherent bichromatic Rabi control of quantum dot hole spin qubits, offering a spatially selective approach for large qubit arrays...journal article 2024
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Hsiao, T. (author), Cova Fariña, P. (author), Oosterhout, S.D. (author), Jirovec, D. (author), Zhang, X. (author), van Diepen, C.J. (author), Lawrie, W.I.L. (author), Wang, C.A. (author), Sammak, A. (author), Scappucci, G. (author), Veldhorst, M. (author), Vandersypen, L.M.K. (author)Quantum systems with engineered Hamiltonians can be used to study many-body physics problems to provide insights beyond the capabilities of classical computers. Semiconductor gate-defined quantum dot arrays have emerged as a versatile platform for realizing generalized Fermi-Hubbard physics, one of the richest playgrounds in condensed matter...journal article 2024
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Degli Esposti, D. (author), Stehouwer, L.E.A. (author), Gül, Önder (author), Samkharadze, Nodar (author), Déprez, C.C. (author), Meyer, M. (author), Meijer, Ilja N. (author), Tryputen, L. (author), Karwal, S. (author), Vandersypen, L.M.K. (author), Sammak, A. (author), Veldhorst, M. (author), Scappucci, G. (author)The electrical characterisation of classical and quantum devices is a critical step in the development cycle of heterogeneous material stacks for semiconductor spin qubits. In the case of silicon, properties such as disorder and energy separation of conduction band valleys are commonly investigated individually upon modifications in selected...journal article 2024
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Corley-Wiciak, Cedric (author), Richter, Carsten (author), Zoellner, Marvin H. (author), Zaitsev, Ignatii (author), Manganelli, Costanza L. (author), Hendrickx, N.W. (author), Sammak, A. (author), Veldhorst, M. (author), Scappucci, G. (author)A strained Ge quantum well, grown on a SiGe/Si virtual substrate and hosting two electrostatically defined hole spin qubits, is nondestructively investigated by synchrotron-based scanning X-ray diffraction microscopy to determine all its Bravais lattice parameters. This allows rendering the three-dimensional spatial dependence of the six...journal article 2023
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Meyer, M. (author), Déprez, C.C. (author), van Abswoude, Timo R. (author), Meijer, Ilja N. (author), Liu, Dingshan (author), Wang, C.A. (author), Karwal, S. (author), Oosterhout, S.D. (author), Borsoi, F. (author), Sammak, A. (author), Hendrickx, N.W. (author), Scappucci, G. (author), Veldhorst, M. (author)Highly uniform quantum systems are essential for the practical implementation of scalable quantum processors. While quantum dot spin qubits based on semiconductor technology are a promising platform for large-scale quantum computing, their small size makes them particularly sensitive to their local environment. Here, we present a method to...journal article 2023
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Tosato, A. (author), Levajac, V. (author), Wang, J. (author), Boor, Casper J. (author), Borsoi, F. (author), Botifoll, Marc (author), Sammak, A. (author), Veldhorst, M. (author), Scappucci, G. (author)The co-integration of spin, superconducting, and topological systems is emerging as an exciting pathway for scalable and high-fidelity quantum information technology. High-mobility planar germanium is a front-runner semiconductor for building quantum processors with spin-qubits, but progress with hybrid superconductor-semiconductor devices is...journal article 2023
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Tidjani, H. (author), Tosato, A. (author), Ivlev, A.S. (author), Déprez, C.C. (author), Oosterhout, S.D. (author), Stehouwer, L.E.A. (author), Sammak, A. (author), Scappucci, G. (author), Veldhorst, M. (author)Gate-defined quantum dots in silicon-germanium heterostructures have become a compelling platform for quantum computation and simulation. Thus far, developments have been limited to quantum dots defined in a single plane. Here, we propose to advance beyond planar systems by exploiting heterostructures with multiple quantum wells. We...journal article 2023
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Sarkar, Abhikbrata (author), Wang, Zhanning (author), Rendell, Matthew (author), Hendrickx, N.W. (author), Veldhorst, M. (author), Scappucci, G. (author), Khalifa, Mohammad (author), Salfi, Joe (author), Saraiva, Andre (author)Hole spin qubits in group-IV semiconductors, especially Ge and Si, are actively investigated as platforms for ultrafast electrical spin manipulation thanks to their strong spin-orbit coupling. Nevertheless, the theoretical understanding of spin dynamics in these systems is in the early stages of development, particularly for in-plane magnetic...journal article 2023
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Lawrie, W.I.L. (author), Russ, M.F. (author), van Riggelen, F. (author), Hendrickx, N.W. (author), de Snoo, S.L. (author), Sammak, A. (author), Scappucci, G. (author), Helsen, J. (author), Veldhorst, M. (author)Practical Quantum computing hinges on the ability to control large numbers of qubits with high fidelity. Quantum dots define a promising platform due to their compatibility with semiconductor manufacturing. Moreover, high-fidelity operations above 99.9% have been realized with individual qubits, though their performance has been limited to 98...journal article 2023
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Wang, C.A. (author), Déprez, C.C. (author), Tidjani, H. (author), Lawrie, W.I.L. (author), Hendrickx, N.W. (author), Sammak, A. (author), Scappucci, G. (author), Veldhorst, M. (author)Simulations using highly tunable quantum systems may enable investigations of condensed matter systems beyond the capabilities of classical computers. Quantum dots and donors in semiconductor technology define a natural approach to implement quantum simulation. Several material platforms have been used to study interacting charge states,...journal article 2023
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Unseld, F.K. (author), Meyer, M. (author), Madzik, M.T. (author), Borsoi, F. (author), de Snoo, S.L. (author), Amitonov, S. (author), Sammak, A. (author), Scappucci, G. (author), Veldhorst, M. (author), Vandersypen, L.M.K. (author)Semiconductor spin qubits have gained increasing attention as a possible platform to host a fault-tolerant quantum computer. First demonstrations of spin qubit arrays have been shown in a wide variety of semiconductor materials. The highest performance for spin qubit logic has been realized in silicon, but scaling silicon quantum dot arrays...journal article 2023
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Stehouwer, L.E.A. (author), Tosato, A. (author), Degli Esposti, D. (author), Costa, D.C. (author), Veldhorst, M. (author), Sammak, A. (author), Scappucci, G. (author)We grow strained Ge/SiGe heterostructures by reduced-pressure chemical vapor deposition on 100 mm Ge wafers. The use of Ge wafers as substrates for epitaxy enables high-quality Ge-rich SiGe strain-relaxed buffers with a threading dislocation density of ( 6 ± 1 ) × 10 5 cm − 2 , nearly an order of magnitude improvement compared to control...journal article 2023
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Borsoi, F. (author), Hendrickx, N.W. (author), John, V. (author), Meyer, M. (author), Motz, Sayr (author), van Riggelen, F. (author), Sammak, A. (author), de Snoo, S.L. (author), Scappucci, G. (author), Veldhorst, M. (author)The efficient control of a large number of qubits is one of the most challenging aspects for practical quantum computing. Current approaches in solid-state quantum technology are based on brute-force methods, where each and every qubit requires at least one unique control line—an approach that will become unsustainable when scaling to the...journal article 2023
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Meyer, M. (author), Déprez, C.C. (author), Meijer, Ilja N. (author), Unseld, F.K. (author), Karwal, S. (author), Sammak, A. (author), Scappucci, G. (author), Vandersypen, L.M.K. (author), Veldhorst, M. (author)The small footprint of semiconductor qubits is favorable for scalable quantum computing. However, their size also makes them sensitive to their local environment and variations in the gate structure. Currently, each device requires tailored gate voltages to confine a single charge per quantum dot, clearly challenging scalability. Here, we...journal article 2023
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Tosato, A. (author), Ferrari, B.M. (author), Sammak, A. (author), Hamilton, Alexander R. (author), Veldhorst, M. (author), Virgilio, Michele (author), Scappucci, G. (author)A hole bilayer in a strained germanium double quantum well is designed, fabricated, and studied. Magnetotransport characterization of double quantum well field-effect transistors as a function of gate voltage reveals the population of two hole channels with a high combined mobility of (Formula presented.) and a low percolation density of ...journal article 2022
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Philips, S.G.J. (author), Madzik, M.T. (author), Amitonov, S. (author), de Snoo, S.L. (author), Russ, M.F. (author), Kalhor, N. (author), Volk, C.A. (author), Lawrie, W.I.L. (author), Brousse, D. (author), Tryputen, L. (author), Paquelet Wuetz, B. (author), Sammak, A. (author), Veldhorst, M. (author), Scappucci, G. (author), Vandersypen, L.M.K. (author)Future quantum computers capable of solving relevant problems will require a large number of qubits that can be operated reliably1. However, the requirements of having a large qubit count and operating with high fidelity are typically conflicting. Spins in semiconductor quantum dots show long-term promise2,3 but demonstrations so far use...journal article 2022
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Bavdaz, P.L. (author), Eenink, H.G.J. (author), van Staveren, J. (author), Lodari, M. (author), Almudever, C. G. (author), Clarke, J. S. (author), Sebastiano, F. (author), Veldhorst, M. (author), Scappucci, G. (author)We demonstrate a 36 × 36 gate electrode crossbar that supports 648 narrow-channel field effect transistors (FET) for gate-defined quantum dots, with a quadratic increase in quantum dot count upon a linear increase in control lines. The crossbar is fabricated on an industrial <sup>28</sup>Si-MOS stack and shows 100% FET yield at cryogenic...journal article 2022
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Petit, L. (author), Russ, M.F. (author), Eenink, H.G.J. (author), Lawrie, W.I.L. (author), Clarke, James S. (author), Vandersypen, L.M.K. (author), Veldhorst, M. (author)Spin qubits in quantum dots define an attractive platform for quantum information because of their compatibility with semiconductor manufacturing, their long coherence times, and the ability to operate above one Kelvin. However, despite demonstrations of SWAP oscillations, the integration of this two-qubit gate together with single-qubit...journal article 2022
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van Riggelen, F. (author), Lawrie, W.I.L. (author), Russ, M.F. (author), Hendrickx, N.W. (author), Sammak, A. (author), Rispler, M.R.R. (author), Terhal, B.M. (author), Scappucci, G. (author), Veldhorst, M. (author)The fault-tolerant operation of logical qubits is an important requirement for realizing a universal quantum computer. Spin qubits based on quantum dots have great potential to be scaled to large numbers because of their compatibility with standard semiconductor manufacturing. Here, we show that a quantum error correction code can be...journal article 2022
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Lodari, M. (author), Kong, O. (author), Rendell, M. (author), Tosato, A. (author), Sammak, A. (author), Veldhorst, M. (author), Hamilton, A. R. (author), Scappucci, G. (author)We demonstrate that a lightly strained germanium channel (ϵ / / = - 0.41 %) in an undoped Ge/Si0.1Ge0.9 heterostructure field effect transistor supports a two-dimensional (2D) hole gas with mobility in excess of 1 × 10 6 cm2/Vs and percolation density less than 5 × 10 10 cm-2. This low disorder 2D hole system shows tunable fractional quantum...journal article 2022