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Nanoscale mapping of the 3D strain tensor in a Germanium Quantum Well hosting a functional Spin Qubit Device

Corley-Wiciak, C. (author), Richter, C. (author), Zoellner, M.H. (author), Zaitsev, I. (author), Manganelli, C.L. (author), Zatterin, E. (author), Schülli, T.U. (author), Corley-Wiciak, A.A. (author), Katzer, J. (author), Reichmann, F. (author), Klesse, W.M. (author), Hendrickx, N.W. (author), Sammak, A. (author), Veldhorst, M. (author), Scappucci, G. (author), Virgilio, M. (author), Capellini, 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 strain...

article 2023

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Phase flip code with semiconductor spin qubits

van Riggelen, F. (author), Lawrie, W.I.L. (author), Russ, M. (author), Hendrickx, N.W. (author), Sammak, A. (author), Rispler, M. (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 implemented...

article 2022

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Spiderweb array: a sparse spin-qubit array

Boter, J.M. (author), Dehollain, J.P. (author), van Dijk, J.P.G. (author), Xu, Y. (author), Hensgens, T. (author), Versluis, R. (author), Naus, H.W.L. (author), Clarke, J.S. (author), Veldhorst, M. (author), Sebastiano, F. (author), Vandersypen, L.M.K. (author)

One of the main bottlenecks in the pursuit of a large-scale–chip-based quantum computer is the large number of control signals needed to operate qubit systems. As system sizes scale up, the number of terminals required to connect to off-chip control electronics quickly becomes unmanageable. Here, we discuss a quantum-dot spin-qubit architecture...

article 2022

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Universal control of a six-qubit quantum processor in silicon

Philips, S.G.J. (author), Mądzik, M.T. (author), Amitonov, S.V. (author), de Snoo, S.L. (author), Russ, M. (author), Kalhor, N. (author), Volk, C. (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 between...

article 2022

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Lightly strained germanium quantum wells with hole mobility exceeding one million

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 ("// = −0.41%) in an undoped Ge/Si0.1Ge0.9 heterostructure field effect transistor supports a 2D hole gas with mobility in excess of 1 × 106 cm2/Vs and percolation density less than 5 × 1010 cm−2. This low disorder 2D hole system shows tunable fractional quantum Hall effect at low density...

article 2022

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A High-Mobility Hole Bilayer in a Germanium Double Quantum Well

Tosato, A. (author), Ferrari, B. (author), Sammak, A. (author), Hamilton, A.R. (author), Veldhorst, M. (author), Virgilio, M. (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 3.34 × 105 cm2 V−1 s−1 and a low percolation density of 2.38 ...

article 2022

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Single-hole pump in germanium

Rossi, A. (author), Hendrickx, N.W. (author), Sammak, A. (author), Veldhorst, M. (author), Scappucci, G. (author), Kataoka, M. (author)

Single-charge pumps are the main candidates for quantum-based standards of the unit ampere because they can generate accurate and quantized electric currents. In order to approach the metrological requirements in terms of both accuracy and speed of operation, in the past decade there has been a focus on semiconductor-based devices. The use of a...

article 2021

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A four-qubit germanium quantum processor

Hendrickx, N.W. (author), Lawrie, W.I.L. (author), Russ, M. (author), van Riggelen, F. (author), de Snoo, S.L. (author), Schouten, R.N. (author), Sammak, A. (author), Scappucci, G. (author), Veldhorst, M. (author)

The prospect of building quantum circuits using advanced semiconductor manufacturing makes quantum dots an attractive platform for quantum information processing. Extensive studies of various materials have led to demonstrations of two-qubit logic in gallium arsenide, silicon and germanium. However, interconnecting larger numbers of qubits in...

article 2021

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A two-dimensional array of single-hole quantum dots

van Riggelen, F (author), Hendrickx, N.W. (author), Lawrie, W.I.L. (author), Russ, M. (author), Sammak, A. (author), Scappucci, G. (author), Veldhorst, M. (author)

Quantum dots fabricated using techniques and materials that are compatible with semiconductor manufacturing are promising for quantum information processing. While great progress has been made toward high-fidelity control of quantum dots positioned in a linear arrangement, scalability along two dimensions is a key step toward practical quantum...

conference paper 2021

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Enhancement of proximity-induced superconductivity in a planar Ge hole gas

Aggarwal, K. (author), Hofmann, A. (author), Jirovec, D. (author), Prieto, I. (author), Sammak, A. (author), Botifoll, M. (author), Martí-Sánchez, S. (author), Veldhorst, M. (author), Arbiol, J. (author), Scappucci, G. (author), Danon, J. (author), Katsaros, G. (author)

Hole gases in planar germanium can have high mobilities in combination with strong spin-orbit interaction and electrically tunable g factors, and are therefore emerging as a promising platform for creating hybrid superconductor-semiconductor devices. A key challenge towards hybrid Ge-based quantum technologies is the design of high-quality...

article 2021

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The spider-web array - a sparse spin qubit array

Boter, J.M. (author), Dehollain, J.P. (author), van Dijk, J.P.G. (author), Xu, Y. (author), Hensgens, T. (author), Versluis, R. (author), Naus, H.W.L. (author), Clarke, J.S. (author), Veldhorst, M. (author), Sebastiano, F. (author), Vandersypen, L.M.K. (author)

conference paper 2021

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Quantum dot arrays in silicon and germanium

Lawrie, W.I.L. (author), Eenink, H.G.J. (author), Hendrickx, N.W. (author), Boter, J.M. (author), Petit, L. (author), Amitonov, S.V. (author), Lodari, M. (author), paquelet Wuetz, B. (author), Volk, C. (author), Philips, S.G.J. (author), Droulers, G. (author), Kalhor, N. (author), van Riggelen, F. (author), Brousse, D. (author), Sammak, A. (author), Vandersypen, L.M.K. (author), Scappucci, G. (author), Veldhorst, M. (author)

Electrons and holes confined in quantum dots define excellent building blocks for quantum emergence, simulation, and computation. Silicon and germanium are compatible with standard semiconductor manufacturing and contain stable isotopes with zero nuclear spin, thereby serving as excellent hosts for spins with long quantum coherence. Here, we...

article 2020

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Quantum Inspire – QuTech’s platform for co-development and collaboration in Quantum Computing

Last, T. (author), Samkharadze, N. (author), Eendebak, P.T. (author), Versluis, R. (author), Xue, X. (author), Sammak, A. (author), Brousse, D. (author), Loh, K.K.L. (author), Polinder, H. (author), Scappucci, G. (author), Veldhorst, M. (author), Vandersypen, L. (author), Maturová, K. (author), Veltin, J. (author), Alberts, G.J.N. (author)

The mission of QuTech is to bring quantum technology to industry and society by translating fundamental scientific research into applied research. To this end we are developing Quantum Inspire (QI), a full-stack quantum computer prototype for future co-development and collaborative R&D in quantum computing. A prerelease of this prototype system...

conference paper 2020

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On-chip integration of Si/SiGe-based quantum dots and switched-capacitor circuits

Xu, Y. (author), Unseld, F.K. (author), Corna, A. (author), Zwerver, A.M.J. (author), Sammak, A. (author), Brousse, D. (author), Samkharadze, N. (author), Amitonov, S.V. (author), Veldhorst, M. (author), Scappucci, G. (author), Ishihara, R. (author), Vandersypen, L.M.K. (author)

Solid-state qubits integrated on semiconductor substrates currently require at least one wire from every qubit to the control electronics, leading to a so-called wiring bottleneck for scaling. Demultiplexing via on-chip circuitry offers an effective strategy to overcome this bottleneck. In the case of gate-defined quantum dot arrays, specific...

article 2020

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Fast two-qubit logic with holes in germanium

Hendrickx, N.W. (author), Franke, D.P. (author), Sammak, A. (author), Scappucci, G. (author), Veldhorst, M. (author)

Universal quantum information processing requires the execution of single-qubit and two-qubit logic. Across all qubit realizations1, spin qubits in quantum dots have great promise to become the central building block for quantum computation2. Excellent quantum dot control can be achieved in gallium arsenide3–5, and high-fidelity qubit rotations...

article 2020

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A Scalable Cryo-CMOS 2-to-20GHz Digitally Intensive Controller for 4×32 Frequency Multiplexed Spin in Qubits/Transmons in 22nm FinFET Technology for Quantum Computers

Patra, B. (author), van Dijk, J.P.G. (author), Subramanian, S. (author), Corna, A. (author), Xue, X. (author), Jeon, C. (author), Sheikh, F. (author), Juarez-Hernandez, E. (author), Esparza, B.P. (author), Rampurawala, H. (author), Carlton, B. (author), Samkharadze, N. (author), Ravikumar, S. (author), Nieva, C. (author), Kim, S. (author), Lee, H.J. (author), Sammak, A. (author), Scappucci, G. (author), Veldhorst, M. (author), Vandersypen, L.M.K. (author), Babaie, M. (author), Sebastiano, F. (author), Charbon, E. (author), Pellerano, S. (author)

Quantum computers (QC), comprising qubits and a classical controller, can provide exponential speed-up in solving certain problems. Among solid-state qubits, transmons and spin-qubits are the most promising, operating ≪ 1K. A qubit can be implemented in a physical system with two distinct energy levels representing the |0⟩ and |1⟩ states, e.g....

conference paper 2020

document

CMOS-based cryogenic control of silicon quantum circuits

Xue, X. (author), Patra, B. (author), van Dijk, J.P.G. (author), Samkharadze, N. (author), Subramanian, S. (author), Corna, A. (author), Jeon, C. (author), Sheikh, F. (author), Juarez-Hernandez, E. (author), Perez Esparza, B. (author), Rampurawala, H. (author), Varlton, B. (author), Ravikumar, S. (author), Nieva, C. (author), Kim, S. (author), Lee, H.J. (author), Sammak, A. (author), Scappucci, G. (author), Veldhorst, M. (author), Sebastiano, F. (author), Babaie, M. (author), Pellerano, S. (author), Charbon, E. (author), Vandersypen, L.M.K. (author)

The most promising quantum algorithms require quantum processors hosting millions of quantum bits when targeting practical applications. A major challenge towards large-scale quantum computation is the interconnect complexity. In current solid-state qubit implementations, a major bottleneck appears between the quantum chip in a dilution...

conference paper 2020

document

Low percolation density and charge noise with holes in germanium

Lodari, M. (author), Hendrickx, N.W. (author), Lawrie, W.I.L. (author), Hsiao, T.K. (author), Vandersypen, L.M.K. (author), Sammak, A. (author), Veldhorst, M. (author), Scappucci, G. (author)

conference paper 2020

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Effect of quantum Hall edge strips on valley splitting in silicon quantum wells

Paquelet Wütz, B. (author), Losert, M.P. (author), Tosato, A. (author), Lodari, M. (author), Bavdaz, P.L. (author), Stehouwer, L. (author), Amin, P. (author), Clarke, J.S. (author), Coppersmith, S.N. (author), Sammak, A. (author), Veldhorst, M. (author), Friesen, M. (author), Scappucci, G. (author)

We determine the energy splitting of the conduction-band valleys in two-dimensional electrons confined to low-disorder Si quantum wells. We probe the valley splitting dependence on both perpendicular magnetic field B and Hall density by performing activation energy measurements in the quantum Hall regime over a large range of filling factors....

article 2020

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A Scalable Cryo-CMOS Controller for the Wideband Frequency-Multiplexed Control of Spin Qubits and Transmons

van Dijk, J.P.G. (author), Patra, B. (author), Subramanian, S. (author), Xue, X. (author), Samkharadze, N. (author), Corna, A. (author), Jeon, C. (author), Sheikh, F. (author), Juarez-Hernandez, E. (author), Perez Esparza, B. (author), Rampurawala, H. (author), Carlton, B.R. (author), Ravikumar, S. (author), Nieva, C. (author), Kim, S. (author), Lee, H.J. (author), Sammak, A. (author), Scappucci, G. (author), Veldhorst, M. (author), Vandersypen, L.M.K. (author), Charbon, E. (author), Pellerano, S. (author), Babaie, M. (author), Sebastiano, F. (author)

Building a large-scale quantum computer requires the co-optimization of both the quantum bits (qubits) and their control electronics. By operating the CMOS control circuits at cryogenic temperatures (cryo-CMOS), and hence in close proximity to the cryogenic solid-state qubits, a compact quantumcomputing system can be achieved, thus promising...

article 2020