A5035144864- Quantum and electron transport phenomena
- Advancements in Semiconductor Devices and Circuit Design
- Semiconductor Quantum Structures and Devices
- Semiconductor materials and devices
- Quantum Information and Cryptography
- Quantum Computing Algorithms and Architecture
- Topological Materials and Phenomena
- Advanced Materials Characterization Techniques
- Ion-surface interactions and analysis
- Force Microscopy Techniques and Applications
- Quantum-Dot Cellular Automata
- Silicon and Solar Cell Technologies
- Surface and Thin Film Phenomena
- Advanced Data Storage Technologies
- Interconnection Networks and Systems
- Semiconductor materials and interfaces
- Cloud Computing and Resource Management
- Mechanical and Optical Resonators
- Photonic and Optical Devices
- Advanced Optical Network Technologies
- Magnetic properties of thin films
- Graphene research and applications
Delft University of Technology
2020-2025
QuTech
2020-2025
Qubits that can be efficiently controlled are essential for the development of scalable quantum hardware. Although resonant control is used to execute high-fidelity gates, scalability challenged by integration high-frequency oscillating signals, qubit cross-talk, and heating. Here, we show engineering hopping spins between dots with a site-dependent spin quantization axis, established discrete signals. We demonstrate hopping-based logic obtain single-qubit gate fidelities 99.97%, coherent...
Abstract Electron spins in Si/SiGe quantum wells suffer from nearly degenerate conduction band valleys, which compete with the spin degree of freedom formation qubits. Despite attempts to enhance valley energy splitting deterministically, by engineering a sharp interface, fluctuations remain serious problem for qubit uniformity, needed scale up large processors. Here, we elucidate and statistically predict holistic integration 3D atomic-level properties, theory transport. We find that...
We grow strained Ge/SiGe heterostructures by reduced-pressure chemical vapor deposition on 100 mm Ge wafers. The use of wafers as substrates for epitaxy enables high-quality Ge-rich SiGe strain-relaxed buffers with a threading dislocation density (6±1)×105 cm−2, nearly an order magnitude improvement compared to control Si associated reduction in short-range scattering allows drastic the disorder properties two-dimensional hole gas, measured several heterostructure field-effect transistors....
Abstract The electrical characterisation of classical and quantum devices is a critical step in the development cycle heterogeneous material stacks for semiconductor spin qubits. In case silicon, properties such as disorder energy separation conduction band valleys are commonly investigated individually upon modifications selected parameters stack. However, this reductionist approach fails to consider interdependence between different structural electronic at danger optimising one metric...
Abstract Spin qubits in germanium gate-defined quantum dots have made considerable progress within the last few years, partially due to their strong spin-orbit coupling and site-dependent g -tensors. While this characteristic of -factors removes need for micromagnets allows possibility all-electric qubit control, relying on these -tensors necessitates understand sensitivity confinement potential that defines dots. Here, we demonstrate a S − T _ whose frequency is function voltage applied...
Addressing and mitigating decoherence sources plays an essential role in the development of a scalable quantum computing system, which requires low gate errors to be consistently maintained throughout circuit execution. While nuclear spin-free materials, such as isotopically purified silicon, exhibit intrinsically promising coherence properties for electron spin qubits, omnipresent charge noise, when converted magnetic noise under strong field gradient, often hinders stable qubit operation...
As one of the few group IV materials with potential to host superconductor–semiconductor hybrid devices, planar germanium hosting proximitized quantum dots is a compelling platform achieve and combine topological superconductivity existing new qubit modalities. We demonstrate dot in Ge/SiGe heterostructure by platinum germanosilicide (PtSiGe) superconducting lead, forming lead–quantum dot–superconducting lead junction. show tunability coupling strength between gate control ratio charging...
Arrays of gate-defined semiconductor quantum dots are among the leading candidates for building scalable processors. High-fidelity initialization, control, and readout spin qubit registers require exquisite targeted control over key Hamiltonian parameters that define electrostatic environment. However, due to tight gate pitch, capacitive crosstalk between gates hinders independent tuning chemical potentials interdot couplings. While virtual offer a practical solution, determining all...
Gate-defined quantum dots in silicon-germanium heterostructures have become a compelling platform for computation and simulation. Thus far, developments been limited to defined single plane. Here, we propose advance beyond planar systems by exploiting with multiple wells. We demonstrate the operation of gate-defined double dot strained germanium well, where both are tunnel coupled reservoirs parallel transport occurs. analyze capacitive coupling nearby gates find be accumulated under central...
We determine the energy splitting of conduction-band valleys in two-dimensional electrons confined to low-disorder Si quantum wells. probe valley dependence on both perpendicular magnetic field $B$ and Hall density by performing activation measurements regime over a large range filling factors. The mobility gap valley-split levels increases linearly with is strikingly independent density. data are consistent transport model which depends incremental changes $eB/h$ across edge strips, rather...
Disorder in the heterogeneous material stack of semiconductor spin qubit systems introduces noise that compromises quantum information processing, posing a challenge to coherently control large-scale devices. Here, we exploit low-disorder epitaxial strained wells Ge/SiGe heterostructures grown on Ge wafers comprehensively probe properties complex micron-scale devices comprising up ten dots and four rf-charge sensors arranged two-dimensional array. We demonstrate an average charge...
Arrays of gate-defined semiconductor quantum dots are among the leading candidates for building scalable processors. High-fidelity initialization, control, and readout spin qubit registers require exquisite targeted control over key Hamiltonian parameters that define electrostatic environment. However, due to tight gate pitch, capacitive crosstalk between gates hinders independent tuning chemical potentials interdot couplings. While virtual offer a practical solution, determining all...
Abstract Atom probes generate three‐dimensional atomic‐scale tomographies of material volumes corresponding to the size modern‐day solid‐state devices. Here, capabilities atom probe tomography are evaluated analyze buried interfaces in semiconductor heterostructures relevant for electronic and quantum Employing brute‐force search, current dominant reconstruction protocol tomographic images from Probe data is advanced its limits. Using Si/SiGe heterostructure qubits as a model system, authors...
We grow strained Ge/SiGe heterostructures by reduced-pressure chemical vapor deposition on 100 mm Ge wafers. The use of wafers as substrates for epitaxy enables high-quality Ge-rich SiGe strain-relaxed buffers with a threading dislocation density (6$\pm$1)$\times$10$^5$ cm$^{-2}$, nearly an order magnitude improvement compared to control Si associated reduction in short-range scattering allows drastic the disorder properties two-dimensional hole gas, measured several heterostructure...
Spin qubits in germanium gate-defined quantum dots have made considerable progress within the last few years, partially due to their strong spin-orbit coupling and site-dependent $g$-tensors. While this characteristic of $g$-factors removes need for micromagnets allows possibility all-electric qubit control, relying on these $g$-tensors necessitates understand sensitivity confinement potential that defines dots. Here, we demonstrate a $S-T\_$ whose frequency is function voltage applied...
Qubits that can be efficiently controlled are essential for the development of scalable quantum hardware. While resonant control is used to execute high-fidelity gates, scalability challenged by integration high-frequency oscillating signals, qubit crosstalk and heating. Here, we show engineering hopping spins between dots with site-dependent spin quantization axis, established discrete signals. We demonstrate hopping-based logic obtain single-qubit gate fidelities 99.97\%, coherent...
Addressing and mitigating decoherence sources plays an essential role in the development of a scalable quantum computing system, which requires low gate errors to be consistently maintained throughout circuit execution. While nuclear spin-free materials, such as isotopically purified silicon, exhibit intrinsically promising coherence properties for electron spin qubits, omnipresent charge noise, when converted magnetic noise under strong field gradient, often hinders stable qubit operation...
Planar germanium quantum wells have recently been shown to host hard-gapped superconductivity. Additionally, dot spin qubits in are well-suited for information processing, with isotopic purification a nuclear spin-free material expected yield long coherence times. Therefore, as one of the few group IV materials potential superconductor-semiconductor hybrid devices, proximitized dots is compelling platform achieve and combine topological superconductivity existing novel qubit modalities. Here...
As quantum computing advances towards practical applications, reducing errors remains a crucial frontier for developing near-term devices. Errors in the gates and state readout could result noisy circuits, which would prevent acquisition of exact expectation values observables. Although ultimate robustness to is known be achievable by error correction-based fault-tolerant computing, its successful implementation demands large-scale processors with low average rates that are not yet widely...
We investigate the disorder properties of two-dimensional hole gases in Ge/SiGe heterostructures grown on Ge wafers, using thick SiGe barriers to mitigate influence semiconductor-dielectric interface. Across several heterostructure field effect transistors we measure an average maximum mobility $(4.4 \pm 0.2) \times 10^{6}~\mathrm{cm^2/Vs}$ at a saturation density $(1.72 0.03) 10^{11}~\mathrm{cm^{-2}}$, corresponding long mean free path $(30 1)~\mathrm{\mu m}$. The highest measured is $4.68...
We investigate the disorder properties of two-dimensional hole gases in Ge/SiGe heterostructures grown on Ge wafers, using thick SiGe barriers to mitigate influence semiconductor–dielectric interface. Across several heterostructure field effect transistors, we measure an average maximum mobility (4.4±0.2)×106 cm2/Vs at a saturation density (1.72±0.03)×1011 cm−2, corresponding long mean free path (30±1)μm. The highest measured is 4.68×106 cm2/Vs. identify uniform background impurities and...
Quantum computers require the systematic operation of qubits with high fidelity. For holes in germanium, spin-orbit interaction allows for \textit{in situ} electric fast and high-fidelity qubit gates. However, also causes a large variability due to strong g-tensor anisotropy dependence on environment. Here, we leverage advances material growth, device fabrication, control realise two-dimensional 10-spin array, coupled up four neighbours that can be controlled By exploring parameter space...
Electron spins in Si/SiGe quantum wells suffer from nearly degenerate conduction band valleys, which compete with the spin degree of freedom formation qubits. Despite attempts to enhance valley energy splitting deterministically, by engineering a sharp interface, fluctuations remain serious problem for qubit uniformity, needed scale up large processors. Here, we elucidate and statistically predict holistic integration 3D atomic-level properties, theory transport. We find that concentration...
Gate-defined quantum dots in silicon-germanium heterostructures have become a compelling platform for computation and simulation. Thus far, developments been limited to defined single plane. Here, we propose advance beyond planar systems by exploiting with multiple wells. We demonstrate the operation of gate-defined vertical double dot strained germanium well. In transport measurements observe stability diagrams corresponding system. analyze capacitive coupling nearby gates find two...