Gate-controlled quantum dots and superconductivity in planar germanium

Abstract

Superconductors and semiconductors are crucial platforms in the field of quantum computing. They can be combined to hybrids, bringing together physical properties that enable the discovery of new emergent phenomena and provide novel strategies for quantum control. The involved semiconductor materials, however, suffer from disorder, hyperfine interactions or lack of planar technology. Here we realise an approach that overcomes these issues altogether and integrate gate-defined quantum dots and superconductivity into a material system with strong spin-orbit coupling. In our germanium heterostructures, heavy holes with mobilities exceeding 500,000 cm${}^2$/Vs are confined in shallow quantum wells that are directly contacted by annealed aluminium leads. We demonstrate gate-tunable superconductivity and find a characteristic voltage $I_c{R}_n$ that exceeds 10 $\mu$V. Germanium therefore has great promise for fast and coherent quantum hardware and, being compatible with standard manufacturing, could become a leading material in the quantum revolution.

arXiv comment7 pages, 5 figures

References in corpus (23)

• Signatures of Majorana fermions in hybrid superconductor-semiconductor nanowire devices
• Spins in few-electron quantum dots
• Coherent control of macroscopic quantum states in a single-Cooper-pair box
• An addressable quantum dot qubit with fault-tolerant control fidelity
• A Two Qubit Logic Gate in Silicon
• A >99.9%-fidelity quantum-dot spin qubit with coherence limited by charge noise
• A programmable two-qubit quantum processor in silicon
• Quantum CNOT Gate for Spins in Silicon
• One-Dimensional Hole Gas in Germanium/Silicon Nanowire Heterostructures
• A Coherent Spin-Photon Interface in Silicon
• A Semiconductor Nanowire-Based Superconducting Qubit
• Strong spin-photon coupling in silicon
• Double quantum dot with integrated charge sensor based on Ge/Si heterostructure nanowires
• Ge hole spin qubit
• Spin Relaxation in Ge/Si Core-Shell Nanowire Qubits
• Hybrid superconductor-semiconductor devices made from self-assembled SiGe nanocrystals on silicon
• Cubic Rashba spin-orbit interaction of two-dimensional hole gas in strained-Ge/SiGe quantum well
• On the nature of tunable hole g-factors in quantum dots
• Resonant tunnelling features in the transport spectroscopy of quantum dots
• Orbital and valley state spectra of a few-electron silicon quantum dot
• Electron spin coherence of shallow donors in natural and isotopically enriched germanium
• Evaluating charge noise acting on semiconductor quantum dots in the circuit quantum electrodynamics architecture
• Origin of Hysteresis in a Proximity Josephson Junction

Cited by in corpus (84)

• A four-qubit germanium quantum processor
• The germanium quantum information route
• Fast two-qubit logic with holes in germanium
• A single-hole spin qubit
• Semiconductor Quantum Computation
• Low disordered, stable, and shallow germanium quantum wells: a playground for spin and hybrid quantum technology
• Quantum Dot Arrays in Silicon and Germanium
• Direct manipulation of a superconducting spin qubit strongly coupled to a transmon qubit
• Theory of Hole-Spin Qubits in Strained Germanium Quantum Dots
• Germanium quantum well Josephson field effect transistors and interferometers
• Parity-conserving Cooper-pair transport and ideal superconducting diode in planar Germanium
• Light effective hole mass in undoped Ge/SiGe quantum wells
• Recent advances in hole-spin qubits
• Generating a topological anomalous Hall effect in a non-magnetic conductor
• Self-controlled growth of highly uniform Ge/Si hut wires for scalable qubit devices
• Hard superconducting gap in germanium
• Electrical control of the $g$-tensor of a single hole in a silicon MOS quantum dot
• Hole spin driving by strain-induced spin-orbit interactions
• Majorana bound states in semiconducting nanostructures
• Single-shot readout of hole spins in Ge
• Spin relaxation benchmarks and individual qubit addressability for holes in quantum dots
• Enhancement of Proximity Induced Superconductivity in a Planar Ge Hole Gas
• Lightly-strained germanium quantum wells with hole mobility exceeding one million
• Non-linear Hall Effects: Mechanisms and Materials
• Semiconductor materials stacks for quantum dot spin qubits
• A two-dimensional array of single-hole quantum dots
• Tunable coupling and isolation of single electrons in silicon metal-oxide-semiconductor quantum dots
• Multiple Andreev reflections and Shapiro steps in a Ge-Si nanowire Josephson junction
• Ballistic supercurrent discretization and micrometer-long Josephson coupling in germanium
• Strong tunable coupling between two distant superconducting spin qubits
• Probing resonating valence bonds on a programmable germanium quantum simulator
• Electrical operation of planar Ge hole spin qubits in an in-plane magnetic field
• Quantum control of hole spin qubits in double quantum dots
• A gate tunable transmon qubit in planar Ge
• Charge-4e supercurrent in a two-dimensional InAs-Al superconductor-semiconductor heterostructure
• Single and Double Hole Quantum Dots in Strained Ge/SiGe Quantum Wells
• Planar Josephson junctions in germanium: Effect of cubic spin-orbit interaction
• High-fidelity two-qubit gates of hybrid superconducting-semiconducting singlet-triplet qubits
• Strong hole-photon coupling in planar Ge for probing charge degree and strongly-correlated states
• Charge-noise induced dephasing in silicon hole-spin qubits
• Stable quantum dots in an InSb two-dimensional electron gas
• Gate control of superconducting current: Mechanisms, parameters and technological potential
• The emergent linear Rashba spin-orbit coupling offering the fast manipulation of hole-spin qubits in germanium
• Majorana zero modes in gate-defined germanium hole nanowires
• Majorana bound states in germanium Josephson junctions via phase control
• A quantum dot in germanium proximitized by a superconductor
• Exploiting epitaxial strained germanium for scaling low noise spin qubits at the micron-scale
• G-factor of electrons in gate-defined quantum dots in a strong in-plane magnetic field
• Impact of electrostatic fields in layered crystalline BCS superconductors
• Electrical operation of hole spin qubits in planar MOS silicon quantum dots
• Microscopic analysis of proximity-induced superconductivity and metallization effects in superconductor-germanium hole nanowires
• Gate-tunable Electronic Transport in p-type GaSb Quantum Wells
• Vanishing Zeeman energy in a two-dimensional hole gas
• Coupled vertical double quantum dots at single-hole occupancy
• Tuning spatial entanglement in interacting few-electron quantum dots
• Democratizing Spin Qubits
• Signatures of quantum mechanical Zeeman effect in classical transport due to topological properties of two-dimensional spin-3/2 holes
• Modular Autonomous Virtualization System for Two-Dimensional Semiconductor Quantum Dot Arrays
• Germanium-based hybrid semiconductor-superconductor topological quantum computing platforms: Disorder effects
• Non-linear anomalous Hall effect of two-dimensional spin-3/2 heavy holes
• An upper and lower bound to the orientation-dependent linear Rashba spin-orbit coupling of two-dimensional hole gases in semiconductor quantum wells
• Dephasing of planar Ge hole spin qubits due to 1/$\text{f}$ charge noise
• Modelling of planar germanium hole qubits in electric and magnetic fields
• Hybridization mechanism of the dual proximity effect in superconductor-topological insulator interfaces
• Effects of spin-orbit coupling and in-plane Zeeman fields on the critical current in two-dimensional hole gas SNS junctions
• Correlation induced $d$-wave pairing in quantum dot square lattice
• InP/GaSb core-shell nanowires: a novel hole-based platform with strong spin-orbit coupling for full-shell hybrid devices
• Superconducting-semiconducting voltage-tunable qubits in the third dimension
• A backgate for enhanced tunability of holes in planar germanium
• Light-hole spin confined in germanium
• Robust entangling gate for capacitively coupled few-electron singlet-triplet qubits
• The effect of external electric fields on silicon with superconducting gallium nano-precipitates
• Entangled Photon-Pair Emission in Waveguide Circuit QED from a Cooper Pair Splitter
• Superconducting Proximity Effect in Two-Dimensional Hole Gases
• Non-linear spin filter for non-magnetic materials at zero magnetic field
• Phase transformation-induced superconducting aluminium-silicon alloy rings
• Cancelling second order frequency shifts in Ge hole spin qubits via bichromatic control
• Effect of disorder and strain on the operation of planar Ge hole spin qubits
• Single photon controlled steady state electron transport through a resonance DQD-Cavity system in a strong coupling regime
• Supercurrent and multiple Andreev reflections in Ge hut nanowire Josephson Junctions
• Majorana bound states with chiral magnetic textures
• Thermal activation of low-density Ga implanted in Ge
• Anomalous zero-field splitting for hole spin qubits in Si and Ge quantum dots
• Disentangling orbital and confinement contributions to $g$-factor in Ge/SiGe hole quantum dots