Ballistic supercurrent discretization and micrometer-long Josephson coupling in germanium

Abstract

We fabricate Josephson field-effect-transistors in germanium quantum wells contacted by superconducting aluminum and demonstrate supercurrents carried by holes that extend over junction lengths of several micrometers. In superconducting quantum point contacts we observe discretization of supercurrent, as well as Fabry-Perot resonances, demonstrating ballistic transport. The magnetic field dependence of the supercurrent follows a clear Fraunhofer-like pattern and Shapiro steps appear upon microwave irradiation. Multiple Andreev reflections give rise to conductance enhancement and evidence a transparent interface, confirmed by analyzing the excess current. These demonstrations of ballistic superconducting transport are promising for hybrid quantum technology in germanium.

References in corpus (31)

• A generic new platform for topological quantum computation using semiconductor heterostructures
• Majorana fermions in a tunable semiconductor device
• Demonstration of Two-Qubit Algorithms with a Superconducting Quantum Processor
• An addressable quantum dot qubit with fault-tolerant control fidelity
• A programmable two-qubit quantum processor in silicon
• 10-qubit entanglement and parallel logic operations with a superconducting circuit
• A Coherent Spin-Photon Interface in Silicon
• A Semiconductor Nanowire-Based Superconducting Qubit
• Strong spin-photon coupling in silicon
• Ge/Si nanowire mesoscopic Josephson junctions
• Realization of microwave quantum circuits using hybrid superconducting-semiconducting nanowire Josephson elements
• Ballistic Josephson junctions in edge-contacted graphene
• Ge hole spin qubit
• Coherent spin-qubit photon coupling
• Ballistic superconductivity in semiconductor nanowires
• Quantized conductance doubling and hard gap in a two-dimensional semiconductor-superconductor heterostructure
• Hybrid superconductor-semiconductor devices made from self-assembled SiGe nanocrystals on silicon
• Low disordered, stable, and shallow germanium quantum wells: a playground for spin and hybrid quantum technology
• Transparent Semiconductor-Superconductor Interface and Induced Gap in an Epitaxial Heterostructure Josephson Junction
• Gate-controlled quantum dots and superconductivity in planar germanium
• Strong Superconducting Proximity Effect in Pb-Bi2Te3 Hybrid Structures
• Quantum information transfer between topological and spin qubit systems
• Induced superconductivity in high mobility two dimensional electron gas in GaAs heterostructures
• Universal Quantum Computation with Hybrid Spin-Majorana Qubits
• Germanium quantum well Josephson field effect transistors and interferometers
• Anomalous Fraunhofer Interference in Epitaxial Superconductor-Semiconductor Josephson Junctions
• Single-shot readout of hole spins in Ge
• Electron spin coherence of shallow donors in natural and isotopically enriched germanium
• Ballistic one-dimensional holes with strong g-factor anisotropy in germanium
• Using hybrid topological-spin qubit systems for two-qubit-spin gates
• Josephson coupling through one-dimensional ballistic channel in semiconductor-superconductor hybrid quantum point contacts

Cited by in corpus (27)

• The germanium quantum information route
• A single-hole spin qubit
• Quantum Dot Arrays in Silicon and Germanium
• Low disordered, stable, and shallow germanium quantum wells: a playground for spin and hybrid quantum technology
• Germanium quantum well Josephson field effect transistors and interferometers
• Light effective hole mass in undoped Ge/SiGe quantum wells
• Hard superconducting gap in germanium
• Enhancement of Proximity Induced Superconductivity in a Planar Ge Hole Gas
• Lightly-strained germanium quantum wells with hole mobility exceeding one million
• Planar Josephson junctions in germanium: Effect of cubic spin-orbit interaction
• Quantifying quantum coherence of multiple-charge states in tunable Josephson junctions
• Majorana zero modes in gate-defined germanium hole nanowires
• Majorana bound states in germanium Josephson junctions via phase control
• Time-dependent Andreev bound states of a quantum dot coupled to two superconducting leads
• Direct microwave spectroscopy of Andreev bound states in planar Ge Josephson junctions
• From nonreciprocal to charge-4e supercurrents in Ge-based Josephson devices with tunable harmonic content
• Quantized critical supercurrent in SrTiO${}_3$-based quantum point contacts
• Microscopic analysis of proximity-induced superconductivity and metallization effects in superconductor-germanium hole nanowires
• Assessing the potential of Ge/SiGe quantum dots as hosts for singlet-triplet qubits
• Germanium-based hybrid semiconductor-superconductor topological quantum computing platforms: Disorder effects
• Gate-defined superconducting channel in magic-angle twisted bilayer graphene
• Effects of spin-orbit coupling and in-plane Zeeman fields on the critical current in two-dimensional hole gas SNS junctions
• Impact of surface treatments on the transport properties of germanium 2DHGs
• Phase transformation-induced superconducting aluminium-silicon alloy rings
• Supercurrent and multiple Andreev reflections in Ge hut nanowire Josephson Junctions
• Electrical Properties of Selective-Area-Grown Superconductor-Semiconductor Hybrid Structures on Silicon
• Towards a $\cos (2\phi )$ Josephson element using aluminum junctions with well-transmitted channels