Measurements of Phase Dynamics in Planar Josephson Junctions and SQUIDs

Abstract

We experimentally investigate the stochastic phase dynamics of planar Josephson junctions (JJs) and superconducting quantum interference devices (SQUIDs) defined in epitaxial InAs/Al heterostructures, and characterized by a large ratio of Josephson energy to charging energy. We observe a crossover from a regime of macroscopic quantum tunneling to one of phase diffusion as a function of temperature, where the transition temperature $T^{\ast }$ is gate-tunable. The switching probability distributions are shown to be consistent with a small shunt capacitance and moderate damping, resulting in a switching current which is a small fraction of the critical current. Phase locking between two JJs leads to a difference in switching current between that of a JJ measured in isolation and that of the same JJ measured in an asymmetric SQUID loop. In the case of the loop, $T^{\ast }$ is also tuned by a magnetic flux.

References in corpus (7)

• Epitaxy of Semiconductor-Superconductor nanowires
• Hard gap in epitaxial semiconductor-superconductor nanowires
• Anomalous Fraunhofer Interference in Epitaxial Superconductor-Semiconductor Josephson Junctions
• Direct transition from quantum escape to phase diffusion regime in YBaCuO biepitaxial Josephson Junctions
• Enhancement of Proximity Induced Superconductivity in a Planar Ge Hole Gas
• Thermal fluctuations in moderately damped Josephson junctions: Multiple escape and retrapping, switching- and return-current distributions and hysteresis
• Flux Dependent Crossover Between Quantum and Classical Behavior in a dc-SQUID

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• Charge-4e supercurrent in a two-dimensional InAs-Al superconductor-semiconductor heterostructure
• Control over epitaxy and the role of the InAs/Al interface in hybrid two-dimensional electron gas systems
• Zeeman and Orbital Driven Phase Transitions in Planar Josephson Junctions
• InAs on Insulator: A New Platform for Cryogenic Hybrid Superconducting Electronics
• Flux-tunable Josephson Effect in a Four-Terminal Junction
• Phase dynamics of tunnel Al-based ferromagnetic Josephson junctions
• Development of a Nb-based semiconductor-superconductor hybrid platform
• Self-heating effects and switching dynamics in graphene multiterminal Josephson junctions
• Multiple Majorana bound states and their resilience against disorder in planar Josephson junctions
• Magnetic field-free braiding and nontrivial fusion of Majorana bound states in high-temperature planar Josephson junctions