Current-phase relation of a WTe2 Josephson junction

Abstract

When a topological insulator is incorporated into a Josephson junction, the system is predicted to reveal the fractional Josephson effect with a 4$\pi$-periodic current-phase relation. Here, we report the measurement of a $4\pi$-periodic switching current through an asymmetric SQUID, formed by the higher-order topological insulator WTe${}_2$. Contrary to the established opinion, we show that a high asymmetry in critical current and negligible loop inductance are not sufficient by themselves to reliably measure the current-phase relation. Instead, we find that our measurement is heavily influenced by additional inductances originating from the self-formed PdTe${}_{\text{x}}$ inside the junction. We therefore develop a method to numerically recover the current-phase relation of the system and find the $1.5\mu \text{m}$ long junction to be best described in the short ballistic limit. Our results highlight the complexity of subtle inductance effects that can give rise to misleading topological signatures in transport measurements.

arXiv commentAs accepted by Nano Letters, includes main text (7 pages, 3 figures) and supplementary information (16 pages, 7 figures)

References in corpus (29)

• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Topological Insulators with Inversion Symmetry
• Quantized Electric Multipole Insulators
• Higher-Order Topological Insulators
• Flux-controlled quantum computation with Majorana fermions
• Higher-Order Topology, Monopole Nodal Lines, and the Origin of Large Fermi Arcs in Transition Metal Dichalcogenides XTe${}_2$ (X=Mo,W)
• Tunable superconducting nanoinductors
• Observation of topological states residing at step edges of WTe2
• Fermion-parity anomaly of the critical supercurrent in the quantum spin-Hall effect
• Measurement of the current-phase relation of superconducting atomic contacts
• High Kinetic Inductance NbN Nanowire Superinductors
• Ballistic edge states in Bismuth nanowires revealed by SQUID interferometry
• Evidence of Higher Order Topology in Multilayer WTe${}_2$ from Josephson Coupling through Anisotropic Hinge States
• Supercurrent-carrying density of states in diffusive mesoscopic Josephson weak links
• Relating Andreev Bound States and Supercurrents in Hybrid Josephson Junctions
• One-Dimensional Edge Transport in Few-Layer WTe${}_2$
• Probing the helical edge states of a topological insulator by Cooper-pair injection
• Niobium and niobium nitride SQUIDs based on anodized nanobridges made with an Atomic Force Microscope
• Superconductivity in type-II Weyl-semimetal WTe2 induced by a normal metal contact
• Edge superconductivity in Multilayer WTe2 Josephson junction
• Current-phase relation of a WTe2 Josephson junction
• Zeeman effect induced 0-$\pi$ transitions in ballistic Dirac semimetal Josephson junctions
• Asymmetric nanowire SQUID: linear CPR, stochastic switching, and symmetries
• Compact SQUID realized in a double layer graphene heterostructure
• The impact of kinetic inductance on the critical current oscillations of nanobridge SQUIDs
• Transparent Josephson Junctions in Higher-Order Topological Insulator WTe2 via Pd Diffusion
• Long-lived Andreev states as evidence for protected hinge modes in a bismuth nanoring Josephson junction
• Superconducting Contact and Quantum Interference Between Two-Dimensional van der Waals and Three-Dimensional Conventional Superconductors
• Onset of phase diffusion in high kinetic inductance granular aluminum micro-SQUIDs

Cited by in corpus (13)

• Charge-4e supercurrent in a two-dimensional InAs-Al superconductor-semiconductor heterostructure
• Current-phase relation of a WTe2 Josephson junction
• Large Second-Order Josephson Effect in Planar Superconductor-Semiconductor Junctions
• Limitations of the current-phase relation measurements by an asymmetric dc-SQUID
• Direct measurement of a $\sin (2\phi )$ current phase relation in a graphene superconducting quantum interference device
• Driving a Josephson Traveling Wave Parametric Amplifier into chaos: effects of a non-sinusoidal current-phase relation
• SQUID oscillations in PbTe nanowire networks
• Crystalline superconductor-semiconductor Josephson junctions for compact superconducting qubits
• Supercurrent reversal in Zeeman-split Josephson junctions
• Unveiling Topological Hinge States in the Higher-Order Topological Insulator WTe${}_2$ Based on the Fractional Josephson Effect
• Pre-Patterned Superconducting Contacts for Clean Superconductor-Topological Material Interfaces Enabling Long-Range Josephson Coupling
• Probing the topological protection of edge states in multilayer tungsten ditelluride with the superconducting proximity effect
• Gate- and flux-tunable sin(2$\phi$) Josephson element with proximitized Ge-based junctions