Influence of Topological Edge States on the Properties of Al/Bi2Se3/Al Hybrid Josephson Devices

Abstract

In superconductor-topological insulator-superconductor hybrid junctions, the barrier edge states are expected to be protected against backscattering, to generate unconventional proximity effects, and, possibly, to signal the presence of Majorana fermions. The standards of proximity modes for these types of structures have to be settled for a neat identification of possible new entities. Through a systematic and complete set of measurements of the Josephson properties we find evidence of ballistic transport in coplanar Al-Bi2Se3-Al junctions that we attribute to a coherent transport through the topological edge state. The shunting effect of the bulk only influences the normal transport. This behavior, which can be considered to some extent universal, is fairly independent of the specific features of superconducting electrodes. A comparative study of Shubnikov - de Haas oscillations and Scanning Tunneling Spectroscopy gave an experimental signature compatible with a two dimensional electron transport channel with a Dirac dispersion relation. A reduction of the size of the Bi2Se3 flakes to the nanoscale is an unavoidable step to drive Josephson junctions in the proper regime to detect possible distinctive features of Majorana fermions.

11 pages, 14 figures

References in corpus (20)

• The electronic properties of graphene
• Non-Abelian Anyons and Topological Quantum Computation
• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Signatures of Majorana fermions in hybrid superconductor-semiconductor nanowire devices
• Majorana Fermions and a Topological Phase Transition in Semiconductor-Superconductor Heterostructures
• Evidence of Majorana fermions in an Al - InAs nanowire topological superconductor
• Observation of Majorana Fermions in a Nb-InSb Nanowire-Nb Hybrid Quantum Device
• Anomalous modulation of a zero bias peak in a hybrid nanowire-superconductor device
• Topological origin of subgap conductance in insulating bilayer graphene
• Two-dimensional Dirac fermions in a topological insulator: transport in the quantum limit
• Observation of Dirac Holes and Electrons in a Topological Insulator
• Surface State Transport and Ambipolar Electric Field Effect in Bi2Se3 Nanodevices
• Momentum-Resolved Landau-Level Spectroscopy of Dirac Surface State in Bi2Se3
• Proximity-induced high-temperature superconductivity in topological insulators Bi2Se3 and Bi2Te3
• Dirac and Normal Fermions in Graphite and Graphene: Implications to the Quantum Hall Effect
• Proximity DC squids in the long junction limit
• Direct transition from quantum escape to phase diffusion regime in YBaCuO biepitaxial Josephson Junctions
• Crossover from hc/e to hc/2e current oscillations in rings of s-wave superconductors
• Optimizing the Majorana character of SQUIDs with topologically non-trivial barriers
• Microstrip filters for measurement and control of superconducting qubits

Cited by in corpus (5)

• Non-sinusoidal current-phase relationship in Josephson junctions from the 3D topological insulator HgTe
• Spontaneous supercurrent and $\varphi$0 phase shift parallel to magnetized topological insulator interfaces
• Proximity Induced Superconductivity in CdTe-HgTe Core-Shell Nanowires
• Geometric dependence of Nb-Bi${}_2$Te${}_3$-Nb topological Josephson junction transport parameters
• Incipient Berezinskii-Kosterlitz-Thouless transition in two-dimensional coplanar Josephson junctions