Phase Coherence and Andreev Reflection in Topological Insulator Devices

Abstract

Topological insulators (TIs) have attracted immense interest because they host helical surface states. Protected by time-reversal symmetry, they are robust to non-magnetic disorder. When superconductivity is induced in these helical states, they are predicted to emulate p-wave pairing symmetry, with Majorana states bound to vortices. Majorana bound states possess non-Abelian exchange statistics which can be probed through interferometry. Here, we take a significant step towards Majorana interferometry by observing pronounced Fabry-Perot oscillations in a TI sandwiched between a superconducting and normal lead. For energies below the superconducting gap, we observe a doubling in the frequency of the oscillations, arising from the additional phase accumulated from Andreev reflection. When a magnetic field is applied perpendicular to the TI surface, a number of very sharp and gate-tunable conductance peaks appear at or near zero energy, which has consequences for interpreting spectroscopic probes of Majorana fermions. Our results demonstrate that TIs are a promising platform for exploring phase-coherent transport in a solid-state system.

9 pages, 7 figures

References in corpus (18)

• Ultrahigh electron mobility in suspended 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
• 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
• Phase Coherent Transport of Charges in Graphene Quantum Billiard
• Electrically detected interferometry of Majorana fermions in a topological insulator
• Two-dimensional Dirac fermions in a topological insulator: transport in the quantum limit
• Topological origin of subgap conductance in insulating bilayer graphene
• Coexistence of the topological state and a two-dimensional electron gas on the surface of Bi2Se3
• Bulk Band Gap and Surface State Conduction Observed in Voltage-Tuned Crystals of the Topological Insulator Bi${}_2$Se${}_3$
• Zero-bias anomaly in a nanowire quantum dot coupled to superconductors
• Klein Backscattering and Fabry-Perot Interference in Graphene Heterojunctions
• Multi-mode Fabry-Pérot conductance oscillations in suspended stacking-faults-free InAs nanowires
• Influence of Topological Edge States on the Properties of Al/Bi2Se3/Al Hybrid Josephson Devices
• Dynamical Gate Tunable Supercurrents in Topological Josephson Junctions

Cited by in corpus (26)

• Topological superconductors: a review
• Phase Diagram of the Interacting Majorana Chain Model
• Discovery of segmented Fermi surface induced by Cooper pair momentum
• Theory of diode effect in d-wave superconductor junctions on the surface of topological insulator
• Superconducting proximity effect in three-dimensional topological insulators in the presence of a magnetic field
• Anomalous low-temperature enhancement of supercurrent in topological-insulator nanoribbon Josephson junctions: evidence for low-energy Andreev bound states
• Bulk and surface states carried supercurrent in ballistic Nb-Dirac semimetal Cd3As2 nanowire-Nb junctions
• Topological supercurrents interaction and fluctuations in the multiterminal Josephson effect
• Gate-tunable supercurrent and multiple Andreev reflections in a superconductor-topological insulator nanoribbon-superconductor hybrid device
• Enhancement of crossed Andreev reflection in normal-superconductor-normal junction of thin topological insulator
• Specular Andreev reflection in thin films of topological insulators
• A Topological SQUIPT based on helical edge states in proximity to superconductors
• Proximity-induced superconductivity within the InAs/GaSb edge conducting state
• Long-Range Propagation and Interference of $d$-wave Superconducting Pairs in Graphene
• Tricritical Ising phase transition in two-ladder Majorana fermion lattice
• Proximity induced time-reversal topological superconductivity in Bi2Se3 films without phase tuning
• Fabry-Pérot resonant vortices and magnetoconductance in topological insulator constrictions with magnetic barriers
• Gapless helical superconductivity on the surface of a three-dimensional topological insulator
• Robust Fabry-Perot interference in dual-gated Bi${}_2$Se${}_3$ devices
• Time-dependent Andreev reflection
• Scanning tunneling microscopy of superconducting topological surface states in Bi${}_2$Se${}_3$
• Effect of impurities on the Josephson current through helical metals: Exploiting a neutrino paradigm
• Protected gap closing in Josephson junctions constructed on Bi${}_2$Te${}_3$ surface
• Photoemission Spectroscopic Evidence of Multiple Dirac Cones in Superconducting BaSn${}_3$
• Parity-protected superconducting qubit based on topological insulators
• Electronic correlations in magnetized helical edge states coupled to s-wave superconductors