Unusual Superconducting Proximity Effect in Magnetically Doped Topological Josephson Junctions

Abstract

The transport properties of a topological Josephson junction fabricated from a magnetically doped topological insulator (TI) were investigated. The conductance spectra of the Nb/Fe-Bi${}_2$Te${}_2$Se/Nb junction below 1 K showed an unusual trident-shaped zero-bias conductance peak with a tiny peak width of $\sim$ 6 $\mu$V. The central peak of the trident peak presents the dc-Josephson current, and the side peaks may reflect an induced unconventional Cooper pairing. Additionally, the critical currents followed inverse to temperature, which may also reflect the presence of an unconventional proximity effect. Furthermore, microwave irradiation derived a drastic change in the conductance spectra from the peak structure into oscillatory ones, a hallmark of the ac-Josephson supercurrent. The current-phase relation of the ac-Josephson effect under high power radiofrequency-irradiation was found to be 4$\pi$-periodic. The results suggest that the junction based on magnetically doped 3D TIs may realize an unconventional Cooper pairing, thus enabling access to the basic physics of Majorana bound states and unconventional superconductivity.

arXiv comment19 pages, 6 figures

References in corpus (42)

• Anyons in an exactly solved model and beyond
• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Unpaired Majorana fermions in quantum wires
• Signatures of Majorana fermions in hybrid superconductor-semiconductor nanowire devices
• Observation of Majorana Fermions in a Nb-InSb Nanowire-Nb Hybrid Quantum Device
• Observation of the fractional ac Josephson effect: the signature of Majorana particles
• Josephson Current and Noise at a Superconductor-Quantum Spin Hall Insulator-Superconductor Junction
• Colloquium: Majorana Fermions in nuclear, particle and solid-state physics
• A spin triplet supercurrent through the half-metallic ferromagnet CrO2
• Large bulk resistivity and surface quantum oscillations in the topological insulator Bi2Te2Se
• Majorana mode in vortex core of Bi2Te3/NbSe2 topological insulator-superconductor heterostructure
• Symmetry and Topology in Superconductors - Odd-frequency pairing and edge states -
• Manipulation of Majorana fermion, Andreev reflection and Josephson current on topological insulators
• Scaling of Majorana Zero-Bias Conductance Peaks
• $4\pi$-periodic Josephson supercurrent in HgTe-based topological Josephson junctions
• Josephson supercurrent through a topological insulator surface state
• Gapless Andreev bound states in the quantum spin Hall insulator HgTe
• Topological Surface States and Dirac point tuning in ternary Bi2Te2Se class of topological insulators
• Experimental Phase Diagram of a One-Dimensional Topological Superconductor
• Quantum Oscillations in a Topological Insulator Bi${}_2$Te${}_2$Se with Large Bulk Resistivity (6 $\Omega$cm)
• Josephson Effect due to Odd-frequency Pairs in Diffusive Half Metals
• Majorana Fermions and Odd-frequency Cooper Pairs in a Nano Wire
• Anomalous Josephson effect in p-wave dirty junctions
• Proximity induced superconductivity by Bi in topological $B{i}_{2}T{e}_{2}Se$ and $B{i}_{2}S{e}_3$ films: Evidence for a robust zero energy bound state possibly due to Majorana Fermions
• Topological Surface States with Persistent High Spin Polarization across Dirac Point in Bi${}_2$Te${}_2$Se and Bi${}_2$Se${}_2$Te
• Superconducting proximity effect in three-dimensional topological insulators in the presence of a magnetic field
• Proximity effect at superconducting Sn-Bi2Se3 interface
• Majorana qubits in topological insulator nanoribbon architecture
• Influence of Topological Edge States on the Properties of Al/Bi2Se3/Al Hybrid Josephson Devices
• Induced unconventional superconductivity on the surface states of Bi${}_2$Te${}_3$ topological insulator
• Joule overheating poisons the fractional ac Josephson effect in topological Josephson junctions
• Fractional Order Shapiro Steps in Superconducting Nanowires
• Josephson and proximity effects on the surface of a topological insulator
• Josephson interferometer in a ring topology as a symmetry prove of Sr_2RuO_4
• Detecting topological superconductivity using low-frequency doubled Shapiro steps
• Theory of Josephson effect in unconventional superconducting junctions with diffusive barriers
• Tunneling spectroscopy of topological superconductors
• The origin of bias independent conductance plateaus and zero bias conductance peaks in Bi2Se3/NbSe2 hybrid structures
• Observability of surface Andreev bound states in a topological insulator in proximity to an s-wave superconductor
• Effects of finite superconducting coherence lengths and of phase gradients in topological SN and SNS junctions and rings
• Conduction spectroscopy of a proximity induced superconducting topological insulator
• Generalized parafermions and non-local Josephson effect in multi-layer systems

Cited by in corpus (1)

• AC Josephson effect in a gate-tunable Cd${}_3$As${}_2$ nanowire superconducting weak link