Time Reversal Symmetry Breaking in the Fe-Chalcogenide Superconductors

Abstract

Topological superconductivity has been sought for in a variety of heterostructure systems, the interest being that a material displaying such a phenomenon could prove to be the ideal platform to support Majorana fermions, which in turn could be the basis for advanced qubit technologies. Recently the high Tc family of superconductors, $FeS{e}_{x}T{e}_{1-x}$, have been shown to exhibit the property of topological superconductivity and further, evidence has been found for the presence of Majorana fermions. We have studied the interplay of topology, magnetism and superconductivity in the $FeS{e}_{x}T{e}_{1-x}$ family using high-resolution laser-based photoemission. At the bulk superconducting transition, a gap opens at the chemical potential as expected. However, a second gap is observed to open at the Dirac point in the topological surface state. The associated mass acquisition in the topological state points to time-reversal symmetry breaking, probably associated with the formation of ferromagnetism in the surface layer. The presence of intrinsic ferromagnetism combined with strong spin-orbit coupling provides an ideal platform for a range of exotic topological phenomena.

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Cited by in corpus (28)

• Ironing out the details of unconventional superconductivity
• Superconducting phenomena in systems with unconventional magnets
• Magnetic, superconducting, and topological surface states on Fe${}_{1+y}$Te${}_{1-x}$Se${}_x$
• Observation of Superconductivity Induced Ferromagnetism in an Fe-Chalcogenide Superconductor
• Dirac lines and loop at the Fermi level in the Time-Reversal Symmetry Breaking Superconductor LaNiGa${}_2$
• Revealing the Origin of Time-reversal Symmetry Breaking in Fe-chalcogenide Superconductor FeTe1-xSex
• Phase-manipulation-induced Majorana Mode and Braiding Realization in Iron-based Superconductor Fe(Te,Se)
• Emergent vortex Majorana zero mode in iron-based superconductors
• Nonunitary Superconductivity in Complex Quantum Materials
• Orbital Selective Mott Transition Effects and Non-Trivial Topology of Iron Chalcogenide
• Origin of Topological Surface Superconductivity in FeSe${}_{0.45}$Te${}_{0.55}$
• Direct observation of quantum anomalous vortex in Fe(Se,Te)
• High-order Time-Reversal Symmetry Breaking Normal State
• Spontaneous magnetization in unitary superconductors with time reversal symmetry breaking
• Shot-noise and differential conductance as signatures of putative topological superconductivity in FeSe${}_{0.45}$Te${}_{0.55}$
• Picosecond Trajectory of Two-dimensional Vortex Motion in FeSe${}_{0.5}$Te${}_{0.5}$ Visualized by Terahertz Second Harmonic Generation
• Competing topological superconducting phases in FeSe${}_{0.45}$Te${}_{0.55}$
• Non-unitary multiorbital superconductivity from competing interactions in Dirac materials
• Anomalous Shiba states in topological iron-based superconductors
• Spin-orbit-coupled superconductivity with spin-singlet non-unitary pairing
• Phase diagrams of superconducting topological surface states
• Anomalous Shiba spectrum and superconductivity induced magnetic interactions in materials with topological band inversion
• Fe${}_{1+y}$Te${}_x$Se${}_{1-x}$: a delicate and tunable Majorana material
• In-situ local imaging of ferromagnetism and superconductivity in RbEuFe${}_4$As${}_4$
• Evolution of the intertwining correlated topological phases in iron-based superconductor Fe(Te,Se)
• Potentiometric detection of spin polarization expected at the surface of FeTe0.6Se0.4 in the effective p-wave superconducting state
• A mesoscopic device for a realization of the Topological Kondo effect
• Pair-mixing induced Time-reversal-breaking superconductivity