On the interplay of paramagnetism and topology in the Fe-based High Tc Superconductors

Abstract

The high Tc superconductor FeTe0.55Se0.45 has recently been shown to support a surface state with topological character. Here we use low-energy laser-based ARPES with variable light polarization, including both linear and circular polarization, to re-examine the same material and the related FeTe0.7Se0.3, with larger Te concentration. In both cases we observe the presence of a surface state displaying linear dispersion in a cone-like configuration. The use of circular polarization confirms the presence of helical spin structure. These experimental studies are compared with theoretical studies that account for the local magnetic effects related to the paramagnetism observed in this system in the normal state. In contrast to previous studies we find that including the magnetic contributions is necessary to bring the chemical potential of the calculated electronic band structure naturally into alignment with the experimental observations.

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• Spin-Orbit Interactions and the Nematicity Observed in the Fe-Based Superconductors
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• Magnetic, superconducting, and topological surface states on Fe${}_{1+y}$Te${}_{1-x}$Se${}_x$
• Time Reversal Symmetry Breaking in the Fe-Chalcogenide Superconductors
• Observation of Superconductivity Induced Ferromagnetism in an Fe-Chalcogenide Superconductor
• Triplet Superconductivity from Nonlocal Coulomb Repulsion in an Atomic Sn Layer Deposited onto a Si(111) Substrate
• Revealing the Origin of Time-reversal Symmetry Breaking in Fe-chalcogenide Superconductor FeTe1-xSex
• Pairing symmetry and topological surface state in iron-chalcogenide superconductors
• Emergent vortex Majorana zero mode in iron-based superconductors
• Magnetism and superconductivity in Fe${}_{1+y}$Te${}_{1-x}$Se${}_x$
• Orbital Selective Mott Transition Effects and Non-Trivial Topology of Iron Chalcogenide
• Origin of Topological Surface Superconductivity in FeSe${}_{0.45}$Te${}_{0.55}$
• Topological superconductivity on the honeycomb lattice: Effect of normal state topology
• Competing topological superconducting phases in FeSe${}_{0.45}$Te${}_{0.55}$
• Phase diagrams of superconducting topological surface states
• Fe${}_{1+y}$Te${}_x$Se${}_{1-x}$: a delicate and tunable Majorana material