Influence of Spin-Orbit Coupling in the Iron-Based Superconductors

ORAL

Abstract

In addition to the remarkable resilience of unconventional superconductivity, the iron-based superconductors (FeSCs) are characterized by a broad phenomenology across their phase diagram. This diversity has compounded the challenge of defining a minimal model for these complex materials. We explore the essential role of spin-orbit coupling (SOC) in the FeSCs via circularly-polarized spin- and angle-resolved photoemission spectroscopy (CPS-ARPES), a technique which provides direct access to both spin and orbital degrees of freedom [1]. Applying this technique to both LiFeAs and FeSe, we establish a strong momentum dependence of the spin-orbital entanglement near the Fermi surface imbued by SOC. Influenced strongly by the details of the crystal field, the relevance of SOC to the states near the Fermi level, and consequently to superconductivity and magnetism is found to be strongly material-dependent. Furthermore, in the case of hole-like carriers in FeSe, SOC is observed to be of comparable strength to orbital order, allowing spin-orbit mixing to persist into the nematic phase.

[1] R. P. Day et al, Phys. Rev. Lett. 127, 076401 (2018)

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Presenters

  • Ryan Day

    Quantum Matter Institute, University of British Columbia

Authors

  • Ryan Day

    Quantum Matter Institute, University of British Columbia

  • Giorgio Levy

    University of British Colombia, QMI, University of British Columbia, Physics and Astronomy, University of British Columbia, Quantum Matter Institute, University of British Columbia, Department of Physics & Astronomy, University of British Columbia

  • Matteo Michiardi

    University of British Colombia, QMI, University of British Columbia, Physics and Astronomy, University of British Columbia, Quantum Matter Institute, University of British Columbia, Department of Physics & Astronomy, University of British Columbia

  • Berend Zwartsenberg

    Quantum Matter Institute, University of British Columbia, Department of Physics & Astronomy, University of British Columbia

  • Marta Zonno

    QMI, University of British Columbia, Department of Physics & Astronomy, University of British Columbia, Quantum Matter Institute, University of British Columbia

  • Shun Chi

    University of British Columbia, Quantum Matter Institute, University of British Columbia, Univ of British Columbia

  • Ivana Vobornik

    Elettra Synchrotron

  • Walter Hardy

    University of British Columbia, Quantum Matter Institute, University of British Columbia

  • Douglas Bonn

    Stewart Blusson Quantum Matter Institute, University of British Columbia, Stewart Blusson Quantum Matter Institute, University of British Columbia, Quantum Matter Institute, University of British Columbia

  • Ilya Elfimov

    Quantum Matter Institute, University of British Columbia, Stewart Blusson Quantum Matter Institute

  • Andrea Damascelli

    Quantum Matter Institute, University of British Columbia