The anomalous high magnetic field electronic state of the nematic iron-based superconductor FeSe<i><sub>1-x</sub></i>S<i><sub>x</sub></i>

ORAL

Abstract

Superconductivity is closely linked to the electronic states from which it emerges. Here we investigate the normal electronic state of the nematic superconductor FeSe1-xSx using magneto-transport and Hall Effect studies in magnetic fields up to 35 T (Nijmegen) and 70 T (Toulouse) over a large temperature range. Inside the nematic phase we find anomalous magneto-resistivity behaviour in very high magnetic fields, well above the upper critical field. The behaviour changes outside the nematic phase, where we show that at low temperatures Fermi-liquid behaviour is recovered. We account for the multiband structure and trace the carrier densities and motilities across the nematic phase transition. We also investigate the regime of superconducting fluctuations, which is expected to varying significantly in this isoelectronic series. We will discuss our results in relation to both Fermi liquid and non-Fermi liquid behaviour, and superconducting fluctuations.

*This work was support by the Engineering and Physical Sciences Research Council (EPSRC, UK) (EP/I004475/1, EP/I017836/1, EP/M020517/1, EP/N01085X/1). Part of this research was also supported by the Oxford Centre for Applied Superconductivity (CFAS) and the John Fell Fund of the Oxford University.

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Presenters

  • Matt Bristow

    • Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, U.K

Authors

  • Matt Bristow

    • Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, U.K

  • Pascal Reiss

    • Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, U.K

  • Amir Haghighirad

    • Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany
    • Institute for Solid-State Physics, Karlsruhe Institute of Technology
    • Institute for Solid State Physics, Karlsruhe Institute of Technology

  • Alix McCollam

    • High Field Magnet Laboratory (HFML-EMFL), Radboud University, 6525 ED Nijmegen, The Netherlands
    • High Field Magnet Laboratory (HFML-EMFL), Radboud University, Toernooiveld 7, 6525 ED, Nijmegen, The Netherlands
    • High Field Magnet Laboratory (HFML-EMFL), Radboud University

  • William Knafo

    • Laboratoire National des Champs Magnétiques Intenses (LNCMI), CNRS-UJF-UPS-INSA, Toulouse, France

  • Amalia Coldea

    • Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, U.K
    • Department of Physics, University of Oxford