Electronically-driven orthorhombic distortion in FeSe

ORAL

Abstract

FeSe is structurally the simplest of Fe-based superconductors, and exhibits a tetragonal-to-orthorhombic structural transition at $\sim$ 90 K, but no long-range magnetism at any temperature. We report measurements of the resistivity anisotropy in FeSe above Ts finding a large and divergent response to an applied strain, with a comparable magnitude and temperature-dependence to measurements in Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$, but opposite sign. We compare this data with literature reports on NMR and our own ARPES data, which taken together indicate that the structural transition is electronically-driven with orbital degrees of freedom playing a central role.

*This work was supported by EPSRC, UK (EP/I004475/1) and Diamond Light Source.

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Authors

  • Matthew Watson

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

  • Nathaniel Davies

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

  • Amir Haghighirad

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

  • Arjun Narayanan

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

  • Timur Kim

    • Diamond Light Source, Harwell Campus, Didcot, OX11 0DE

  • Moritz Hoersch

    • Diamond Light Source, Harwell Campus, Didcot, OX11 0DE

  • Samuel Blake

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

  • Amalia Coldea

    • Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU
    • University of Oxford, UK