Local distortions with the substitution of Se for Te in FeSe$_{0.5}$Te$_{0.5}$

ORAL

Abstract

The isovalent substitution of Te for Se in the superconductor FeSe$_{1-x}$Te$_{x}$ increases T$_{c}$ in comparison to $\alpha$-FeSe but, on average, decreases the chalcogen-Fe bond angle. However, we find that the local symmetry is lower than the one presumed on average, \textit{P4/nmm}, because the Se and Te ions do not share the same site, and have two distinct textit{z}-coordinates exhibiting two types of bond angles and bond lengths with Fe. Simultaneously, ab-initio calculations based on spin density function theory yielded an optimized structure with distinct \textit{z} -coordinates for Se and Te, in agreement with the experiment.

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Authors

  • Despina Louca

    • University of Virginia

  • K. Horigane

    • Tohoku University

  • A. Llobet

    • Lujan Neutron Scattering Center, Los Alamos National Laboratory
    • Los Alamos National Kaboratory

  • R. Arita

    • Department of Applied Physics, University of Tokyo, JST-TRIP, JST-CREST
    • University of Tokyo