Evidence for orbital order and its relation to superconductivity in FeSe0.4Te0.6.

Singh, Udai R; White, Seth C; Schmaus, Stefan; Tsurkan, Vladimir; Loidl, Alois; Deisenhofer, Joachim; Wahl, Peter · Sci Adv · 2015

basic_science · Level V

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Abstract

The emergence of nematic electronic states accompanied by a structural phase transition is a recurring theme in many correlated electron materials, including the high-temperature copper oxide- and iron-based superconductors. We provide evidence for nematic electronic states in the iron-chalcogenide superconductor FeSe0.4Te0.6 from quasi-particle scattering detected in spectroscopic maps. The symmetry-breaking states persist above T c into the normal state. We interpret the scattering patterns by comparison with quasi-particle interference patterns obtained from a tight-binding model, accounting for orbital ordering. The relation to superconductivity and the influence on the coherence length are discussed.