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

Abstract

The emergence of nematic electronic states which break the symmetry of the underlying lattice is a recurring theme in many correlated electron materials, among them the high temperature copper-oxide and iron-based superconductors. Here we provide evidence for the existence of nematic electronic states in the iron chalcogenide superconductor FeSe0.4Te0.6. The symmetry breaking states persist above TC into the normal state. We find an anisotropic coherence length, which is suppressed in a direction perpendicular to the nematic modulations. We interpret the scattering patterns by comparison with quasiparticle interference patterns obtained within a tight-binding model, accounting for orbital ordering.