Abstract
High-resolution angle-resolved photoelectron spectroscopy is used to examine the electronic band structure of near the Brillouin zone center. A consistent separation of the and bands is observed with little dependence of the band. First-principles calculations for bulk and thin films demonstrate that the antiferromagnetic coupling between the Fe atoms and hybridization-induced spin-orbit effects lifts the degeneracy of the Fe and orbitals at the zone center leading to orbital ordering. These experimental and computational results provide a natural microscopic basis for the nematicity observed in the Fe-based superconductors.
- Received 8 March 2014
DOI:https://doi.org/10.1103/PhysRevLett.114.167001
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