Abstract Submitted for the MAR13 Meeting of The American Physical Society Nematicity driven by hybridization in the iron-based superconductors1 VALENTIN

Submitted for the MAR13 Meeting of The American Physical Society Nematicity driven by hybridization in the iron-based superconductors1 VALENTIN STANEV, Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, PETER LITTLEWOOD, Physical Sciences and Engineering, Argonne National Laboratory, Argonne, Illinois 60439, USA — We introduce an effective three-orbital model to study the normal state of the iron-based superconductors. It has both itinerant and localized electrons the former originate from the dxz/dyz iron orbitals, and the latter from the dxy iron orbitals. These distinct degrees of freedom are coupled through hybridization and onsite interactions. On a mean-field level this model has an excitonic instability, driven by the effective delocalization of the dxy electrons. Because of the multiband character of the itinerant Fermi surface the ordered state can spontaneously break the lattice rotation symmetry (and thus is nematic) and generate orbital order. In this scenario the nematic state is induced by the coupling of the dxz/dyz with the dxy iron orbitals, rather than the presence of magnetic order, or the proximity to such. We propose this mechanism as an explanation of the tendency towards nematicity observed in several iron-based compounds, and study some of its experimental consequences. 1This work was supported by the Center for Emergent Superconductivity, a DOE Energy Frontier Research Center, Grant No. DE-AC0298CH1088. Valentin Stanev Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 Date submitted: 28 Nov 2012 Electronic form version 1.4