Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 35: Superconductivity: Fe-based Superconductors - 122 and Theory
TT 35.9: Vortrag
Dienstag, 13. März 2018, 11:45–12:00, A 053
Orbital loop currents in iron-based superconductors — •Markus Klug1, Jian Kang2, Rafael M. Fernandes2, and Jörg Schmalian1,3 — 1Institute for Theoretical Condensed Matter Physics, Karlsruhe Institute of Technology, D-76131 Karlsruhe, Germany — 2School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA — 3Institute of Solid State Physics, Karlsruhe Institute of Technology, D-76344 Eggenstein-Leopoldshafen, Germany
We show that the stripe spin-density wave state commonly observed in the phase diagrams of the iron-based superconductors necessarily triggers loop currents characterized by charge transfer between different Fe 3d orbitals. This effect is rooted on the glide-plane symmetry of these materials and on the existence of an atomic spin-orbit coupling that couples states at the X and Y points of the 1-Fe Brillouin zone. We show that the two main manifestations of the orbital loop currents are the emergence of magnetic moments in the pnictide/chalcogen site and an orbital-selective band splitting in the magnetically ordered state, both of which could be detected experimentally. Our results highlight the unique intertwining between orbital and spin degrees of freedom in the iron-based superconductors, and reveal the emergence of an unusual correlated phase that may impact the normal state and superconducting properties of these materials.