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arXiv · 1409.8669

Direct observation of spin-orbit coupling in iron-based superconductors

Sergey Borisenko·Danil Evtushinsky·Igor Morozov·Sabine Wurmehl·Bernd Büchner·Alexander Yaresko·Timur Kim·Moritz Hoesch·Thomas Wolf·Nikolai Zhigadlo
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Abstract

Spin-orbit coupling (SOC) is a fundamental interaction in solids which can induce a broad spectrum of unusual physical properties from topologically non-trivial insulating states to unconventional pairing in superconductors. In iron-based superconductors (IBS) its role has so far been considered insignificant with the models based on spin- or orbital fluctuations pairing being the most advanced in the field. Using angle-resolved photoemission spectroscopy we directly observe a sizeable spin-orbit splitting in all main families of IBS. We demonstrate that its impact on the low-energy electronic structure and details of the Fermi surface topology is much stronger than that of possible nematic ordering. Intriguingly, the largest pairing gap is always supported exactly by SOC-induced Fermi surfaces.

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Sergey Borisenko, Danil Evtushinsky, Igor Morozov, Sabine Wurmehl, Bernd Büchner, Alexander Yaresko, Timur Kim, Moritz Hoesch, Thomas Wolf, Nikolai Zhigadlo. 2015-03-27. Direct observation of spin-orbit coupling in iron-based superconductors. https://arxiv.org/abs/1409.8669

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