Interplay of nematic order and spin-orbit interaction in iron-based superconductors from ARPES

I will give an overview of our recent ARPES results on very fine details of the electronic structure of iron-based superconductors (IBS) and their influence on the superconductivity [1-3]. In particular, we have determined the energy scale caused by nematic, spin-orbit, and exchange interactions, as well as the orbital composition of electronic states near the Fermi edge throughout the Brillouin zone in major representatives of three families of IBS. Using the novel ARPES technique based on parallel detection in 3D-momentum space instead of conventional energy-momentum datasets, we obtained new information about the topological properties of IBS.
Our results show a non-trivial behavior of the orbitals near the Fermi level, which may hold the key to the mystery of high temperature superconductivity in IBS.

[1] Nematic superconductivity in LiFeAs. Y. Kushnirenko et al. Physical Review B 102, 184502 (2020)
[2] Strongly correlated superconductor with polytypic 3D Dirac points. S. Borisenko et al. npj Quantum Materaisl 5, 67 (2020)
[3] Energy scale of nematic ordering in the parent iron-based superconductor. A. Fedorov et al. Physical Review B 100, 024517 (2019)