Interplay between electronic correlations and spin-orbit coupling for topological superconductivity of iron chalcogenide

We investigate the bulk electronic structure and corresponding topological surface Dirac cone of an iron chalcogenide, FeSe_0.5Te_0.5, in the framework of the combination of linearized quasiparticle self-consistent GW and dynamical mean field theory (LQSGW+DMFT) with spin-orbit coupling. It is shown that the present method predicts the bulk electronic structure and the surface Dirac cone of FeSe_0.5Te_0.5 in good agreement with angle resolved photoemission experiments. [1,2,3,4] We confirmed that the interplay between electronic correlations and spin-orbit coupling are of great importance for the correct description of non-trivial Z₂ and the excitation spectrum of FeSe_0.5Te_0.5. In particular, the Hund-coupling induced band renormalization is a decisive factor for the surface topological superconductivity in the un-doped system by locating the surface Dirac cone at the chemical potential. [4]

 

[1] H. Lohani et al., Phys. Rev. B 101, 245146 (2020)

[2] H. Miao et al., Phys. Rev. B 98, 020502 (2018)

[3] P. Johnson et al., Phys. Rev. Lett. 114, 167001 (2015)

[4] P. Zhang et al., Science 360, 182 (2018)