Unusual band renormalization in the simplest iron-based superconductor FeSe1-x

The electronic structure of the iron chalcogenide superconductor FeSe1-x was investigated by high-resolution angle-resolved photoemission spectroscopy (ARPES). The results were compared to DFT calculations showing some significant differences between the experimental electronic structure of FeSe1-x, DFT calculations, and existing data on FeSexTe1-x. The bands undergo a pronounced orbital-dependent renormalization, different from what was observed for FeSexTe1-x and any other pnictides.