Supression of electronic correlations in FeSe1-xSx

In iron-based superconductors, the interplay between nematicity, magnetism, and superconductivity is still not fully understood. Experimentally, the isoelectronic series FeSe1−xSx provides an ideal playground to tune different electronic ground states and to selectively investigate their mutual interplay. Here, we use high-resolution angle-resolved photoemission spectroscopy to compare the electronic structure of different single crystals in the tetragonal phase. We find that in the absence of nematicity and magnetism, the substantial reduction of electronic correlations correlates with the decrease of the superconducting transition temperature from FeSe to FeS. This work was published in Physical Review B, Rapid Communications as an Editor's suggestion. Further details can be found at Phys. Rev. B 96, 121103(R) (2017) or as open access at archive. ARPES experiments were performed at I05 ARPES beam line at the Diamond Light Source in the UK.