The effect of electronic correlations on the nematic electronic phase of FeSe_1-xTe_x

Orbitally-dependent electronic correlations can play an important role in the stabilization of the nematic and superconducting states of iron-chalcogenides. In FeSe nematicity is supressed using isoelectronic substitution of sulphur and tellurium, but the increase in bandwidths only occurs with sulphur substitution leading to reduced correlations.  Here we will present a study of the electronic structure of the nematic superconductors FeSe_1-xTe_x using ARPES to understand the role of orbitally-dependent correlations on the nematic electronic state with tellurium substitution. We assess the degree of band renormalisation by comparing our ARPES data to DFT band structure calculations. From the linewidths and Fermi velocities of the energy dispersions we access the imaginary part of the self-energy which corresponds to the quasiparticle lifetime. Next, we extract the size of the Fermi surface and its k_z-dependence and compare these findings to previous studies on FeSe_1-xS_x. Lastly, by using deep energy cuts, we discuss the formation of a Hubbard-like band in FeSe_1-xTe_x as compared with FeSe.