Electronic Structure of FeSe1-xTex Studied by X-ray Spectroscopy and Density Functional Theory

We study the electronic properties of the FeSe(1-)xTe(x) system (x = 0, 0.25, 0.5, 0.75, and 1) from the perspective of X-ray spectroscopy and density functional theory (DFT). The analysis performed on the density of states reveals marked differences in the distribution of the 5p states of Te for x > 0. We think that this finding can be associated with the fact that superconductivity is suppressed in FeTe. Moreover, using resonant inelastic X-ray scattering, we estimate the spin state of our system which can be correlated to the magnetic order. We find that the spin state of the FeSe1xTex system fluctuates, as a function of x, between S = 0 and S = 2 with Fe in FeSe in the highest spin state. Finally, our DFT calculations nicely reproduce the X-ray emission spectra performed at the Fe L-edge (which probe the occupied states) and suggest that the FeSe1xTex system can be considered at most as a moderately correlated system.