Strongly enhanced temperature dependence of the chemical potential in FeSe

Employing a 10-orbital tight-binding model, we present a set of hopping parameters fitted directly to our latest high-resolution angle-resolved photoemission spectroscopy (ARPES) data for the high-temperature tetragonal phase of FeSe. Using these parameters, we predict a large 10 meV shift of the chemical potential as a function of temperature. To confirm this large temperature dependence, we performed ARPES experiments on FeSe and observed a similar to 25 meV rigid shift to the chemical potential between 100 and 300 K. This strong shift has important implications for theoretical models of superconductivity and of nematic order in FeSe materials.