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 ∼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.