Temperature-evolution of spectral function and optical conductivity in heavy fermion compound Ce$_{2}$IrIn$_{8}$ under crystalline electric field

We investigate the role of the crystalline electric field (CEF) in the temperature ($T$)-evolution of the Kondo resonance states and its effect on optical conductivity. We perform the combined first principles calculation of the density functional theory and dynamical mean field theory on Ce$_{2}$IrIn$_{8}$. The calculated spectral function reproduces the experimental observed CEF states at low $T$, while it shows a drastic change of the Fermi surface upon increasing $T$. The effect of the CEF states on the Fermi surface as a function of $T$ is elucidated through the first principles calculations as well as the analysis on the Anderson impurity model. Consequently, we suggest the importance of the CEF-driven orbital anisotropy in the low-energy states of optical experiments.