Supplement material

See the supplementary materials for spectroscopic ellipsometry data and fitted parameters ($\Psi$ and $\Delta$) at 300 K, as well as temperature-dependent ellipsometric spectra across the metal-insulator transition for both cooling and heating cycles. It includes comparisons between experimental and model-calculated spectra, detailed oscillator parameters used in the dielectric function modeling, and fits using the anisotropic Bruggeman effective medium approximation ($a$BEMA) across the transition region.