Insulator-to-metal transition and correlated metallic state of V ₂O ₃ investigated by optical spectroscopy

The optical properties of V ₂O ₃ thin films are investigated across the insulator-to-metal transition and in the metallic state. The spectral weight transfer observed across the transition, over an energy scale of 5eV, is consistent with the Mott-Hubbard model for correlated electron systems. In the metallic phase, a strong Drude peak is observed, which exhibits a pronounced temperature dependence related to the transfer of states from the Hubbard bands to the quasiparticle peaks as the temperature is reduced. The analysis of the far-infrared spectra reveals signatures of strong electronic correlations in V ₂O ₃. Finally, a comparison to VO ₂ data is presented.