Metal‐Insulator Transition in VO2 Studied by Optical Spectroscopy

We have investigated the charge dynamics of VO2 by optical reflectivity measurements. Optical conductivity clearly shows a metal‐insulator transition. In the metallic phase, a broad Drude‐like structure is observed. On the other hand, in the insulating phase, a broad peak structure around 1.3 eV is observed. It is found that this broad structure observed in the insulating phase shows strong temperature dependence. We attribute this to the electron‐phonon interaction as in the photoemission spectra.