Electronic and Optical Properties of Monoclinic and Rhombohedral Vanadium Sesquioxide

摘要

The electronic and optical properties of monoclinic and rhombohedral V2O3 are investigated in the framework of density functional theory (DFT) and GGA+U. It is found that, the metal-insulator transition (MIT) in V2O3 is induced by the on-site correlation effect, accompanied with a distinct orbital occupation change. The MIT is independent of the structural transition. The theoretical energy gap 0.6 eV agrees with the experimental value of 0.66±0.05 eV very well. Subsequently, the optical properties are also investigated. Interestingly, the insulating V2O3 shows minimal absorption in the infrared region, but the metallic V2O3 becomes opaque in such region. Therefore, a threshold at about 1 eV interprets the experimental charge gap (Perucchi et al., 2009) theoretically. Such infrared thermochromism makes it a potential candidate for several optical applications.