Electronic and optical properties of the VO2 monoclinic phase using SCAN meta-GGA and TB-mBJ methods

Abstract First principles calculations based on density functional theory (DFT) using TB-mBJ and SCAN+U methods were used to study the electronic and optical properties of the monoclinic VO2 (M1) phase. TB-mBJ gives values of the energy gap (Eg) and Δd|| band splitting in agreement with experiments. Systematic investigation of SCAN+U, U varies from 0 to 10 eV, shows that agreement with experimental values of both Eg and Δd|| was achieved at U* = 5.75 eV. Moreover, TB-mBJ and SCAN+U* were able to reproduce frequency and polarization dependence of the optical constants that agree with the reported experimental results of the the monoclinic VO2 (M1) phase. The high value of U needed to reproduce the experimental values of electronic and optical parameters of the monoclinic VO2 (M1) phase is a strong indication that VO2 is a Mott insulator and the Mott-Hubbard scheme plays an important role in the metal-insulator transition.