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 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.
•The electronic and optical properties of the insulating monoclinic VO2 (M1) phase were studied using TB-mBJ and SCAN+U.•The size of the energy gap (Eg) and d|| band splitting and some optical constants of the VO2 (M1) phase were calculated.•TB-mBJ and SCAN+U gave Eg and Δd|| band splitting values in agreement with experiments.•TB-mBJ and SCAN+U were able to predict the frequency and polarization dependence of n, a, ε1, ε2 of the VO2 (M1) phase.•The current calculations reveal that Mott-Hubbard electron correlation is dominant in the metal-insulator transition in VO2.