First-principles studies on electronic structure and optical properties of two-dimensional ZrO₂

Two-dimensional 1T-ZrO2 material is investigated via first-principles calculations based on density functional theory (DFT) method. The band gap of cubic, tetragonal and monoclinic ZrO2 is 6.095 eV, 5.784 eV and 5.835 eV respectively obtained in the paper also. [Formula: see text] method is determined to adopt to study two-dimensional 1T-ZrO2 in the paper. The results show that the band gap of 1T-ZrO2 material is 7.513 eV and it is an indirect wide band gap semiconductor structure. At the same time, it can be seen from the density of states (DOS) that the valence band of the 1T-ZrO2 material is mainly due to the contribution of 2p electron of O atom. 4p, 4d and 5s electron of Zr atom also contributes a little to the valence band. 4p, 4d, 5s electron of Zr atom and 2s, 2p electron of O atom contribute to the conduction band, but main contribution has come from 4d of Zr atom. These results are in good agreement with the electron orbitals diagram. 1T-ZrO2 material has maximum reflectivity of 11.61% and refractive index of 1.62. It has high absorption coefficient and energy loss in this region. The peak of dielectric function may be mainly caused by the inter-band transition from electron-occupied state to non-occupied state. The real part of the photoconductivity tends to zero in the visible region with low energy and the maximum conductivity of 2.087 corresponds to the peak of other photoelectric properties of 1T-ZrO2 material.