Strategy for the optical property studies in ultraviolet nonlinear optical crystals from density functional theory

Unit cells for several UV NLO crystals with representative structures are shown in left panel, and the comparison of experimental energy band gaps and calculated values with various exchange–correlation functionals are plotted in right panel, in which the corresponding computational time are also displayed. [Display omitted] ► Almost all representative structural features of known UV NLO crystals are studied. ► Various XC functionals are used to study the electronic and optical properties. ► Hybrid and sX-LDA XC functionals are good at energy band gap prediction. ► Scissors-corrected LDA and GGA are good at optical property prediction. ► Their combinations can accurately predict optical properties without parameter. The predictive capabilities of the density functional theory with various exchange–correlation functionals on the energy band gaps and optical properties in ultraviolet nonlinear optical (UV NLO) crystals are systematically investigated. We find that the energy band gaps of these crystals can be accurately predicted by the non-local hybrid functionals and sX-LDA functionals, but their calculated optical properties are not consistent with the experimental results compared to the usually adopted LDA or GGA functionals with the scissors corrections. Accordingly, we propose that a precise and effective strategy to study the optical properties in the UV NLO crystals without any experimental parameter should be the combination of different functional calculations.