DFT based studies on the structural, electronic and optical properties of LiNbO ₃ using some hybrid techniques

Structural, electronic, and optical properties of ferroelectric material, Lithium niobate (LiNbO 3 ) are explored and studied using two different techniques namely, OLCAO-MGGA-TB09+c and OLCAO-GGA-PBES + U under the framework of density functional theory (DFT). The electronic properties such as band diagram, the effective mass of charge carriers, the total density of state (TDOS), and partial density of state (PDOS) are investigated in depth. Band gap values obtained using MGGA-TB09+c is 3.79 eV whereas, it is 3.78 eV for GGA-PBES + U. Furthermore, several optical properties such as dielectric constant, reflectivity, refractive index, optical conductivity, loss function, and absorption coefficient have also been extracted. It is seen that the results so obtained are consistent with experimental data which shows the soundness of our calculations. From the statistical analysis, it is found that both the techniques provide very good results on electronic and optical properties of LiNbO 3 compared to existing computational work as both give an approximation of experimental data. The methods presented here will be useful for researchers to get accurate results on structural, electronic, and optical properties of other materials.