Ground State Properties of LiNbO3 from First-principles Calculations.

A systematic investigation has been carried out to study the ground state properties of LiNbO3 semiconductor using generalized gradient approximation within the density functional theory. The lattice constants (a and c) are calculated from the optimized unit cell and compare with the experimental values. The energy gap has been calculated along the G direction found to be 3.59 eV. The partial and total densities of state have been discussed. We have also calculated the frequency dependent dielectric constant and refractive index of LiNbO3 semiconductors for the first time in this paper. The values of elastic constants (Cij), bulk modulus and shear modulus have been calculated. The calculated values of above parameters are compared with the available experimental values and values reported by different workers. A good agreement has been found between them. [ABSTRACT FROM AUTHOR]