Revealing some physical properties of li3bro compound with density functional theory

In this study, some physical properties of cubic Li3BrO crystal in perovskite structure are investigated by Density Functional Theorem (DFT). Generalized Gradient Approximation (GGA) and Local Density Approximation (LDA) approaches are used in this study. The ABINIT computer programme based on the DFT was used to investigate the structural, electronic and elastic properties of the Li3BrO crystal, while the Vesta programme was used for the unit cell representation, bond types and bond length calculations. Firstly, the cut-off energy was optimized and the cutting energy value was calculated as 40 Hartree under both approaches. Then, k-point number calculations were completed. As a result of the number of k-points calculations, 20 k-points were found for both approaches for 8x8x8 Monkhorst-Pack grid. This cut-off energy and number of k-points were used in the same way in all remaining calculations. Then, the lattice parameter of Li3BrO crystal was calculated theoretically by volume optimization. At this stage, since the lattice parameter value obtained under the GGA approach is closer to the value obtained from the literature, electronic and elastic property calculations were performed only under the GGA approach. The electronic properties of the crystal are revealed by electronic band curve and density of state graphs. The density of states were calculated as total and partial densities of states and all graphs are given in the study. According to the results obtained, Li3BrO crystal is a direct transition semiconductor. All electronic property graphs are in agreement with each other. In order to reveal the elastic properties, elastic stiffness coefficients were focused firstly. Bulk Modulus, Shear Modulus, Young's Modulus, Poisson's ratio, elasticity coefficient, Debye temperature value were calculated using the elastic stiffness coefficients obtained. This crystal was found to be elastically stable but brittle. With this study, the electronic and elastic properties of Li3BrO crystal have been revealed for the first time and introduced to the literature. It is hoped that this thesis study will shed light on the researchers who will work in this field.