First Principles Study of Structural, Electronic and Mechanical Properties of LiBeF3 under Pressure Effect

Abstract

The structural, electronic and elastic properties of LiBeF₃ under high pressure were investigated using the density functional theory. The optimized lattice constant and the bulk modulus of elasticity at 0 GPa were obtained as 3.500 Å and 104.79 GPa, respectively, which are in good agreement with the previously available results. To study the effect of pressure, variable-cell relaxation (vc-relax) calculations were performed at different pressures ranging from 0 to 50 GPa. The mechanical properties of LiBeF₃ reveal that it is mechanically stable at the chosen pressures of 0, 10, 20, 30, 40 and 50 GPa. The Pugh’s ratio and Poisson’s ratio for LiBeF₃ were consistent throughout the increase in pressure, suggesting the brittle nature and dominance of ionic bonding in LiBeF₃. The electronic band gap of LiBeF₃ at 0 GPa was found to be 7.46 eV with indirect nature. On further increasing the pressure, the band gap of the LiBeF₃ crystal increased while maintaining its indirect nature. The Young’s modulus, shear modulus and anisotropy factor of LiBeF₃ were also investigated and presented in this paper.