Structural and Mechanical Properties of Orthorhombic Libeh3: AB-Initio Study

The structural parameters and the elastic properties of orthorhombic LiBeH material were predicted theoretically using the density functional theory (DFT). The exchange-correlation potential term was treated using the local density approximation (LDA). Our values of the structural parameters and elastic constants predicted for LiBeH material agree well with other results of the literature. The bulk modulus calculated from the BFGS technique is comparable with the value obtained from the elastic constants. The universal anisotropy factor, Young's and shear moduli, Poisson's ratio, Pugh’s ratio, Lame’s coefficients and the microhardness were also determined for an ideal polycrystalline LiBeH material. Based on the results of Poisson's ratio and Pugh’s ratio obtained in this work, this hydride material would be classified as a brittle material in nature. We estimate also the elastic wave velocities, the Debye temperature and the acoustic impedance of the polycrystalline material. Our predicted values obtained from the local density approximation for LiBeH material agreed well with the data of the literature obtained from the generalized gradient approximation (GGA).