Elastic and electronic properties of Li2ZnGe

We have investigated the structural, elastic and electronic properties of Li2ZnGe in both C 1 b and L 2 1 phases. The calculation are carried out by means of the full potential linearized augmented plane wave method within the density functional theory. The exchange and correlation effects have been treated using the local density and the generalized gradient approximations. The total energy minimizations give structural parameters in good agreement with available experimental data and show that C 1 b is the most stable and energetically favorable phase of this compound. The bulk modulus values indicate that the L 2 1 phase is softer than the C 1 b one. The calculated elastic constants within the LDA show that the studied phases satisfy the stability criteria and the C 1 b phase is more stable. However, the GGA approximation predicts that L 2 1 is not stable. The elastic moduli and the Debye temperature of polycrystalline samples are also calculated. tructure calculation shows that C 1 b phase exhibits a semiconducting behavior with a narrow indirect gap. The conduction band valleys follow the X–L– Γ ordering of increasing energy. The L 2 1 is found to be metallic. The valence charge density analysis show that the bonding in the C 1 b phase is partially covalent and partially ionic.